The More the Better? Multi-Species vs Single-Species Cover Crops for Carrots

Published on September 1, 2022 in 2022/Crop Production/Current Issue/Fall 2022/Grow Organic/Seeds/Tools & Techniques

By Frank Larney, Haley Catton, Charles Geddes, Newton Lupway, Tom Forge, Reynald Lemke, and Bobbi Helgason

This article first appeared in Organic Science Canada magazine and is printed here with gratitude.

In recent years, diverse cover crop mixes or ‘cocktails’, which contain as many as 15 different cover crop species, have gained popularity. Are these multi-species cover crop mixes any better than their less sophisticated counterparts (e.g., fall rye or barley/pea)? It’s a complicated system to untangle. Our early data suggests that the multi-species mixes can foster more active soil life, but that they could also have impacts on the following crop: they caused more forked carrots, which decreases profit. We also looked closely at how weeds in the cover crops affected soil fertility. Spoiler alert, they may be helping…

Cover crops can provide many benefits including enhanced soil organic matter and soil health, nitrogen retention, weed suppression, soil moisture conservation and, as a result of these, higher subsequent crop yields. Cover crops can be grown in the main season (replacing a cash crop in rotation) or seeded in fall to protect the soil from wind and water erosion throughout winter and early spring. In our study funded by the Organic Science Cluster, we compared how different cover crops impacted the soil, pests, and the following crop.

The control cover crop treatment which was essentially a fallow predominated by lamb’s quarters, cleavers, and redroot pigweed, July 30, 2018. Maybe weeds are not all that bad? …as long as they don’t go to seed before soil incorporation. Credit: Frank Larney.

Our research team collaborated with Howard and Cornelius Leffers who run an irrigated organic farm near Coaldale, Alberta. They specialize in carrots and red beets for restaurants, farmers’ markets and organic grocery stores, and they also grow alfalfa, winter wheat and dry beans. We evaluated seven cover crop treatments ahead of carrots. We have completed two cycles of the two-year cover crop–carrot rotation (Cycle 1: 2018 & 2019, Cycle 2: 2019 & 2020), with a third cycle (2021 & 2022) currently underway. Cover crops were established in June during the first year of each cycle as follows:

Buckwheat;

Faba bean;
Brassica (white + brown mustard);
Mix*;
Mix* followed by barley which grew until the first killing frost;
Mix* followed by winter wheat which survived the winter, regrew in early spring, then was terminated by tillage; and
Control (no cover crop, weeds allowed to grow).
*Mixture of five legumes, four grasses, two brassicas, flax, phacelia, safflower, and buckwheat (15 species in total)

Fagopyrum esculentum Moench, Polygonum fagopyrum L. Credit: Johann Georg Sturm.

In August, all treatments and the control were incorporated into the soil by disking. The control and treatments 1-4 were left unplanted over the winter; weeds were allowed to grow. Treatments 5 and 6 were seeded to other cover crops. In the second year of each cycle, carrots were planted in June and harvested in the fall. We took cover crop and weed biomass samples just before disking in August of the first year of each cycle. We measured the carbon (C) and nitrogen (N) concentrations of the cover crops, as well as the main weed species. In 2018, the multi-species, brassica, and buckwheat cover crops were more competitive with weeds. The faba bean cover crop was not competitive with weeds and had the same amount of weeds (by weight) as the control treatment.

Weeds can be a troublesome part of organic systems. In this case, we wanted to see if they were redeeming themselves as part of the cover crop, or in the case of the control treatment, by taking the place of a seeded cover crop. Weeds are no different from any other plant: they take up soil nutrients and when they break down, they put carbon (including organic matter), nitrogen, and other nutrients back into the soil. As long as annual weeds don’t go to seed, maybe they are making a useful contribution to soil health, similar to a seeded cover crop.

Since weeds were incorporated into the soil in August along with the seeded cover, the less-competitive faba bean treatment and the weedy control actually returned more total carbon to the soil (average, 2220 kg/ha C) due to greater weed biomass (weed “yield”) than buckwheat, brassica or the multi-species mixture (850–1330 kg/ha C). Moreover, being a nitrogen-fixing legume, the faba bean cover crop (including its weeds) returned the most nitrogen to the soil at 99 kg/ha N. After the carrot harvest, our team rated carrots into Grade A (visually appealing with no deformities: ideal for restaurants, farmers’ markets, and organic grocery stores) and Grade B (downgraded due to wireworm damage, forking, scarring or misshaping: suitable for juicing only). Grade B carrots are worth about one third of Grade A carrots.

Vicia faba. Credit: Dr. Otto Wilhelm Thomé, Flora von Deutschland.

Despite the differences we measured in the C and N contributions of the cover crops and the weeds, it wasn’t enough to affect the carrot yields. In 2019, Grade A carrot yield was statistically the same with all the cover crop options. For soil health, the multi-species mixture had more microbial activity than either brassica or buckwheat cover crops (this is based on microbial biomass C – an index of microbial mass – and permanganate oxidizable C – the active or easily-decomposable C). However, a possible downside of the multi-species mix showed up when we looked at the following carrot crop. In 2019, treatments 4, 5 and 6 resulted in a greater proportion of the Grade B category, including forked carrots. Forking and misshaping are caused by many reasons, including soil compaction, weed interference, and insect or nematode feeding on root growing tips.

We also looked at the value of fall-seeded cover crops (Treatments 5 and 6) and their impact on wireworm and nematodes. These pests might actually be helped by cover crops; they appear to have greater survival during the winter season when living roots are present. But having winter cover may lead to better carrot yields, too: in 2020, total carrot yields (Grades A and B) were 10% higher after the fall-seeded cover crops when compared to the spring – seeded brassica cover crop, which led to the lowest yielding carrots. So far, we haven’t seen any effect of the different cover crop treatments on root lesion nematode populations, but the fall-season cover crops led to a small increase in wireworm damage on the carrots (this only showed up in 2019). More soil analyses and the results from the 2021-22 season are still to come. The additional information will help us tease out the pros and cons of multi-species vs single-species cover crops for irrigated organic carrots.

To learn more about OSC3 Activity 8, please visit

dal.ca/oacc/osciii

The Organic Science Cluster 3 is led by the Organic Federation of Canada in collaboration with the Organic Agriculture Centre of Canada at Dalhousie University, and is supported by the AgriScience Program under Agriculture and Agri-Food Canada’s Canadian Agricultural Partnership (an investment by federal, provincial and territorial governments) and over 70 partners from the agricultural community.

Feature image: Left to right: Charles Geddes (Weed Ecology & Cropping Systems, AAFC-Lethbridge); Howard Leffers (farmer-collaborator, Coaldale, AB); and James Hawkins (visiting Nuffield scholar, Neuarpurr, Victoria, Australia) in the 15-species cover crop, August 7, 2018. Credit: Frank Larney.

Biodynamic Farm Story: Cold Comforts

Published on April 1, 2022 in Crop Production/Grow Organic/Land Stewardship/Soil/Spring 2022

By Anna Helmer

Alas, alak. Which is to say, phew. My self-celebrated cull potato Biodynamic compost pile is not available to evaluate in time for this article deadline: the snowpack beneath which it languishes lingers still. Truth be told, I am relieved. I have not been shy about leading us all to believe I am a composting genius, capable of turning old potatoes into a priceless pile of loamy soil teeming with life, energy, and spiritual sensitivity. On the other hand, it might be a pile of mucky old potatoes. I am saved, for now, from the big reveal.

This winter’s snowpack has had a more notable affect on life this winter than just preserving my pride. Most of it is from December’s excesses, when several feet accumulated in just a few days. The temperature plunged and the farm was in the proverbial grip of winter. The work focus narrowed: clear greenhouse, shovel path to chicken house, monitor the cooler temperatures, keep water pumps from freezing. As always, the first few days of minus twenty were fine, but then things started to freeze. It’s amazing how much work this becomes.

Rain is inevitable of course, which adds crushing weight to snow that was this year extra sticky, clinging even to the metal roofs of barns and homes. This became a grave concern. Not only is there the potential collapsing problem, but a very real danger to anyone or anything in the line of the sliding snow when it finally does let go.

Our farm escaped the situation with little more than one blown apart railing, one bent greenhouse rib (from a tractor-mounted snow blower injury), and a day or two of frozen water pump. It’s not hard to spot other winter casualties in the area and it is considered polite to avert your eyes and not mention it.

Meanwhile, under the snow, the soil has been hard at work. It’s hard to believe, as the landscape seems so inert in the depths of winter, but Rudolph Steiner says it’s so. This year in particular the soil seemed so remote, buried under four feet of concrete snow. A lot of the time it was a walkable snowpack and striding about the farm on an elevated even surface felt like freedom. Anyway, it was easy to assume there wasn’t much going on down there.

Biodynamically-speaking, however, winter is a time of dynamic change in the soil. I really don’t pretend to understand the technical aspects of many of Steiner’s arguments, and this one has really confused me. Something to do with the formation of crystals deep down which will collect the forces emanating from the further reaches of the universe and stream them upwards into the plants. Don’t quote me.

Obviously, there is activity. We habitually try to rotavate the next year’s potato field last thing in the fall before winter. Just a shallow rotavate, and perhaps a slightly deeper spading. It breaks up the sod that has formed over the previous five years of cover-cropping. It’s pretty rough, but in the spring, this field will dry a little quicker and much of the organic matter will have broken down. This is a sign of winter activity, isn’t it?

It’s more than that, though I am struggling to put my finger on it. My understanding was nudged along when we went to dig the equipment trailer out of the snow. We had parked it under a barn roof line. Oops. See above. It was buried early and often this winter. The extraction project took place over a two-day period and involved heavy equipment. When done, a churned-up mess of soil, snow, ice, and mud was left in its place. The ground won’t recover from that this year.

We would never do this to a field, but the message remains the same: we farmers ruin soil. The soil needs winter so it can get away from us and do its thing. If you haven’t slapped your head with understanding then I haven’t done a good job of writing, for this is very profound.

Think about the fall-rotavated potato field. It will emerge from the winter ready for an (almost) single tractor pass for final seed bed preparation. When we don’t do the fall rotavating and spading it takes several passes with disc, cultivator, spader, rotavator, and harrow to do the same job, with likely a substandard result.

The field, left alone in the grip of winter, was busy, busy, busy and did a better job of it than we could have done.

The BD500 preparation, which some call the gateway drug of Biodynamics, is buried over winter. I won’t get into the details, but it transforms from a muck of fresh manure into a dryish plug of pure power. I wouldn’t go so far as to say it makes sense, but I admit to a slight glimmer of understanding.

Now I am kind of excited to see the compost pile. I think it was always out of my hands.

Anna Helmer farms in Pemberton and is grateful for the opportunity. helmersorganic.com

Featured image: Credit: Hemler’s Organic Farm

Biodynamic Farm Story: Convergence & Composting Chaos

Published on January 1, 2022 in 2022/Climate Change/Crop Production/Grow Organic/Land Stewardship/Soil/Winter 2022

By Anna Helmer

Well, I am thrilled to discover that the likely theme for this edition of BC Organic Grower magazine is: Composting Chaos. The suggestion that chaos may be composted is encouraging and practical…and it is always a treat to find something compostable that is in such good supply. Further thrills at the possibility of extending the concept to include the composting of lived experiences, especially those whose silver lining is perceived to be absent, invisible, or inadequate. The composting metaphor is very supportive: just stash it all in a heap until a more palatable, useful, and frankly understandable state is revealed.

I am obviously over-thrilled, and I will now tone it down. Composting takes ages, of course. These things don’t happen overnight.

I am certainly not over-thrilled at what I feel was a weak performance this year on the farm, biodynamically speaking. I didn’t accomplish very much of what I set out to do. I had grand plans to make some preparations, attend more zoom lectures, plant the garden according to the Celestial Planting Calendar, and generally advance myself towards being thought of as a wise, middle-aged, biodynamic farmer.

In fact, I didn’t do any of that, and I even took steps backwards. Not in ageing, unfortunately. Still relentlessly marching along that path, sorry to say.

The season started with a good old case of undermining myself: I did not apply BD 500 to the carrot field even though I have always known that a good carrot crop is conditional upon a spring application of BD 500. Other factors contribute of course: a June 1 planting date, into moist soil prepared just so; the crop to be hand-weeded twice, mechanically weeded thrice; judiciously watered but not wantonly; and harvest commencing no earlier than the third Monday in August. All that and very little more often guarantees a successful carrot crop in terms of yield, storability, and most importantly taste.

Early in the spring I improperly mixed BD 500 using assorted batches of stale-dated preparation—just to get rid of the clutter, really. I applied it within flinging distance of the barrel in a non-intentional manner. I didn’t go anywhere near the carrot-field-to-be, assuming I could be relied upon to complete the task closer to the planting date, at a more propitious time indicated by the calendar, and with something a little fresher and properly prepared. I did not do that.

I thought for sure the carrot crop was doomed but that was just the beginning. We proceeded to somehow insert change into just about every other aspect of successful Helmer carrot cropping procedure. Planting dates, seeder set-up, spacing, cultivation plan, mechanical weeding plan, and watering schedule: it was carrot chaos, really.

Jumping to the end of what has become a boring carrot story, we got a big crop of great-tasting carrots that seems to be storing well. It is an absolute mystery of variables, and I must kick myself for failing to properly apply BD 500 because now that doesn’t get to be part of the success calculus.

Hence, I am extra keen to flatter myself that the cull potato compost pile, carefully finished with some lovely compost preparations from our friends at the Biodynamic Association of BC, is quite gloriously successful. In terms of structure and appearance it does indeed look promising: it looks like a heap of rich dark soil and there are no longer potatoes visible.

It did not look at all promising to begin with, and although it reached temperature twice, I think that just encouraged the potatoes to grow more, seeing as they were nice and warm. With great gobs of them merrily sprouting and creating new potatoes it all seemed a bit futile.

My final move was to mix it, pile it nicely, cover it with hay, and apply the compost preparations. Since then, it has been through a heat dome and three heat waves, then three months of solid rain. It sits perched on a bit of high ground in a flooded field. It has basically been abandoned.

The current plan, then, is to ignore it till next spring. I’ll open it up for a look and decide if it is ready for that most stern test of quality: application to soil. Expectations are managed.

In the meantime, I am building the next cull potato compost pile, adding a few hundred pounds every other week or so as we wash and sort the crop. It looks like more culls than last year. There are whacks of maple and birch leaves layered in, and hay. I’d like to get some seaweed, next time I am at the seashore, and I am considering drenching it from time to time with BD 500, the Biodynamic gateway drug of which I’ve got extra.

My biodynamic journey chugs along, I suppose, although I am refraining from setting biodynamic goals for next season. I am still far too busy composting the last one.

Anna Helmer farms with her family in Pemberton, BC where the current mission is finding the right winter work gloves.

Feature image: Compost in hand. Credit: Thomas Buchan.

Ask an Expert: BC Farmers & Ranchers Learning Together

Published on April 1, 2021 in 2021/Ask an Expert/Crop Production/Grow Organic/Land Stewardship/Soil/Spring 2021/Tools & Techniques

Emma Holmes

The Sustainable Agricultural Landscapes (SAL) Lab at UBC’s Faculty of Land and Food Systems is taking a collaborative approach to research that supports producers in making management decisions that are science-based and regionally grounded.

I recently had the opportunity to catch up with Sean Smukler, DeLisa Lewis, Amy Norgaard, and Raelani Kesler from the SAL Lab to get an update on their Organic Vegetable Nutrient Management and Climate Resilient Vegetable Farming research projects.

Something that stood out to me, and that I feel is especially pertinent to this issue, is the mentorship and collaborative, on-farm approach the SAL Lab is taking. The research design includes two demonstration “mother sites” at UBC Farm in Vancouver and Green Fire Farm on Vancouver Island, as well as 20 “sister sites” on working organic farms in the Fraser Valley, Pemberton Valley, Vancouver Island, and the Kootenays.

The mother sites are controlled and replicated—they allow for the collection of scientifically rigorous data so that the researchers can tease out trends and gain a deeper understanding of how different elements in the system are interacting and impacting each other.

While a rigorous approach is important, it is very difficult to implement one on working farms because farmers are already trying to manage so much complexity in terms of crop rotation, timing, etc. Adding a full-blown research project with rigorous controls can take away from the primary goal of running a profitable business.

The sister sites are simpler experiments, without controls and replicates, that are done on multiple working farms in different regions of the province. They provide insights into regional and site variability, and allow us to see whether trends from the mother sites are true across different regions in BC The regional sister sites also create the opportunity for farmers to participate in the research by pointing SAL researchers to key practical challenges and unanswered questions.

Collecting soil samples with a soil auger; hundreds of soil samples were collected for the regional field trials. Credit: Amy Norgaard.

Organic Vegetable Nutrient Management

The SAL Lab recently shared the results from their two-year Organic Vegetable Nutrient Management Project regional field trials, where they assessed organic nutrient management strategies that are most likely to balance goals of crop production and environmental stewardship.

A key takeaway is the importance of regionally-specific nutrient management recommendations due to the big differences in soil types, availability, and cost of amendments. Taking soil tests and applying nutrients based on a farm-specific soil management strategy is important for land stewardship across all regions, but regional variances due to differing soils, climate, and access to and cost of amendments are important considerations.

For example, the abundance of nutrient-rich animal manures in the Fraser Valley increases the possibility of unintentionally over applying nitrogen (N) and phosphorus (P). This can result in post-harvest nitrate and phosphorous concentrations that can compromise well water quality and wetland health in the area, and are higher than what is permitted under BC’s new Agricultural Environmental Management Regulation.

There are also cost implications of over-applying nutrients. On Vancouver Island, where amendments are relatively expensive, targeted nutrient applications based on soil testing and matching crop nutrient demand can allow for significant savings compared to applying amendments without that knowledge.

Carmen Wong collects soil samples from research plots on an organic vegetable farm in Pemberton, BC for the UBC nutrient management regional field trial study Credit: Amy Norgaard.

Climate Resilient Vegetable Farming

SAL’s Climate Resilient Vegetable Farming research project is studying the interactions between organic nutrient management and water issues (e.g. too much, too little, wrong timing) on organic farms. Increased fall and spring precipitation shortens the soil workability time window, thus shortening the growing season and increasing the challenge of establishing and incorporating cover crops as part of a nutrient management strategy.

Raelani Kesler, Master of Science student, explained that the Climate Resilient Vegetable Farming research project hopes to quantify the impact of three alternative approaches to soil management: fall application of organic amendments, tile drains, and overwinter tarping. Silage tarps are increasingly being used to cover soil in places where it is difficult to establish or maintain a cover crop. With tarping, the soil is protected from erosion, but there are no inputs from cover crop biomass. Drainage tiles are being used to manage moisture but this too can lead to losses. The project is currently gearing up for its second field season.

Amy Norgaard in the field. Credit: Kira Border.

Knowledge Sharing

The benefit of having the research on-farm extends beyond the access to regional data. Including farmers as partners allows for horizontal learning between both researchers and farmers, as well as supporting farmer-to-farmer knowledge exchange.

Amy Norgaard, a Master of Science student in SAL, spoke to the knowledge-sharing elements of the project. “I was able to be physically on farm having conversations with the farmers and learning from them about what they do and why, and was able to incorporate each farm’s unique amendment strategy into the study,” she said. “Farmers were able to see how their ‘business as usual’ compost and fertilizer applications compared to strategies targeting N and P crop demand, and also saw how their strategies compared to other farmers.”

Chris Bodnar, a project farm partner, said “The on-farm research and collaborative sharing of results was incredible for us to be part of”.

Although not a direct goal of the program, Norgaard shared that getting out and having conversations with partner farmers allowed her to gain useful information that she was then able to share across the community. “I really enjoyed the relationship building and knowledge sharing aspects of the program and wish I could continue doing it even though my two-year research project has come to an end. I think there is a lot of value there.”

In the Kootenays, SAL was able to partner with Rachael Roussin of the Kootenay Boundary Farm Advisors (KBFA) program. KBFA has been providing extension services for farmers for several years, and Kesler said the established relationships and close contact Rachael had with growers made it much more feasible to conduct regional field trials in the Kootenays. For example, Rachael was able to reach out to her network to recruit farm research partners. Her existing relationships and proximity to the growers made it easier to check in about details, such as when they were planning on removing their tarps so she could get to the farm to take a soil sample. Coordinating on this level would be very difficult to do from UBC and so having a partner like KBFA opens up regional on-farm research possibilities that wouldn’t exist otherwise. Kesler hopes to see more regions across BC adopt similar extension programs that would allow for these forms of university-farm partnerships to become more widespread.

Similar Approaches Happening Across Canada

The topic of collaborative on-farm research with mother-sister sites, and the many benefits of approaching agricultural research this way, also came up at a recent meeting I attended for provincial and federal organic specialists. The Quebec organic specialists spoke highly of the mother-daughter model to ensure a constant exchange and mutual learning between farmers and researchers.

In 2019 Agriculture and Agri-Food Canada announced a new Living Laboratory Initiative. Similar to UBC’s SAL lab, it will use mother-sister sites as part of a “collaborative approach to research that will bring stakeholders together on working farms to develop, test and adopt new practices and technologies that will tackle important environmental issues.”

You can find more details about this announcement here.

Footnotes from the Field: Waste Not, Want Not

Published on September 1, 2020 in 2020/Fall 2020/Footnotes from the Field/Livestock/Preparation/Soil

Empowering the Human Micronutrient Supply Chain from the Soil Up

Marjorie Harris

I have long accepted that the saying “Healthy Soil, Healthy Plants, Healthy people” fully explained the human nutrient supply chain. Turns out, this is not entirely accurate. In fact, the mineral requirements for healthy plants, animals, and people are quite different.

During organic farm inspection tours, I met a BC farm family diagnosed with selenium deficiency syndromes. The local health unit had identified the conditions. One person suffered from a significant fused spinal curvature from a skeletal muscle disease caused by selenium deficiency.

The farm’s soil tests confirmed that the garden soils were indeed deficient in selenium. The farmer was aware that his newborn livestock required selenium shots to prevent white muscle disease and that his livestock were fed selenium-fortified commercial organic livestock feed.

That BC farmer’s “Aha!” moment came when he made the connection between his garden soils’ lack of selenium and his family’s health problems. My curiosity was piqued. What was going on here—what is selenium and where do we find it?

Selenium is recognized as an essential trace mineral for healthy livestock and it is standard best practice to give selenium shots shortly after birth. In the year 2000, the Canadian government, along with the rest of North America, mandated the addition of selenium minerals to commercial livestock feeds (poultry, swine, beef/dairy, goat, and sheep) as a way to increase animal health and fortify the human food supply in dairy, meat, and eggs. Canadian wildlife surveys have determined that wild creatures also suffer from selenium deficiency diseases. Chronic and subclinical selenium deficiency could be a contributing factor to recent wildlife population declines, as other causes have not been identified.

I was surprised to learn from the government of Alberta’s Agri-Fax sheet that plants do not use selenium and do not show deficiency symptoms from its lack in the soil. At the same time, there are a few plants, such as locoweeds, that can hyperaccumulate selenium to levels that are toxic to livestock when selenium concentrations are high in the soil.

It was only relatively recently that we realized selenium was essential for human health. In 1979, Chinese scientists made the discovery while investigating the deaths of thousands of young women and children in the Keshan County of North Eastern China. The condition associated with these deaths was named Keshan disease, after the county where it was first recognized. The Chinese scientists discovered that selenium supplementation could correct the disorder. Since then, much has been learned about how selenium acts as a mineral in the human body in conjunction with other trace minerals such as chromium and iodine, which are also not used by plants.

Selenium deficiency is regarded as a major worldwide health problem with estimates of between 500 million to 1 billion people living with selenium deficiency diseases. Even larger numbers of people are consuming less then what is needed for optimal protection against cancer, cardiovascular diseases, and infectious diseases.

Researchers have found that selenium is widely distributed throughout the body’s tissues and of high importance for many regulatory and metabolic functions. Selenium is very much like a “Goldilocks” micronutrient: you need just the right amount. Too much or too little can lead to serious health consequences. The Recommended Daily Amount (RDA) in Canada for adults and children 14 and up is 55 micrograms per day. Our dietary selenium is taken up in the gut and becomes incorporated into more than 30 selenoproteins and selenoenzymes that play critical roles in human biological processes. Selenium is considered a cornerstone of the body’s antioxidant defense system as an integral component required for glutathione peroxidase (GPx) activity. The GPx enzyme family plays a major role in protection against oxidative stress.

In addition, selenoproteins regulate many physiological processes, including the immune system response, brain neurotransmitter functioning, male and female reproductive fertility, thyroid hormone functioning, DNA synthesis, cardiovascular health, mental health, and heavy metal chelation. Selenoproteins have a protective effect against some forms of cancer, possess chemo-preventive properties, and regulate the inflammatory mediators in asthma.

Many chronic diseases have been linked to selenium deficiency. A short list includes: diabetes, Alzheimer’s, lupus, autoimmune disease, arthritis, schizophrenia, cardiovascular disease, degenerative muscle diseases, neurological diseases, and rheumatoid arthritis. The selenium GPX-1 immune defense system has demonstrated antiviral capability. GPx-1 is found in most body cells, including red blood cells.

Some lipid-enveloped viruses pirate host selenium resources as a strategy to outmaneuver the host immune selenium-activated GPX-1 antioxidant system. If a host is selenium-deficient the virus can overwhelm the host GPX-1 immune response. In selenium-competent individuals the GPX-1 initiates an immune response cascade which inhibits viral replication and clears the virus from host. Selenium’s antiviral defense ability has been documented for Ebola, coronavirus, SARS-2003, influenza viruses (swine and bird flus), HIV, herpes viruses, cytomegalovirus (CMV), Epstein-Barr virus (EBV), hepatitis B and C, Newcastle disease virus, rubella (German measles), varicella (chicken pox), smallpox, swine fever, and West Nile virus. There are a number of studies showing that selenium deficiency negatively impacts the course of HIV, and that selenium supplementation may delay the onset of full-blown AIDS.

While the research is still unfolding and it is too early to make determinative conclusions about COVID-19 and potential treatments, preliminary research indicates several interesting lines of inquiry. COVD-19 researchers in China published new data on April 28, 2020 making an association the COVID-19 “cure rates and death rates” and the soil selenium status of the region. Higher deaths rates were observed in populations living inside soil selenium-poor regions such as Hubei Province. Regional population selenium status was measured through hair samples. Samples were collected and compared from 17 different Chinese cities: “Results show an association between the reported cure rates for COVID-19 and selenium status. These data are consistent with the evidence of the antiviral effects of selenium from previous studies.”

By now, you’ve probably figured out that we can’t live without selenium. The evidence is clear: human and animal health is dependent on selenium, and yet it is the rarest micronutrient element in the Earth’s crust. Selenium is classed as a non-renewable resource because there are no ore deposits from which Selenium can be mined as the primary product. Most selenium is extracted as a by-product of copper mining.

Selenium has many industrial applications because of its unique properties as a semi-conductor. The most outstanding physical property of crystalline selenium is its photoconductivity. In sunlight electrical conductivity increases more than 1,000-fold, making it prized for use in solar energy panels and many other industrial uses that ultimately draw selenium out of the food chain, potentially permanently.

Selenium is very unevenly dispersed on land masses worldwide, ranging from deficient to toxic concentrations, with 70% to 80% of global agricultural lands considered to be deficient. Countries dominated by selenium-poor soils include Canada, Western and Eastern European, China, Russia, and New Zealand. Worldwide selenium-deficient soils are widespread, and increasing.

Naturally selenium-rich soils are primarily associated with marine environments. Ancient oceans leave behind dehydrated selenium salts as they recede. Here in Canada the receding salt waters of the Western Interior and Hudson seaways left mineral deposits from the Badlands of Alberta, following along the southern borders of Saskatchewan and Manitoba.

Some countries, including Finland and New Zealand, have added selenium (selenite) to fertilizer programs to fortify the soils with some success. Results show that only a small proportion of the selenium is taken up by plants and much of the remainder becomes bound up in non-bioavailable complexes out of reach for future plant utilization. On this basis, it is thought that large scale selenium biofortification with commercial fertilizers would be too wasteful for application to large areas of our planet. The geographic variability of selenium content, environmental conditions, and agricultural practices all have a profound influence on the final selenium content of our foods. Iodine, which works hand-in-hand with selenium, is even more randomly variable in soils and food crops.

The Globe and Mail ran the following January 2, 2020 headline: “Canadian researchers combat arsenic poisoning with Saskatchewan-grown lentils.” In 2012, it was estimated by the WHO that 39 million Bangladeshis were exposed to high levels of arsenic in their drinking water, and the World Health Organization (WHO) deemed Bangladesh’s arsenic poisoned groundwater crisis the “largest mass poisoning of a population in history.” As it turns out, the lentils from southern Saskatchewan accumulate enough selenium that they could be used as a “food-medicine” in Bangladesh as a cure for arsenic poisoning. Clinical trials conducted from 2015 to 2016 found that participants eating selenium-rich lentils had a breakthrough moment when urine samples confirmed that arsenic was being flushed from their bodies. Other studies have also shown that selenium binds to mercury to remove it from the body.

Now that we are finally wrapping our minds around the fact that our personal health depends on just the right amount of selenium, we find out that the health of future generations may depend on it even more. It takes more than one parent’s generation to produce a single child. While a female fetus is growing in the womb, the eggs of the gestating mother’s grandchildren are also being formed in the ovaries of the fetus. The viability of the grandchildren’s DNA is protected from oxidative stress damage by antioxidant selenium. Oxidative stress on the new DNA could potentially result in epigenetic changes for future generations. The selenium intake of the grandparent directly affects the grandchildren. From this point of view, it is seen as imperative that all childbearing people have access to sufficient selenium. Selenium is essential for healthy spermatogenesis and for female reproductive health, as well as the brain formation of the fetus. In short, humanity is dependent on selenium for health—now and forever.

The world’s selenium resources are scarce and need to be carefully managed for future generations. Since both the human and livestock food chains are being fortified with this scarce resource, the manures from these sources are worth more then their weight in gold. The natural cycles of returning resources dictates that livestock manures need to be guided back into the soil for crop production. Human biosolids can be guided into fiber crops or forest production. Over time, livestock manures will fortify the soils with all of the micronutrients passing through their systems. Human manures passing through fiber crops can eventually be composted and recycled into crop production, returning selenium continually to the human micronutrient supply chain.

Waste not, want not.

Marjorie Harris, IOIA VO and concerned organophyte.

References:
Evans, I., Solberg, E. (1998). Minerals for Plants, Animals and Man, Agri-Fax Alberta Agriculture, Food and Rural Development: agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex789/$file/531-3.pdf?OpenElement
Haug, A., et al. (2007). How to use the world’s scarce selenium resources efficiently to increase the selenium concentration in food, Microbial Ecology in Health and Disease: Dec 19: 209 – 228. DOI: 10.1080/08910600701698986
Jagoda, K. W., Power, R., Toborek, M. (2016). Biological activity of
selenium: Revisited, IUBMB Life – Review: Feb;68(2):97-105. DOI: 10.1002/iub.1466
Brown, K.M., Arthur, J.R. (2001). Selenium, Selenoproteins and human health: a review, Public Health Nutrition: Volume 4, Issue 2b pp. 593-599. DOI: https://doi.org/10.1079/PHN2001143
Harthill M., (2011). Review: Micronutrient Selenium Deficiency Influences Evolution of Some Viral Infectious Diseases, Biol Trace Elem Res. 143:1325–1336. DOI: doi.org/10.1007/s12011-011-8977-1
Zhang, J. et al. (2020). Association between regional selenium status and reported outcome of COVID-19 cases in China, Am J Clin Nutr. doi.org/10.1093/ajcn/nqaa095.
Carbert, M., (2020). Canadian researchers combat arsenic poisoning with Saskatchewan-grown lentils, The Globe and Mail: theglobeandmail.com/canada/alberta/article-canadian-researchers-combat-arsenic-poisoning-with-saskatchewan-grown/
Sears, M.E. (2013). Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review, The Scientific World Journal. doi.org/10.1155/2013/219840

Organic Stories: Covert Farms, Oliver, BC

Published on September 1, 2019 in 2019/Climate Change/Crop Production/Fall 2019/Grow Organic/Land Stewardship/Organic Community/Organic Stories/Water Management

Covert Family Farm - Portrait proud family vintners in vineyard

Fighting Drought through Complex Ecosystems

By Emma Holmes

Irecently had the pleasure of visiting Covert Farms Family Estate in Oliver, where Gene Covert, a third-generation farmer, gave me a tour of his family’s 650 acre organic farm, vineyard, and winery. Gene’s grandpa George Covert bought the desert-like piece of land back in 1959, and although some laughed, thinking the land would not be suitable for agriculture, he, his son, and eventually grandson, Gene, have built the farm into a robust, flourishing, certified organic farm that embraces biodynamic, permaculture, and regenerative farming methods.

Gene studied ecosystem complexity as a Physical Geography student at UBC and has carried this learning through to his farming career, approaching it with a high level of curiosity for the natural world and experimentation. His wife, Shelly Covert, a holistic nutritionist, has been co-managing the family farm and in 2010 they were awarded the Outsanding Young Farmer Award BC/Yukon. Gene and Shelley are deeply connected to their land: “The relationships of our land are complex and most have yet to be discovered. As we learn more we find interest, intrigue, and humility.”

Like many places in BC, Oliver is expected to face increasing warmer and drier conditions. Already a drought prone desert, it is more important than ever to find ways to slow the water down, trap it at the surface, give it time to infiltrate, and store it in the soil.

The secret to storing more water lies in soil organic matter. Soil organic matter holds, on average, 10 times more water than its weight. A 1 percent increase in soil organic matter helps soil hold approximately 20,000 gallons more water per acre.¹

The Covert’s guiding philosophy is that “only by creating and fostering complexity can we hope to grow food with complex and persistent flavours. Flavours are the ultimate expression of the mineralization brought about by healthy soil microbial ecosystems.” To increase the organic matter content of his sandy soil, Gene took inspiration from organic and regenerative farmers in other agricultural sectors and began experimenting with cover crop cocktails, reduced tillage, and integrating livestock into his system.

Cover Crop Cocktails

Cover crop cocktails are mixtures of three or more cover crop species that allow producers to diversify the number of benefits and management goals they can meet using cover crops. Farmers like Gabe Brown are leading the way and driving the excitement around cover crop cocktails, and research is following suit, with universities starting research programs such as Penn’s State Cover Crop Cocktail for Organic Systems lab.²

To help him in meeting the right mix for his system, Gene uses the Smartmix calculator, made by farmers for farmers³. He has found that seven or more species affords the most drought tolerance. He uses a combination of warm and cool season grasses, lentils, and brassicas. Some of the species in his blend include guargum, a drought tolerant N-fixing bean, radish to break up soil at lower depths, and mustards as a cutworm control.

Gene plants Morton lentils right under the vine to fix N and suppress downy brome. This type of lentil was developed by Washington State University for fall planting in minimum tillage systems. Crop establishment is in the fall and early spring, which is when evapo-transpiration demand is minimal, thus improving water-use efficiency.

The diverse benefits of his cover crop include N fixation, increase in soil organic matter, weed control, pest control, and increased system resilience in a changing climate.

Low-Till

Frequent tillage can negatively impact soil organic matter levels and water-holding capacity. Regular tillage over a long-time period can have a severe negative impact on soil quality, structure, and biological health.

The challenge for organic systems is that tillage is often used for weed control, seedbed preparation, soil aeration, turning in cover crops, and incorporating soil amendment. Thus, new management strategies need to be adopted in place of tillage. Cover cropping, roller crimping, rotational grazing, mowing, mulching, steaming, flaming, and horticulture vinegars are cultural weed control practices that can be used in organic systems as an alternative to tillage. The most successful organic systems embrace and build on the complexity of their system, and utilize several solutions for best results.

Gene used to cultivate five to six times a year, mostly for weed control, but now cultivates just once a year to incorporate cover crop seeds under the vines. Instead of regular tilling to control weeds, he uses cover crops that will compete with weeds but that won’t devigorate the crop and that can be controlled through non-tillage management strategies like roller crimping and rotational grazing. For cover crop seeds between the rows, he uses a no-till seeder.

Intensive Rotational Grazing

Integrated grazing sheep or cattle in vineyards is not a new concept, but it became much less common since the rise in modern fertilizers. It has been increasingly gaining steam in recent years due to the myriad benefits it provides. The animals act as cover crop terminators, lawn mowers, and weed eaters while also improving the overall soil fertility and biological health⁴. The appropriate presence of animals increases soil organic matter, and some on-farm demonstration research out of Australia showed significant reductions in irrigation use, reduced reliance on machinery, fuels, and fertilizers, and increased soil organic matter.⁵

Incorporating livestock into a horticultural system adds a completely new management challenge and thus level of complexity. It comes with the risk of compaction and over grazing if not managed properly. The key is to move herds frequently, controlling their access to different sections and never letting them stay too long in one area. As well, the grazing window needs to be limited to after harvest and before bud-break to prevent damage to the cash crop

Grapevines and mountains. Credit: Covert Farms

Increased Resiliency

Since experimenting with and adopting these management practices, Gene has found his cost of inputs has dropped and he has noticed a significant increase in soil organic matter and reduced irrigation requirements. Based on his success so far, he has a goal of eventually dryland farming. No small feat on a sandy, gravelly, glacio-fluvial soil in a desert climate facing increasing droughty conditions!

On-Farm Demonstration Research

A farmer’s experience and observations are critical in problem solving and the development of new management practices. Increasing farmer-led on-farm research is fundamental to improving the resiliency of producers in the face of ongoing climate change impacts, such as drought and unpredictable precipitation.

Farmer-led on-farm research compliments and builds experience by allowing a farmer to use a small portion of their land to test and identify ways to better manage their resources in order to achieve any farming goal they have, including climate adaptation strategies such as increasing soil organic matter to reduce irrigation requirements. The beauty of on-farm demonstration research is that it is farmer directed, it can be carried out independently, and it uses the resources a typical farmer would have on hand.

If you’re inspired by an idea, or a practice you have seen used in another agricultural system and are interested in conducting your own field trials, I highly recommend the BC Forage Council Guide to On-Farm Demonstration Research: How to Plan, Prepare, and Conduct Your Own On-Farm Trials.⁶ It is an accessible guide that covers the foundations of planning and conducting research, allowing you to achieve the best results. While it was created for the forage industry, the guide covers the basics of research and is applicable to farmers in any sector.

My highest gratitude and praise for the farmers who are finding the overlaps at the edges of agricultural models, where one becomes another—and leading the way into the new fertile and diverse opportunities for sustainable food production in a changing climate.

Thank you to Gene Covert and Lisa Wambold for their knowledge, passion, and insights.

Emma Holmes has a BSc in Sustainable Agriculture and an MSc in Soil Science, both from UBC. She farmed on Orcas Island and Salt Spring Island and is now the Organics Industry Specialist at the BC Ministry of Agriculture. She can be reached at: Emma.Holmes@gov.bc.ca

References and Resources:

1. Bryant, Lara. Organic Matter Can Improve Your Soil’s Water Holding Capacity. nrdc.org/experts/lara-bryant/organic-matter-can-improve-your-soils-water-holding-capacity
2. agsci.psu.edu/organic/research-and-extension/cover-crop-cocktails/project-summary
3. greencoverseed.com
4. Niles, M.T., Garrett, R., and Walsh, D. (2018). Ecological and economic benefits of integrating sheep into viticulture production. Agronomy and Sustainable Development. 38(1). link.springer.com/article/10.1007%2Fs13593-017-0478-y
5. Mulville, Kelly. Holistic Approach to Vineyard Grazing. grazingvineyards.blogspot.com
6. BC Forage Council. (2017). A Guide to On-Farm Demonstration Research. Farmwest.com. farmwest.com/node/1623

Adapting at Fraser Common Farm Cooperative

Published on September 1, 2019 in 2019/Climate Change/Crop Production/Fall 2019/Grow Organic/Land Stewardship/Livestock/Organic Community/Pest Management/Seeds/Soil/Tools & Techniques/Water Management

Photos and text by Michael Marrapese

In 2018 Fraser Common Farm Co-operative—home of Glorious Organics—undertook a year long on-farm research project to explore how small farms could adapt to climate change. Seeing the changes in seasonal rainfall, climate predictions by Environment Canada, and new ground water regulations from the provincial government, the cooperative could see that water availability would eventually become a significant limiting factor in farming operations.

The discussions about adaptation were complex and multi-factored. Every operation on the farm is connected to something else and many systems interconnect in differing ways throughout the season. Changing practices can be difficult, time consuming, and sometimes risky.

During the year-long project, funded by Vancity, Co-op members worked to evaluate farming practices and areas of opportunity and weakness in farm management. The project generated several feasible solutions to decrease the demand on groundwater, buffer water demand, harvest rain water, and use irrigation water more efficiently. Some solutions were fairly straightforward and easy to implement. Others required more expertise, better data, and further capital.

Mark Cormier: Improving Water Practices

Mark Cormier explains how Glorious Organics uses edible, nitrogen fixing peas, and Fava beans for cover crops. He’s moved away from overhead spray irrigation to drip tape for the bulk of Glorious Organics’ field crops. He puts drip tape under black plastic row mulch. The plastic mulch significantly increases water retention and suppresses weeds. After the first crop comes off the field he rolls up the plastic and plants salad greens in the same row without tilling. Glorious Organics plans to double the size of the artificial pond and and dredge out a smaller natural spring basin to provide more water for the longer, drier summers the region is experiencing. Cormier notes that this year they are selling a lot of plums, a crop that they don’t water at all.

Mark with black plastic mulch and drip tape irrigation.

Artificial pond and solar powered pumping station.

David Catzel: Developing Diversity

Catzel has several plant breeding and selection projects on the go to develop populations of productive, flavourful, and marketable crops. Preserving and expanding bio-diversity on the farm is vital for long-term sustainability. With his multi-year Kale breeding project, David has been seeking to develop a denticulated white kale and in the process has seen other useful characteristics, like frost-hardiness, develop in his breeding program. He’s currently crossing varieties of watermelon in order to develop a short-season, highly productive variety. His development of seed crops has also become a significant income source. He estimates his recent batch of Winter White Kale seed alone will net $1,500 in sales. As the Co-operative diversifies its product line to include more fruit and berries, organic orchard management practices have become increasingly important. Catzel has been instrumental in incorporating sheep into orchard management. A critical component of pest management is to keep the orchards clean and to remove any fruit on the ground to reduce insect pest populations. The sheep eat a lot of the fallen fruit and keep the grass and weeds in check making it easier to keep the orchards clean.

David Catzel and the Kale Breeding Project.

David Catzel crossing Watermelon varieties.

David Catzel with his Winter White Kale seed crop.

Barry Cole: Gathering Insect Data

With the arrival of the spotted wing drosophila fruit fly, Fraser Common Farm was facing a management crisis. There seemed to be little organic growers could do to combat the pest, which destroys fruit before is is ripe. Infestations of Coddling Moth and Apple Maggot were making it difficult to offer fruit for sale. Barry Cole set about to gather meaningful data to help understand pest life cycles and vectors of attack. He’s set up a variety of traps and tapes and monitors them regularly to determine when pests are most active and which trees they prefer. The “Bait Apples” attract a large number of Apple Coddling Moths. The yellow sticky tapes help determine which species are present at various times in the season. Since many of the fruit trees are more than 20 years old, he also monitors and records tree productivity and fruit quality to better determine which trees should be kept and which should be replaced.

Barry Cole inspecting walnuts for pests.

Michael Marrapese is the IT and Communications Manager at FarmFolk CityFolk. He lives and works at Fraser Common Farm Cooperative, one of BC’s longest running cooperative farms, and is an avid photographer, singer, and cook.

Feature image: David Catzel’s watermelon varieties.

Clockwise from left: ; the fake apple trap; identifying active pests; Barry Cole inspects walnutd for pests; Mark Cormier with fava bean cover crop; plums in the upper orchard; David Catzel with his White Winter Kale seed crop. Credit: Michael Marrapese.

Biodynamic Farm Story: Putting the Dynamic in Biodynamic

Published on September 1, 2019 in 2019/Crop Production/Fall 2019/Grow Organic/Land Stewardship/Soil/Tools & Techniques

Anna Helmer

I used to write a small weekly column for the local paper, telling stories about the farm each week. I kept it going through the busy times and the not busy times. I hardly remember how I managed to write the required 600 coherent words during those intensely busy summer weeks. Maybe they weren’t coherent. Likely not, now that I think about it. Maybe coherence was not a goal. If you can’t do it, don’t make it a goal, I always say.

Those winter columns, though. I remember writing those. They were the ones where I had done precious little farm work during the week and now had to write about it. They were a challenge to compose. At least in the summer weeks there was lots of material. However, I did learn how to make 600 entertaining words out of, say, a flat tire and a quiet market.

I am feeling reminiscent of those lazy days of winter and cobbling together something interesting about scant farming activities because I have agreed to do another installment of Biodynamic Farm Story, but I really haven’t done much Biodynamic stuff lately.

The blame for this lies entirely with the farm. In addition to non-descript regular farm work, each tractor has broken down several times, we’ve poured new concrete, built a new shed, and started attending our local market about six weeks earlier than ever before. The events have very much taken precedence over Biodynamic activities. The original Biodynamic lectures don’t seem to specifically address what to do when this happens.

Those lectures contain a fair amount about the importance of talking with other farmers about Biodynamic methods, however. I gather Steiner, the lecturer, understood that much of his content was untested in real farm-world situations. There is also acknowledgement that every single farm, being its own entity consisting of its own unique people, soil, and environment, will have to find its own way.

(Cosmic) Hightland Cow. Credit: Nilfanion (CC)

I think that’s the story this time: how does it work to be a Biodynamic farm (or farmer!) when events overtake intentions? This is about how we can’t seem to follow the Biodynamic calendar very well, and how in actual fact, we seem to forget all about being Biodynamic when the fur starts flying on a busy farm season. Perhaps this is when the “dynamic” part comes into play.

I would like to think that the work we do in the shoulder seasons—creating composts, using the preparations, planning planting around propitious dates in the calendar—all contribute to the strength of the farm now, when it is being fully taxed. I suppose it possibly might be so.

Theoretically, what would a biodynamically active farmer not like me be doing right now on the farm? I would have two things on the list: compost management and Biodynamic Preparation 508.

Priority one: turn the cow manure pile and bung in more Biodynamic preparations, purchased in a set from the Josephine Porter Institute—nettle, yarrow, dandelion, oak bark, chamomile and valerian. They are intended to not only stimulate the biological breakdown of the material into humus and whatnot, but also to create a source of energy for the farm. How cool is that?

I came across a metaphor for the Biodynamic compost heap several years ago, the source regretfully forgotten, the actual meaning mangled: Cosmic Cow. Consider the cow that can transform the energy of the sun (via green grass) turning it into precious manure that may be used to grow our eating plants. It is a remarkable feat that is accomplished in a complex digestive system. Even more remarkable, the function carries on despite the animal eating all kinds of garbage along with the lovely grass. And through thick and thin, the animal maintains a more or less even disposition, emanating a particular energy that is quite powerful, in its own way.

So the Cosmic Cow Biodynamic Compost heap can do the same sort of thing. Its digestive system is powered up to produce the desired dirt, and the whole thing is solidly grounded to be able to broadcast the infinite energy of the universe to the farm.

If I had some time, and if the loader tractor hadn’t developed a leak in the axle and the right seal had been sent from the source of seals and if it therefore had a wheel, I totally would have done that job by now. Pretty certain it is high on Dad’s list too. The wheel will eventually go back on, surely. Meanwhile, the pile sits patiently in the field, the essential activity continuing despite neglect.

I am also looking into the preparation called 508. It uses horsetail in either a tea form (very easy to make) or a more complicated distillation. There has been a lot of rain, heat, and wind lately and fungal issues may arise. The 508 may help cope with that. Plus, it is all the rage right now in Biodynamics and I am nothing if not keen to fit in.

If there is one weed we have plenty of in the potatoes this year, it is horsetail. Do I go to the effort of picking it, boiling it up and spraying it around? So far, I do not.

A look into my farm notes for the past couple of months reveals at least a passing nod to the Biodynamic Calendar. I have noted when something I did was done because it was a good day to do it according to the position of the moon and the planets. It still means nothing to me, but I think the plants get it, so that’s good. For example, the carrots were done right. As that field also had a good helping of BD 500 both last fall and this spring, I could expect one of our best crops ever. I don’t, however. Biodynamics is a method, not a guarantee.

Unlike chemical fertilizers. They are more of a guarantee. It is very plain to see the appeal of popping in a wee bit of N, P, and K at planting time. Conventional farmers in Pemberton who planted potatoes weeks later than us are pleased that theirs came into flower right at the same time and achieved row cover well ahead. It’s just a fact of science.

A fact that means nothing to me. Today when I walked through our potato field, I would have needed a machete to get through the White Rose and Fingerlings. As an aside, did you know that potato flowers smell delicious?

I boast like this because I think Biodynamic farming can be a difficult sell to…well…most farmers. Let’s face it. The positive results are heavily anecdotal. I must add my own.

Anna Helmer farms with her family and friends in the Pemberton Valley and could have submitted the picture that featured a lot of weeds but instead chose the one that did not.

Feature image: Tractor wheel in a beautifully weed-free potato crop. Credit: Anna Helmer

Soil Health & Cover Crops

Published on April 1, 2019 in 2019/Climate Change/Crop Production/Grow Organic/Land Stewardship/Seeds/Soil/Spring 2019

A Recipe for Success in Achieving Long Term Soil Conservation

Saikat Kumar Basu

Why Care for our Soils?

Soil is an important constituent of both agriculture and forestry; unfortunately, it is taken for granted most of the time. It is a cheap, easily accessible or available global resource for which we have often forgotten to take the necessary care. We have used it non-judiciously without proper planning and vision for the future.

The concept of soil health has always been there since the dawn of human civilization—but only quite recently have we started to better understand, appreciate, and care for our soils as part of sustainable agriculture. We as humans have possibly matured over time and realized that our exploitative and non-judicious use of our soil resources can limit our long-term agricultural productivity and jeopardize successful crop production.

Unless we are serious enough to take good care of one of our most abundant yet highly sensitive natural resources of this planet, the soils, we ourselves will be solely to blame for the degradation of our soils—thanks to the self-destructive approaches we’ve used to achieve very short-term objectives of making easy profits without thinking deeply about the long-term consequences.

Soil health today has emerged as an important aspect of proper soil management as a component of sustainable agriculture to help in quality crop production without depleting or damaging soil quality and helping in proper soil conservation at the same time (Fig. 1).

What Impacts Soil Health?

Several factors impact soil health, among the most important being over application of fertilizers and pesticides. The soil represents a dynamic ecosystem and an intricate playground of delicate physics, chemistry, geology, and biology. Any chemical application on the soil therefore has some positive or negative impact on the soil quality by interfering with the physicochemical and biogeological processes associated with soil formation. These changes include shifting the soil pH due to various anthropogenic activities that slowly impact the soil quality. Drastic reduction in pH makes soil acidic, while rapid increase in pH leads to alkalinity or salinity; both conditions make the soil unsuitable for a long time for quality crop production. Furthermore, increased emphasis on monoculture associated with our modern industrial agriculture year after year depletes the soil of essential macro and micro nutrients necessary for maintaining optimal soil health (Fig. 2).

Fig 2. Increased emphasis on crop monoculture is detrimental to long term soil health.

Over application of synthetic chemical fertilizers and various pesticides to secure crop production adds too much pressure on our soil, impacting not only the physicochemical and geological processes active in the soil, but also negatively impacting the soil macro and micro flora and fauna devastatingly over a long period of time. Several beneficial microbes like soil bacteria, Cyanobacteria, soil fungi, soil borne insects, spring tails (Collembola), earthworms, and other critters essential for maintaining soil health suffer population collapse due to non-judicious over application of synthetic fertilizers and pesticides.

Many such chemical residues remain in the soil for prolonged period and often percolate deep into the soil, reaching the groundwater table or adjacent surface fresh water resources via surface run off, with long term negative impacts on both soil and water. Often the beneficial soil macro and micro flora and fauna are altered or replaced by harmful species that prove detrimental to soil health and significantly impact crop production and forest ecology. Random unplanned crop rotations and fallow harm our soil more than we actually realize; making them susceptible to weed and pest infestations (Fig. 3), loss of precious top soil and lower crop production due to poor soil health.

Fig 3. Untended soil is subjected to weed infestation that interferes with quality crop production.

Best Management Practices (BMPs) for Promoting Sustainable Soil Health

To maintain optimal soil health for long term success in achieving quality crop production we need to take necessary steps and plan carefully. This takes needs patience, and deeper understanding, as well as painstaking observations to implement good soil health practices on cropland.

Regular soil tests are important to ensure that we are aware of the excesses as well as depletion of necessary macro and micro nutrients in the soil. We also need to look into the topography of the crop field, the low and high spots in the field, the areas impacted by acidification and salinity issues, detailed history of fertilizer and pesticide applications over the years and the successive crops grown. Any past issues associated with the soil should be recorded for future reference. The nature of pest and weed infestations should be recorded to identify any specific patterns with respect to local pest and weed populations. Such detailed record keeping together with advanced GPS- and GIS-generated high-quality images of the field over the years will provide a farmer or crop producer or a professional agronomist ample reference to make judicious decisions to secure comprehensive soil health strategy and crop management for the future.

Based on the above information, we need to adopt a specific crop rotation plan to ensure that the soil is not exhausted of essential soil nutrients. Application of fertilizers and pesticides should follow manufacturer’s guidelines stringently to avoid over application (Fig 4).

Fig 4. It is important to keep track of weed and pest species impacting crop production in a particular field for making judicious decisions regarding appropriate chemical applications at the appropriate stage and dosage following manufacturer’s instructions.

It is also important to note if soil compaction is causing a problem for the field. If this is an issue, then highly mechanized farming activities and movements of heavy vehicles need to be restricted to a specific easily accessible area to reduce negative impacts of soil compaction on the field.

Intercropping could be practised depending upon the farming need and also to use the soil resources judiciously. This can enhance crop production and add crop diversity to the field important for maintaining soil health.

Role of Cover Crops in Promoting Long-Term Soil Health and Soil Conservation

Cover crops are an important aspect for maintaining general soil health if used with scientific outlook and proper planning. Several cover crops choices are available. Annual and perennial legumes, various clovers and sweet clovers, bird’s-foot trefoil, hairy vetch, common vetch, cicer milkvetch, sainfoin (Fig. 5), fenugreek, fava beans, soybeans, field pea or forage pea, cowpea, chickpea, green pea, black pea, different species of beans, oil crops such as annual and perennial sunflower, safflower, flax, forage canola, different mustard species (Fig. 6), brassicas such as forage rape, turnips, collards, radish, forage crops such as tef grass, Sudan grass, sorghum, sorghum x Sudan grass hybrids, corn, cereals such as winter rye, wheat and triticale, different millets, such as Proso millet, Japanese millet, German millet, red millet, special or novelty crops such as hemp (Fig 7) , chicory, plantain, phacelia, buckwheat, and quinoa are only a handful of choices to mention from a big basket of abundant crop species currently available across Canada.

Fig 5. Mustard cover crop in full bloom.

Fig 6. Perennial forage legume sainfoin is an excellent cover crop that can be successfully used in crop rotation cycles. Sainfoin is also exceptional for pollinators, attracting bees and other insects in large numbers.

Fig 7. Hemp is a new speciality crop for Canada and has been generating serious interest among farmers for agronomic productions. Hemp has been found to attract diverse species of insect pollinators too.

Several grass species such as orchard grass, tall fescue, short fescue, meadow fescue, creeping fescue, chewing fescue, festulolium, timothy, annual and perennial rye grass, Italian rye grass, and various other forage and native species are being used in specific legume-grass mix, in highly planned and organized crop rotations or in soil reclamation and pollinator mixes for attracting insect pollinators to the crop fields and in checking soil erosion effectively.

Cover crops should be selected based on the agro-climatic zone and soil zones of the region and used in planned rotations. Species or different appropriate cover crop mixes are to be selected based on the long-term objective of the crop production. For example, cover crop mixes used as pollinator mixes could not only be planted in the field during a fallow; but can also be used in agronomically unsuitable areas, along field perimeter, under the centre pivot stand, hard to access areas of the farm, shelter belts or adjacent to water bodies or low spots in the field too.

Forage cover crops could be used where the field is partly subjected to animal foraging or grazing or ranching. Similarly, oil crops, pharmaceutical or neutraceutical crops, or specialty or novelty cover crops could be used in crop rotations with major food or industrial crops grown in the particular field in a specific agro-climatic region.

Fig 8 Cover crops rotations can be an effective long term solution for managing optimal soil health with long term positive impacts on soil quality and soil conservation.

Cover crops not only play an important role in crop rotation cycle; but, also help in retaining soil temperature and moisture as well as protect top soil from erosive forces like wind and water. The presence of live roots in the soil and a rich diversity of crops stimulate the growth and population dynamics of important soil mega and micro fauna and flora for sustaining long term soil health, soil quality and soil conservation. Cover crops help in balancing the use of essential soil macro and micro nutrients in the soil, as well as promoting better aeration, hydration, nitrogen fixation, and recycling of essential crop minerals, assisting bumper production of food or cash crops due to improvement in soil quality for successive high-quality crop production.

It is important for all of us to understand and appreciate that soil is a non-renewable resource and needs special care and attention. Unless we are careful to use this special resource so deeply associated with our agricultural and forestry operations judiciously, we may be slowly jeopardizing crop productivity—and our common future—in the not so distant future.

Proper planning and scientific soil management practices can play a vital role in keeping our soil productive as well as healthy. Use of crop rotations and cover crops are some of the important approaches towards long-term soil health, soil conservation, and crop productivity. We need to learn more about our local soil resources for our future food security and incorporate more soil friendly practices to prolong the life and quality of our soil.

Saikat Kumar Basu has a Masters in Plant Sciences and Agricultural Studies. He loves writing, traveling, and photography during his leisure and is passionate about nature and conservation
Acknowledgement: Performance Seed, Lethbridge, AB

Featured Image: Fig 1. Scientific management of soil health contributes towards long term high quality crop production as well as soil conservation. Image Credit: All photos by Saikat Kumar Basu

Ask an Expert: Soil Testing

Published on April 1, 2019 in 2019/Ask an Expert/Crop Production/Grow Organic/Land Stewardship/Soil/Spring 2019

Tools for your Nutrient Management Toolkit

Amy Norgaard, Dru Yates, & Emma Holmes

Every year farmers align countless variables to produce healthy crops that make it to market. Crop planning. Bed prep. Transplanting. Irrigation. Weed management. Pest management. Harvest. Storage and transport. Typically, there is a sweet spot in terms of either quantity or timing for each of these, and there are indicators or measures to stay in that ideal range. For example, the weather forecast and local temperatures highlight best times for transplanting, thermometers track temperatures in storage facilities, and in-field insect traps help monitor pest pressures. Nutrient management is another one of these farm management components that we can stack in our favour—and soil sampling is an essential tool to make informed decisions in this area.

The main reason for soil sampling in agriculture is to assess soil fertility and related properties like pH and texture. Results not only inform management practices for the current season but can also act as a report card for past decisions. Just like we can feel or measure the soil to make irrigation decisions, we can use soil tests to provide us with a snapshot of fertility status and amend accordingly. Being able to apply the right nutrients in the right quantities is just another opportunity to add another piece to the puzzle on the way to our yield, quality, and/or productivity goals.

Best Practices for Taking a Soil Sample

When collecting soil for analysis, the goal is to obtain a sample that is representative of the area you are interested in. Since soil properties vary across fields, there are several steps to ensuring the most reasonable average possible.

1. Take several sub-samples from your area of interest and mix them together to get a composite sample:

If your garden plot is small (100 – 200 sq. ft), take 4 – 5 samples.
If your garden is larger (500 – 10,000 sq. ft.), take 9 – 10 samples.
If you are measuring a larger area (i.e. 1 – 25 acres) and that area is relatively uniform in cropping and management history, take about 15 – 30 samples to make your composite sample.
If your sample area is larger than 25 acres, try to arrange your sampling areas so that a single composite sample does not represent more than 25 acres.

2. Avoid spots that look different from the rest, or that have been managed differently. For example:

Wet spots in an otherwise well drained field.
Areas where plants are growing exceptionally well, or exceptionally poorly compared to the rest of the field.
Greenhouses that are left covered over winter.
If you are curious about an area that is different from the rest, sample it separately.

3. Make sure each sub-sample is the same volume and is taken to the same rooting depth (usually 6 inches for most nutrient tests).

4. Collect samples randomly from the entire field area. A soil probe is the ideal tool as it is fast and ensures consistency among depth and volume of samples, but if you don’t have one readily available, a trowel or garden spade works well. You will also need a bucket and plastic bags. It helps to pre-label the bags with the sample name using a sharpie so that samples don’t get mixed up! Clean any equipment that comes into contact with the sample (eg. shovel and bucket) with clean potable water and dilute soap.

5. Start collecting samples from the sampling area and add into the bucket. Remove any bits of vegetation, pebbles, or fauna with a gloved hand. Once you have all your sub-samples for your area in a bucket, mix them together and take a ½ cup of soil and put into the prelabeled ziplock bag.

6. Repeat for other samples, making sure to clean your tools between sites.

For more details on taking a soil sample, please refer to this factsheet, which can be accessed by searching for ‘Soil Sampling for Nutrient Management’ on the BC Ministry of Agriculture website

Due to inherent variability in analytical methods, two labs can provide different values for the same nutrient of interest because labs use different extraction methods and equipment. Even when using the same method there is lab to lab variability. Therefore, it is important to use the same lab consistently to monitor trends over time. It is also important to take into consideration the methods used when analyzing the results.

On Testing Compost and Amendments (It’s a Good Idea)

Composts are commonly used in organic agriculture as a source of organic matter and plant nutrients. However, these amendments vary widely in their composition depending on many factors, such as feed-stock, composting process, and storage conditions. These not only affect the initial nutrient content, but also influence nutrient loss prior to spreading, as well as the soil nutrient dynamics (release and availability to crops) when the amendment is spread in the field. Therefore, testing a compost pile shortly before spreading gives us the best snapshot of its composition and represents another tool in our toolkit when making site-specific nutrient management decisions in systems using these products.

Composts can be tested for a variety of properties, including both macro- and micro-nutrient content, carbon to nitrogen ratio (C:N), pH, electrical conductivity (EC), organic matter content, etc. Together, these provide an overall picture of compost quality and can help predict the subsequent effects on soil quality and nutrient supply to crops. The specific parameters to test for depend on the goals for using the product, and any specific concerns or goals. For example, farms that already have salinity issues may want to test potential soil amendment sources for EC as an indicator of salt content to avoid exacerbating this pre-existing situation.

From a broad nutrient management perspective, testing for C:N, nitrogen (N), and phosphorous (P) are valuable first steps in balancing these nutrients, as compost products are often used to supply all or at least part of the N and P needs in organic farming systems. Additionally, these nutrients are important to consider because they are not only needed in significant quantities, but are also environmentally damaging when lost to surrounding ecosystems. In general, applying compost to target crop N requirements results in the over-application of P, and over time we see excess P levels in soils where this management practice is common (Sullivan & Poon, 2012). This highlights the advantage of implementing soil and compost testing, where we can not only monitor our soil P levels over time, but also be aware of the quantity we are applying by testing our amendments.

Finally, while N and P are two important plant macronutrients, compost provides a variety of other plant nutrients that can be important considerations, depending on the crop we are amending, soil test values, and any other farm-specific considerations. Implementing compost testing as a tool to be more informed about the properties of these amendments allows for more specific, targeted use and more efficient, environmentally-friendly farming systems overall.

How to Calculate Amendment Needs

While compost and soil tests answer the question “What’s there?”, there are still a few steps to go from these values to a target amendment application rate in the field. This can often be the most intimidating element and involves a few calculations. However, there are several online or downloadable calculators and resources for this process. The two nutrient calculators listed below are good starting points, and are accompanied by several resource pages and/or documents to get oriented to how they work. The BC Ministry of Agriculture’s Nutrient Management Calculator allows you to pick your lab when inputting your values, and will assist you in choosing the right rate and nutrient source for your crops.

Amendment Calculators:
Organic Cover Crop and Fertilizer Calculator (OSU Extension)
BC Ministry of Agriculture Nutrient Management Calculator

Additional Nutrient Management Resources:
Fertilizing with Manure and Other Organic Amendments (PNW)
Nutrient Management for Sustainable Vegetable Cropping Systems in Western Oregon (OSU)

Soil Fertility in Organic Systems – A guide for gardeners and small acreage farmers (PNW)

Post-harvest Nitrate Testing

The post-harvest nitrate test (PHNT) is a soil test performed in the late-summer to early-fall to evaluate nitrogen (N) management, and is another soil test to add to your nutrient management toolkit. This test measures the amount of nitrate-N remaining in the soil following harvest, and represents the plant-available N that was not used by the crop during the growing season.

Nitrate is highly mobile within the soil system and so is highly susceptible to leaching during winter months. For example, in coastal BC, effectively all soil nitrate is assumed to be lost from the root zone (in absence of an established cover crop) due to high winter rainfall. As such, it is:
1. common for spring nitrate-N soil test values to be minimally informative, and
2. important to manage soil N in ways that keep PHNT values low.

The PHNT is often referred to as a “report card” assessment of N management as it is used in retrospect—an evaluation of the impacts of nutrient management decisions that were made for the previous season. It provides a way for growers to assess and adjust their N management, to both get the most effective use out of the fertilizer inputs they are paying for, and to reduce environmental impacts of excess nitrates entering waterways.

Rating	General Interpretation	PHNT (kg/ha) 0-30 cm
Low	Continue present N management	< 50
Medium	Adjust N management to improve plant uptake efficiency	50-99
High	Reduce N inputs, implement strategy to reduce N leaching (e.g. cover crop)	100-199
Very High		>200

Table 1. Post-Harvest Nitrate Test (PHNT) ratings developed for corn and grass in the B.C. Lower Mainland (taken from Kowalenko et al. 2007).

To take a sample for PHNT, follow the general instructions for a taking a soil sample (see above in ‘Best Practices for Taking a Soil Sample’), plus the following modifications. Note that PHNT sampling protocols are somewhat crop and region specific. The following are generalized tips:

Timing: the general guideline is to sample after harvest, and before cover crop seeding, soil amending, and significant rainfall. For example, sampling before 125mm cumulative rainfall in south coastal BC on fine to medium textured soils is ideal.

Depth: sample to a minimum of 30cm. This is deeper than standard nutrient sampling recommendations.

Adjust for volume: take the nitrate-N value that you get from the soil lab and multiply by depth (0.3m), multiply by the bulk density of the soil (kg/m^3), and divide by 100 to get PHNT value in kg/ha. Soil bulk density will vary by soil type, and farm-specific values can be attained by paying for a bulk density test at a soil lab. The finer the texture, the denser the soil – many commonly used book-values fall between 1150 to 1300 kg/m^3.

For certain forage crops in coastal BC, such as silage corn and grass, target PHNT values have been developed to indicate whether N inputs should be managed differently in the following season. Under these rating systems (Table 1), higher ratings mean lower N-use efficiency and greater risk for leaching loss of nitrate-N.

The typical, potential reasons for inefficient N-uptake are:

N applications were in excess of total crop needs;
N was not applied at the optimal time(s) for crop uptake; or,
N was not applied where it was accessible to plant roots, or that other growing conditions (e.g. moisture, temperature, other nutrients) were limiting to crop uptake of N.

Relative differences in PHNT values are a useful tool in N management decisions, regardless of crop-specific target PHNT values. If you can identify a field or crop with high PHNT relative to your other fields, this is something to note, adjust nutrient management, and evaluate how that impacts your PHNT values the following season. This PHNT approach to N testing will provide much more insight into your N management than the N values you will receive from your spring soil tests. To address the need for more PHNT information in other field vegetable crops besides silage corn and grass, work is ongoing in BC to better understand PHNT testing and its implications.

Further detail on taking samples and interpreting PHNT values is available through the OSU Extension Catalog, search ‘Post-Harvest Soil Nitrate Testing’.

Assistance can also be found by contacting your Organics Specialist, Emma Holmes (Emma.Holmes@gov.bc.ca) at the BC Ministry of Agriculture.

Soil Labs

AGAT Laboratories
120 – 8600 Glenlyon Parkway, Burnaby, BC V5J 0B6
Phone: (778) 452-4000

Exova (formerly Bodycote/Norwest)
#104, 19575 – 55A Avenue, Surrey, BC V3S 8P8
Phone: (604) 514-3322 Fax: (604) 514-3323
Toll free: (800) 889-1433

Maxxam Analytics (formerly Cantest Ltd.)
4606 Canada Way, Burnaby BC V5G 1K5
Phone: 604-734-7276 Toll-free: 1 (800) 665-8566
Email : info@maxxamanalytics.com

Ministry of Environment Analytical Laboratory
4300 North Road
PO BOX 9536 Stn Prov Govt Victoria, BC
Phone: 250-952-4134
Email: NRlab@gov.bc.ca

MB Laboratories Ltd.
By Courier: 4 – 2062 West Henry Ave, Sidney BC V8L 5Y1
By Mail: PO Box 2103, Sidney BC V8L 3S6
Phone: (250) 656-1334
Email: mblabs@pacificcoast.net

Pacific Soil Analysis Inc.
5 – 11720 Voyageur Way, Richmond BC V6X 3G9
Phone: (604) 273-8226
Email: cedora19@telus.net

Plant Science Lab (affiliated with TerraLink Horticulture Inc.)
464 Riverside Road, Abbotsford, BC V2S 7M1
Phone: (604) 864-9044 x1602
Email: pwarren@terralink-horticulture.com

Amy Norgaard: Amy has a BSc in Agroecology and is now working on a MSc in Soil Science in the Sustainable Agricultural Landscapes lab at UBC. She has worked on several small-scale organic farms and is an Articling Agrologist with the BCIA. Her research is focused on nutrient management on organic vegetable farms. She can be reached at: amynorgaard@alumni.ubc.ca

Dru Yates: Dru has a M.Sc. in Soil Science from UBC, is an Articling Agrologist with the BCIA, and currently works as a consultant with E.S. Cropconsult Ltd. Her work includes providing integrated pest management (IPM) services to vegetable and blueberry growers throughout the Fraser Valley, as well as performing sampling and local research trials related to nutrient management. She can be reached at: dru@escrop.com

Emma Holmes: Emma Holmes has a B.Sc. in Sustainable Agriculture and a M.Sc. in Soil Science, both from UBC. She farmed on Orcas Island and Salt Spring Island and is now the Organics Industry Specialist at the BC Ministry of Agriculture. She can be reached at: Emma.Holmes@gov.bc.ca

References

Kowalenko, C.G., Schmidt, O., and Hughes-Games, G. (2007). Fraser Valley Soil Nutrient Study 2005. A Survey Of The Nitrogen, Phosphorus And Potassium Contents Of Lower Fraser Valley Agricultural Soils In Relation To Environmental And Agronomic Concerns.

Sullivan, C. S., & Poon, D. (2012). Fraser Valley Soil Nutrient Survey 2012.

Feature Image: Amy Norgaard sampling soil. Credit: Teresa Porter

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