As farmers know, their work does not end after harvesting the nutritious food that feeds the world. In fact, farmers work year-round to produce the high-quality crops we consume. In order to yield these results year after year, farmers must ensure they replenish the soil after each harvest for the following season.
In this article we will be discussing some techniques used in the agricultural industry to replenish the soil after harvest. We will go through six tips to ensure sustained, year over year success in both crop and soil health.
1. Soil Test
The first thing that a farmer should do after harvest is take soil tests of multiple sites throughout their farm. Theses soil tests will notify farmers about the current state of their soil and how it differs throughout their farm. Farmers will gain insights into the nutrients they have an abundance of and the nutrients they are lacking from their soil. Understanding these details will allow farmers to cater their nutrient programs to address the needs of the soil, making them more efficient and precise. Addressing the needs of the soil maximize efficiency of resources and reduces waste, allowing farmers to save costs on fertilizers and other soil amendments.
2. No Till Or Minimal Till In The Soil
Secondly, farmers should try to engage in a no till or minimal till practices. Tillage causes severe damage to the soil, thus impacting crops. When tilling a field, all the vital nutrients needed for producing high quality and nutritious crops is released from the soil. This reduces the fertility and composition of the soil [i]. Additionally, tillage increases the likelihood of compaction zones in the soil. Compaction zones reduce the ability of soil to absorb oxygen and water while making it difficult for plant roots to extend down into the soil [ii].
In severe cases tillage leads to “dead” soil that is deficient in nutrients and will have trouble draining and absorbing water. Rather, farmers should try to avoid tillage when possible or use vertical or minimal tillage when it is a necessity. This will allow the soil to maintain its composition and organic matter.
3. Cover Crops
The next step is to plant a cover crop between crop cycles. Building off the soil test, farmers can cater the cover crop they plant to the nutrients they are lacking in their soil. Rather than applying fertilizers to address these deficiencies, cover crops provide similar nutritional boosts while conserving the soil over the winter months [iii]. For example, if a farmer notices they are lacking nitrogen, they can opt for legumes as a cover crop as it is excellent at fixating nitrogen into the soil. Another benefit from some cover crops - such as peas - is they can be sold, creating further revenue sources. Additionally, the farmer may throw a diverse set of seed down to try and suppress weeds and provide a range of nutrients back into the soil [iv].
Covering the soil is the most important step in replenishing the nutrients in your soil. By leaving the soil bare over winter, frost and erosion will decimate the organic matter levels of the soil, reducing the number of productive microbes, bacteria, and fungi [v]. Soil organic matter is essential to crop and soil quality as organic matter can hold ten times its weight in water [vi]. By cover cropping, the soil will remain protected and nutritious for the following spring, allowing farmers to reduce costs on fertilizer and pesticides.
4. Crop Rotation
Another step to generating healthy soils year over year is to plan crop rotations. A diversified crop rotation helps to control pests, effectively manage nutrients, and improve soil fertility and yield which increases the long-term profitability of the field [vii]. By rotating crops every few years, the soil will have a chance to recuperate during off years and support vigorous plant growth.
Alternating plants that are nitrogen dependent or potassium reliant will allow a balance within the soil. Maintaining the same crop on a field year over year, will result in a depletion of certain nutrients. For example, corn utilizes lots of nitrogen, by continually growing corn on a single field the soil will have deficiencies in nitrogen. Rather, by swapping corn with a crop that does not need much nitrogen or fixes nitrogen into the soil, allows the soil to rebalance its nitrogen levels and support healthy crop growth [viii]. Diversity of crops within a field whether they be cash crops or cover crops will translate into a healthy diverse soil.
5. Soil Amendments
The next step is to add amendments to the soil. At the end of harvest, it is beneficial to replenish some of those nutrients used by the crops in previous years. This can be done a few ways:
Organic Amendments
Firstly, farmers can utilize organic amendments such as compost and manure. Often times, these inputs can be found on the farm or for relatively low costs. Composts can also be transformed into teas or other sprays that can be used as an alternative to fertilizers. Composting allows farmers to reuse waste in a way that benefits their crops. For example, composting scapes from garlic is an excellent way to reduce waste and replenish the soil.
Additionally, homemade compost, leaves, or farm animal manure could be amendments used to revitalize the soil post-harvest. Leaves are readily available come autumn and hold great nutritional qualities. Leaves have more nutrients pound for pound than manure [ix]. Compost and manure can be harvested in many ways. It is important to ensure that there are no harmful pathogens, and the concentration of compost or manure is not too strong when applying it to the soil. Some strategies are to mix small amounts of physical compost into the soil or create a diluted spray.
Chemical Fertilizers
Secondly, some farmers may choose to use chemical fertilizers. When using synthetic fertilizers, be cautious and precise on the amount being added to the soil. Significant amounts of synthetic fertilizers applied to crop fields cannot be utilized by the plants and can be detrimental to the soil and surrounding waterways [x]. Thus, the soil test is important to provide farmers with the exact deficiencies in the soil. Understanding the soil test will ensure only the nutrients needed are being applied and the farmer can ensure they are not over fertilizing the soil.
Microbial Fertilizer
Another option is using a microbial fertilizer, where some farmers prefer to feed and cultivate microbial populations through organic inputs such as manure and compost. Microbial fertilizers such as Nurture Growth Biofertilizer can be a much simpler way to increase soil organic matter and vital microorganism populations in the soil. These microbes can expedite the decomposition process of manures and compost while preventing harmful pathogens, pests, and diseases for the following year. Microbes improve overall soil quality and plant resiliency. By increasing microbial populations in the soil, soils can nurture and expedite plant growth and health for the following year. Microbes improve plant resiliency, health and production quality [xi].
6. Insulation
Finally, farmers should insulate their field where they can. Adding 4-6 inches of mulch on top of your field can act as an insulator throughout the winter and summer seasons, provide beneficial nutrients, and suppress weeds [xii]. Mulching in combination to cover crops will help maximize the amount of nutrients you can retain in the soil. Mulch helps retain water and cool temperatures in the summer while keeping the soil warm throughout the winter.
Other insulation strategies include creating a bushy tree line along the edge of your farm field to minimize the effects of wind. Wind can cause erosion on empty soils reducing the fertility in your soil [xiii]. By insulating the soil, farmers can minimize soil disturbances while providing beneficial cover and nutrients to the soil.
In conclusion, by engaging in some of these practices, farmers will see long lasting success on their farms that can be sustained or improved year over year. While this is not a one size fits all solution, the adoption of some of these practices can alleviate some of the challenges farmers face while improving the long-term health of their land and business.
Blogger Biography
Eric is a graduate of the Environmental Science program at the University of Toronto. Coming from the green roof and landscaping industries, he does not hesitate to get his hands in the soil. He is actively searching for new ways to learn about our agricultural systems and get involved with his local agricultural community. Eric is an avid birdwatcher and advocate for environmental responsibility.
References:
[i] Moissac, L. de. (n.d.). What happens to soil microbes when you till? RealAgriculture.com. Retrieved December 13, 2021, from https://www.realagriculture.com/2021/01/what-happens-to-soil-microbes-when-you-till/#:~:text=By%20tilling%20you're%20also,phosphorus%20%E2%80%94%20back%20into%20the%20soil.
[ii] Ross, McKenzie. H., Agricultural Soil Compaction: Causes and Management, 1–10 (2010). Edmonton, Alberta; Government of Alberta.
[iii] MacKenzie, J. (n.d.). Cover crops and green manures in Home Gardens. UMN Extension. Retrieved December 13, 2021, from https://extension.umn.edu/how-manage-soil-and-nutrients-home-gardens/cover-crops-and-green-manures.
[iv] Creech, E., Gallahan, N., & Randall, B. (2021, September 27). Discover the cover: Managing cover crops to suppress weeds and save money on herbicides. Farmers.gov. Retrieved December 13, 2021, from https://www.farmers.gov/blog/conservation/discover-cover-managing-cover-crops-suppress-weeds-and-save-money-herbicides.
[v] Evans, R. (n.d.). Frost Heave. Frost Heave - an overview | ScienceDirect Topics. Retrieved December 13, 2021, from https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/frost-heave.
[vi] Bryant, L. (2016, December 15). Organic matter can improve your soil's water holding capacity. NRDC. Retrieved December 13, 2021, from https://www.nrdc.org/experts/lara-bryant/organic-matter-can-improve-your-soils-water-holding-capacity.
[vii] Snyder, L. D., Gómez, M. I., & Power, A. G. (2020, May 6). Crop varietal mixtures as a strategy to support insect pest control, yield, economic, and nutritional services. Frontiers. Retrieved December 13, 2021, from https://www.frontiersin.org/articles/10.3389/fsufs.2020.00060/full.
[viii] Beegle, D. (2021, November 19). Nitrogen fertilization of corn. Penn State Extension. Retrieved December 13, 2021, from https://extension.psu.edu/nitrogen-fertilization-of-corn.
[ix] Kohlhaase, B. (2019, August 8). Composting leaves (leaf mold, Mulch & compost). Planet Natural. Retrieved December 13, 2021, from https://www.planetnatural.com/leaf-mold/.
[x] Berg, M., & Meehan, M. (n.d.). Environmental Implications of Excess Fertilizer and Manure on Water Quality. North Dakota State University - Publications. Retrieved December 13, 2021, from https://www.ag.ndsu.edu/publications/environment-natural-resources/environmental-implications-of-excess-fertilizer-and-manure-on-water-quality.
[xi] Bharti V.S., Dotaniya M.L., Shukla S.P., Yadav V.K. (2017) Managing Soil Fertility Through Microbes: Prospects, Challenges and Future Strategies. In: Singh J., Seneviratne G. (eds) Agro-Environmental Sustainability. Springer, Cham. https://doi.org/10.1007/978-3-319-49724-2_5
[xii] 4 great benefits of mulching. Hansen Lawn & Garden. (2021, August 26). Retrieved December 13, 2021, from https://www.greensideup.com/4-great-benefits-of-mulching/.
[xiii] Government of Alberta. (2019, March). An introduction to wind erosion control . Alberta.ca. Retrieved December 13, 2021, from https://open.alberta.ca/dataset/5ab5fe3e-deba-4730-b178-93be8b87a2cb/resource/c0b85736-f28d-4a54-a12b-36c2b9a2ee79/download/introduction-wind-erosion-control.pdf.
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