Enhancing Soil Health: Benefits of Cover Crops and Practical Examples
Cover cropping is centered around planting crops, not necessarily to harvest but to create a cover over the soil to improve and protect the characteristics and health of the soil used for agriculture. Cover cropping has become increasingly popular (Storr, 2018) to promote soil health markers (Haruna, 2020), such as soil carbon, nitrogen, water levels, and holdings of key nutrients. Furthermore, increasing numbers of scientific papers and discussions have focused on cover cropping to rehabilitate global agricultural soils. Options such as living mulch (Elliott, n.d.), intercropping (Xiao-Fei Li, 2021), and symbiotic plant species (Curell, 2014) have, when practiced, promoted soil health. The continued development of cover crops offers a versatile option for the global agricultural community, especially considering the ever-deepening climate crisis. Planting leafy cover reduces water loss (Meyer, 2018) from the soil during hotter summer months, as seen worldwide. In addition, using deep-rooted cover crops such as ryegrass over fallow years can increase the soil structure (W Gao, 2016), limiting run-off nutrients and increasing soil aeration.
The benefits of using cover crops with deep roots
The use of deep-rooted cover crops such as ryegrass has proven to increase soil structure (Valenzuela, 2002), reversing the compaction that can be caused by heavy mechanical equipment (DEFRA, H.M. Government, 2024). The increased macropore space within the soil layer (gaps in the soil) enables water droplets to form and supply the crops during drought, protecting them from stress and wilting (O’Green, 2013). Improved soil structure can also increase the number of invertebrate species in the typical – healthy agricultural field. This occurs when the deep roots force the compacted soils to loosen up, enabling worms, beetles, and spiders to re-enter the topsoil (Cock, 2012). This also enables natural predators to commence hunting, which is especially beneficial when targeting pest species such as hessian fly larvae. This rebirth of the topsoil ecosystem can reduce the demand for pesticides and fertilizers used on the soil (Farm Advisory Service, 2024), benefiting both farmers and the agroecosystem.
Overall, the utilization of deep-rooted cover crop options such as ryegrass can revert compacted soils, increase natural predators, and improve crop yield. As the climate crisis deepens, farmers globally will be aided to utilize these options in their agricultural systems to reduce the risk posed by drought, compacted soils, and aerial erosion.
Nitrogen fixers
In today’s world of modern agriculture, it is commonplace to deploy synthetic fertilizers to maximize good yields. The addition of nitrogen and phosphorus into global agricultural soils provides good yields and reduced risk. However, the use of intercropping cover crops like clover has increased the levels of key nutrients within the soil, such as nitrogen (University of Georgia, 2016). This increased level of nutrients enables a greater yield in the chosen crop (Heshmati, 2020). This boost in nutrients occurs due to a symbiotic relationship between certain plants and microbes called Rhizobium (University of Georgia, 2016). This raised level of Rhizobium enables a greater level of nitrogen transfer to occur within the soil, promoting the level of free nitrogen available to the growing crops. With greater nutrients, crops can grow at increased rates and produce better crops when harvested (Sun, 2020). This natural boost to soil nutrients reduces the demand for artificial fertilizer (DEFRA, 2024). This product has only increased in cost in recent years (Eardley, 2022) and promises to continue to trend upward as the climate crisis deepens. Therefore, deploying natural nutrient-boosting crops such as clover could offer the agricultural community an opportunity to reduce costs, increase yield, and promote the overall health of the land they farm.
Living mulch
The increasing use of practices such as living mulch has seen boosts to soil carbon levels (USDA, 2024), enabling better crop yields and reduced weed abundance (Fracchiolla, 2020). The option to incorporate living mulch within an agricultural system is normally deployed when a field is allocated to become fallow for a year or more, as the process relies upon the sowing of plants like chickweed or alfalfa and leaving them to grow with limited aid from the farmer. Once fully grown and normally post-harvest of important crops, these plants are mown down and left on the field’s surface or trodden into the topsoil. As they begin to break down, the carbon that was sequestered during the growing season is locked into the soil, enabling increased soil carbon levels (Lowth, 2022) for the coming year when the farmer can plant a crop such as wheat, corn, or rapeseed. This process is becoming increasingly popular in the agricultural community for its cheap and easy way to promote soil health. Furthermore, this option reduces the erosional process from air and rain due to the living mulch being left on the surface or just below, acting as a structural agent to bind the soil together (Oakbank, 2024) over the harsh winter months. The option to deploy living mulch within an agricultural system can be incredibly beneficial to the farmer and the agricultural system in which they operate, increasing soil carbon and nutrients and reducing erosion and demand on the soil.
Concluding remarks
This article explored how cover cropping options can increase soil health markers such as moisture, carbon, and key nutrients. Options such as deep-rooted ryegrass, clover, other nitrogen-fixing agents, and living mulch can restore agricultural soil to fight fit. Farmers looking to incorporate regenerative farming practices could start with some of the options listed above: all offer benefits to the farmer and crop and the wider agricultural system. As the farming world stares down the climate crisis, enlarging global population, and changing consumer demands, it is apparent that agriculture will need new practices and methods to meet these challenges. It is clear from research and scientific papers that there are benefits to slowing down the farming calendar and reducing the consumption of artificial fertilizers, pesticides, and herbicides.
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