Cover crops can help protect soil and prevent degradation

Photo credit: Foodtank

Cover crops are being rediscovered at the forefront of new agriculture.


Don’t Farm Naked


Cover crops such as rye, alfalfa, and clovers are needed to protect soil from excessive rain and sun, provide organic structure, distribute nutrients, and limit harmful pests and weeds. They also provide economic benefits through reduced fertilizer needs, fewer problems with pests and weeds, and often, larger yields.

Cover crops are classified into legumes and non-legumes with each grouping having its particular applications and benefits.

Legumes like alfalfa, clovers, cowpeas, medics, soybeans, sunn hemp, velvet bean, and woolypod vetch are part of the pea family. Often referred to as green manure, leguminous cover crops can be tilled under and incorporated into the soil where their decomposition provides nitrogen, phosphorus, and other nutrients to subsequent crops. Legumes also help prevent erosion, add organic matter to soil, and attract beneficial microorganisms and insects.

Cereal grains, grasses, brassicas, and mustards make up the non-legume category.

The high carbon content of grasses and grains like barley, oats, rye, sorghum-sudangrass, wheat, spelt, and triticale leads to a slower breakdown of their organic materials. This biomass lasts longer and is effective at limiting weeds, especially when left on ground as mulch. Their low nitrogen content relative to legumes also makes them effective nitrogen scavengers, important for balancing soil that has become oversaturated with nitrogen. This leads to a higher all around nutrient extraction with less nutrients left over for the next crop. Buckwheat is particularly effective at drawing out phosphorus and calcium from the soil. Like legumes and most cover crops, grasses and cereals also help limit soil erosion.

Brassicas and mustards like arugula, kale, rapeseed, and turnips, while not legumes, are in between legumes and grasses regarding nitrogen content and rate of breakdown. They are effective pest controllers due to strong chemical compounds released during their decomposition process that are toxic to pests and weeds, while reducing the prevalence of disease in subsequent crops. Brassicas and mustards tolerate cold and drought well, have expansive roots, and serve as useful feed for grazing animals.

Following on traditional farming practices around the world, the Land Institute focuses on crops which are perennial, meaning they live all year, and are harvested multiple times, instead of just once before dying. The Land Institute believes in agriculture in harmony with nature. The complexity that perennials and cover crops bring to soil supports biodiversity and improves soil health. “This web of checks and balances, predator and prey that make up complex ecosystems make it difficult for any single species to dominate. Instead, a self-regulating equilibrium sets in.”

Read the full article: Foodtank

Author: Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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