Long before commercial fertilizers and modern pesticides were developed, farmers utilized cover crops to assist with soil fertility and weed control. Today cover crops are an under-utilized soil and water conservation practice. Since the National Agricultural Statistics Service does not routinely collect information on the use of cover crops, the extent of its adoption in terms of acres is relatively unknown. Interest in cover crops seems to be growing especially in the corn belt of the Midwestern United States.
Cover crops as defined in the Encyclopedia of Soil Sciences are those crops that are grown for improving soil, air, and water conservation and quality; nutrient scavenging, cycling and management; increasing populations of beneficial insects in integrated pest management; and/or for short-term (e.g., over-winter) animal-cropping grazing systems. Cover crops are not usually grown to maturity to produce grain, seed or fruit.
Cover crops can provide a variety of soil and water conservation benefits including:
- Reduce erosion from wind and water
- Increase soil organic matter content
- Capture and recycle or redistribute nutrients in the soil profile
- Promote biological nitrogen fixation
- Increase biodiversity
- Weed suppression
- Provide supplemental forage
- Soil moisture management
- Reduce particulate emissions into the atmosphere
- Minimize and reduce soil compaction
Depending on the soil and climatic conditions of a given field, the benefits of cover crops can vary greatly. One of the barriers to adoption of cover crops is the perceived notion that cover crops are not profitable. While it’s true that cover crops are not grown as a commodity in and of itself, they can provide benefits that over the long-term can provide cost-savings by reducing crop inputs. In fact, some scientists tout cover crops as an important practice to long-term production and sustainability. Although documenting these benefits in terms of dollars is difficult, the cost of cover crops can be offset through USDA-NRCS cost share programs such as EQIP. For example, in the Cache River MRBI project area (See article in this newsletter) eligible producers can receive financial assistance to establish winter cover crops.
Researchers at the University of Arkansas’ Division of Agriculture are investigating the potential benefits of cover crops in helping to control Roundup-Ready resistant pigweed in cotton and soybeans while plant pathologists are investigating the use of winter cover crops in the brassica family such as Indian mustard as a bio-fumigant for nematodes in cotton and strawberry production. Some producers have recently inquired about the use of “tillage radishes” as a cover crop that is touted to break up soil compaction. Little research has been conducted in Arkansas on cover crops that reduce soil compaction to document its effectiveness. Cover crops have long been used in cotton production in Arkansas on sandy soils to reduce the shredding effects of wind-blown soil particles on young cotton plants.
Certainly cover crops are a beneficial soil conservation practice that provides cover to otherwise bare soils and thereby reducing soil erosion, and in turn may reduce sediment loading to streams and rivers. Benefits from cover crops accumulate over time and these benefits can vary from field to field. If you think cover crops may benefit your cropping system but you are hesitant to try due to costs, you can apply for financial assistance from USDA. If establishing cover crops is a new practice, then start small, perhaps in a field or two, and give it some time to observe possible benefits. For information on EQIP or cover crops, contact your local conservation district or County Extension office.
– Mike Daniels