Near the coast of Louisiana in the Gulf of Mexico, there is an area the size of Connecticut that is completely void of any life. This area, which is known as the Gulf’s “dead zone,” is created by a number of environmental factors acting in tandem. One contributor is fertilizer runoff, which contains the macro-nutrients nitrogen and phosphorus, is leached out of soils and into waterways (known as erosion), like the Mississippi River. The water pollution originates in all areas (both from cities and farmland), and these macro-nutrients are carried downstream and pour into the Gulf of Mexico. Because the nutrient levels become so high, algal blooms occur rapidly, depleting much of the oxygen in the area (this condition is otherwise known as hypoxia). Discharge from wastewater management systems is another large contributor to the hypoxia problem. This expeditious depletion of oxygen kills off any animal or plant that once lived there.
Scientists discovered the “dead zone” in the Gulf in 1972. It is the largest man-made hypoxic zone in the world, and in 2002, the zone became as large as the size of Massachusetts. Farmers today are doing everything they can to help decrease the hypoxic zone. One significant way they are minimizing their impact, as well as helping to improve waterways and promote general soil health, farmers have begun to use cover crops.
Cover crops include any crop that grows between periods of regular crop production. Cover crops benefit agricultural land because they enrich soil and protect it from erosion. Their extensive root system improves aeration in soil, allowing more air and water to infiltrate. Additionally, the root system creates pathways for a diverse array of soil animals that break down unavailable nutrients and make them available for crop uptake – an acre of healthy soil has the equivalent of 4 cows worth of microorganisms living in it! Cover crops create a more fertile and resilient agriculture field that can increase crop yield while also maintaining soil health.
Cover crops also reduce soil erosion caused by sediments, nutrients, and agricultural chemicals. The root system of these crops and the soil’s biological community take up or hold onto excess nitrogen, preventing it from leaching into waterways. Not only does reduced leaching mean less nutrient runoff into the Gulf (and therefore decreasing the effects of hypoxia), but this also improves the quality of drinking water over time.
Planting cover crops is very beneficial to both the environment and to crop production. When planting, it is important to use a cover crop that compliments the following harvest to maximize the benefits from the cover crop. You can even create cover crop ‘cocktails’ to achieve a multitude of benefits at one time; a field that uses a mix of cover crops is able to take up excess nutrients, suppress weeds, and create soil aggregation all in one area!
If you’re thinking of planting cover crops, whether it is on a small or large-scale, remember to do your research and start small. Additionally, if you want to learn more about cover crops you can attend an Illinois Demo Day, held in multiple counties throughout the summertime. If we all start to utilize cover crops within our agricultural lands, the soil will be more sustainable, and we may see a significant change in the size of the “dead zone” in the Gulf of Mexico.
University of Illinois