Jennifer Volk, Extension Environmental Quality and Management Specialist; jennvolk@udel.edu
Did you know that you might already be employing strategies to help your operation prepare for climate change? Turns out that some of the same best management practices that have been utilized for decades for their benefits to the environment are also excellent tools to help combat and prepare for a changing climate.
It is pretty well known that cover crops are one of the best agricultural practices for improving water quality due to their ability to reduce nitrogen running off and leaching from agricultural fields. Depending on the varieties and mixtures used, cover crops can also suppress weed and insect pests. But, it is their ability to improve soil health that makes cover crops an excellent tool in the adaptation tool box for climate change.
One of the greatest benefits of cover crops is their ability to improve soil tilth. The root systems of cover crops, legumes especially, promote beneficial fungi (mycorrhizae) and other microorganisms in soil. These fungi and microorganisms help bind soil aggregates and well-aggregated soils allow for more water infiltration and retention and ultimately increase a soil’s capacity for plant available water. This is important given that we are anticipating hotter annual average and summer temperatures, warmer nights, and more hot, dry days in the future – all of which will likely lead to an increase in water demand by crops. Cover crops can help improve soil moisture conditions which could provide protection to crops during the hot dry conditions to come.
Cover crops also decrease risks of erosion through several pathways. First, the plants themselves hold the soil in place but the cover they provide also protects the soil from wind and raindrops. Additionally, since cover crops contribute to better aggregation of soils, the particles are more closely bound together and less susceptible to erosive forces. And, because more water can filter through well-aggregated soils, less water runs off, reducing the potential for soil to move with it. These are important benefits as climate projections indicate that precipitation will be more intense in the future and intense rains have a higher probability of eroding soils.
Finally, cover crops are often reported to increase soil carbon due to the stable organic matter left behind by woody and fibrous grains, grasses, and non-legumes. But, other agronomic practices could counteract this benefit, especially tillage. Conventional tillage not only breaks up the soil aggregates that improve soil tilth, but it also creates more soil surface area for microorganisms to decompose organic matter ultimately decreasing soil carbon. So, best results for soil health come when you utilize cover crops and minimal tillage systems together.
Because cover crops can help build soil carbon, they can in effect sequester carbon from the atmosphere, offsetting a portion of the carbon being emitted to the atmosphere which is causing climate change in the first place. A recent Natural Resource Defense Council Report, “Climate-Ready Soil: How cover crops can make farms more resilient to extreme weather risks,” (https://www.nrdc.org/sites/default/files/climate-ready-soil-IB.pdf) reports that if cover crops are used on half of the corn and soybean acres in the top 10 agricultural states, more than 19 million metric tons of carbon will be captured by those soils each year and that is equivalent to taking four million cars off of the road.
Granted, it takes a long time to increase the organic content of soil, so there are no false claims that cover crops will produce changes overnight. Rather, using cover crops can be thought of as a long-term strategy to protect and improve your soil health – which works in the context of climate change since that too is a long term process. The healthier your soil, the more prepared your operation will be to deal with changing climate conditions. So, why not start using cover crops today to help prepare your soil for the future!
Sign up for cover crop cost share at the Kent and Sussex County Conservation Districts began June 13th and runs through August 5th. The New Castle Conservation District will begin accepting applications for cover crops on Monday, August 1st and will accept them through August 31st or until funds are no longer available. Call your local district to learn more:
New Castle County, call 302-832-3100, extension 3
Kent County, call 302-741-2600, extension 3
Sussex County, call 302-856-3990 extension 3
In addition to their standard cover crop cost share program, the Sussex Conservation District offers two additional programs. One is their air seeder program which allows you to utilize their air seeder to plant your cover crop into your standing cash crop. They are also taking applications for an NRCS Regional Conservation Partnership Project that will give participants farming in the Chesapeake Bay watershed a $25 per acre bonus when they plant cereal rye or a cereal rye mix.