Cover Crop Conclusion - Keep it green and Keep the soil!

We participated in the USDA cover crop cost share program through EQIP this last fall.  In an earlier post I talked about the airplane flying to sow the cover crop into the standing soybean crop before the leaves dropped as the soybeans matured before harvest.  The cold winter kept the cover crop from getting tall but it still did it's job.

We broadcasted annual rye, clover and tillage radishes last September into the standing soybean crop.  the cover crop germinated well.  The unusually cool temperatures in October and November kept the radishes from growing and killed them around Thanksgiving.  The rye and clover held on through the very cold winter though.  Although we would have like to have seen more growth the cover still did it's job.  The fields we sowed cover on did not develop washes in drains during heavy rain events.  We had one 3 inch rain in February while the ground was frozen that washed ditches in some of our fields without cover.  I was very pleased with how well the cover kept the ground from eroding on the slopes in the fields.

The root mass in this picture shows why the cover helped to hold the soil down during the heavy rain events.  The soil is bound with these roots and makes it harder to move away with the rain water.

The soil is alive with earth worms.  These little critters eat up left over nutrients in the soil and recycle them for the next crop to use this growing season.  Worms create pores in the soil profile that will increase the water holding capacity of the soil.  This decreases runoff during rain events and stores more water for the corn crop to utilize during the hot summer months that can tend to be dry and hurt the yield potential.  I am anxious to see if there is any yield difference where we had cover and where we did not.  We left a strip out in one field so we could look at any differences in yield from the cover crops. 

Cover Crops scavenge nutrients that were left over from last year's soybean crop and store it up for this year's corn crop.  When we kill the cover it will break down as "green manure" returning the nutrients they stored up back into the ground in a form that is readily available for this year's corn crop to consume.  Secondly, the cover creates more organic matter in the soil profile.  Water holding capacity increases as organic matter increases in the soil.  This organic matter causes the ground  to be more loose and tilthy in the spring.  This will help our corn crop as it sprouts and emerges from the ground.  During the summer months soil tends to get hard and hot the organic matter will have a cooling effect on the root zone layer of the soil.  This will be a welcome effect for the corn crop this summer.  Lastly, and most importantly all the residue on top of the soil helps hold the soil down to prevent erosion from rain and wind.