The fact is with tight margins a new practice has to show economic gain as well. We can't buy the seed, plant or hire it seeded, and manage another crop without added costs. We have to figure out how to make cover crops pay for themselves by either saving on fertility costs for the next crop and or increasing yields to offset the cost of growing the cover crop. There is no doubt that cover crops reduce erosion during the winter months compared to bare fields with nothing growing on them. It is hard to quantify that gain with a monetary value. The University of TN is currently conducting research to give farmers a guide on what the soil savings is worth on our crop budgets. It's worth a lot to our family and the owners of farms we lease. Without the soil it is impossible to grow crops for a living.
Our cover crop mix this year included 5 species. Winter Peas (the large round seed) and Crimson Clover (the small yellow looking seed) are legumes. They "fix" or create nitrogen in the soil for the next crop, which will be soybeans in this particular field and corn in the other fields, next spring. Cereal Rye (the green tinted long seed) and Oats (the longest yellow seed) once established scavenge nutrients and help hold the soil down and reduce erosion when it rains during the winter months. The smaller red round seed is the Tillage Radish. Theses radishes work hard in the soil. They scavenge excess nutrients left in the soil from the previous crop. They will grow a large underground tuber that will store these nutrients. As the tuber grows it will help reduce compaction in the soil and loosen the soil for spring crop roots to penetrate deeper into the soil profile giving them access to more moisture during the growing season. These seed may be small but they are giving us BIG results and are working hard.
Once established the cover crop species begin to grow and spread out across the fields. The picture below shows the species well. The radish is the biggest plant. The rye and oats look like grass. The winter pea is directly behind the radish. The clover can be seen in the background close to the ground. The residue from the previous corn crop is there to act as a barrier to reduce erosion also.