Cover crops are nothing new to agriculture, but in these times of high commodity prices, competition, steeper land rents and inflated input costs, every bushel counts. It wasn’t long ago that producers/agronomists only looked at N-P-K and soil pH as of primary importance in raising the yield barrier.

The next emphasis came with micronutrient fertility (hopefully soil applied from my point of view). But our progressive and ever competitive agriculture industry is now looking more than ever at cover crops. Vetches, cereal rye, clover, tillage radish and more are all gaining momentum and are being more widely implemented in various crops in North America. Advantages of cover crops can range from reducing top soil erosion, reducing soil compaction, nutrient retention, suppressive weed control, building organic matter and more.

BENEFITS AND PROFIT

Often the cover crop of choice is selected by the planting equipment available on the farm, the harvestable crop to follow and the rotational benefit. Seed costs for cover crops are generally far less expensive than we have been accustomed to paying for traditional crops. And because of the lack of patents and GMO restrictions, often times a producer can harvest the cover crop seed and use it the following year. Although I am sure that is changing already and patents are being acquired and soon genetically modified cover crops will arise.

In general, many cover crops are not harvested and sold for profit, unless to provide the seed for other producers to use in a similar fashion. But an ideal cover crop would be one that could be harvested and sold for food/animal feed, or even biofuel feedstock and at the same time increasing yields or other benefits to the subsequent primary crop. Any crop that grows on arable land in the off season without mining the soils can be a great benefit.

RHIZOSPHERE MYSTERY

The most beneficial impact of a carefully selected cover crop to the subsequent mainstream commodities grown have more to do with the soil rhizosphere—the living component of top soil surrounding the root zone—than nutrients, compaction or weed control. The rhizospere is a complicated mystery that no scientist may ever be able to explain fully. And this rhizosphere changes dramatically depending on what plant species are being grown on that acre at any given time.

We have seen the results of what monoculture can do to diminish yields. The tricky part is to break the cycle using the right mixture of plant species, and at the same time not impede the proper planting window, weed control, increasing insect problems, etc. for the primary crop. And if additional revenue can be generated from harvesting the cover crop for profit, it’s icing on the cake.