Winter Cover Crops Offer Opportunities and Challenges

Cover crops are a lot like apple pie and motherhood. Everyone is in favor of them, but too much apple pie will get you in trouble and motherhood has its own set of consequences.

The value of cover crops is beneficial ground cover during the off season, erosion control, improved soil health, weed control, sequestering of excess soil nitrogen and the potential of another “crop.” The down side is they add complexity and risk, they might require additional equipment and they can add cost.

Your climate has a major impact on any cover crop system. The further south, and a longer growing season, allows more time to fit another crop in your farming system. In northern areas, the time from a corn silage harvest to the end of the growing season window may be too short to get the manure applied, crop established and have time for sufficient growth to produce a productive forage crop. What works one season might not happen every year.

Cropping decisions include the selection of cover crop, varieties, seeding rates and methods, timing following prior crop harvest and manure application. In northern areas, some modification of the prior crop may be necessary to accommodate the establishment of the cover crop.

Spring considerations include harvest timing, equipment selection and managing of field conditions. Fields must be in condition to get harvest equipment over them during the spring time harvest period.

The most popular cover crops

The most popular crops for cover crops are cereal rye, winter triticales and in some cases, winter wheat. There are some mixes and blends used in local areas with varied results.

Most likely, winter triticales have the best potential for forages from a yield and quality standpoint. It is important to get them planted as soon as possible in the fall to encourage vigorous fall growth. This will get them going in the spring for lush, leafy growth.

The nature of cereal grains is that they develop very quickly as the spring growing season progresses. The target growth stage for forage harvest is just as the stem elongates during the pre-boot stage. The window between vigorous growth and the heads starting to emerge can be very short, and if it occurs during a period of adverse weather conditions it can be problematic. It can go from a good forage crop to mostly straw in a very few days.

It is critical to be able to manage the harvest window, be prepared to act quicly and have a backup plan if weather and harvest conditions go bad. An out of control cover crop can be a disaster for the subsequent corn silage crop. If it causes a delay in planting the corn crop, the losses in silage yield may be more than the gain in feed tonnage from the cover crop.

Storing the crop

Storage management needs special attention. The crop will likely be of limited tonnage and needing a dedicated silage location. There is a high probability that the feed may be high moisture causing excess leachate and poor storage conditions. However, due to the drying characteristics of cereal grains, they may quickly become over dried before harvest is completed during any one day. Often producers opt to use silage bags as an alternate storage system.

Feeding protocols often depend on how much feed is harvested, the feed composition, its quality and what is the normal forage base of the diet. If it is appropriate to become a major ration ingredient, then the normal ration balancing techniques need to be used. The decision of what group to feed it to is often driven by feed quality and inventories.

Often the feed becomes a minor ingredient in the ration, and feed out rates become an issue to maintain feed quality at the storage area. If it becomes an issue to stretch supplies, then feed-out would be dictated to meet the time versus inventory needs. 

 

Note: This story appears in the June 2017 issue of Dairy Herd Management.

Comments