Research Project Year: 2014-2018
Corn silage is a primary source of feed on most New England dairy farms, and feed is the largest annual expense. The corn growing season spans mid-May through early-October, with variation according to weather, region, and the maturity period (days to harvest) of the corn that the farmer selects. Corn planted in Massachusetts ranges from 85 days to maturity to well over 114 days to maturity.
Following the corn harvest, farmers will spread stored manure onto their fields to make space to store manure that will accumulate over the coming winter months. Before or after the manure application, farmers will ideally plant a cover crop. Cover crops are typically not harvested for profit, and rather serve to protect the soil until the following spring, when corn will again be planted.
By selecting corn varieties that reach maturity earlier in the fall, farmers can harvest corn in early September and plant their cover crops earlier. Planting the cover crop earlier means better soil protection and improved nutrient capture from the fall-applied manure, especially environmentally-important nitrogen and phosphorous. Improving nutrient capture and protecting the soil results in better nutrient cycling on farm, which in turn provides both environmental and economic sustainability.
In order to make these management practice adjustments more desirable and worthwhile to growers, we are studying ways in which to manage the fall cover crop so that it can also be harvested as high quality forage in the spring. By doing so, several goals are achieved:
1. Increased feed production
This system is referred to as Dual Purpose Double Cropping. In this case, the winter cover crop serves the “dual purpose” as a cover crop and as feed, and the “double cropping” means harvesting the corn and the cover crop in one year, instead of only a single crop of corn.
2. Reduced reliance on corn, and improved resiliency to both the economy and the environment
Due to a changing climate, the summers are hotter and drier. Silage corn is not irrigated, and is dependent on summer rainfall; in the event of a drought year, farmers risk not producing enough feed to last the winter, and must spend money to purchase feed. By managing the cover crop as a feed crop, farmers can reduce their risk of relying primarily on corn and can save money by not having to purchase feed.
3. Increased nutrient capture
Planting cover crops earlier gives the plants more time to grow in the fall before the days become too short and cold to support growth, at which point winter-hardy crops (i.e. rye, wheat, triticale) will go dormant for the winter. The more time these plants have to grow in the fall, the more nitrogen and phosphorous they can accumulate from the soil before the nutrients are lost to the environment.
4.Compliance with state nutrient management regulations
Current state regulations require that manure is applied before September 15; if manure is applied after September 15, the manure must be applied to a living, growing crop (i.e. a cover crop, pasture, or hayfield).
We are identifying the specific details of planting, fertilizing, and harvesting winter-hardy cover crops, rye, wheat, and triticale, in order for them to be suitable as feed crops. Our results suggest an additional 2-4 Tons of Dry Matter per Acre can be harvested in this dual-purpose double cropping system, while also catching 60+ Pounds of Nitrogen per Acre and 40+ Pounds of Phosphorous per Acre that could otherwise be lost to deep soil, ground water, and the atmosphere.
We are also investigating the field management practices required to terminate the cover crop and plant the summer corn crop. This includes tillage practices, herbicide requirements, and corn fertilization needs.
The success of the system is measured in terms of total yield, total milk production, nutrient capture, ecosystem services (such as improving soil health and avoiding negative environmental impacts), feasibility of management, no negative impact of the cover crop on subsequent corn production, and overall economic value.