Penn State University | 4/2/2019 | Via ScienceDaily
Dairy farmers in the Northeast can improve water quality and boost the profitability of their operations by changing the timing and method of applying manure to their fields in the fall, along with planting rye as a cover crop between corn crops — or by double-cropping rye and corn, according to Penn State researchers.
In a two-year study at Penn State’s Russell E. Larson Agricultural Research Center, researchers compared the effects on nitrogen conservation of three field-management options that could be implemented by farmers, to determine whether new strategies would yield environmental and crop-production benefits.
In a “three-factor factorial experiment,” researchers compared injecting manure into the soil versus broadcasting it on the surface; planting rye as a winter cover crop versus allowing the rye to grow longer in the spring and harvesting it as forage; and applying manure before the cover crop is planted in September — after the harvest of corn for silage — versus waiting until November to apply the manure into the established rye crop.
The results indicate that dairy farmers can take advantage of win-win opportunities, according to Heather Karsten, associate professor of crop production ecology. By incorporating a few changes into their operations, they can produce more feed for their cattle and reduce the amount of nitrogen lost from their fields.
Karsten, whose research group in the College of Agricultural Sciences conducted the study, pointed out that the research is rooted in both practical and environmental considerations: Dairy farmers typically are limited to six months of manure storage, requiring them to apply manure spring through fall. But in the fall, there is a higher risk of water quality impairment if manure is applied to bare ground and can be washed into streams by precipitation.