Location: Dairy Forage ResearchTitle: Interseeded alfalfa reduces soil and nutrient runoff losses during and after corn silage production
|OSTERHOLZ, WILLIAM - University Of Wisconsin|
|RENZ, MARK - University Of Wisconsin|
|JOKELA, WILLIAM - Retired ARS Employee|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/2018
Publication Date: 2/1/2019
Citation: Osterholz, W.R., Renz, M.J., Jokela, W.E., Grabber, J.H. 2019. Interseeded alfalfa reduces soil and nutrient runoff losses during and after corn silage production. Journal of Soil and Water Conservation. 74:85-90.
Interpretive Summary: First year yields of conventionally spring-seeded alfalfa are particularly low. Often yields are one-half that of subsequent full production years. One way to bypass the low yielding establishment year would be to interseed alfalfa into corn. This would jumpstart full production of alfalfa the following year. Researchers are developing workable and reliable methods for establishing alfalfa in corn by interseeding. In addition to improving forage yield, interseeded alfalfa could also serve as a cover crop for corn to reduce soil and nutrient loss from cropland. Results from rain simulator studies indicated alfalfa interseeding reduced runoff of both soil and nutrients by 37 to 87% during and after silage corn production. This is compared to a conventional system where alfalfa was spring seeded after corn silage. Therefore, alfalfa interseeding shows promise for both improving crop yields and for reducing soil and nutrient loss from cropland. We anticipate interseeding could be implemented on farms in northern states where alfalfa cannot be successfully established in the fall after corn silage harvest.
Technical Abstract: Interseeding alfalfa (Medicago sativa L.) into corn (Zea mays L.) harvested for silage is a method of establishing alfalfa that can increase overall forage production and may also help address the risk of soil and nutrient losses from corn silage production. Rainfall simulations in southwest Wisconsin were used to assess the runoff reduction benefits of alfalfa interseeded into silage corn. Simulations were conducted at three times: within three weeks of crop planting in early June, October following corn silage harvest, and the following April during alfalfa growth resumption. Compared to corn silage grown without an interseeded crop and followed by spring-seeded alfalfa, interseeded corn/alfalfa reduced losses of total suspended solids (49-87%), total N (37-74%), total P (37-81%), and dissolved P (40-74%) in every rainfall simulation. Additionally, total runoff volume and losses of dissolved solids and NO3- were reduced in the October and April events. Interseeded alfalfa enhanced total soil cover by 48-70% at the simulation times, which was negatively related to losses of total suspended solids.