Evaluation of cover crop species and seeding practices

The cover crop managment trial was initiated at SWROC in Fall 2002 to compare the performance of two grass/legume mixtures seeded with various practices. The objectives of the project are to determine:

a) whether either grass/legume mixture provides superior cover crop establishment, biomass production and N contribution

b) what seeding practice allows superior cover crop establishment

c) how soybean yield following corn is affected by each grass/legume mixture and seeding practice

Grass / legume mixtures of winter rye / hairy vetch and annual ryegrass / red clover will be evaluated in the experiment. Cover crops will be seeded at three dates, each of which will require a unique seeding practice. Crops seeded in late June will be broadcast with a drop-seeded and incorporated during the final row cultivation. Crops seeded in early August will be broadcast from a spin-seeder mounted on a “high-boy” and left unincorporated. Crops seeded following corn harvest in early October will be seeded into the standing crop residue using a no-till drill.

Cover crop establishment will be measured 14-20 days after each planting date. Plants will be measured in late fall to determine the number of individuals that survived during summer. Plants will be counted again in spring to determine winter mortality. Cover crop biomass samples will be harvested immediately prior to incorporation the following spring and used to estimate organic matter and nitrogen contributions to soil.

Multiple factors will be used to understand soybean performance following the different grass/legume mixtures and seeding practices. Soybean stand will be measured in late June to determine whether allelopathy from the cover crops may be a factor. Soil moisture will be measured regularly during the summer to determine whether cover crops contribute to dry soil conditions. Weed population and height will be measured to determine cover crop effects on those species. Finally, soybean grain yield will be measured.

Researchers:

Craig Sheaffer, University of Minnesota Department of Agronomy and Plant Genetics

Funding:

USDA – CREES