Cover Crop Biomass Affected by Topographical Features and Its Relationship with Row-Crop Yields.

The use of cover crops in rotational agricultural systems is becoming popular due to its promising benefits to the soil quality and subsequent row-crop. However, scarce information is available for cover crop performance under different topographical scenarios. We hypothesize that cover crop biomass is affected by landscape positions, thus plant residues and its effect will be spatially variable. Since the relationship between row crop yields as affected by topography and biomass depositions of cover crops is not well studied yet; the objectives of this study are to describe the spatial relationships between topography, cover crop growth and corn yield in a rotational system and to identify whether these relationships are relevant or not under this agro-system. The study was conducted in the Kellogg Biological Station, Michigan. Five fields were used in the first year and four fields were used in the second year. Red clover biomass measurements were collected at random points within each field at three phenological stages. Corn biomass was collected at random points at V8 stage, whereas corn yield was available via yield monitor. Topographical classification was performed for three positions (summit, steep slope and depression). Random coefficient analysis and ANOVA were used to analyze the data. Results indicate that topographical features partially describe the variability in clover biomass; however these results highly depend on the phenological stage and particular field. Wetness index was positive correlate to clover biomass in most of the fields, indicating the importance of water dynamics in plant growth. Multiple linear models for each field indicate that corn yield is moderately affected by topographical features, particularly by wetness index, relative elevation and flow length. By the time of the conference, relationship between corn yield, topography and red clover biomass will be presented using random coefficient models and ANOVA for three topographical positions.