Rolling hill topography is common in agricultural land throughout the Southeastern United States. In areas of complex topography, downslope movement of soil nutrients and water can lead to nutrient losses and soil degradation, as well as spatial yield variability. Additionally, differences in the accumulation of water, slope aspect, and crop biomass production can lead to disparate conditions of soil moisture and soil temperature throughout a given field. Winter cover crops can reduce erosion and mitigate nutrient losses, while also potentially providing a source of nitrogen (N) to the subsequent cash crop as the cover crop residue decomposes. However, given that moisture and temperature at the soil surface are primary controls on residue decomposition, topographic heterogeneity may lead to variable rates of cover crop breakdown and N return to the system. We investigated the effect of landscape position on soil volumetric moisture and temperature at 5 cm depth, and the decomposition and N release rate of two cover crop residues, a sole-seeded cereal rye (Secale cereale L.) cover crop, and a cereal rye/crimson clover (Trifolium incarnatum) mixture over two maize (Zea mays L.) growing seasons in Lexington, KY. We found differences in soil moisture and soil temperature across landscape positions, with backslope positions tending to be the warmest and driest positions, and toeslope positions tending to be wettest. However, we did not observe significant differences in decomposition or residue N release rate among landscape positions or cover crop treatments. Our results emphasize the inherent variability present in abiotic factors in rolling hill cropland but indicate that cover crop residue persistence and N release are relatively consistent among landscape positions.
|Journal||Agriculture, Ecosystems and Environment|
|State||Published - Oct 15 2021|
Bibliographical noteFunding Information:
This work was supported by the University of Kentucky College of Agriculture Food and the Environment , the University of Kentucky Department of Plant and Soil Sciences , the Southern Sustainable Agriculture Research and Education Graduate Student Grant [ GS19–231 ], the United States Department of Agriculture National Institute of Food and Agriculture Grant Number [ 2020-67013-30860 ], the Kentucky Corn Growers Association, and the Karri Casner Environmental Sciences Fellowship .
© 2021 Elsevier B.V.
- Cereal rye
- Crimson clover
- N release
ASJC Scopus subject areas
- Animal Science and Zoology
- Agronomy and Crop Science