|Zhu, Qing - Chinese Academy Of Sciences|
|Schmidt, John - Pioneer Hi-Bred, Inc|
Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2014
Publication Date: 3/5/2015
Citation: Zhu, Q., Schmidt, J.P., Bryant, R.B. 2015. Maize (Zea mays L.) yield response to nitrogen as influenced by spatio-temporal variations of soil-water-topography dynamics. Soil and Tillage Research. 146(B):174-183. doi:10.1016/j.still.2014.10.006.
Interpretive Summary: An improved understanding of the spatial-temporal variability of corn yield response to nitrogen (N) will help farmers meet economic and environmental objectives and was the focus of this study. For a hillslope in the Ridge and Valley region of Pennsylvania, the spatial variability of corn yield response to N fertilizer was significantly affected by soil silt content, soil depth, profile curvature, slope percent, soil wetness, and soil moisture temporal stability – an indicator of below surface soil water contributions. Nitrogen fertilizer applications to corn can be improved by developing site-specific N recommendations that incorporate indicators of soil variability, topography, hydrology, and recent weather conditions; realistic expectations given the availability of GPS and GIS technologies.
Technical Abstract: Reducing nitrogen (N) loss from agricultural lands and applying N fertilizer at rates that satisfy both economic and environmental objectives is critical for sustainable agricultural management. This study investigated spatial variability in maize yield response to N and its controlling factors along a typical agricultural hillslope in the Northern Appalachian Ridge and Valley Physiographic Province in the USA. Spatial variation of soil, topography and soil moisture along the hillslope were determined through electromagnetic induction surveys, digital elevation model, and soil moisture monitoring. Minimum, maximum, and delta yields and optimum N rate at different slope positions were determined using quadratic-plateau maize yield - N rate models. Results from 2008 and 2009 indicate that spatial variability of maize yield response to N was influenced by silt content, soil depth, profile curvature, slope percent, soil wetness and soil moisture temporal stability. In both drier and wetter years, optimum N rates increased with temporal variation of soil moisture, which is an indicator of soil water contributions from subsurface flow paths. In the drier year of 2008, maize yield was little varied along this hillslope (11.7-12.0 Mg per ha), while greater yield response to N (represented as delta yield) was observed in upper convex and steep slope areas with low minimum yield. However, in the wetter year of 2009, greater maize yield and yield response to N were observed in lower concave slope areas with deeper soil depth and thus greater water and nutrient storage. Results from this study illustrate that site-specific N fertilizer applications could be improved by incorporating within field variability of soil, topography and hydrology with the yearly variation of weather condition.