Importance of Spatial Variability in Soil Properties to Spatial and Temporal Cotton Leaf N Status. (S08-varco565234-oral)
Authors:
J.J. Varco* - Mississippi State Univ.
D.M. Emerine - Mississippi State Univ.
Abstract:
The utility of variable fertilizer N application is dependent on a comprehensive understanding of factors influencing available soil N and crop needs. Our objective was to determine relationships governing spatial variability in N availability in soils derived from Mississippi River alluvium. A 26.3 ha field was mapped on a 0.2 ha grid and soil and plant samples were collected at the center of each grid. Soils samples were obtained after planting to a depth of 0.60 m and were analyzed for sand, silt, and clay contents, and ammonium and nitrate. Recently matured cotton (Gossypium hirsutum L.) leaves were sampled at early squaring, early flowering, and peak flowering stages of growth for total N analysis.
Spatial structure was determined and values were kriged to develop prediction maps. Early season available N increased with increasing silt content, decreased with increasing clay content, and was not influenced by sand content. Soil available N content influenced leaf N at all sampled stages of growth.
Leaf N was most strongly related to silt content at early squaring, clay content at early flowering, and sand content at peak flowering. Increased N fertilization efficiency may be possible through variable rate application based partially on the spatial structure of soil texture and at planting available N content on these soils.
Speaker Information: Jac Varco, Mississippi State Univ., Dept. of Plant and Soil SciencesBox 9555, Mississippi State, MS 39762; Phone: 662-325-2737; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 10:25 AM-12:15 PM Presentation Start: 11:30 AM
Keywords: Spatial variability; Available Soil N; Kriging of Soil properties; Leaf Tissue N Status
