State-Space Description of Field Heterogenity: Water and Nitrogen Use in Cotton

Date

2002

Authors

Segarra, Eduardo
Bronson, Kevin F.
Wilson, L.Ted
Booker, Jill
Lascano, Robert J.
Li, Hong

Journal Title

Journal ISSN

Volume Title

Publisher

The Soil Science Society of America

Abstract

Field heterogeneity in soil texture and site elevation (SE) may affect crop water and N use. A 2yr (1998-1999) study was conducted on the Texas High Plains to determine the interdependence between management (irrigation and N fertilization), soil heterogeneity (texture, soil water, and N03-N) and topography, and their impact on cotton (Gossypium hirstum L.) lint yield and N uptake. Treatments were irrigation at 50 and 75% estimated cotton evapotranspiration (ET) and N rates at 0, 90, and 135 kg ltu-1, Soil water content (SWC), lint yield, N uptake, and N fertilizer recovery, measured us II function of management and space, were higher on low positions. Mixed model analysis showed that irrigation was significant on SWC, lint yield, and N uptake (P < 0.05) each year. The N treatment had no effect on lint yield or N uptake in 1998 because of high soil residual NOJ-N. and the model residual was significant for 011 measured variables (P < 0.0001). Sand, SWC, lint yield, and N uptake were negatively correlated with SE (r 2: -0.64). In 1998. lint yield, SWC, clay, sand, and SE were cross correlated within 60 to 80 m. Multivariate statespace analysis showed that lint yield at position i was weighted on lint yield, SWC, clay, sand, and SE at previous position i - 1. It is concluded that 75% ET and N rate at 90 kg ha-1 would be the basis to consider variable water and N rates related to field conditions, and the state-space model quantified spatial interdependence between irrigation, fertilization, and field heterogeneity.

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Citation

Li, J., R.J. Lascano, J. Booker, Jr., L. T. Wilson and E. Segarra. "State-Space Description of Field Heterogeneity: Water and Nitrogen Use in Cotton." _Soil Science Society of America Journal_ 66.2 (2002):585-595.