Cotton Lint Yield Variability in a Heterogeneous Soil at a Landscape Scale

Li, H¹.  R.J. Lascano¹, J. Booker¹, L.T. Wilson², and K.F. Bronson¹

¹Texas A&M University, Texas Agricultural Experiment Station, Lubbock , Texas

²Texas A&M University, Texas Agricultural Experiment Station, Beaumont , Texas

Abstract

A landscape-scale study was conducted in a centre pivot irrigated field on the southern High Plains of Texas, USA in 1999 to assess soil water, soil NO3-N, cotton (Gossypium hirsutum) lint yield, and N uptake variability in the landscape, and to determine the spatial correlation between these landscape variables using a state-space approach. The treatments were irrigation at 50 and 75% cotton potential evapotranspiration (ET). Neutron access tubes were placed at a 15-m interval along a 710 m (50% ET) and 820 m (75% ET) transect across the field. Soil NO3-N in early spring was autocorrelated at a distance varying between 60 and 80 m. Measured soil volumetric water content (WC), total N uptake, and lint yield were generally higher on lower landscape positions. Cotton lint yield was significantly correlated to soil WC (r=0.76), soil NO3-N (r=0.35), and site elevation (r=-0.54). Differences of site elevation between local neighbouring points explained the soil water, NO3-N and lint yield variability at the micro-scale level in the landscape. Soil WC, cotton lint yield, N uptake, and clay content were crosscorrelated with site elevation across a lag distance of plus or minus 33-40 m. The state-space analysis showed that cotton lint yield was positively weighted on soil WC availability and negatively weighted on site elevation. Cotton lint yield state-space models give insights on the association of soil physical and chemical properties, lint yield, and landscape processes, and have the potential to improve water and N management at the landscape-scale.

Reference:  Li Hong, R.J. Lascano, J. Booker, L.T. Wilson, and K.F. Bronson.  2001.  Cotton lint yield variability in a heterogeneous soil at a landscape scale. Soil & Till. Res. 58: (3/4):245-258.