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Texas Agricultural Experiment Station and Texas Agricultural Extension Service
Principal Investigator:
William A. Payne
2301 Experiment Station Rd
Bushland, TX 79012
Telephone: 806-354-5801
Fax: 806-354-5829
w-payne@tamu.edu
Primary Research Location:
Bushland
Project Title:
PRECISION MANAGEMENT OPPORTUNITIES FOR A DRYLAND SORGHUM/WHEAT CROPPING SYSTEM IN A HETEROGENEOUS FIELD
Project Objectives:
1. Assess opportunities for differential management of dryland crops (sorghum and wheat) in a heterogeneous field
2. Evaluate the utility of modeling differential rates of soil evaporation and crop transpiration (which is linearly related to yield), and differential canopy temperature (a proxy for crop stress) across a spatially variable field
Reporting Period: January 1, 2001 – December 31, 2001
A fourth cropping season was completed. We now have two years of yield map data for both wheat and sorghum. Yield maps (Fig. 1) illustrate that the eastern side of the field tends to be less productive than the west. Our hypothesis is that this is largely a result of soil physical and hydrological properties. Transects running from east to west in the northern portion of the field have been measured for soil textural properties and soil moisture using neutron probes. Soil texture, illustrated in Fig. 2 for one depth layer, tends to become finer from east to west, suggesting greater water-holding capacity. Neutron probe data, used to calculate moisture storage in the upper six feet of soil, confirm that more moisture is held in the western portion of the field compared to the eastern portion (Fig. 3). In dryland agriculture, water availability is the most limiting factor to crop production.
Hydrological soil characterization and more detailed crop measurements will begin with this year’s sorghum crop. Once a post-doc is recruited, the modeling phase of this study will begin.
One Master’s Student at WTAMU
One Post-doctoral scientist (ongoing recruitment process).
Chen, Chengci, and W.A. Payne. 2001. Measured and Modeled Unsaturated Hydraulic Conductivity For a Walla Walla Silt Loam. Soil Science Society of America Journal 65:1385-1391
E. Precision agriculture proposals:Spatial Modeling of Regional Soil Water Balance from Remotely Sensed Data and Indigenous Knowledge to Predict Crop Stress and Mitigate Food Deficit in Niger: Funded for $105,000 ($35,000 per year for three years).
Chlorophyll Fluorescence, Canopy Temperature Depression and Reflectance in Visible Spectrum as Crop Stress Indicators of Wheat and Cotton under Semi-arid Conditions of Texas and Israel ($50,000 for one year; still waiting for this year’s RFP).
Attended the PA symposium at American Society of Agronomy Meetings, Charlotte, NC
G. Other developments: (Anything that impacted research progress, positive or negative)
The largest difficulty by far has been in recruiting a qualified post-doctoral candidate. This process began last October with an advertisement in CSSA news. Of about a dozen applicants, three were well qualified, and a fourth was marginally qualified. I am now in the final negotiating phases with the three well qualified candidates. All three are interested in coming, but none can come immediately because of professional or personal commitments. I’m pretty sure that this can be resolved sometime between late March and early June.
Figure
2. Soil texture along an east-west transect of the Bush farm for the
84-96 inch depth-layer. Because the eastern portion of the field tends
to be coarser than the western portion, it has greater water-holding
capacity.
Figure 3. Soil moisture storage in upper six feet
of soil along an east-west transect during the 2000-2001 growing season.
Storage tends to be greater in the finer-textured soil to the west,
where yields tend to be greater.
