Monday, November 5, 2007
19-11
Evaluating Electrical Conductivity Based Management Zones for Cotton Lint Quality.
Scott Stanislav, Texas A&M University - Agronomy Club, Texas A&M University, 370 Olsen Boulevard, College Station, TX 77843 and Cristine Morgan, Department of Soil & Crop Sciences, Texas A&M University, College Station, TX 77845-2474.
Cotton producers can maximize profits and yield by using soil electrical conductivity (EC) measurements to help manage fields. Using soil EC maps, producers can harvest by segregating high quality lint that scores premium prices from lower quality, lower priced lint. The project objectives are to 1) create a map of cotton lint-quality zones using soil electrical conductivity (EC) measurements; 2) test the usefulness of this map in irrigated and dryland cotton fields; and 3) determine a relationship between soil water variability and fiber quality. The selected site was Texas A&M University’s IMPACT center which is located nine miles west of College Station, TX in the Brazos River floodplain. In the 2006 growing season, 24 measurement locations were selected in a dryland and irrigated cotton field, 12 locations in each field. The sites were selected using a map of soil EC, three EC categories and four replications. At each location soil texture, soil moisture (weekly), and lint quality (AFIS and HVI) and quantity were measured. The measured soil textures ranged from sandy loam to clay. Lint yield in the irrigated field was higher than dryland yield. In the irrigated field the middle EC category had the highest yield, while in the dryland field the highest EC category had the highest yield. In the irrigated field the lowest EC category had significantly poorer lint quality, while in the dryland field the highest EC category had significantly better lint quality (p-value 0.05). The EC map responded to different soil textures, exhibited differences in water holding capacities, and indicated locations in each field with significantly different lint yield and quality, making EC maps a useful precision harvesting tool.