A Precision Agriculture Approach to Managing Cotton Fiber Quality as a Function of Variable Soil Properties

Abstract

Cotton producers can maximize yield and fiber quality by understanding soil variability throughout the fields, thus receiving premium prices for the cotton lint. A better understanding of how soil water holding capacity affects cotton lint yield and quality can result in improved management practices that can maximize fiber quality while minimizing inputs. The objectives of this study were to 1) create management zones using a soil ECa map, 2) test the usefulness of this map using measurements of lint quality and lint quantity in both irrigated and dryland fields, and 3) determine a relationship between soil water holding capacity fiber quality parameters. 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 and 2007 growing seasons, 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 ECa, three ECa categories and four replications. At each location soil texture, soil water holding capacity, and lint quality (HVI) and quantity were measured. The ECa categories successfully identified significant differences in clay content water holding capacity, lint yield, lint quality, and loan values. The 2006 season was relatively dry. Weather, soil variability, and management affected the yield and yield quality responses. Water availability was not a factor for lint yield or quality in 2007. In this situation, the soil was the primary factor for field heterogeneity. The cotton yield still responded to soil variability but lint quality and loan value was uniform. The uniformity of lint quality and non-uniformity of lint quantity leads to the conclusion that these soils have individual yield thresholds, but without water stress the quality threshold is uniform. This conclusion illuminates opportunities for precision management strategies. One management strategy that may result from this work is to reduce seeding rates in lower production areas of the field, if the plants will compensate for yield to still reach the soils yield potential, perhaps less competition for water would improve lint quality.