Relationships between Cotton Lint Yield, Fiber Quality, and Soil Apparent Electrical Conductivity

Soil ECa (apparent electrical conductivity) is proven to be useful in capturing the in-field variation of soils. Soil attributes that affect ECa include clay content, water holding capacity, salinity, organic matter, etc. A multi-year, multi-field study was conducted to quantify the relationships between cotton lint yield and fiber quality and soil ECa. Spatially exhaustive ECa surveys with an EM-38 sensor and Differential GPS were carried out in these research fields. The lint yield information was estimated by two means: (1) yield monitor data followed by proper calibration if a cotton yield monitor was available during harvest, and (2) weighing hand-harvested cotton samples from known-size sampling locations (e.g., 1/1000 ac) across the fields. The hand-harvested cotton samples were also sub-sampled and analyzed with an HVI testing line for fiber quality determination. Simple linear regression analysis and geostatistics were used to quantify the relationships among these variables. The results showed that, though not consistent over years, significant relationships between yield and fiber quality parameters and soil ECa existed in each field. A large portion of variation in both lint yield and fiber quality parameters could be explained by soil ECa. This study demonstrated that ECa could be an effective tool for site-specific crop management in cotton production.