Cotton cultivar response to potassium fertilizer under irrigated and dryland conditions

Abstract

Cotton (Gossypium hirsutum L.) cultivars vary in their response to environmental factors. Recently, interest in cotton cultivars' response to varying potassium (K) fertilizer application rates and irrigation has increased. As such, the effect of cotton varieties (early and mid‐maturing), K fertilizer application rates, and irrigation on cotton growth, development, and yield were investigated in Starkville, MS, on two soil mapping units (SMUs): a Leeper silty clay loam (LSCL) and a Marietta fine sandy loam (MFSL). Cotton plant height was positively correlated with SMU, especially LSCL, reaching 60–110 cm on average, in both irrigated and rainfed conditions. Cotton lint yield, fiber quality, and leaf K concentration responded to K and irrigation, and these responses were SMU specific. Particularly, in LSCL, the early‐maturing cultivar, DP 1518 B2XF, responded to K application rate in a positive linear manner in terms of lint yield under both irrigated and rainfed conditions, whereas mid‐maturing DP 1646 B2XF did not. Moreover, lint yield in irrigated MFSL soil increased with K application rate, whereas no responses were observed in rainfed conditions. These data suggest that irrigation, SMU, and cultivar combination could have an impact on K response of cotton and should be considered when making fertility recommendations or decisions.