Plant growth regulation enhanced potassium uptake and use efficiency in cotton

Abstract

The effects of plant growth regulators (PGRs) and potassium (K) fertilizer on cotton (Gossypium hirsutum) yield have been well documented but the role of PGRs on K use efficiency is poorly understood. Our specific objective was to determine whether foliar application of PGRs could improve K use efficiency in field-grown cotton. Field experiments were conducted with or without K at two sites (Beijing and Hebei, China) varying in available soil K during 2010 and 2011, with cotton cvs. Guoxinmian3 (GX3) and SCRC28 as test materials. Foliar application of the PGRs, mepiquat chloride (MC) and Miantaijin [MTJ, a combination of MC with diethyl aminoethyl hexanoate (DA-6)] during squaring and flowering periods significantly increased the lint yield and K uptake in most situations at Beijing location and had a consistent tendency to increase lint yield across K fertilizers and years at Hebei location. The partial factor productivity (PFPK) and agronomic efficiency of K (AEK) were enhanced by the application of the PGRs in most situations in Beijing, especially in 2011 and for the cultivar GX3. Although differences in the apparent recovery efficiency of K (REK) between PGRs and control were not significant, a positive and consistent effectiveness of PGRs on REK was observed across sites, years and cultivars. Therefore, the application of PGRs would be a useful practice for improving K nutrition and lowering the cost of K fertilizer input in cotton production.