Optimal planting density and sowing date can improve cotton yield by maintaining reproductive organ biomass and enhancing potassium uptake

Cotton is the fifth major oil crop and grown primarily for natural fiber globally. Suitable management practices like planting density (PD) and sowing date (SD) are the major drivers of cotton crop productivity. Cotton production with a normal practice of 3 plants m−2 in Yangtze River Valley China, resulting in an average yield of 1200 kg ha−1 although, high input costs and low productivity are the two major consequences in cotton production systems. The production costs can be decreased and profits can be increased through optimal PD and adjusting SD. The objectives of this study were to optimize growth, yield, biomass partitioning and potassium (K) distribution of a cotton crop under a short growing season and elevated PD. Experiments were conducted with two sowing dates i.e. early (S1, May 20 and late S2, June 04) as the main plot and three plant densities (D1, low 7.5; D2, moderate; 9.0 and D3, high; 10.5 plants m−2) as the subplot laid out in a split arrangement with four replicates. D3 crops significantly delayed cotton growth period under late sowing date compared with early planted crops. Compared with S2 crops, S1 plants produced 29% and 26% higher seed cotton and lint yield, respectively. Among the PD, D2 plants produced 12%, 15%, 13% and 6% more seed cotton yield and lint yield over D1 and D3 crops respectively. The increment in yield was due to increased plant reproductive organs biomass occasioned by moderate density and longer cropping season which allowed the utilization of available resources. Higher K acquisition i.e. (0.9 VM kg ha−1d−1), further improved reproductive structures formation in S1 combined with D2 crops. The S1 in combination with D2 crops resulted in the highest average (77 VT kg ha−1d−1) and maximum (93 VM kg ha−1d−1) rates of reproductive organs biomass accumulation than other combinations. Conclusively, use of medium density under both sowing dates is an effective strategy for optimal seed cotton and lint yield.