Quantifying the effects of irrigation, nitrogen application rate, and plant growth management on seed characteristics and seed component yields in cotton

Abstract

Cotton ( Gossypium hirsutum L.) growth and production are affected by irrigation management approaches, nitrogen (N) application rates, and plant growth regulation strategies. However, their combined effects on cotton seed composition and yield remain understudied. The objective of this experiment was to investigate how irrigation, N application rate, and mepiquat chloride (MC) application strategy interact to affect cottonseed oil and protein concentrations and seed, oil, and protein yields. The study was conducted in 2022 and 2023 using a split‐split plot design. When N effects were observed, N fertilization positively affected seed yields (kg ha ⁻¹ ), protein percentage, and oil and protein yields. When irrigation effects were documented, irrigated cotton produced higher seed yields, oil percentage, and oil yields than dryland. Conversely, protein percentages were increased under yield limiting drought, and protein yields were unchanged. In 2022, there was a significant interaction between N and MC for seed and oil yield, where MC application maximized yields under N fertilization but had no effect under N deficiency. In 2023, a significant interaction between irrigation and N was observed for oil and protein concentration, where oil concentration declined with increasing N rates under dryland conditions but was unaffected by N rate under irrigated conditions. Conversely, protein percentage increased with N rate under dryland conditions. Producers can apply this knowledge to enhance seed composition and the yield of seed, oil, and protein. This work may also have implications for seed or seedling vigor as planting seed composition can be a strong indicator of stand establishment.