Effects of partial replacement of potassium by sodium on cotton seedling development and yield

Potassium (K) deficiency can affect cotton (Gossypium hirsutum L) growth but sodium (Na) can share some functions with K. This study examined the effects of replacing K with Na at different ratios on cotton growth, nutrition uptake, and yield under greenhouse and field conditions. The results indicated that cotton germination rate, total dry weight, and nutrition absorption were affected by the replacement of K with Na. Increased early development appeared when replacing 1/3 K with Na. However, replacing K with 2/3 Na or completely with Na restrained cotton seedling growth and nutrition uptake. Furthermore, dry weights and levels of K and Na varied among the selected treatments at the different growth stages of seedling, first square, and peak bloom. Consequently, the highest final cottonseed yield appeared when K and Na were added at rates of 115 and 65 mg kg(-1), respectively, in the top 20 cm of soil. The results of this study imply that cotton growth and yield could be improved by adding appropriate amounts of K and Na.