Effects of different potassium fertilizer types and dosages on cotton yield, soil available potassium and leaf photosynthesis

A two-year field experiment was conducted to explore the effects of different potassium fertilizer types and dosages on cotton yield, soil available potassium and leaf photosynthetic capacity. The experiment included seven treatments: (1) No potassium fertilizer (Control); (2) potassium chloride (PC) applied at 126 kg ha(-1) (70% PC); (3) PC applied at 180 kg ha(-1) (100% PC); (4) potassium sulfate (PS) applied at 126 kg ha(-1) (70% PS); (5) PS applied at 180 kg ha(-1) (100% PS); (6) polymer-coated potassium chloride (PCPC) mixed with PS (ratio 7:3) applied at 126 kg ha(-1) (70% mix); and (7) PCPC mixed with PS (7:3 ratio) applied at 180 kg ha(-1) (100% mix). Under the same potassium application rate, the lint yield of the mix treatments increased by 4.48-9.38% compared with the other potassium fertilizer treatments . The yield and net profit of the 70% mix treatment were similar to 100% PS and markedly higher than 100% PC. In addition, the 70% mix treatment could still enhance the soil available potassium content and leaf photosynthesis. Overall study indicated that 70% mix treatment could be effective for cotton production.