Response of Cotton (Gossypium Hirsutum L.) to Phosphorus Levels and Irrigation Intervals

Exploring proper phosphorus level and irrigation interval which enhances cotton production and lint quality was the basis of this research. A field study was conducted in Dera Ismail Khan, Pakistan during 2016 to assess the impact of irrigation interval and phosphorus rates on cotton grown under reduced tillage system (one tiller followed by one rotavator at 7–10 cm depth). Five irrigation intervals (7^th, 10^th, 13^th, 16^th and 19^th day) and phosphorus levels (0, 50, 100, 150 and 200 kg P2O5 ha^-1) were kept in main- and subplots, respectively in RCBD with split plots arrangement with three replications. Results revealed that irrigation intervals significantly affected all the parameters such as plant height, sympodial branches, seed cotton yield, and quality-related traits such as fiber length, fiber strength, micronaire, and fiber uniformity. Frequent irrigation interval (7^th day) produced taller plants (139 cm) and more sympodial branches (18.3) compared to less frequent irrigations (10- 19^th day). However, 19th day irrigation interval significantly improved seed cotton yield and fiber quality traits (fiber length, fiber strength, micronaire, and fiber uniformity). Likewise, phosphorus at 150 kg ha^-1 significantly improved seed cotton yield (3794 kg ha^-1) and ginning out turn (39.1%) compared to other phosphorus levels. In conclusion, P at 150 kg ha^-1 with 19 days irrigation interval optimized yields and quality attributes.