Impact of sowing date and level of phosphorus application on economic returns in cotton

This study explored the economic dynamics of cotton (Gossypium hirsutum L.) production in Msilale village, Chato District, Tanzania. The experiment utilized a factorial design with sowing dates on November 25^th, December 15^th, and January 4^th, and phosphorus levels at 0, 20, 40, and 60 kg P ha^-1, replicated three times. Results indicated significantly higher cotton yields (6.1 t ha^-1 and 6.3 t ha^-1) for November and December sowings compared to January (3.8 t ha^-1). This is a 61% and 66% increase in cotton yields for November and December sowings, respectively relative to January sowing. Though not significant, 20 kg P ha^-1 and 40 kg P ha^-1 applications yielded 5.8 t ha^-1 and 5.4 t ha^-1, respectively, while 60 kg P ha^-1 yielded 5.3 t ha^-1. This is a 9.4% and 1.9% increase in cotton yields at 20 and 40 kg P ha^-1, respectively relative to absolute control and 60 kg P ha^-1 application. Economic analysis revealed that late sowing (January) had the lowest net profit (Tshs. 3,723,400 ≈ USD 1,486) and benefit-to-cost ratio (BCR) of 11.2. Early sowings recorded higher net profits (Tshs. 6,679,527 ≈ USD 2,666 and Tshs. 6,861,283 ≈ USD 2,738) and BCRs (18.4 and 18.8, respectively). This is a 79% (BCR = 64%) and 84% (BCR = 68) increase in net benefits from early sowings compared to late sowing. Applications of 20, 40, and 60 kg P ha^-1 resulted in net benefits of Tshs. 5,452,572 ≈ USD 2,176 (BCR = 19.2), Tshs. 5,209,904 ≈ USD 2,079 (BCR = 15.1), and Tshs. 5,748,786 ≈ USD 2,294 (BCR = 14.1), respectively, with a significant (p = 0.017) BCR at 20 kg P ha^-1 indicating cost-effectiveness. This is a 36% and 7.1% economic benefit at 20 and 40 kg P ha^-1, respectively compared to 60 kg P ha^-1 application. Optimizing sowing dates and P levels can boost economic returns in cotton production and promote sustainability.