Cotton yield and water productivity responses to fertilizer application strategies under drip and furrow irrigation

Abstract Upland cotton ( Gossypium hirsutum L.) production in the Samarkand province is dependent on irrigation. Although reduced irrigation requirements under drip compared with furrow irrigation can partly address water scarcity problems in the region, cotton fertilizer requirements likely vary in response to irrigation method. In a 3‐year field study, we examined the yield response of upland cotton to furrow and drip irrigation under conventional on‐farm and improved nutrient (nitrogen, phosphorus, and potassium) split application methods at two rates: 150, 105, and 75 kg ha −1 and 200, 140, and 100 kg ha −1 of N, P, and K, respectively. Irrigation method significantly influenced seed cotton yield in 2 years ( p ≤ 0.039), with drip irrigation having greater seed cotton yields in all 3 years. Drip irrigation water productivity was 74% greater than furrow irrigation and saved an average of 3000 m 3 ha −1 year −1 . Improved fertilizer application methods significantly increased yield in all study years ( p ≤ 0.013) with a greater yield response to application method under drip (0.69 t ha −1 ) compared with furrow (0.29 t ha −1 ) irrigation. Improved fertilizer application methods also significantly increased first harvest boll weights and 1000‐seed weights. Seed cotton yield significantly responded to the high fertilizer rate ( p ≤ 0.012) in two of the study years. Optimal fertilizer strategies varied with irrigation method, with potentially lower requirements under drip irrigation compared with furrow irrigation. Use of drip irrigation may offer a way to not only reduce irrigation requirements but also nutrient inputs for cotton production in the Samarkand region.