Nitrogen Fertilizer Rates can be Lowered without Compromising Cotton Yield under Drip Irrigation System

Abstract

The effects of reducing N fertilizer use on soil NO3--N content and cotton yield were studied through a three-year (2015 to 2017) field experiment in South Xinjiang of China. Cotton was sown under drip irrigation system using five N fertilizer reduction treatments as: conventional N application rate (N100), N application rate reduced by 16.67% (N-16.67), 33.33% (N-33.33), 50% (N-50), and 100% (N-100). The data were recorded for changes in soil NO3--N content, and the SPAD value of cotton leaves was recorded at the peak bolling stage. The total N content of the plant was recorded at the boll formation stage, while yield was recorded at maturity. The results revealed that the soil NO3--N content in N-16.67, N-33.33, N-50, and N-100 treatments decreased by 10.8, 45.5, 60.7 and 72.3% compared to N100 treatment, respectively. The SPAD values of N-16.67 and N-33.33 treatments were significantly higher than those of N100 treatment, while the SPAD values of N-50 and N-100 treatments were significantly decreased. The total N content of cotton was significantly decreased with the increase in the proportion of N fertilizer reduced. The seed cotton yield in N-16.67 and N-33.33 treatments increased by 9.2 and 7.9% compared to the N100 treatment, respectively. However, the cotton yield decreased significantly when the N application rate was reduced by 50 and 100%. The relationship between the N fertilizer reduction rate and cotton yield suggested that the N application rate can be reduced by 18.47–45.50% without compromising the cotton yield in South Xinjiang of China. © 2021 Friends Science Publishers

Effect of nitrogen application on nitrogen leaching pattern and leaching loss from drip irrigated cotton fields in Southern Xinjiang

“…Nitrogen fertilizer was not applied for the first watering and the last watering of the crop. Besides, techniques such as topping, pest control, use of chemical regulators etc.were consistent with those that are adopted in previous studies [15,17].…”

“…Before sowing the seeds, the mixture of base fertilizers was sprinkled into the soil. Furthermore, the nitrogen fertilizer was utilized as base fertilizer, with 40% incorporated during the initial application, and the remaining 60% employed as top dressing [15]. The three test fields of area 4.8 × 6.9 m each were randomly selected.…”

“…Cotton seeds (Xinluzhong No. 21) were sown in early April; the crop was harvested in late October [15][16][17]. The three links of sowing, laying drip irrigation pipes, and plastic mulch were done sequentially.…”

“…The sowing was carried out using a custom-made tractor-pulled seeder. Polyethylene film was used for covering the ground given its benefits: it is air-tight, but its transparency allows light to reach the ground [15][16][17].…”