Biofertilizer application improved cotton growth, nitrogen use efficiency, and yield in saline water drip-irrigated cotton fields in Xinjiang, China

Saline water irrigation presents a potential solution for addressing freshwater shortages. However, this practice can result in salinity stress for cotton plants. Hence, it is imperative to explore measures that can alleviate salinity stress when implementing saline water irrigation. The aim of this study was to determine the effects of biofertilizer (F2) application on cotton growth, nitrogen use efficiency, yield, and fiber quality under different water: 0.48–1 g L−1 (W1, freshwater), 3 g L−1 (W2, brackish), and 7 g L−1 (W3, salt water) irrigation, compared to the use of chemical fertilizer (F1) alone. A two-year field experiment was conducted in 2021 and 2022 in film-mulched drip-irrigated cotton fields. The results showed that biofertilizers significantly enhance photosynthesis and N utilization efficiency under both W1 and W2 irrigation, compared to treatments where chemical fertilizers were applied alone. At the same time, the cotton total biomass, and cotton fiber elongation were significantly increased, and the cotton seed yield was significantly increased by 6.15–10.56 % (W1) and 6.49–11.81 % (W2) in two years. The application of biofertilizers indirectly increases cotton yield by enhancing cotton biomass and improving N utilization. In conclusion, the application of biofertilizer can effectively alleviate the salinity stress on plants in both W1 and W2 irrigation situations. Future research on saline water irrigation should take into account the long-term effects of using biofertilizers in saline irrigation situations.