Effects of Biochar and Organic Acid Addition on Phosphorus State and Yield of Cotton Field Under Different Phosphate Fertilizer Application Rates

The purpose of this study is to investigate the effect of biochar and organic acid on soil phosphorus effectiveness, plant accumulation phosphorus absorption, yield composition, and phosphorus equilibrium under different phosphorus fertilizer dosage conditions. Using the field test method, different phosphate fertilizer dosage treatments (0, 50, 100, 150 kg P2O5/ha) were set, and a control group, biochar (BC), and organic acid (OA) addition treatment were set up on this basis. During the experiment, the soil fast-acting phosphorus, accumulated phosphorus absorption, and cottonseed yield of cotton were measured, and the utilization of phosphorus fertilizer and phosphorus surplus were calculated. The results showed that the addition of biochar and organic acid significantly improved the soil phosphorus content, plant accumulation phosphorus absorption, cottonseed yield, and phosphate fertilizer utilization. In particular, in terms of plant accumulation of phosphorus absorption, cottonseed production and phosphate fertilizer utilization, biochar was better than organic acids, increasing by 10.2%, 0.29%, and 0.21%, respectively. Under the conditions of phosphorus fertilizer loss, the addition of biochar can effectively improve the effectiveness of phosphorus in soil and regulate the absorption and distribution of phosphorus in cotton, thus promoting the yield of cottonseed. In summary, the addition of biochar has important application potential in phosphorus management in cotton fields, which can provide a scientific basis for the sustainable development of cotton fields in Xinjiang. The results provide a reference for the rational use and management of phosphate fertilizer in cotton fields and promote the sustainable development of agriculture.