Effect of nutrient expert recommendation fertilization on rice yield and fertilizer use in northern Jiangsu Province

The overuse of nitrogen fertilizer, inadequate fertilization rate and time, and low fertilizer use efficiency in intensive agriculture have become the main limiting factors to farmers' income and sustainable agricultural development in northern Jiangsu Province, China. In order to optimize fertilizer management, improve the nutrient use efficiency, and reduce environmental risks in paddy fields in this region, we conducted nutrient expert (NE)-based fertilizer recommendation based on soil properties, targeted yield, and nutrient management information. Field experiments were designed to investigate the effects of NE on rice yield, economic benefit, nutrient uptake, and fertilizer use efficiency. Five treatments were used in the experiments, including (1) nitrogen, phosphorus and potassium fertilizer input calculated using NE, (2-4) eliminating nitrogen, phosphorous or potassium input in the NE treatment, and (5) farmers' conventional fertilization (FP). Results showed that, when compared with the FP treatment, partial productivity of N and P₂O₅ in the NE treatment was 44.77% (P < 0.05) and 6.32% higher respectively, while partial productivity of K₂O decreased significantly by 33.55% (P < 0.05). The recovery efficiency of N and K₂O in NE was significantly higher than that of FP by 4.91% and 19.35%, respectively; while the recovery efficiency of P₂O₅ was approximately the same as that in FP. Where the NE treatment involved reducing nitrogen fertilizer input and ensuring the balanced application of phosphorus and potassium fertilizer, the rice yield and farmers' income in this treatment were improved by 2.23% and 6.24%, respectively; however there were no significant differences compared to FP. The phosphorus and potassium accumulation in rice grains in the NE treatment had increased by 10.32% (P > 0.05) and 51.63% (P < 0.05), respectively. In conclusion, the use of NE-based recommendations resulted in an adequate ratio of N, P, and K, as well as optimizing fertilizer management, promoting the absorption and utilization of N, P, and K in rice, and improving rice yields and farmers' income. Therefore, we highly recommend using the NE system for fertilizer management in rice paddy fields in the northern Jiangsu Province of China.