关键词: 稻油轮作, 施肥模式, 产量, 养分吸收, 肥料利用率, 土壤肥力

Abstract:

【Objective】To explore the potential of optimizing fertilization under rice-rapeseed rotation for increasing crop yield and efficiency in medium and low yield fields, this study analyzed the effects of optimized fertilization on yield, nutrient absorption, and soil fertility in rice-rapeseed rotation, as well as the effectiveness of rice-rapeseed rotation in improving soil fertility. This study aimed to identify fertilization strategies suitable for medium and low yield fields and the potential for improving quality and efficiency in rice-rapeseed rotation, so as to provide the theoretical guidance for reducing obstacles in medium and low yield fields, promoting efficient production in rice-rapeseed rotation, and achieving sustainable development of rice-rapeseed rotation.【Method】The experiment was conducted at the Agricultural Science Research Institute in Rugao City, Jiangsu Province from 2017 to 2024, with low yield fields as the research objects. Through small-scale experiments, no fertilization treatment (CK), no nitrogen treatment (PK), no phosphorus treatment (NK), farmer's habitual fertilization treatment (FFP), and optimized fertilization treatment (OPT) were set up. By analyzing the annual yield of crops in both water and drought seasons, the nutrient absorption of aboveground parts during maturity, and soil nutrient content, the yield change rules under different fertilization systems of rice-rapeseed rotation were clarified, and the main influencing factors were explored.【Result】During the seven year rotation period, compared with FFP, the yield and yield composition of rice and rapeseed treated with OPT were more stable with increasing rotation cycles. Compared with FFP, OPT treatment significantly increased the nitrogen and phosphorus partial productivity of rice and rapeseed, with rice showing 51.5%-73.3% and 81.8%-107.9% higher nitrogen and phosphorus partial productivity, respectively; rapeseed was 137.2%-152.3% and 89.8%-101.9% higher, respectively. During the four-year rotation period, the aboveground biomass of rice and rapeseed treated with OPT was higher than that treated with FFP. Comparing the two annual rotation periods at the beginning and end of the comparative experiment, it was found that the accumulation of nitrogen, phosphorus, and potassium in the aboveground parts of rice and rapeseed treated with OPT was higher than that under FFP treatment, and OPT treatment had a better effect on improving soil organic matter, total nitrogen, and available potassium than FFP treatment. After 7 years of rice-rapeseed rotation, the soil fertility index significantly increased (63.8%-117.2%) under all treatments. Compared with FFP treatment, the average membership degree of five soil chemical indicators in the rice season treated with OPT was higher than that under FFP treatment, and its comprehensive fertility index increased by 13.4%-19.2%. In addition, the soil phosphorus activation coefficient during the three-year rotation period was monitored, and it was found that the OPT treatment had a higher soil phosphorus activation coefficient than under FFP treatment. 【Conclusion】Compared with the traditional fertilization practices of farmers, optimizing fertilization could be achieved by optimizing fertilizer management. Based on reducing nitrogen and phosphorus fertilizer application by 40% and 50% in rice and 60% and 50% in rapeseed, stabilizing their yield composition, maintaining high biomass and nutrient absorption, and achieving stable annual yield in the rice-rapeseed intercropping system; the performance of optimized fertilization treatment in improving fertilizer utilization efficiency and soil fertility was better than that of farmers' habitual treatment. Therefore, optimizing fertilization under long-term fertilizer reduction could coordinate crop nutrient needs and nutrient supply, maintain stable or increased crop yields, and improve fertilizer utilization efficiency. Rice-rapeseed rotation could improve soil fertility in medium and low yield fields, achieve obstacle reduction in medium and low yield fields, and promote sustainable development of rice-rapeseed rotation.

Key words: rice-rapeseed rotation, fertilization modes, yield, nutrient absorption, fertilizer utilization rate, soil fertility