关键词: 稻油轮作, 秸秆还田方式, 产量, 养分吸收, 养分表观平衡

Abstract:

【Objective】This study aimed to investigate the effects of long-term different straw return methods on productivity and apparent balance of nitrogen, phosphorus and potassium nutrients in rice-rapeseed rotation system, in order to provide the theoretical basis for the efficient utilization of straw resources in the rotation system.【Method】The field experiment was located in Wuxue City, Hubei Province, and started in 2014, with three treatments of straw not return (NPK), direct straw return (NPK+St) and burning straw return (NPK+Sb), to determine and analyze the yields, nitrogen/phosphorus/potassium nutrient uptake and their apparent balances and other related indicators of rice and rapeseed in the consecutive 10-year period from 2014 to 2024.【Result】The average results of the 10-year experiment showed that compared with the NPK treatment, the rice and rapeseed yield in the NPK+St treatment increased significantly by 7.7% and 10.7%, respectively; the rapeseed yield in the NPK+Sb treatment increased significantly by 5.2%, and the effect of yield increase on rice was not significant. The yield increase effects of NPK+Sb and NPK+St increased with the increase in years of straw return, and in the 6th year reached the significant level. Based on the annual nutrient uptake characteristics, compared with the NPK treatment, the annual nitrogen uptake in the NPK+St and NPK+Sb treatments increased by an average of 11.6% and 2.9%, respectively, the annual phosphorus uptake increased by an average of 11.9% and 10.2%, respectively, and the annual potassium accumulation increased by an average of 55.8% and 39.1%, respectively. Direct straw return significantly enhanced the absorption of nitrogen, phosphorus and potassium nutrients in the rotation system. Burning straw return effectively increased the absorption of phosphorus and potassium nutrients in the rotation system. The annual nitrogen, phosphorus and potassium surplus of rice-rapeseed rotation in the NPK treatment were 101.3 kg N·hm^-2·a^-1, -8.9 kg P₂O₅·hm^-2·a^-1 and -296.6 kg K₂O·hm^-2·a^-1, respectively. The annual nitrogen surplus in the NPK+St treatment averaged 166.1 kg N·hm^-2·a^-1, with an increase of 64.0%. The annual phosphorus and potassium nutrient surpluses were realized for both NPK+St and NPK+Sb treatments, with surpluses of 33.0 and 19.0 kg P₂O₅·hm^-2·a^-1, 79.4 and 21.3 kg K₂O·hm^-2·a^-1, respectively. 【Conclusion】Direct and burning straw return significantly increased the crops production potential and nutrient uptake by promoting nutrient cycling in the rice-rapeseed rotation system. The effect of stabilizing rice yield and increasing rapeseed yield was shown among the different crops in the rotation. The straw direct return was more favorable to increase crop yield and to maintain the nutrient balance of the farmland than the straw burning return. Therefore, it was recommended to promote the direct straw return approach in the process of farmland production in order to fully utilize its advantages of yield enhancement, stabilization, and nutrient balancing, and to promote the sustainable development of the rice-oil rotation system.

Key words: rice-rapeseed rotation, straw return method, yield, nutrient uptake, nutrient apparent balance