Barley-double cropping rice rotation is a typical cropping system in the middle reaches of Yangtze River. Based on a 34-year long-term experiment, the effects of combined application of organic materials and chemical fertilizers reduction in barley-double cropping rice rotation system on utilization efficiency of solar radiation, GDD (growing degree days), and water resources, use efficiency of nitrogen, phosphorus and potassium resources, and yield of barley were studied. The objective of this study is to provide the theoretical basis and data support for the fertilization management of barley-double cropping rice rotation system with efficient utilization of resources and stable yield and efficiency in barley. In this study, four fertilization treatments in the long-term positioning experiment were selected, including NPK chemical fertilizer treatment (NPK), NPK chemical fertilizer combined with rice straw treatment (NPK+straw), organic fertilizer nitrogen replacement 30% chemical nitrogen treatment (NPK+LOM), and organic fertilizer nitrogen replacement 60% chemical nitrogen treatment (NPK+HOM). To ensure that the N, P2O5 and K2O application rates of the fertilization treatments in the barley season and early rice season and late rice season, each treatment was based on the equal amount of nitrogen, and the insufficient nitrogen, phosphorus, and potassium fertilizers were supplemented with chemical fertilizers. The results were as follows: (1) Compared with NPK + straw treatment, radiation productive efficiency, accumulated heat productive efficiency, water productive efficiency of NPK+HOM treatment were significantly increased by 0.04 g MJ-1, 0.28 kg ℃-1 d-1 hm-2, 0.08 kg m-3, and the increase amplitude was 10.5%, 9.4%, and 9.6% (P < 0.05), respectively. (2) Compared with NPK+straw treatment, the partial productivity of N, P, and K in NPK+LOM treatment increased by 22.5%, 23.4%, and 23.5%, respectively (P < 0.05), and K harvest index increased by 36.7% (P < 0.05), while there was no significant difference of the NPK nutrient partial productivity and N harvest index between NPK+LOM and NPK+HOM treatments; (3) The analysis of stability and sustainability of barley yield indicated that NPK+straw treatment was beneficial to stable yield in barley; (4) The NPK+HOM treatment could improve soil fertility. On the whole, NPK+HOM treatment was superior to other fertilization structures in terms of the utilization of light and hot water resources and soil fertilization in barley; NPK+LOM treatment was better than other fertilization structures in the utilization of NPK nutrient resource in barley; Both NPK+LOM and NPK+HOM treatments could increase the yield of barley. Regarding the barley-double-cropping rice rotation model, combining straw to the field combined with organic fertilizer and chemical fertilizers to regulate the synergistic improvement of barley resource utilization and yield was one of the important research tasks in the future.
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