关键词: 水旱轮作, 水稻, 穗氮, 群体特征, 经济效益

Abstract:

In order to study the cultivation techniques of rice nitrogen reduction in paddy-upland rotation system, in the wheat-rice and broad bean-rice rotation system in the plateau Japonica rice region, Longke 16, a local rice variety, was used as the material, and six nitrogen (N) rates of 0, 90, 120, 150, 180 and 210kg/ha were topdressed as flower promoting and flower preserving fertilizer in ratio of 6:4. Local recommended N management (N 285kg/ha in total, evenly divided and applied as basal, tillering, flower promoting and flower preserving fertilizer in ratio of 0.25:0.25:0.25:0.25) was used as control. The population growth characteristics and economic benefits of rice under two rotation systems were systematically compared. The results showed that in the two rotation patterns, the yield of rice was the same as that of the control when 180kg/ha panicle N was applied without basal N and tillering N, and in the critical leaf stage of productive tillers of rice, the lowest tillering number of rice was 91.09% and 87.62% of the control, and the highest was 95.05% and 91.11% of the control, respectively, under the wheat-rice and broad bean-rice rotation system without basal N and tillering N application. There was no significant difference in the number of effective panicles in the mature period from the control, and applying panicle N without basal N and tillering N could significantly increase percentage of earbearing tillers. Compared with no N application, the effective panicle, dry matter accumulation and population growth rate at filling stage of rice increased after applying panicle N. The application of 180kg/ha pure N without basal N and tillering N as panicle fertilizer reduced 36.84% of N input compared with the control, and the economic benefit of rice was the highest. The goal of saving cost and increasing efficiency of rice was achieved.

Key words: Paddy-upland rotation, Rice, Panicle N, Population characteristics, Economic benefit