应用~(15)N研究施氮时期对寒地不同品种水稻氮吸收和分配的影响

采用~(15)N示踪技术对不同品种水稻的氮素吸收和分配规律进行研究。结果表明,在生育前期,两个水稻品种植株以吸收肥料氮为主,后期以吸收土壤氮为主。但是,穗重型水稻(V7)在灌浆期以前,施蘖肥、穗肥、粒肥处理水稻植株以吸收肥料氮为主,施基肥处理在抽穗期之前以吸收肥料氮为主,而后转向吸收土壤氮;穗数型水稻(V10)在抽穗期以前,施基肥和蘖肥处理水稻植株以吸收肥料氮为主,施穗肥和粒肥处理在灌浆期之前以吸收肥料氮为主,而后转向吸收土壤氮。两个水稻品种籽粒中肥料氮比例随施氮时期的后移而升高,分期施肥氮的利用率要高于一次性施肥。

Nitrogen uptake and distribution of different rice variety as related to nitrogen application time by 15N tracing in cold region

Nitrogen uptake and distribution patterns of two rice varieties were studied with 15N tracing pot culture. The results show that at early growth stage, rice plants of both varieties mainly uptake fertilizer-N, and at later growth stage, mainly uptake soil-N. Before filling stage, Dongnong V7 (big-spike variety) the rice plants with the treatments of tilling-fertilizer, spike-fertilizer and grain-filling fertilizer mainly absorb fertilizer-N, whereas the rice plants with the treatments of base fertilizer mainly absorb fertilizer-N before heading, and then absorb soil-N. Before heading, Dongnong V10 (multiple-spike variety) mainly absorbs fertilizer-N in the treatments of tilling-fertilizer and base fertilizer; whereas in the treatments of spike-fertilizer and grain-filling fertilizer, the rice plant mainly absorb fertilizer-N before filling, and then absorbs soil-N. Later application of nitrogenous fertilizer resulted in higher proportion of fertilizer-N in rice grains of both varieties, and the N utilization efficiency in split application was higher than that in one application of total fertilizer.