轻简氮肥管理对华南双季稻产量和氮肥利用率的影响

Effects of Simplified Nitrogen Managements on Grain Yield and Nitrogen Use Efficiency of Double-Cropping Rice in South China

【目的】针对当前我国水稻种植中面临劳动力短缺、用工成本高、肥料利用率低等突出问题,探索在保障水稻高产高效的前提下更为简化的"一基一追"轻简施氮模式,减少施肥次数,提高种稻效率,为水稻轻简化栽培提供理论依据。【方法】以常规籼稻五山丝苗为试验材料,采用随机区组设计。2018年晚季设置不施氮(N0)、三控施肥(TC)、三控减氮(RTC)和3个轻简施氮(SNM1、SNM2、SNM3)6个处理,2019年早季设置N0、TC、农民习惯施肥(FP)和3个轻简施氮(SNM2、SNM4、SNM5)6个处理,研究不同氮肥管理对华南双季稻产量及其构成、物质生产、氮肥利用效率以及稻米品质的影响。【结果】2018年晚季,SNM2处理与TC处理的产量无显著差异,但二者均显著高于RTC、SNM1和SNM3处理;2019年早季,SNM2、SNM4和SNM5处理的产量与TC处理无显著差异,但比FP处理增产7.36%—7.51%,主要是由于每穗粒数增加。SNM2处理的有效穗数、每穗粒数、结实率和千粒重与TC处理无显著差异(2019年早季千粒重除外),但2个处理的产量构成不同,SNM2处理的单位面积颖花数多,主要通过扩大库容量保持高产。2018年晚季,SNM2处理的氮肥吸收利用率(RE)、氮肥农学利用率(AE)、氮肥生理利用率(PE)和氮素收获指数(NHI)与TC处理相比无显著差异,但氮肥偏生产力(PFP_N)显著增加;SNM1和SNM3处理的RE、AE和PFP_N显著低于SNM2处理。2019年早季,3个轻简施氮处理的5项氮肥利用率指标均与TC处理无显著差异,4个轻简处理的RE、AE和PFP_N显著高于FP处理。SNM2、SNM4、SNM5和TC处理的单位面积颖花数、总生物量和总吸氮量均高于FP处理。2018晚季,SNM2处理的垩白粒率较TC处理显著降低,其他指标与FP和TC处理无明显变化。【结论】采用"一基一追"的轻简氮肥管理SNM2处理,在减少氮肥10%、减少2次施肥的情况下,其水稻产量和氮肥吸收利用率与TC处理无显著差异,但显著高于FP处理,外观品质有所改善,碾磨品质和蒸煮食味品质没有明显变化。因此,在劳动力紧缺问题突出的情况下,采用轻简氮肥管理技术,既可以节约劳动力成本,又可实现水稻的高产和氮肥高效利用,该研究结果对水稻轻简化栽培具有指导意义,具有良好的应用前景。

【Objective】Simplified nitrogen managements(SNMs)are labor saving methods and could make more profits in rice(Oryza sativa L.)cultivation.In view of labor shortage,high labor cost and low fertilizer utilization in rice cultivation of China,the aim of this study was to explore a simplified and efficient application of nitrogen featured by"one basal-dressing and one top-dressing",so that the amount and frequency of nitrogen application could be reduced,and the profit of rice planting could be improved.【Method】In order to study the effects of SNMs on the grain yield,dry matter production,nitrogen use efficiency,and grain quality of double-cropping rice in South China,the field experiment was conducted by a conventional indica rice variety of Wu-Shan-Si-Miao,which was designed by a completely randomized block with four replicates.In 2018,6 treatments were established,i.e.no nitrogen(N0),three-control fertilization(TC),TC with nitrogen reduction(RTC),and 3 simplified nitrogen managements(SNM1,SNM2,and SNM3).In 2019,6 treatments were also established,i.e.no nitrogen(N0),three-control fertilization(TC),famers’fertilizer practice(FP),and 3 simplified nitrogen managements(SNM2,SNM4,and SNM5).【Result】In the later growing season of 2018,the grain yield of SNM2 was not significantly different from that of TC,but the yields of both treatments were significantly higher than those of RTC,SNM1,and SNM3.In 2019,the grain yields of SNM2,SNM4 and SNM5 were also not significantly different from that of TC.However,compared with FP,the yields of those treatments were increased by 7.36%-7.51%,which was mainly due to the spikelet number per panicle was improved in 2019.And the panicle numbers,spikelet number per panicle,seed setting rate,and 1000-grain weight of SNM2 were not significantly different from TC(except for 1000-grain weight in 2019)for both seasons.In 2018,the nitrogen recovery rate(RE),agronomy use efficiency(AE),physiological use efficiency(PE),nitrogen harvest index(NHI)of SNM2 were all not significantly differed from that of TC,while the partial factor production(PFP_N)of SNM2 was significantly higher than that of TC,and the RE,AE,and PFP_N of the SNM1 and SNM3 were obviously lower than that of SNM2.In 2019,the 5 nitrogen utilization indexes(RE,AE,PE,NHI and PFP_N)of the 3 SNMs were not significantly different with those of TC,but the RE,AE and PFP_N of those treatments were all significantly higher than that of FP.The number of spikelets per unit area,biomass,and nitrogen uptake of the SNMs were all higher than those of FP.In addition,the chalky rice rate of SNM2 was significantly lower than that of TC,but other grain quality of SNMs was not significantly different from that of FP and TC in 2018.【Conclusion】The grain yield and nitrogen use efficiency of SNM2,which had 10%less nitrogen application and with only basal application and one topdressing in nitrogen management,was similar with TC.However,SNM2 had significantly higher grain yield and nitrogen use efficiency than FP.Additionally,the appearance quality of SNM2 was significantly improved,while the milling quality,cooking and eating quality were not significantly changed.Thus,it could be widely adopted in rice production in South China for its simplified cultivation.