控释氮肥运筹对钵苗摆栽籼粳杂交稻甬优1540产量及氮肥利用的影响

研究籼粳杂交稻钵苗摆栽超高产栽培模式下适宜的控释氮肥运筹。试验于2016—2017年在安徽庐江进行,以当地高产籼粳杂交稻甬优1540为供试品种,设置控释氮肥一次性基施(single basal application of CRNF,BC)、与尿素分蘖肥配施(basal application of CRNF combined with urea top-dressing at the tillering stage,BC+TU)、与尿素穗肥配施(basal application of CRNF combined with urea top-dressing at panicle initiation,BC+PU)三种运筹模式,以尿素分次施肥(conventional high-yield fertilization,SU)和不施氮肥(0N)为对照,研究控释氮肥运筹对钵苗摆栽籼粳杂交稻产量、氮肥吸收利用及相关农艺指标的影响。结果表明,控释氮肥阶段释放基蘖肥:穗肥比例为7∶3,较传统优化氮肥运筹SU(6∶4)整体表现基蘖肥冗余,穗肥不足,因而BC和BC+TU处理显著降低了钵苗摆栽籼粳杂交稻产量和氮肥利用效率。与BC和BC+TU处理相比,BC+PU通过基肥减量和尿素穗肥配施,在保证水稻营养生长期基本氮素供应的同时,显著增加了穗分化至成熟期氮素吸收,促进了穗分化至成熟期光合物质生产能力,在稳定有效穗数和千粒重的同时,显著提高了钵苗摆栽籼粳杂交稻每穗粒数、结实率和产量,很好的匹配了钵苗摆栽籼粳杂交稻全生育期氮素需求。BC+PU两年的产量和氮肥利用率分别为12.2~13.1 t hm^-2和43.8%~44.1%,分别较BC显著提高7.4%~9.2%和48.5%~59.9%,较BC+TU显著提高8.0%~11.9%和63.9%~74.5%。另外,BC+PU的产量和氮肥利用率与SU无显著差异,但由于大幅降低了施氮人工成本,最终提高净收益6.5%~12.3%。在籼粳杂交稻钵苗摆栽超高产栽培模式下,采用70%控释氮肥+30%尿素穗肥处理可有效取代常规尿素分次施肥,获得无显著差异的水稻产量和氮肥利用效率,同时进一步提高经济效益。

Effects of different application methods of controlled-release nitrogen fertilizer on grain yield and nitrogen utilization of indica-japonica hybrid rice in pot-seedling mechanically transplanted

To investigate the optimal application of controlled-release nitrogen fertilizer(CRNF)under the super-high-yield cultivation of indica-japonica hybrid rice in pot-seedling mechanically transplanted,the field experiments were carried out to investigate the effects of three application methods of CRNFone-time basal application of polymer-coated urea(BC),basal application of polymer-coated urea combined with urea top-dressing at the tillering stage(BC+TU,8:2),and basal application of polymer-coated urea combined with urea top-dressing at panicle initiation(BC+PU,7:3)]on grain yield,nitrogen utilization(NRE),and agronomic traits of Yongyou 1540,a high-yield indica-japonica hybrid rice variety,with the pot-seedling mechanically transplanted in 2016 and 2017.Conventional high-yield fertilization of urea at 280 kg hm^-2(SU)and 0 N treatments were set as the controls.The cumulative release ratio of basal tiller fertilizer to panicle fertilizer for CRNF was 7:3,which was higher than that of SCU(6:4),leading to N redundancy at tillering stage and deficit during the following growth stages.Therefore,BC and BC+TU presented lower rice yields and NRE compared with SU.In comparison with BC and BC+TU,BC+PU was applied in combination with CRNF basal fertilizer reduction and urea fertilizer application at panicle initiation stage,and increased N uptake and photosynthetic capacity from panicle initiation stage to maturity stage ensured the basic N supply during the vegetative growth period in rice,leading to significantly higher spikelets per panicle,grain filling percentage,and grain yield while an equal panicles per m2 and 1000-grain weight.Meanwhile,N application rates can be well matched with rice N uptake patterns during the whole growth period.The grain yield of BC+PU was 12.2-13.1 t hm^-2in 2016 and 2017,which were 7.4%-9.2%and 8.0%-11.9%higher than those of BC and BC+TU,respectively.Moreover,the NRE of BC+PU were 43.8%-44.1%in 2016-2017,which were 48.5%-59.9%and 63.9%-74.5%higher than those of BC and BC+TU,respectively.In addition,compared with SU,there was not significant differences of grain yield and NRE in BC+PU,and net income was higher by 6.5%-12.3%due to the significant reduction of labor cost of N application.In conclusion,the basal application of CRNF combined with urea top-dressing at panicle initiation stage at ratios of 7:3 was the simplified fertilization method that could effectively replace conventional simplified fractional fertilization,and exhibit no significant differences in rice yield,NRE,and higher economic benefits.