氮肥用量和运筹对冷浸田水稻产量和氮素利用率的影响

冷浸田是我国西南地区主要的水稻田,通过合理的氮肥管理,以提高冷浸田水稻产量和氮肥利用率十分必要.本研究通过田间试验研究了不同的氮肥用量和氮肥运筹对稻谷产量及其构成、氮素利用效率的影响,以期为西南地区冷浸田合理的氮肥管理提供依据.试验设5个氮肥施用水平:0(N0),90(N90),120(N120),150(N150),180(N180) kg/hm~2, 3个氮肥运筹方式,即底肥:分蘖肥:穗粒肥氮肥施用比例分别为60∶40∶0(T1),40∶60∶0(T2)和40∶20∶40(T3),以及控释氮肥1次施用处理(T4).结果表明, N120,N150和N180处理水稻产量均显著高于N0和N90处理,其中以N150处理稻谷产量和氮肥利用率最高,分别为9 466.65 kg/hm~2和30.75%,氮肥的回收利用率比N120和N180处理高2.37,3.54个百分点,且N150处理水稻收获指数显著高于N120和N180处理. 3种氮肥运筹方式及控释氮肥处理间水稻产量、生物量及籽粒氮素吸收量差异均无统计学意义,但氮肥采用底肥∶分蘖肥∶穗粒肥=60∶40∶0处理,水稻收获指数、结实率、每穗粒数均高于其余氮肥运筹及控释氮肥处理.鉴于西南地区的冷浸田氮素水平和基础地力较高,施氮量宜为120～150 kg/hm~2;氮肥运筹以普通尿素按底肥∶分蘖肥∶穗肥=60∶40∶0施用较为适宜.

Effects of Nitrogen Rate and Application Regime on Rice Yield and Nitrogen Use Efficiency in Cold Waterlogged Paddy Fields

Cold waterlogged paddy fields were the main form of paddy fields in Southwest China and,therefore,it is necessary to improve rice yield and nitrogen fertilizer utilization rate in cold waterlogged paddy fields through reasonable nitrogen fertilizer management. In order to provide guidance in nitrogen management of cold waterlogged paddy fields in Southwest China,a field experiment was conducted to study the effects of different nitrogen rates and application regimes on the seed yield and yield components of rice and on nitrogen use efficiency. In the experiment,nitrogen was applied at 0,90,120,150 and 180 kg/hm²,designated N0,N90, N120,N150 and N180,respectively. Three nitrogen application regimes were designed,i.e. the proportion of base fertilizer:tillering fertilizer:panicle fertilizer were 60:40:0 (T1),or 40:60:0 (T2),or 40:20:40 (T3),and a single application of controlled release nitrogen fertilizer before transplanting (T4). The results showed that the rice yield of N120,N150 and N180 treatments were significantly higher than that of N0 and N90 treatments. N150 have the highest yield of rice (9 466.65 kg/hm²),and nitrogen use efficiency (30.75%),and its recovery rate of nitrogen fertilizer was 2.37% and 3.54% higher than that of N120 and N180. The rice harvest index (HI) in N150 plot was significantly higher than that in N120 and N180 plots. Although there was no significant difference in rice yield,biomass and grain nitrogen absorption between the three nitrogen fertilizer application regimes and controlled release nitrogen treatment,the harvest index,seed setting rate and grain number per panicle of T1 were higher than those of the other application regimes and controlled release nitrogen treatment. Taking into consideration the fact that the nitrogen level and basic soil fertility of the cold waterlogged paddy fields of Southwest China are relatively high,a nitrogen rate of 120~150 kg/hm² and an application regime of base fertilizer:tillering fertilizer:panicle fertilizer 60:40:0 are recommended.