前氮后移对水稻产量形成和农田氮素流失的影响

基于太湖地区稻田养分流失主要集中在水稻生育前期的特点,以超级稻武运粳29号为供试材料,通过田间小区试验,基肥采用机械深施,在施氮量300 kg/hm2水平下,设计4个氮肥运筹比例,基肥：分蘖肥：穗肥的比例分别为5：2：3 (O1)；4：2：4 (O2)；3：2：5 (O3)；2：2：6 (O4),研究氮肥后移对水稻产量构成和农田地表径流氮素流失量的影响。结果表明,从产量构成因素来看,前氮后移的O4处理较常规氮肥运筹的O2处理水稻有效穗数和每穗粒数均显著下降,但是其结实率和千粒重均明显增加；最终前氮后移的O4处理水稻产量略有下降,但处理间的差异不显著。水稻季农田共发生地表径流6次,径流水总量为3 567.0 m3/hm2。农田地表径流总氮流失量随着前氮后移比例的增加而减少,O4处理较O2处理地表径流总氮流失量下降了12.02%,处理间的差异均达到显著水平。同时,前氮后移能够降低稻田地表径流总氮流失率和水稻氮素偏流失率。

Effect of Postponing N Application on Rice Yield Formation and Nitrogen Runoff Losses from the Field

Based on the characteristics of the paddy soil nutrient loss were mainly concentrated in the early stage of rice growth in Taihu area. A field experiment was conducted to study the effects of postponing N application on rice yield and nitrogen runoff loss. The super rice cultivar of Wuyunjing 29 was field-grown. Four nitrogen application ratios such as basal, tillering fertilizer and panicle fertilizer 5: 2: 3 (O1), 4: 2: 4 (O2), 3: 2: 5 (O3), 2: 2: 6 (O4) were designed, in the amount of nitrogen applied to 300 kg/hm2, with deep basal fertilizer machinery. The result showed that: for the yield components of rice, compared to the conventional nitrogen application (O2), postponing N application (O4) significantly decreased the effective panicles and spikelets number per panicle, but filled grain percentage and 1 000-grain weight showed the opposite trends. Finally O4 treatment of postponing N application declined rice yield a little, but there was no significant difference. There was six times of farmland overland runoff in rice season, and the amount of runoff was 3 567.0 m3/hm2 in this research season. With the increase of the proportion of postponing N application, the total nitrogen runoff loss decreased. The total N loss of O4 treatment was significantly decreased by 12.02% compared with that of O2 treatment. At the same time, postponing N application could decrease the total nitrogen loss rate with overland runoff in the paddy field and nitrogen drift loss rate of rice.