不同施氮量下北方稻田一次与分次施氮对水稻产量的影响

设计了适量和过量总施氮量下的一次和分次施氮的田间试验,研究了不同施肥方式对山西半干旱地区肥力水平较低的盐渍型水稻土水稻产量的影响。结果表明,适宜氮量(N198kghm-2)下,水稻插秧前基肥一次性施氮较分三次在不同生育期施氮稻谷平均增产达10%;但过量施氮下,一次性基肥施氮较分三次施用平均减产6.6%。总施氮量小于适宜施氮量时,基肥一次性施氮较分三次施用平均增产则达到30%。插秧前基肥一次性施氮与基肥和分蘖初期分两次施氮相比,稻谷产量无明显差异。这说明插秧前和分蘖初期是该地水稻的有效施肥期。在不施磷肥或磷肥做基肥一次施用而氮肥分次施用的情况下,基肥氮磷施用比例也影响所施用氮肥的肥效;因此,就所试验的肥力较低的盐渍型水稻土来说,可以实行在减量施氮下的插秧前基肥一次性施氮,而不需要追施氮肥,并且在施P2O5130kghm-2的条件下,总施氮190kghm-2即可满足高产,因而可以减少习惯施氮量的1/3。

Effect of Single or Multiple N Applications under Different Total N Fertilization on Rice Yield in a Paddy Soil of North China

A field experiment was conducted with adequate and over loaded amount of N fertilizer respectively in a low-fertility saline paddy soil in Shanxi, China. The effect of single application as basal fertilizer at seedling and multiple applications at tillering and spiking on rice yield was studied. When total N application was 198kg hm-2, rice yield was increased by 10% under single application as basal N fertilizer compared to triple applications; However, with total N application exceeding 198kg hm-2, reduction of rice yield by 6.6% was observed under single application compared to three time applications. Nevertheless, with total N application below 198 kg hm-2, much higher rice yield (by 30%) was reached under single N application than under triple applications although there was no significant difference in rice yield between single application and twice applications. The results here evidenced a most effective N application time at seedling for single rice in the studied soil and single application as basal fertilizer of N could be practical in farm nutrient management. This study also demonstrated that the conventional N application at 300kg hm-2 should be reduced by one third (100kg hm-2) for rice under a sound phosphorus application of P2O5130 kg ha-1 in this soil.