低丘红壤稻田氮肥施用技术的研究

Studies on the technique of nitrogen fertilizer application in hilly red soil region paddy field:

以早籼浙９２４８、晚籼浙选优３号、晚杂汕优１０号和协优４６为供试品种，于１９９１年和１９９４年在低丘红壤稻田进行氮肥不同施肥时期与用量配比试验。结果表明：低丘红壤稻田在一季总施氮量相同的前提下，适当降低前期用肥量，增施保花肥、粒肥，可以获得更高的产量。保花肥施用的有效时期在倒三叶露尖－剑叶露尖之间，施用量以总用量的２０％～３０％为宜，如表现缺肥症状，用量可适当增加；若用量过多时，宜在倒二叶露尖－剑叶露尖和始穗期时分２次进行。施用保花肥、粒肥的增产机理在于提高后期分蘖的成穗率、减少颖花退化，使每穗实粒数、千粒重增加。

With early Indica Zhe9248, Middle Indica Zhe Xuanyou 3, Hybrid rice Shanyou 10 and Xieyou 46 as test varieties, the experiment of nitrogen fertilizer application was carried out in red earth paddy field in 1991, in 1994. The results showed that the red soil region paddy fields were able to gain higher yield by reducing amount of fertilizer at early stage, by increasing amount of fertilizer at spikelet sustaining and grain stage, when the total nitrogen application being similar during a season. The effective period of spikelets sustaining fertilizer applied was from 3rd top leaf to flag leaf extending; the amount of spike sustaining fertilizer was 20～30% total nitrogen fertilizer. When deficiency disease of rice plants appeared, the amount of nitrogen fertilizer need increase, however, fertilization should be early. When the amount was more than 30% total nitrogen fertilizer, the spike sustaining fertilizer should be divided into twice applying at 2th top leaf extending and initial heading stage. The increasing yield mechanism increased the rate of panicle-bearing of late tillers, reducing spikelets retrogression, making number of grains filled per ear and weight of 1000 grains increase.