稻草还田与施氮量对水稻氮素吸收及产量影响

摘要

The experimental materials were based on the varieties of cold rice,set up no straw returning to field,0.5 times,1.0 times,1.5 times,2 times 5 treatments;N0(no urea),N1(150 kg· hm2),N2(300 kg · hm2) 3 nitrogen application levels,in order to study rice nitrogen absorption,nitrogen accumulation,nitrogen distribution rate and rice yield in different periods.The results showed that the increasing amount of rice straw in tillering stage inhibited the nitrogen absorption and accumulation of rice,and the inhibition effect decreased as the amount of nitrogen increased.The rice straw returning also promoted the absorption of nitrogen in underground part of rice,under the condition of different nitrogen application rates,the amount of nitrogen accumulation was highest in 0.5 times;at the harvest stage,the aboveground and underground nitrogen contents were partially transferred to the grain.The tillers and effective tillers of rice were promoted in the case of straw returning with nitrogen fertilizer,under the N1 fertilization level,the yield reached the highest value after 1 times returning to field,under the N2 fertilization level,the yield reached the highest value after 0.5 times returning to field,excessive straw returning would reduce the rice yield with or without nitrogen fertilizer.%以寒地水稻品种为试验材料,设置稻草不还田、0.5倍、1.0倍、1.5倍、2倍还田5个处理,N0(不施入尿素)、N1(150 kg·hm-2)、N2(300 kg·hm-2)3个氮肥施用水平,研究不同时期水稻氮素吸收情况、氮素积累量、氮素分配率以及水稻产量.结果表明,分蘖期稻草还田量增加抑制水稻氮素吸收及积累,抑制作用随施氮量增加而降低;幼穗分化期稻草还田促进水稻地下部分氮素吸收,在不同施氮量条件下,0.5倍还田处理氮素积累量达最高值;收获期水稻地上和地下部分氮素均向籽粒部分转移,稻草还田配施氮肥情况下水稻分蘖及有效分蘖提升,N1施肥水平下1.0倍还田处理产量达最高值,N2施肥水平下0.5倍还田处理达最高值,稻草还田不配施氮肥或配施氮肥情况下稻草还田过量均降低水稻产量.