秸秆还田配合氮肥减量对稻田土壤养分、碳库及水稻产量的影响

通过大田定位试验,研究秸秆还田和氮肥减量对稻田土壤养分、碳库及水稻产量的影响。结果表明,采用适当的秸秆还田配合氮肥减量处理可以有效改善土壤理化性状,提高水稻产量。与单施纯氮270 kg·hm^-2处理相比,等氮量的秸秆还田配施纯氮240 kg·hm^-2处理的稻田土壤有机质、全氮、速效磷、速效钾、总有机碳含量分别显著(P<0.05)增加了33.86%、13.83%、54.64%、21.60%、33.81%,而铵态氮、可溶性有机碳和微生物碳含量分别显著(P<0.05)减少了13.69%、49.22%和32.36%。在产量方面,秸秆还田配施纯氮240 kg·hm^-2的产量最高,较秸秆不还田不施氮肥处理和秸秆还田不施氮肥处理分别显著(P<0.05)增产57.90%、62.22%。在本试验条件下,秸秆还田配施纯氮240 kg·hm^-2为最优的秸秆还田配合氮肥减量模式,对改善土壤养分、增加土壤碳库、提高水稻产量具有一定作用。

Effect of straw returning and nitrogen reduction on soil nutrition,carbon pool and rice yield in rice field

In order to determine the effects of straw returning and nitrogen reduction on soil nutrition, carbon pool and rice yield, a field experiment was conducted. It was shown that the proper treatment of straw returning and nitrogen reduction could improve soil quality and increase rice yield. Compared with application of 270 kg·hm^-2 N, straw returning with 240 kg·hm^-2 N significantly (P<0.05) increased the contents of soil organic matter, total nitrogen, available phosphorus, available potassium, total organic carbon by 33.86%, 13.83%, 54.64%, 21.60%, 33.81%, respectively, yet the contents of ammonium nitrogen, dissolved organic carbon and microbial biomass carbon were significantly (P<0.05) decreased by 13.69%, 49.22% and 32.36%, respectively. As for yield, straw returning with 240 kg·hm^-2 N was the highest. Compared with the treatments without N application (both without and with straw returning), rice yield of the treatment of straw returning with 240 kg·hm^-2 N was significantly (P<0.05) increased by 57.90% and 62.22%, respectively. Under the experimental conditions, the optimal straw returning and nitrogen fertilizer reduction model was the treatment of straw returning with 240 kg·hm^-2 N, which could improve soil nutrient, enhance soil carbon content, and increase rice yield.