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2008~2010年在宁夏引黄灌区水稻-春小麦-春玉米轮作体系下,采用田间试验研究了不施肥(CK)、平衡施用化肥(NPK)、单施有机肥(M)、化肥+有机肥(NPK+M)和习惯施肥(CON)5个施肥措施对水旱轮作体系作物产量、土壤无机氮残留和氮素表观平衡的影响。结果表明,相对于CK处理,施肥都能提高水旱轮作作物籽粒和秸秆产量。水旱交替易造成旱作季残留的土壤无机氮(NO3--N)在水作季发生淋洗损失。由水稻改种春小麦后,施肥显著提高了0~100 cm各层土壤NO3--N累积量。在水稻、春小麦和春玉米季,NPK和NPK+M较CON处理的氮素表观损失量分别降低了19.8%~39.2%、90.6%~93.1%和19.8%~34.7%。单施有机肥(M)也会增加氮素表观损失风险,其在水稻、春小麦和春玉米季的损失量分别达209.4 kg hm-2、67.0 kg hm-2和198.8 kg hm-2。3年水旱轮作体系下,NPK和NPK+M较CON处理的氮素表观损失量分别降低了46.9%和33.3%。因此,在该水旱轮作体系下,平衡施用氮磷钾及有机无机配施都有利于提高作物产量和降低氮素表观损失。
Under the system of paddy-spring wheat-spring maize rotation system in the Yellow River irrigated area of Ningxia from 2008 to 2010, the effects of no fertilization (CK), balanced application of fertilizers (NPK), single application of organic fertilizer (M), chemical fertilizer + organic fertilizer NPK + M) and conventional fertilization (CON) on crop yield, soil inorganic nitrogen residue and apparent nitrogen balance were studied. The results showed that, compared with CK treatment, fertilization could increase grain yield and straw yield of crop rotation. Alternate water and drought can easily lead to soil organic nitrogen (NO3 - N) remaining in the dry season in the water season for the leaching loss. After spring wheat was replanted by rice, the fertilizer application significantly increased the accumulation of NO3 - N in 0-100 cm soil layers. The apparent nitrogen loss of NPK and NPK + M decreased by 19.8% -39.2%, 90.6% -93.1% and 19.8% -34.7%, respectively, compared with CON treatment in the paddy, spring wheat and spring corn seasons. Single application of organic fertilizer (M) also increased the risk of apparent N loss, with losses of 209.4 kg hm-2,67.0 kg hm-2 and 198.8 kg hm-2.3, respectively, in paddy, spring wheat and spring maize Under the annual rotation-and-drought system, the apparent nitrogen loss of NPK and NPK + M decreased by 46.9% and 33.3% respectively compared with that of CON. Therefore, the balanced application of N, P and K and organic-inorganic fertilizers under the system of rotation and drought were beneficial to increase crop yield and reduce the apparent nitrogen loss.