施肥对水旱轮作作物产量、土壤无机氮残留及氮素平衡的影响

Effect of Fertilization on Crops Yield, Soil Mineral Residual N, and Apparent N Balance in a Paddy-upland Rotation System

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。

With a rotation system of p addy ricespring wheatspring maize in the Yellow River Irrigation Region of Ningxia from 2008 to 2010, a field experiment was conducted to investigate the effect of five different fertilization methods of no fertilizers(CK), balanced application of NPK fertilizers(NPK), dairy manure(M), combined application of chemical and manure fertilizers(NPK + M), and conventional fertilizers(CON) on crops yield, soil mineral residual N, and apparent N balance in the paddy-upland rotation system. The results showed that crop grain and straw yields were increased in different fertilization treatment compared to treatment CK in the paddy-upland rotation system.However, soil residual NO3--N in 0100 cm soil depth profiles was significantly increased after fertilization from paddy rice to spring wheat. According to apparent N balance, apparent N losses in treatments NPK and NPK + M were decreased by 19.8%-39.2%, 90.6%-93.1% and 19.8%-34.7% in compared with treatment CON in the paddy rice,spring wheat, and spring maize season, respectively. Application of manure(M) may also reduce the risk of apparent N losses, which was 209.4, 67.0, and 198.8 kg hm-2in paddy rice, spring wheat, and spring maize season, respectively.In the three-year rotation system, the apparent N losses in treatments NPK and NPK + M were decreased by 46.9%and 33.3% in contrast to treatment CON, respectively. Therefore, the balance application of NPK and the combined application of organic- inorganic N fertilizers could increase crops yield and synchronously reduce apparent N losses in the paddy-upland rotation system.