冬季轮茬作物养分还田特征及其对水稻产量和稻田水环境的影响

采用大田小区试验研究了不同冬季轮茬种植模式下作物养分还田特征,及其对水稻产量和稻田表水环境主要参数的影响,并对各轮茬种植模式下的经济效益进行了分析。结果表明,不同冬季轮茬作物产量差异较大,且其养分含量差异亦较大,导致各轮茬种植模式下养分还田量差异显著。“红花草-水稻”模式下,N、P素还田量均最高。从短期效应来看,冬季作物轮茬对后茬水稻株高、产量及肥料利用率的影响均不显著。然而,从环境效应角度考量,不管何种轮茬种植模式,均应充分考虑水稻季基肥到分蘖肥期间的稻田水环境效应,监测发现,稻田表水总磷（TP）、可溶性总磷（DP）平均含量几乎都超过了易引发水体富营养化的临界水平（溶解磷0.05 mg/L和总磷0.1 mg/L）。同时,从周年经济效益角度考量,“青饲小麦-水稻”和“蚕豆-水稻”种植模式具有较高收益,可进一步推广应用。

Nutrients Return Characteristics of Winter Rotation Crops and the Effects on Grain Yield and Main Parameters of Surface Water Environment during the Successive Rice Growing Season

A field experiment was conducted to study the nutrients （nitrogen, phosphorus and potassium） return characteristics of winter rotation crops and their effects on grain yield and main parameters of surface water environment during the successive rice growing season. The results showed that the yield and nutrients content of winter rotation crops were different significantly, which led to significant difference in the amount of nutrients returned to the paddy field under different winter crop-paddy rice rotation patterns. Under “Chinese milk vetch-paddy rice” rotation pattern, the amount of nitrogen （N） and phosphorus （P） were the highest. In the short term, the effects of winter crop rotation on the plant height, yield and fertilizer utilization of the subsequent rice were not significant. However, from the view of environmental effect, no matter what winter crop-paddy rice rotation patterns, during the rice growing season, the negative environmental impact of surface paddy water should be fully considered during the period from base fertilizer to tiller fertilizer. The monitoring results showed that the average contents of total phosphorus （TP） and dissolved phosphorus （DP） in the surface water of paddy rice field were almost higher than the critical level of water eutrophication （dissolved DP 0.05 mg/L; TP 0.1 mg/L）. Furthermore, from the perspective of annual economic benefits, higher income could be achieved under the green feeding winter wheat-rice rotation pattern and broad bean-rice rotation pattern, which might be further promoted and applied in the agricultural production of Taihu Basin, China.