有机无机肥配施对稻-油系统中重金属污染风险和产品质量的影响

Risk of heavy metal pollution and product quality in rice-rape cropping system as affected by integrated fertilization with commercial organic manure and chemical fertilizers

通过田间试验研究有机无机肥配合施用对水稻—油菜轮作体系重金属污染风险和农产品质量的影响.试验设置化肥(T1)、化肥+低量有机肥(T2)、化肥+中量有机肥(T3)、化肥+高量有机肥(T4)4个处理,各处理氮磷钾用量相等,重复4次.结果表明,不同施肥处理水稻和油菜地上部生物量及籽粒产量没有显著差异(油菜茎杆除外).糙米Cd含量随有机肥配施比例提高而增加,中量和高量有机肥与化肥配施处理(T3和T4)糙米Cd含量已接近谷类污染的临界值0.2mg?kg-1,存在一定的健康风险.根据油菜籽粒的出油率35%折算(其他部分为菜籽饼)和国家饲料卫生标准对饲料中Cd、Pb的卫生要求,油菜籽粒的Cd、Pb含量均在安全范围内.化肥处理(T1)会引起土壤-作物系统Cu和Zn的亏缺,施用有机肥(T2、T3、T4)会导致Cd的积累,全部处理均有Pb的积累.适量有机肥与化肥配合施用既可在一定程度上防止微量营养元素(Cu和Zn)的亏缺,也可有效地控制农田生态系统重金属的污染,是农业可持续发展的有效途径之一.

A field experiment was conducted to assess the impacts of integrated fertilization with commercial organic manure and chemical fertilizers on risk of heavy metal pollution and quality of agricultural products in rice-rape cropping system. Four treatments as chemical fertilizers （T1）, chemical fertilizers ＋ lower rate of organic manure （T2）, chemical fertilizers ＋ medium rate of organic manure （T3）, and chemical fertilizers ＋ high rate of organic manure （T4） were designed in the experiment. The doses of N, P2O5, and K2O of each treatment were equal, and each treatment had four replications. The results indicate that the differences of shoot biomass and grain yields of rice and rape among treatments were not significant （P〉0. 05）. Cadmium concentration in brown rice increased with the increase in the ratio of organic manure applied. Healthy risk existed as cadmium concentration in brown rice of treatments with medium and high rate of organic manure were as high as the limit （0.2 mg·kg^-1） in cereals. According to the oil content of rapeseed 35 %（others are rapeseed meals） and Hygienical Standard for Feeds, cadmium and lead concentrations in rapeseed of all treatments were in the safety arrangement. It was also found that zinc and copper was obviously deficit in soil-crops system with chemical fertilizers （T1）; cadmium was accumulated in the treatments applied with organic manure and lead was accumulated apparently in four treatments. It could be concluded that integrated fertilization with appropriate rate of organic manure and chemical fertilizers could not only remain the balance of zinc and copper, but also minimize the risk of heavy metal pollution in the cropping system, which can be regarded as an effective manner for the construction of sustainable agriculture.