长期肥料试验对土壤和水稻微量元素及重金属含量的影响

长期肥料试验会影响土壤中微量元素和重金属状况以及作物对微量元素和重金属的吸收。本文研究了长期的不同施肥处理对土壤、糙米中微量元素Cu、Zn、Fe、Mn和重金属Pb、Cd含量的影响,结果表明:经17a连续施用猪粪及秸秆还田显著增加了土壤Cu、Zn和Cd全量,而土壤Fe、Mn和Pb全量在不同施肥处理间没有显著差异;施肥增加了土壤有效态Cu、Zn和Fe含量,其中施用猪粪及秸秆还田的3个处理显著增加了土壤有效态Cu、Zn和Cd含量,而土壤有效态Pb含量在不同施肥处理间没有显著差异。不同处理糙米Cu、Zn、Fe、Mn和Pb含量变化较小或没有显著性差异,而在3个施猪粪和秸秆还田处理中,糙米Cd含量均超过国家食品卫生标准(>0.2 mg kg-1)。水稻地上部吸收积累Cu、Zn、Fe、Mn、Pb和Cd总量与其地上部生物量呈正相关,土壤Cu、Zn、Cd有效态与全量含量呈极显著相关关系,而糙米中的镉含量与土壤镉含量有较好的相关关系。长期施用畜粪导致土壤Cd污染问题应引起高度重视。

Effect of long-term fertilization experiment on concentration of micronutrients and heavy metals in soil and brown rice

A long-term fertilization experiment, designed to have nine treatments varying in application rates of N, P, K and pig manure, with or without incorporation of rice straw to the field, was carried out to determine effect of these treatments on the concentrations of Cu, Zn, Fe, Mn, Pb and Cd in soil, rice plant and brown rice. Results showed that the total soil Cu, Zn and Cd concentrations in Treatment MS(application of pig manure with incorporation of rice straw to the field), NMS(application of N, pig manure with incorporation of rice straw to the field) and NPKMS(application of N, P, K, pig manure with incorporation of rice straw to the field) were significantly higher than in the other treatments, however, they were not significantly different from each other in total soil Fe, Mn and Pb. Compared with CK(no fertilizer), all the fertilization treatments increased soil available Cu, Zn and Fe, and, the MS, NMS and NPKMS treatments did soil available Cu, Zn and Cd, significantly, but did not differ much in soil available Pb between the treatments. The Cu, Zn, Fe, Mn and Pb concentrations in brown rice varied slightly or insignificantly from treatment to treatment. However, the Cd concentration in brown rice in Treatments MS, NMS and NPKMS was higher than the upper limit of the criteria (>0.2 mg kg^-1) of the National Standard for Food Hygiene for Cd concentration. The amounts of Cu, Zn, Fe, Mn, Pb and Cd absorbed by rice plant and accumulated in the aerial part the plant was positively related with the biomass of the aerial part. Soil available Cu, Zn and Cd concentration was positively correlated with the total soil Cu, Zn and Cd concentrations in the soil, and only the concentration of Cd in brown rice could be predicted through total and available concentrations of Cd in the soil. Attention should be paid to the soil Cd pollution caused by long-term application of pig manure containing high concentrations of heavy metals.