畜禽粪便有机肥中重金属在土壤剖面中积累迁移特征及生物有效性差异

通过田间小区试验，定量化研究连续4 a施用不同量猪粪、鸡粪有机肥后不同重金属在土壤剖面中迁移积累特征及生物有效性差异，为科学确定农田土壤重金属的环境容量提供依据.结果表明，连续4 a施用猪粪显著增加了耕层土壤中Cu、Cd的含量，与对照比增幅分别是43.8%~118.6%和28.2%~44.9%.施用鸡粪显著增加耕层土壤Cu、Zn、Cd、Cr、As、Pb含量，增幅分别为29.7%~48.5%，239%~456%，19.9%~80.8%，40.4%~163%，11.8%~22.0%和80.3%~95.0%.猪粪带入的Cu、Zn在耕层土壤中的积累率分别为76.4%~119%和14.2%~20.4%，鸡粪带入Cu、Zn在耕层土壤中的积累率分别为72.1%~88.7%和63.9%~78.9%.施用高量的猪粪、鸡粪Cu、Zn存在明显向土壤深层迁移现象，连续4 a施用60 t·hm^-2的猪粪，Cu迁移到了15~30 cm土层.连续4 a施用60 t·hm^-2鸡粪，Zn迁移到了30~60 cm土层.但连续4 a施用不同量猪粪和鸡粪，土壤剖面中耕层以下土层中Cd、Cr、As、Pb含量均没有显著增加.连续4 a施用鸡粪显著降低小麦籽粒中Cu、Cd含量，显著增加了小麦籽粒中Zn、Cr含量和小麦秸秆中Zn含量，连续4 a施用猪粪显著降低了小麦籽粒中Zn含量，60 t·hm^-2猪粪显著增加了小麦子粒中As含量，猪粪处理还显著增加了秸秆中Cu、As含量.4 a小麦收获累计对有机肥带入重金属的携出率小于6%.小麦籽粒对Cu、Zn的累计携出量高于秸秆，对Cd、Cr、As、Pb携出量低于秸秆，有机肥用量越高，小麦收获对有机肥带入重金属的携出率越低.确定农田土壤重金属环境容量时应考虑不同有机肥中重金属在土壤剖面中积累特征和向下迁移量.

Accumulation and Migration Characteristics in Soil Profiles and Bioavailability of Heavy Metals from Livestock Manure

The long term and high dosage application of livestock manure may result in heavy metal accumulation and migration in the soil, which may endanger food security and affect the top soil heavy metal environmental capacity. Thus, one of the most important tasks for prevention of soil heavy metal pollution is scientific determination of the safe use load of heavy metals in livestock manure. A 4-year field plot experiment was carried out to quantitatively study the accumulation and migration characteristics of heavy metals from pig and chicken manure in soil profiles and the differences of bioavailability. The results showed that the contents of Cu and Cd increased significantly by 43.8%-118.6% and 28.2%-44.9% in topsoil(0-15 cm) after 4-consecutive year application of pig manure, and the contents of Cu, Zn, Cd, Cr, As, Pb also increased by 29.7%-48.5%, 239%-456%, 19.9%-80.8%, 40.4%-163%,11.8%-22.0% and 80.3%~95.0% obviously after application of chicken manure. The accumulation rates of Cu and Zn in topsoil were 76.4%-119% and 14.2%-20.4% with pig manure, 72.1%-88.7% and 63.9%-78.9% with chicken manure. Under a high dosage of pig and chicken manure, Cu and Zn migrated to a deeper soil evidently. Applying 60 t·hm^-2 of pig manure after 4-consecutive year, Cu could migrate to 15-30 cm soil layer, Zn migrated to 30-60 cm soil layer with chicken manure. Except topsoil, the contents of Cr, Cd, As, Pb did not significantly increase in other soil layers. 4-year continuous application of chicken manure significantly decreased the contents of Cu and Cd, but increased the contents of Zn and Cr in wheat grain and the content of Zn in wheat straw. Pig manure significantly decreased the content of Zn in wheat grain, but increased As content with 60 t·hm^-2, the contents of Cu and As in wheat straw also increased significantly. Besides, the cumulative rate of heavy metals in wheat was no more than 6%, wheat grain carried out more Cu, Zn than straw, but the Cd, Cr, As, Pb were opposite. The cumulative rate of heavy metals in wheat decreased with the increasing application of manure. This research has an important significance in scientific determination of the heavy metal loads of plow layer, ensuring the quality and safety of agricultural production, and providing a scientific basis for the source control of soil heavy metal pollution and the safety production of agricultural goods.