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Authors
Affiliations
1 Nanjing Agricultural University, Nanjing, Jiangsu, 210031, CN
Source
Nature Environment and Pollution Technology, Vol 16, No 3 (2017), Pagination: 703-710
Abstract
A large number of straw resources are inefficiently used in China. Direct straw manuring is the most common method for efficiently utilizing these resources. The migration of nutrients and the transfer of hazardous elements such as heavy metals during the cycle, endanger the growth of crops, thereby decreasing food production and adversely affecting human health through the food chains. The mechanism of heavy metal-polluted soil under the recycling mode of direct straw manuring is analysed to determine its distribution characteristics. The concentration distribution characteristics of heavy metals such as Pb, Cr, Cd and As in the soil are identified through experiments. Empirical study shows that the contents of the four heavy metals in the soil of the wheat-maize rotating farmland under direct straw manuring mode do not exceed the values listed in the Environmental Quality Standards for Soils (GB15618-1995). The contents of Cr and Cd in the ischolar_mains of wheat and maize are significantly higher than those in the soil, suggesting the accumulation of these metals in the ischolar_mains, while those of Pb and As do not have this phenomenon. The contents of the heavy metals in the ischolar_mains, stems, leaves and seeds of the crops decrease in order. The pollution of the heavy metals including Pb, Cr, Cd, As under the direct straw manuring is explored, and their migration rules in the farmland ecosystem are systematically explored. The results provide a basis for regulating and blocking heavy metals, preventing heavy metal pollution and safeguarding food safety.
Keywords
Direct Straw Manuring, Heavy Metal Pollution in Soil, Distribution Characteristics.
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