Studies On The Accumulation，Transference And Transformation Of Capper Derived-from Livestock Manure In Soil-Wheat System

Pointing to the safety issue of livestock waste pollution and potential use by farmland crop inmodern livestock breeding, pot experiments were conducted in this study to examine the accumulation,transport and transformation of Cu derived from livestock manure (LM) in soil-plant system. Differentconcentrations of Cu (0,100,200,400,600and800mg kg-1soil, added as CuSO4) spikedinto LM to simulate soil Cu contamination by LM application in three soil types. Across2-year growth (2009and2010), Both wheat tissues and soil samples were collected duringripening stage of wheat for analyses of total Cu, available Cu and different forms of Cu. Weaimed to understand the processes of accumulation, transport and distribution of LM-derivedCu in soil, the transport of Cu from soil to wheat and in vivo, and the relationship between theCu contents in wheat tissues and the Cu bioavailability in three different kinds of soil, Themain results were listed as follows:1. In all three soil types (Paddy soil, Fluro-aquic soil and Mollisol), the contents of soiltotal Cu in increased with the increased extraneous Cu concentrations, this index in2009washigher than2010.2. The fractions of Cu in soil and their contents differed with different soil types andextraneous Cu concentrations. When the extraneous Cu entered into soil, Cu waspredominately existed in oxidable and residual fractions. With increasing extraneous Cuconcentrations, Acid-extractable fraction drastically increased in Paddy soil and Fluro-aquicsoil, while reducible fraction drastically increased in Mollisol.3. Both soil available Cu content and its proportion in total Cu increased with increasingextraneous Cu concentrations. The soil available Cu content in2010was significantly lowerthan that in2009, which was due to the decreased bioavailability with prolonged pollutiontime. Available Cu contents in both Paddy soil and Fluro-aquic soil were higher than that inMollisol, especially for the year of2009. 4. The availability of LM-derived Cu was significantly lower, especially in2010.5. The Cu fractions (Acid-extractable, reducible fraction and oxidable fraction) weresignificant positive correlated with soil Cu mobility and availability. In Mollisol,Acid-extractable Cu contributed most to available Cu. In both Paddy soil and Fluro-aquic soil,the contribution of different Cu fractions to Cu availability varied due to different years anddifferent LM application amounts.6. Although the contents of Cu in wheat was generally very low compared with Cuaccumulation in soil, the root Cu concentrations increased with increasing extraneous Cuconcentrations. Cu accumulation in different organs of wheat was according to the order:root>> stem&leaf&grain, indicating the more sensitivity of roots to the soil Cu, Theimmobilized Cu was dominantly enriched in roots with limited translocation to aerial parts,thus the concentrations of Cu in straw and grains were in a narrow range.This research studied the fractions and distribution of LM-derived Cu in soil-plant system.We find Cu could accumulate in soil with high bioavailability after long-term application ofLM with Cu enrichment, potentially leading to Cu accumulation in crops at an unsafe leveland consequent healthy risk to human beings. Therefore, it is necessary to further study theimpact of long-term LM application on field plant growth and sequent environmental safety,in order to provide scientific theory for better predicting soil environmental quality, ensuringthe quality and safety of agricultural products, and guarantying human health.