不同生物质炭对铅污染淡灰钙土的性质与铅形态变化的影响

通过盆栽试验研究了Pb污染淡灰钙土中施加不同量鸡粪衍生生物质炭(CBC)和油菜秸秆衍生生物质炭(RBC)后,土壤性质变化及基于BCR 4步连续提取法的土壤Pb形态转化特征,并通过逐步回归分析探讨了土壤性质变化与Pb形态转化间的相关性。结果显示:随生物质炭施加量的增加,Pb污染淡灰钙土中Pb形态向更稳定态转化,CBC(RBC)施加量为15%时,酸可提取态Pb百分含量分别下降17.04%(12.3%)。当生物质炭处理水平在10%以下时,RBC施入Pb污染淡灰钙土后对Pb的固定作用更加明显;施加量10%以上时,CBC施加后对Pb的固定效果更占优势。随CBC施加量的增加,土壤p H值、碳酸盐含量、有机质含量显著增加(最大增幅分别为11.36%、6.7%、419.13%),并与Pb形态转化相关性显著(P0.05);随RBC施加量的增加,土壤p H值显著增加(最大增幅10.99%)是影响酸可提取态Pb转化的重要因素,而有机质含量显著增加(最大增幅1 334.56%)对铁锰氧化物结合态、有机结合态和残留态Pb的转化影响显著。由于土壤p H过大会降低土壤质量,建议RBC施加量在10%以内,而CBC的施加量应小于5%。

Effects of biochars derived from chicken manure and rape straw on soil properties and lead form transformation in a lead-contaminated light sierozem

This study was to assess the impacts of biochars on soil properties and lead form transformation of lead-contaminated light sierozem. Biochars were prepared from chicken manure(CBC) and rape straw(RBC). Correlation between soil properties and lead form transformation was examined using Stepwise Regression Analysis. Applications of biochars transformed lead into stable forms. At biochar rate of 15%, acid extractable lead decreased by 17.04% for CBC and 12.3% for RBC, as compared with the control. Lead immobilization was more obvious at RBC less than 10% or at CBC higher than 10%. The additions of biochars significantly increased soil pH values by up to 11.36% in CBC-soil and 10.99% in RBC-soil and organic matter content by up to 419.13% in CBC-soil and 1334.56% in RBC-soil, which largely influenced the transformation of lead forms. In addition, elevated content of carbonates(the maximum increment of 6.7%) by CBC addition also influenced the lead transformation. However, too high soil pH might lead to reduction in soil quality. Therefore, it is recommended that biochar application rates should be less than 10% for RBC and less than 5% for CBC.