两种生物炭对污染土壤铜有效性的影响

Effects of Two Kinds of Biochars on Soil Cu Availability in Contaminated Soil

采用盆栽试验，探究了添加不同比例（0，1％，2％，4％）玉米秸秆炭和商陆根生物炭对铜污染红壤中小油菜生长与铜有效性的影响。结果表明，与对照相比，添加两种生物炭均能够增加铜污染红壤上小油菜的生物量。在低铜污染水平下，4％玉米炭和商陆炭处理小油菜生物量分别增加了21．2倍和67．9倍；高铜污染水平下，4％玉米炭和商陆炭处理小油菜生物量分别增加了8．6倍和109．6倍。商陆炭的添加能够显著提高土壤pH值，在低铜污染水平下，商陆炭处理土壤pH值升高了0．4—1．66个单位，较玉米炭处理土壤pH值多升高了0．25-1．35个单位；在高铜污染下，商陆炭处理土壤pH值升高了0．33～1．52个单位，较玉米炭土壤pH值多升高了0．3-1．25个单位。向污染土壤中添加两种生物炭均能够显著降低土壤有效态铜的含量。其中，在低铜污染土壤中，4％玉米炭和商陆炭处理土壤有效态铜含量分别降低了21．9％和45．2％；在高铜污染土壤中，4％玉米炭和商陆炭处理土壤有效态铜含量分别降低了41．9％和53．8％。两种生物炭均能够显著降低小油菜铜累积量，向低铜污染土壤中添加4％的玉米炭和商陆炭，小油菜地上部铜含量下降了21．2％、67．8％。高污染土壤中添加4％的玉米炭和商陆炭小油菜地上部铜含量下降了19．9％、66．8％。两种生物炭均可以改良红壤的酸度，降低土壤铜有效性，并提高小油菜的生物量，降低小油菜铜累积量，但是商陆炭的效果更为明显。

This paper is aimed to research the impacts of different biochars（0,1%,2%,4% ）, including maize biochar and phytolacca root biochar, on rape growth and the soil Cu availability in the Cu-contaminated red soil via a series of pot experiments. The results showed that, compared with the control, the addition of two kinds of hiochars could increase the biomass of the rape. In low Cu-contaminated red soil, added 4% maize biochar and phytolacca root bioehar increased the biomass by 21.2 times and 67.9 times; however, the biomass were in- creased by 8.6 times and 109.6 times under high Cu-contaminated soil. The addition of phytolacea root biochar could increase the soil pH significantly, which has been increased by 0.4~1.6 units with the addition of phytolacca root biochar in low Cu-coataminated red soil, and it had 0.25~1.35 units more than that with maize biochar; In high Cu-contaminated red soil, with the addition of phytolacea root bioehar, soil pH was increased by 0.33-1.52 units, which was 0.3-1.25 units higher than maize biochar. There was a significant effect on reducing the soil Cu availability with the addition of the two biochars. Among them, 4% addition of maize biochar and phytolacca root biochar could reduce soil available Cu content by 21.9% and 45.2% in low Cu-contaminated soil, however, it was decreased by 41.9% and 53.8% in high Cu-contami- nated soil. Both of the two bioehars were able to reduce the Cu accumulation in rape, where there was a decrease by 21.2% and 67.8% with the addition of 4% maize biochar and phytolacca root biochar under low Cu-contaminated soil, and it was decreased by 19.9% and 66.8% in high Cu-contaminated soil respectively. Both of the biochars could ameliorate the acidity and Cu availability in the red soil, enhance the biomass of the rape and reduce the Cu accumulation in rape, but phytolacca root biochar had more effective influence than maize biochar.