蚯蚓粪生物炭配施对铅污染土壤养分和生菜生长的影响

Effects of Combined Application of Earthworm Manure and Biochar on Soil Nutrients and Lettuce Growth in Pb Contaminated Soil

为了研究蚯蚓粪生物炭配施对铅污染土壤及生菜生长的影响,本试验利用盆栽方法以不同水平蚯蚓粪(4%E、8%E、12%E)与生物炭(2.4%B、4.8%B、7.2%B)配施处理Pb污染土壤,以不施蚯蚓粪和生物炭为对照(CK),分别测定了土壤的基本化学性质、重金属铅含量,以及生菜生物量和地上部重金属铅含量。结果显示:与对照相比较,蚯蚓粪生物炭配施显著提高了铅污染土壤中有机质、全氮、碱解氮、有效磷、速效钾含量及生菜生物量(P<0.05);随着蚯蚓粪和生物炭施用量的增加,铅污染土壤有机质、全氮、碱解氮、速效钾含量均呈增加趋势,生菜中铅含量呈降低趋势,说明二者对上述指标的影响存在加和效应,而对铅污染土壤全磷、全钾、有效磷、铅含量及生菜生物量的影响存在互作效应,分别以4%E+7.2%B,12%E+7.2%B,12%E+4.8%B,12%E+7.2%B,8%E+7.2%B最高。综合而言,适宜的蚯蚓粪生物炭配施有助于改善土壤理化性质,提高铅污染土壤铅的固定,降低生菜铅含量并提高生菜产量,本试验以蚯蚓粪8%~12%处理配施生物炭7.2%效果较好。

In order to study the effects of biochar with earthworm manure application on Pb contaminated soil and the growth of lettuce, the experiment was conducted with combining application of earthworm manure (4%E, 8%E, 12%E) and biochar (2.4%B, 4.8%B, 7.2%B) to treat Pb contaminated soil through pots experiment, no earthworm manure and biochar was as control (CK), the soil basic chemical properties, soil Pb content, lettuce biomass and plant Pb content were determined. The results showed that compared with the control, the contents of organic matter, total nitrogen, alkali-hydrolyzed nitrogen, available phosphorus, available potassium and lettuce biomass in the Pb-contaminated soil were significantly increased by the combined application of earthworm manure and biochar (P<0.05). With the increasing of earthworm manure and biochar application amount, the content of organic matter, total nitrogen, alkali-hydrolyzed nitrogen and available potassium in Pb contaminated soil increased while the lettuce Pb content decreased, indicating that the combined application of earthworm manure and biochar had an additive effect on the above indices. However, the combined application of earthworm manure and biochar had an interaction effects on the total phosphorus, total potassium, available phosphorus, Pb content and lettuce biomass in Pb contaminated soil, of which the maximum value were occurred at 4%E+7.2%B, 12%E+7.2%B,12%E+4.8%B,12%E+7.2%B,8%E+7.2%B,respectively. In summary, proper combined application of earthworm manure and biochar was helpful to improve the physical and chemical properties and even the Pb fixation of Pb contaminated soil, reduce the lettuce Pb content and increase the lettuce yield. In this experiment, the comprehensive effects were optimal when the earthworm manure application amounts were between 8% and 12%.and the biochar application amount was 7.2%.