施用生物炭对Cd污染土壤生物学特性及土壤呼吸速率的影响

摘要

[目的]为研究施用生物炭对Cd污染土壤生物学特性及土壤呼吸速率的影响.[方法]于2016年采用盆栽试验(每盆装土25 kg),外源添加Cd 0 mg/kg(G0)、30 mg/kg(G1)、60 mg/kg(G2),分别添加生物炭0 g/kg(T0)、10 g/kg(T1)、20 g/kg(T2),二因素试验共计9个处理,分别为:G0T0、G0T1、G0T2、G1T0、G1T1、G1T2、G2T0、G2T1、G2T2.测定不同时期的土壤微生物数量,土壤微生物生物量碳、氮,土壤酶活性及土壤呼吸速率.[结果]土壤脲酶活性、土壤细菌、放线菌数量和土壤微生物生物量碳、微生物生物量氮含量和土壤呼吸速率均随施加Cd浓度的升高呈现降低的趋势,随生物炭的施用而显著增加,且均在移栽后55 d达到较高水平.土壤呼吸速率随生育期的延长呈升高的趋势,在Cd污染严重的土壤中,土壤呼吸速率随生物炭施用量的增加显著提高.[结论]施用生物炭能明显改善Cd污染土壤的生物学特性,提高土壤呼吸速率,从而达到改善Cd污染土壤质量的目的.%[Objectives]This paper aimed to study eff ects of biochar on soil biological characteristics and soil respiration rate of Cd contaminated soil.[Methods]Experiment was carried out in 2016 by means of pot plants (25kg soil per pot). The added exogenous Cd concentrations were 0mg/kg (G0), 30mg/kg (G1), 60 mg/kg (G2) and the biochar concentrations were 0g/kg (T0), 10g/kg (T1), 20g/kg (T2) respectively. A total of nine treatments were used for the two-factor test, which were G0T0, G0T1, G0T2, G1T0, G1T1, G1T2, G2T0, G2T1, G2T2. Soil microorganisms and soil microbial biomass (carbon, nitrogen), soil enzyme activity and soil respiration rate were measured in diff erent periods. Results showed that soil urease activity, number of soil bacteria and actinomycetes and soil microbial biomass carbon and microbial biomass nitrogen and soil respiration rate increased significantly along with the application of biochar, and all reached higher level 55d after transplanting. Soil respiration rate increased with growth period, and soil respiration rate increased significantly with the increase of biochar application in heavily Cd contaminated soil.[Conclusions]Application of biochar can signifi cantly improve biological characteristics of Cd contaminated soil and improve soil respiration rate, so as to improve quality of Cd contaminated soil.