生物炭对菜园土壤微生物功能多样性的影响

摘要

研究生物炭的施用及其与不同肥料混施对菜园土壤中微生物群落功能多样性的影响,为农业废弃物的合理利用和菜园土优化培肥提供科学依据和理论指导.以清远市连州县代表性菜园土(属肥熟旱耕人为土)为研究对象,通过盆栽试验,利用BIOLOG方法对10个施肥处理(对照CK(0％生物碳+无肥)、T1(0％生物碳+0.1％商品有机肥)、T2(0.1％生物碳+无肥)、T3(0.25％生物碳+无肥)、T4(0.5％生物碳+无肥)、T5(1％生物碳+无肥)、T6(100(N) +30(P2O5) +75 (K2O) mg/kg干土)、T7(0.1％生物碳+0.1％商品有机肥)、T8(0.1％生物碳+100(N) +0(P2O5) +75(K2O) mg/kg干土)、T9(0.1％生物碳+100(N) +30(P2O5)+75(K2O) mg/kg干土)、T10(0.1％生物碳+0.1％商品有机肥+100(N) +0(P2O5) +75(K2O) mg/kg干土))的土壤微生物群落功能多样性进行分析.结果表明:(1)T1和T3处理比其它处理显著提高土壤微生物对碳源的利用率(P＜0.05),但生物炭施用量增加会降低平均颜色变化率(AWCD值);(2)T1处理可以显著提高土壤微生物的群落物种均匀度(Mclntosh指数),而T3处理显著提高土壤微生物的物种丰富度和均匀度(Shannon和Mclntosh指数);(3)T1和T3处理对聚合物类、碳水化合物类、羧酸类、氨基酸类和酚类碳源利用率最高;(4)添加化肥处理中磷肥的施用可以提高土壤微生物活性,增加土壤微生物碳源利用能力,而氮肥和钾肥的添加显著降低了土壤微生物的碳源利用能力;(5)主成分分析表明,T1、T2和T3处理的微生物碳代谢功能群结构相似;单施有机肥或适量生物炭对土壤微生物群落结构的影响较混合施用更为显著;化学磷肥的添加及在施用化肥的基础上配施适量生物炭改变了土壤微生物对碳源种类的利用.%Biochar can be effectively used to reduce the release of greenhouse gases and fulfill the consequences of carbon sinks.It can also be used to restore degraded soil and improve the structure of soil microbial communities and enhance their functions.This study investigated the effects of different biochar doses and the combined application of biochar with other fertilizers on soil microbial functional diversity,which would provide a scientific basis and theoretical guidance for the rational use of agricultural waste and optimal management of soil fertility in vegetable gardens.In the present study,the representative vegetable garden soil (Fimi-Orthic Anthrosols) was sampled from Lianzhou County,Qingyuan City.Pot experiments were conducted for 40 days in the laboratory.Ten treatments were performed as follows:CK (0％ biochar + 0％ fertilizer),T1 (0％ biochar + 0.1％ commercial organic manure),T2 (0.1％ biochar + 0％ fertilizer),T3 (0.25％ biochar + 0％ fertilizer),T4 (0.5％ biochar + 0％ fertilizer),T5 (1.0％ biochar + 0％ fertilizer),T6 (100(N) + 30 (P 2O5) + 75 (K2 O) mg/kg oven-dried soil),T7 (0.1％ biochar + 0.1％ commercial organic manure),T8 (0.1％ biochar + 100(N) + 0(P2O5) + 75(K2O) mg/kg oven-dried soil),T9 (0.1％ biochar + 100(N) + 30(P2O5) + 75(K2O) mg/ kg oven-dried soil),and T10 (0.1％ biochar + 0.1％ commercial organic manure + 100(N) + 0(P2O5) + 75(K2O) mg/kg oven-dried soil),with three replicates each.Soil microbial functional diversity of the harvested soil samples was analyzed using the Biolog method.Significant variations in soil microbial functional diversity were shown in the treatments with different biochar doses.First,the T1 (0.1％ organic manure) and T3 (0.25％ biochar) treatments significantly increased soil microbial utilization of carbon substrates more than the other treatments (P＜0.05),but further increases of biochar (＞0.25％) reduced average well color development (AWCD).Second,both T1 and T3 treatments had significantly higher species richness (McIntosh index),and only the T1 treatment had higher evenness of community species (Shannon index)than the other treatments.Moreover,T1 and T3 had the highest utilization of polymers,carbohydrates,carboxylic acids,amino acids,and phenols.For the chemical fertilizer treatments,soil microbial activity and microbial utilization of carbon substrates were increased by phosphate fertilizer,but were significantly reduced by nitrogen and potassium fertilizers.Furthermore,a principal component analysis showed that there were similar soil microbial community functional structures in the treatments of T1,T2 (0.1％ biochar),and T3.A single application of organic manure or biochar had stronger effects on the soil microbial community structures than the combined application;however,phosphate fertilizer and the combined application of biochar and chemical fertilizers also changed the soil microbial utilization of carbon substrates.This study indicates that it is necessary to ascertain the treatment doses of biochar and standardize their criteria to promote biochar application at large scales and in different fields.However,the biochar had some negative effects on the eco-environment.Therefore,the biochar sources and amount of biochar doses should be studied to determine the negative effects on soil,to prevent these in future treatments for optimal results.