生物炭对新疆沙土微生物区系及土壤酶活性的影响

为评估生物炭在新疆改良沙土的潜力,在新疆和田设生物炭施用量为0(CK)、22 500、67 500、112 500kg·hm~(-2)和225 000 kg·hm~(-2)5个处理的微区试验,轮作方式为绿豆-冬小麦。通过对试验结束后小区土壤可培养微生物和生理菌群计数、土壤酶活性测定,研究不同用量生物炭对沙土土壤微生物区系及土壤酶活性影响。结果表明:施用生物炭对沙土土壤养分含量、微生物区系和土壤酶产生显著影响。22 500~67 500 kg·hm~(-2)生物炭施用量能显著提高沙土土壤有机碳、速效磷和速效钾含量。生物炭影响沙土中可培养细菌、真菌及放线菌数量,在生物炭施用量为67 500 kg·hm~(-2)下细菌数量最高,比CK增加了63.83%;施用量为22 500 kg·hm~(-2)放线菌数量最高,增加了250.00%;施用量为67 500 kg·hm~(-2)真菌数量最少,降低了71.43%。生物炭影响沙土中纤维素分解菌和自生固氮菌数量,随着施用量增加,其数量呈先增加后降低趋势,其中施用量为112 500 kg·hm~(-2)纤维素分解菌和自生固氮菌数量最多,分别比CK增加了211.11%和1 057.89%。土壤中添加67 500~112 500 kg·hm~(-2)的生物炭土壤中蔗糖酶、过氧化氢酶和蛋白酶活性最高。相关分析表明,不同生物炭施用量条件下,土壤养分与细菌、亚硝化细菌、反硝化细菌、土壤酶(磷酸酶除外)关系密切。因此,适量施用生物炭能提高沙土土壤养分、增加微生物菌群数量和土壤酶活性,在本试验点最适生物炭用量为67 500 kg·hm~(-2)。

Effects of biochar application amount on microbial flora and soil enzyme activities in sandy soil of Xinjiang

In order to assess the potential of biochar application to sandy soil ,a two-year bean-wheat rotation plot field experiment was conducted in Hetian ,Xinjiang Province .Through analyzing the amount of soil culturable microor-ganisms ,the number of bacterial physiological groups and soil enzyme activities ,and the influence of difference biochar application amount on sandy soil microbial flora and soil enzyme were studied .The experiment was designed to have five treatments in biochar application rates ,including 0 kg·hm-2 (CK) ,22 500 kg·hm-2 ,67 500 kg·hm-2 ,112 500 kg·hm-2 and 225 000 kg·hm-2 of biochar application .Results showed that application of 22 500~67 500 kg·hm-2 biochar could significantly improve content of OM ,available P ,and available K .In addition ,the number of bacteria and actinomycetes by applications of different amounts of biochar soils were increased first and then became decreased .The number of bacteria with application of 67 500 kg·hm-2 biochar was increased by 63 .83% .The number of actinomycetes with application of 22 500 kg·hm-2 biochar was increased by 250 .00% .The number of fungi was decreased first and then increased .The number of fungi with application of 67 500 kg·hm-2 biochar was decreased by 71 .43% .Further-more ,the numbers of cytophaga and azotobacter with applications of different amounts of biochar soils were increased first and then decreased .The number of bacteria with application of 112500 kg·hm-2 biochar was increased by 211 .11% and 1 057 .89% , respectively . Also , invertase , catalase and protease activities with applications of 67 500 ~ 112 500 kg·hm-2 biochar were the highest .Correlation analysis also showed that soil nutrition and bacteria ,nitrifying bacteria , denitrifying bacteria , soil enzyme activities (except for phosphatase ) were related closely . The results showed that biochar at 67 500 kg·hm-2 caused the greatest effects in increasing soil nutrient contents ,improving the number of mi-crobial community and enhancing soil enzyme activities supply in sandy soil .