园林废弃物资源化处理对人工林土壤养分及微生物碳源利用的影响

Effects of garden waste reuse treatments on soil nutrients and microbial carbon source utilization in plantation soil

【目的】园林废弃物经资源化处理利用是人工林土壤培肥和增强碳汇功能的有效途径。研究园林废弃物不同资源化方式对人工林土壤化学性质和微生物群落功能的影响,可为园林废弃物的高效利用提供科学依据。【方法】在北京市房山区金叶榆Ulmuspumila‘Jinye’人工林下开展试验,设置粉碎物、堆肥、生物质炭等3种园林废弃物资源化物料和1、2、4 kg·m-23个基于碳当量的施用量,采用Biolog-ECO微平板法测定土壤微生物代谢强度,分析了不同物料和施用量对土壤pH、养分质量分数、微生物碳源利用程度和功能多样性指数的影响。【结果】①3种物料均提高了土壤有机碳和硝态氮质量分数,粉碎物和堆肥处理显著降低了弱碱性土壤的pH,对铵态氮和有效磷质量分数影响不大;生物质炭处理则提高了土壤pH,降低了铵态氮和有效磷质量分数;②土壤微生物对碳源利用程度和微生物群落功能多样性从大到小依次为粉碎物、堆肥、生物质炭;③在6类碳源中,糖类、羧酸类和氨基酸类是区分碳源微生物对3种物料利用的主要碳源种类;3种物料均促进了土壤微生物对酚酸碳源的利用,降低了对氨基酸碳源的利用,粉碎物和堆肥处理下微生物对氨基酸、聚合物等碳源利用强于生物质炭处理,且生物质炭处理下微生物对糖类利用最强;④不同施用量对土壤微生物碳源利用的影响差异不显著,随施用量增大微生物群落功能多样性有增加趋势。【结论】园林废弃物粉碎物、堆肥及生物质炭均能在一定程度上改善人工林土壤质量,其中,粉碎物和堆肥处理对降低弱碱性土壤pH、增加土壤肥力及提高土壤微生物群落功能多样性的效果优于生物质炭。

[Objective]Resource utilization of garden waste is an effective way to improve soil fertility and enhance carbon sink function of plantations.Study on the effects of different reuse treatments of garden waste on soil chemical properties and microbial community in the plantation soil can provide scientific basis for efficient utilization of garden waste.[Method]Experiments were carried out in an Ulmus pumila‘Jinye’plantation,in Fangshan District,Beijing City.Experimentation including three types of garden wastes products,crushed material,compost and biochar,and 1,2 and 4 kg·m^(−2) carbon-based amounts were set up.Biolog-ECO microplate method combined with conventional soil chemical properties measurement were conducted in order to analyze the effects of different materials of garden waste and their application amounts on soil pH,nutrient content,microbial carbon source utilization and functional diversity indices of soil microbial community. [Result] (1) All three types of organic materials increased the content of soil organic carbon and nitrate nitrogen while crushed material and compost significantly reduced the pH value of weakly alkaline soil, with little impact on the content of ammonium nitrogen and available phosphorus. Meanwhile, biochar increased the soil pH value and decreased the content of ammonium nitrogen and available phosphorus;(2) The microbial utilization of carbon sources and the functional diversity of microbial community are as follows: crushed material>compost>biochar. (3) Among the six types of carbon sources, carbohydrate, carboxylic acids and amino acid carbon source were the main carbon sources used by microorganisms, which could distinguish the three treatments of garden waste. The three organic materials all promoted the microbial utilization of phenolic acid carbon source and reduced the utilization of amino acid carbon source. The utilization of amino acid, polymer and other carbon sources by carbon-oriented microorganisms in treatment of crushed materials and compost were stronger than that of biochar while the microbial utilization of carbohydrate carbon source in biochar is the strongest among the three treatments;(4) The effect of application amounts on soil microbial carbon source utilization was not significant, and functional diversity of microbial community increased with the increase of application amounts. [Conclusion] Garden waste could be used to improve the soil quality of plantation by three types of treatments. Compared to biochar, crushed material and compost were more effective in reducing the pH of weakly alkaline soil, increasing soil fertility, and improving the functional diversity of soil microbial community.