食用菌菌渣对土壤氮循环的影响机制研究

China has already become the world's largest mushroom producer, and annual mushroom residues are up to 150 million tons. Mushroom residues contain a large number of macro and trace elements essential for crop growth. Applications of mushroom residue compost into agricultural soils have the potentials to enhance soil fertility and to reduce the environmental pollution caused by mushroom residues. As a novel nitrification inhibitor, 3,4-dimethylpyrazole phosphate (DMPP) has the potentials to increase fertilizer utilization rate, and the combined applications of mushroom residue compost and nitrification inhibitor DMPP might increase crop yield and improve crop quality. However, researches about the impacts of mushroom residues on soil nitrogen cycling are relatively little, especially under different soil moistures, and more attention should be paid to the combined effects of mushroom residues and nitrification inhibitor DMPP on soil quality and crop growth. In the current research project, typically intensive agricultural soil is selected, and oyster mushroom (Pleurotus ostreatus) residues are applied into the soils and incubated under different moisture conditions. During the incubation, soil samples are collected to analyze soil nutrient contents, nitrogen cycling rates and microbial properties including biomass, activities and communities. The comprehensive relationships among residue application rates, soil nutrient contents and nitrogen cycling rates are also linked. Simultaneously, the mushroom residue compost is applied into the tillage soils with the nitrification inhibitor DMPP to reveal the impacts of mushroom residue compost, alone or together with the DMPP on soil environmental quality and crop growth. Our studying results will reveal potential impacts of mushroom residues on soil nitrogen cycling and provide scientific and detailed support for ecological risk assessment of mushroom residue applications in intensive agriculture. The conclusion will be helpful for resource utilization of mushroom residues and promoting the sustainable development of mushroom industry.

我国已成为世界第一大食用菌生产国且每年亟待处理的食用菌菌渣高达1.5亿吨。菌渣中富含农作物生长所需的多种养分，将菌渣还田或与硝化抑制剂DMPP联合施用有助于提高土壤肥力并可以解决菌渣不恰当处理所造成的环境污染问题。目前菌渣施用对土壤氮循环的影响机制尚不清楚，菌渣有机肥与硝化抑制剂DMPP联合施用后土壤环境质量-氮循环-农作物生长之间的耦合机制仍不明晰。本研究拟选取平菇菌渣与典型设施农业土壤为研究对象，探究菌渣施用在不同水分含量梯度下对土壤肥力、氮循环与微生物群落的作用机制。同时开展盆栽实验研究菌渣有机肥与硝化抑制剂DMPP联合施用对土壤环境质量、氮循环与农作物生长的影响。本项目的研究结果将有助于揭示菌渣施用对土壤环境质量与氮循环的影响机制，为设施农业条件下资源化利用食用菌菌渣与提高菌渣有机肥的利用率提供技术支持，有利于促进食用菌产业的健康可持续发展。

本项目选取平菇菌渣与典型设施农业土壤为研究对象。阐明在不同土壤水分含量梯度下菌渣施用后土壤养分-酶活性-温室气体之间的综合关系，开展盆栽实验定量分析菌渣有机肥与硝化抑制剂联合施用在增加农作物产量，改善品质以及影响土壤氮转化过程与微生物群落的作用机制。结果表明：（1）菌渣的添加虽然提高了土壤酶活性，但是也提高了全球增温潜势。综合评估土壤酶活性与温室气体排放以确定适宜菌渣添加量；（2）揭示菌渣与硝化抑制剂联合配施可以提高生菜产量但会导致土壤中抗性基因丰度的增加，需要进一步关注食用菌渣施用所带来的健康风险；（3）菌渣和硝化抑制剂的施用不仅可以提高果实产量，还可通过影响土壤pH、NH4+-N含量和果实内生细菌群落结构、多样性和功能，来降低因作物NO3--N积累带来的健康风险；（4）菌渣的施加对土壤氮矿化与硝化速率的影响不显著，但显著影响了土壤氮循环功能基因的丰度并改变了土壤微生物的群落结构。上述结果揭示食用菌菌渣对土壤氮循环与环境质量影响的调控机制，为设施农业条件下资源化利用菌渣与提高菌渣有机肥的利用率提供技术支持。