中國科學院東北地理與農業生態研究所草地農牧業學科組基於“玉米秸稈養牛-糞便基質化-草生菌栽培”循環系統，探究了莫能菌素及秸稈種類對氮回收率的影響，旨在明確該循環系統中氮的回收率，並揭示莫能菌素影響循環系統中氮轉化的微生物學機制。相關成果發表於Waste Management（IF=8.816）。

研究工作得到中科院戰略性先導科技專項、吉林省與中科院科技合作高技術產業化專項資金項目、吉林省科技發展計劃項目以及中科院青年創新促進會優秀會員人才專項的支持。

doi：10.1016/j.wasman.2022.06.015

Mushroom cultivation recycled 3.33–5.88 % N from straw and cattle manure.

Monensin reduced N loss by inhibiting ammonification and denitrification.

Monensin decreased recycled N mainly by inhibiting growth of Agaricus bisporus.

Corn straw was better than wheat straw as substrate due to lower N loss.

Although crop-livestock integration recycling systems improve nitrogen (N) utilization in agroecosystems, there are limited studies regarding impacts of residual antibiotics in livestock manure on N transformation in entire recycling system. The objective was to evaluate effects of feeding monensin on N recycling during “straw feeding-substrate fermentation-mushroom cultivation”. This experiment contained 3 steps. During straw feeding, beef cattle were allocated into 2 groups and fed diets with or without monensin, respectively. During fermentation, beef cattle manure (with or without monensin) and straw (corn or wheat) and were co-fermented for 35 d to produce substrates. During cultivation, Agaricus bisporus was cultivated on 4 substrates to recycle N in the form of mushrooms. Rates of N retention during fermentation were significant higher for monensin and corn straw treatments and there was an significant interaction between straw and antibiotic on N retention rate during cultivation. However, residual monensin significantly reduced amount of recycled N during entire recycling system, due to changes in N transformation-associated enzyme activity, ammonification and denitrification plus microbial community structure and succession. Specifically, residual monensin inhibited growth of dominant bacterial phylum Bacteroidetes and fungal phylum Neocallimastigomycota, and increased bacterial phylla Actinobacteriota and Firmicutes. These alterations in functional microbes increased N retention rates but reduced mushroom yields in antibiotic treatments during cultivation. In conclusion, monensin decreased the N recycling rate in recycling system, but also reduced N losses during fermentation by inhibiting ammonification and denitrification, so, avoiding antibiotics usage is an effective strategy to improve the efficiency of recycling systems.

氮參與蛋白質、核酸等生命必需生物大分子的合成，是生物體中的重要成分。生物圈中的氮循環是氮的生物地球化學循環的重要組成部分之一。隨著農業和畜牧業的發展，大量畜禽糞便和農作物秸稈被閒置、浪費，被稱為“農業廢棄物”。種養循環技術模式是促進營養物質循環利用、提高農牧業生產效率的重要農業生產方式。目前，種養循環系統中關於氮循環效率及其調控的研究較為薄弱。中國科學院東北地理與農業生態研究所草地農牧業學科組基於“玉米秸稈養牛-糞便基質化-草生菌栽培”循環系統，探究了莫能菌素及秸稈種類對氮回收率的影響（氮回收率定義為蘑菇子實體中總氮與初始原料中總氮的比值），旨在明確該循環系統中氮的回收率，並揭示莫能菌素影響循環系統中氮轉化的微生物學機制。

研究發現，在四種發酵基質（無抗牛糞+玉米秸稈、無抗牛糞+小麥秸稈、有抗牛糞+玉米秸稈、有抗牛糞+小麥秸稈）上栽培雙孢蘑菇，可以蘑菇氮的形式回收秸稈和糞便中總氮的3.33%~5.88%。殘留的莫能菌素抑制了基質中氨化與反硝化菌的活性，從而降低了基質發酵過程中的氮損失，提高了氮轉化效率（表1）。而發酵和栽培過程中，基質中與氮轉化相關的酶活性（表2）以及微生物群落結構和演替變化（圖1）引起的氮損失變化，莫能菌素最終降低了整個循環系統中氮回收率的0.13%~1.57%。該研究為構建高效的種養一體化循環農業技術模式提供了數據支撐。

表1 基質發酵、蘑菇栽培及採收過程中的氮回收率

NC= no-antibiotic manure and corn straw, NW: no-antibiotic manure and wheat straw, AC= antibiotic manure and corn straw, AW= antibiotic manure and wheat straw, N retention rate= Total N in fermented substrate/Total N in starting substrate, N retention rate= Total N in cultivated substrate/Total N in fermented substrate, N recycled rate= Total N in fruit body of mushroom/ Total N in starting substrate.

表2 基質發酵和蘑菇栽培過程中的關鍵酶活性

圖1 基質發酵第0天（a）、14天（b）、35天（c）基於16S rDNA測序的門水平相對丰度；堆肥第0天（d）、14天（e）、35 天（f）基於ITS測序的門水平相對丰度。

校對和審核：張陽 王農