近日，華中農(nóng)業(yè)大學(xué)植物科學(xué)技術(shù)學(xué)院低碳稻作團(tuán)隊(duì)利用13C同位素示蹤技術(shù)，探明了稻菇模式通過(guò)利用秸稈栽培食用菌促進(jìn)土壤外源碳固定，減少稻田甲烷排放的機(jī)理。

 

　　低碳稻作模式關(guān)系到“雙碳”目標(biāo)的達(dá)成，傳統(tǒng)稻作模式秸稈還田雖可減少焚燒產(chǎn)生的碳排放和環(huán)境污染，并向土壤輸入外源碳等養(yǎng)分，但冬季氣溫低水稻秸稈降解慢，秸稈碳有很大比例以溫室氣體等形態(tài)流失，土壤碳庫(kù)固定量有限。另外秸稈腐解不及時(shí)也會(huì)減少后茬作物種子與土壤的接觸，不利冬季作物出苗，并為病蟲越冬提供有利生存環(huán)境。食用菌可以秸稈為基質(zhì)獲取養(yǎng)分進(jìn)行生長(zhǎng)，其菌絲體在促進(jìn)秸稈降解的同時(shí)可促進(jìn)土壤團(tuán)聚體層級(jí)結(jié)構(gòu)發(fā)育。在秋冬季利用秸稈栽培菌菇的新型稻作模式，因其較高的周年生產(chǎn)收益目前在湖北、湖南、江西、四川等省份大面積推廣應(yīng)用。為完善秸稈管理、加強(qiáng)稻田土壤碳匯功能、促進(jìn)稻田生產(chǎn)碳中和，我校植物科學(xué)技術(shù)學(xué)院低碳稻作團(tuán)隊(duì)聯(lián)合東北農(nóng)業(yè)大學(xué)土壤保護(hù)與修復(fù)重點(diǎn)實(shí)驗(yàn)室，利用13C同位素示蹤技術(shù)，對(duì)稻菇模式菌絲生長(zhǎng)對(duì)土壤團(tuán)聚體秸稈碳固定和碳庫(kù)化學(xué)特性的影響機(jī)制開展了研究工作。

 

　　團(tuán)隊(duì)開展了稻菇模式四種食用菌接種量對(duì)秸稈外源碳轉(zhuǎn)化的影響研究，在大田試驗(yàn)初期，通過(guò)13CO2脈沖標(biāo)記制備13C標(biāo)記秸稈。試驗(yàn)結(jié)果顯示，秸稈接種食用菌還田后，土壤真菌和菌絲體豐度顯著升高，菌絲生長(zhǎng)促進(jìn)了秸稈外源碳向土壤有機(jī)碳庫(kù)的輸入，顯著降低外源碳甲烷轉(zhuǎn)化比例。與此同時(shí)，食用菌菌絲生長(zhǎng)顯著降低了土壤有機(jī)碳庫(kù)芳香性，促進(jìn)了土壤小團(tuán)聚體膠結(jié)，加快土壤團(tuán)聚體層級(jí)結(jié)構(gòu)發(fā)育，加強(qiáng)土壤團(tuán)聚體固碳能力。秸稈外源碳在土壤中的固存率與接種量正相關(guān)，食用菌菌絲體對(duì)土壤結(jié)構(gòu)起到了保護(hù)作用，在本研究中食用菌接種量為3000 kg/hm2時(shí)，秸稈堆肥外源碳土壤碳庫(kù)轉(zhuǎn)化比例最高，甲烷轉(zhuǎn)化量最低。

 

　　研究結(jié)果以“The rice-edible mushroom pattern promotes the transformation of composted straw-C to soil organic carbon”為題發(fā)表在Agriculture Ecosystems & Environment 期刊上。華中農(nóng)業(yè)大學(xué)植物科學(xué)技術(shù)學(xué)院博士生胡權(quán)義為論文第一作者，東北農(nóng)業(yè)大學(xué)劉天奇副教授為通訊作者，華中農(nóng)業(yè)大學(xué)曹湊貴教授、黃見良教授、李成芳副教授等老師和河南大學(xué)丁會(huì)納博士參與了該研究的指導(dǎo)。該研究得到“十四五”國(guó)家重點(diǎn)研發(fā)計(jì)劃“長(zhǎng)江中下游坡耕地紅黃壤與中低產(chǎn)稻田產(chǎn)能提升技術(shù)模式及應(yīng)用”項(xiàng)目（2021YFD1901205）、國(guó)家自然科學(xué)基金（32272230）和中國(guó)博士后科學(xué)基金（2020M672373）資助。

 

　　英文摘要：

 

　　The application of composted straw in conventional rice cultivation patterns can enhance soil organic carbon （SOC）； however, it increases methane （CH4） emission, thereby reducing its net carbon sequestration efficiency in paddy fields. The rice–edible mushroom pattern may improve this phenomenon because edible mushrooms can promote straw decomposition and soil aggregate formation. Here, we investigated the effect of four inoculation amounts of edible mushroom on the transformation of composted straw-C in paddy fields using 13C tracer technology under rice–edible mushroom pattern. The results indicated that the inoculation of edible mushrooms increased the abundance of soil microorganisms and fungal mycelium, reduced SOC aromaticity, and promoted the formation of macroaggregates. Inoculation of edible mushrooms stimulated the transformation of composted straw-C to SOC and reduced its conversion to CH4. The sequestration efficiency of composted straw-C in the soil increased as the inoculation amounts of edible mushrooms increased. When the edible mushroom inoculation amount was 3000 kg ha–1, the highest amount of composed straw-C was sequestrated in soil. With more inoculation amount, more fungal mycelium was produced, which enhanced the physical protection of composted straw-C by promoting the formation of soil aggregates. This study indicated that under the rice–edible mushroom pattern, transformation of composted straw-C to the soil carbon was favored compared with its transformation to CH4, and this conversion efficiency increased with the increasing inoculation amounts of edible mushrooms.

 

　　論文鏈接：https://doi.org/10.1016/j.agee.2023.108560