不同轮作模式对土壤活性碳组分及矿化的影响

Effects of different rotation modes on the concentrations of soil activate carbon fractions and characteristics of carbon mineralization

为研究不同花生轮作模式下土壤活性碳库变化,在大田条件下进行定位试验。试验以春花生一年一作(CP)为对照,设置4种轮作种植模式:春花生→冬小麦-夏玉米两年三作(P→W-M)、冬小麦-夏玉米一年两作(W-M)、冬小麦-夏花生一年两作(WP)、冬小麦-夏花生→冬小麦-夏玉米两年四作(W-P→W-M),共计5个处理,研究不同种植模式下土壤有机碳及土壤可溶性有机碳、微生物生物量碳等活性碳组分含量变化和碳矿化特征。结果发现:相较于CP模式,P→W-M模式显著提高了0~40 cm土层有机碳(52.7%~53.3%)、可溶性有机碳(13.3%~344.8%)及微生物生物量碳含量(25.3%~101.4%),W-P模式显著提高了0~40 cm土层有机碳(39.3%~46.8%)及0~20 cm土层可溶性有机碳(271.4%)、微生物生物量碳含量(44.3%),W-P→W-M模式则显著降低了20~40 cm土层各碳组分含量。各种植模式土壤有机碳矿化速率均符合一级动力学模型。CP和W-P模式具有较低的潜在矿化有机碳库,W-M和W-P→W-M模式显著提高了潜在矿化有机碳库与土壤有机碳的比值。研究表明,P→W-M和W-P模式可提升土壤有机碳和活性碳组分含量,有效降低土壤潜在矿化有机碳量,提高土壤有机碳的固持。

To assess the effects of various planting modes on soil active carbon pools in field experiments,four rotation modes were applied with continuous cultivation of peanut(Arachis hypogaea Linn.)(CP)as a control.The four rotation modes were as follows:spring peanut→winter wheat(Triticum aestivum L.)-summer maize(Zea mays L.)rotation(P→W-M),winter wheat-summer maize rotation(W-M),winter wheat-summer peanut rotation(W-P),winter wheat-summer peanut→winter wheat-summer maize rotation(W-P→W-M).The concentration of soil organic carbon(SOC)and active carbon fractions such as dissolved organic carbon(DOC)and microbial biomass carbon(MBC),and carbon mineralization characteristics were assessed.The results showed that compared with CP,P→W-M significantly increased the content of SOC(52.7%~53.3%),DOC(13.3%~344.8%),and MBC(25.3%~101.4%).W-P significantly increased the content of SOC in the 0~40 cm soil layers(39.3%~46.8%)and that of DOC(271.4%)and MBC(44.3%)in the 0~20 cm layer.The concentrations of all carbon fractions in the W-P→W-M treatment were significantly decreased.Carbon mineralization in all planting modes was consistent with the first-order dynamic model.Lower potentially mineralized carbon(C0)was found in CP and W-P,while W-M and W-P→W-M significantly increased the value of C0/SOC.In conclusion,P→W-M and W-P can increase the concentration of SOC and active carbon fractions,reduce the potentially mineralized carbon,and improve soil organic carbon sequestration.