摘要
探究不同花生轮作模式对土壤团聚体粒径分布以及团聚体碳组分含量的影响,2017-2021年于山东烟台,以当地典型作物轮作模式冬小麦-夏玉米一年两作(WM)和春花生一年一作(CP)为对照,设置3种花生轮作模式,即冬小麦-夏花生一年两作(WP)、春花生→冬小麦-夏玉米两年三作(PWM)和冬小麦-夏花生→冬小麦-夏玉米两年四作(WPWM),研究种植模式对土壤团聚体组成和团聚体总有机碳、可溶性有机碳和微生物量碳含量的影响.结果发现:(1)相较于CP模式,PWM和WPWM模式下0～40 cm土层1～2 mm粒级团聚体百分含量分别显著提高14.75～21.25和12.47～16.17个百分点,且WPWM模式更有利于提高土壤团聚体的平均重量直径;(2)除0.25～0.5 mm粒级外,WPWM模式下0～40 cm土层各粒级团聚体有机碳含量均显著高于CP模式;WP和WPWM模式下0～20 cm土层1～2 mm、＜1 mm粒级团聚体有机碳贡献率均显著高于CP模式;(3)WPWM模式下,0～20 cm土层＞5 mm、0.5～1 mm和＜0.25 mm粒级团聚体可溶性碳含量较对照(CP和WM)分别显著提高50.75%～81.18%、100.12%～120.12%、69.44%～90.07%;(4)WPWM模式下,0～40 cm土层团聚体微生物量碳含量较对照(CP和WM)模式提升最大;20～40 cm土层,与对照(CP和WM)相比,PWM、WP、WPWM模式均显著提高1～2 mm团聚体微生物量碳贡献率.(5)有机碳与可溶性碳、微生物量碳及可溶性碳与微生物量碳在2～5 mm、1～2 mm、0.5～1 mm团聚体中均显著相关.综合而言,WPWM模式,即冬小麦-夏花生→冬小麦-夏玉米两年四作的模式可提高0～40 cm土层的平均重量直径、细大团聚体(1～2 mm)含量以及1～2 mm粒级团聚体中有机碳、可溶性碳、微生物量碳的含量和贡献率,有助于改善土壤结构,更符合绿色低碳发展需求.
Abstract
To better evaluate planting mode,effects of different peanut rotation patterns were explored on parti-cle size distribution and carbon content in soil aggregates.From 2017 to 2021,studies were carried out in Yantai,Shandong Province,by using local typical crop modes as contols,including winter wheat-summer maize(WM)and spring peanut(CP).Other peanut rotation patterns were set up,namely,WP(winter wheat-summer peanut rotation),PWM(spring peanut → winter wheat-summer maize rotation),and WPWM(winter wheat-summer peanut → winter wheat-summer maize rotation).Effects of planting patterns were investigated on soil aggregate composition and soil organic carbon content,dissolved organic carbon content,and microbial biomass carbon in the aggregates.Results showed that compared with CP mode,the percentage content of 1-2 mm aggregates in 0-40 cm soil layer under PWM and WPWM modes was significantly increased by 14.75-21.25 and 12.47-16.17 percentage points,respec-tively,and WPWM mode was more conducive to increase average weight diameter of soil aggregates.Soil organic carbon content of aggregates in 0-40 cm soil layer under WPWM mode was significantly higher than that under CP mode,except for the particle size of 0.25-0.5 mm.The contribution rate of soil organic carbon in 0-20 cm soil layer of 1-2 mm and<1 mm in WP and WPWM mode was significantly higher than those in CP.Under WPWM mode,dissolved organic carbon content of>5 mm,0.5-1 mm and<0.25 mm aggregates in 0-20 cm soil layer were signifi-cantly increased by 50.75%-81.18%,100.12%-120.12%and 69.44%-90.07%compared with the 2 controls(CP and WM),respectively.In WPWM mode,microbial biomass carbon content of 0-40 cm soil layer aggregates in-creased the most than those of the controls(CP and WM).Compared with the controls in 20-40 cm soil layer,the contribution rate of microbial biomass carbon in 1-2 mm aggregates was significantly increased under PWM,WP and WPWM modes.Soil organic carbon was significantly correlated with dissolved organic carbon,microbial bio-mass carbon,and dissolved organic carbon with microbial biomass carbon in aggregates of 2-5 mm,1-2 mm,and 0.5-1 mm.In general,WPWM increased mean weight diameter in 0-40 cm soil layer,the content of fine and large aggregates(1-2 mm),and the content and contribution rate of soil organic carbon,dissolved organic carbon and mi-crobial biomass carbon in 1-2 mm aggregates,which would improve soil structure and be more in line with the needs of green and low-carbon development.
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