施用生物炭和秸秆对植烟土壤团聚体稳定性及有机碳分布的影响

Effects of biochar and straw on stability and organic carbon distribution of tobacco-planting soil aggregates

为揭示生物炭与腐熟小麦秸秆对植烟土壤团聚体的影响机制,有效改良植烟土壤,以许昌烟田土壤为研究对象,对常规施肥(CK)、常规施肥+生物炭(T1)、常规施肥+腐熟秸秆(T2)、常规施肥+生物炭+腐熟秸秆(T3)4个处理的0~10、10~20和20~30 cm土层团聚体稳定性及有机碳分布进行分析。结果表明:①施用生物炭和秸秆可以显著增加0~20 cm土层中0.500~1.000 mm粒级团聚体含量(质量分数),显著降低<0.250 mm粒级团聚体含量,其中生物炭与秸秆配施处理表现最好。②与对照相比,施用生物炭和秸秆显著增加0~20 cm土层中平均质量直径(Mean Weight Diameter,MWD)、几何平均直径(Geometric Mean Diameter,GMD)、大于0.250 mm粒级团聚体含量(>0.250 mm Water-stable Macroaggregate,WR0.250)和水稳系数(Water Stability Coefficient,K),显著降低破坏率(Percentage of Aggregate Disruption,PAD)、土壤不稳定团粒指数(Unstable Aggregate Index,ELT)和分形维数(Fractal Dimension,D);其中生物炭与秸秆配施处理的MWD、GMD、WR0.250和K值在0~10 cm土层中最高,而PAD、ELT和D值在0~10 cm土层中最低。③施用生物炭和秸秆显著提高0~30 cm土层各粒级团聚体有机碳含量,以单施生物炭处理各粒级团聚体有机碳含量最高。④施用生物炭和秸秆可提高0~30 cm土层大团聚体有机碳贡献率,其中生物炭与秸秆配施处理的提高幅度最大。因此,生物炭与秸秆配施处理可明显提高0~20 cm土层大团聚体含量和团聚体稳定性;单施生物炭处理可有效增加0~30 cm土层土壤总有机碳含量和各粒级团聚体有机碳含量。

In order to reveal the influence mechanisms of biochar and decomposed wheat straw on tobacco-planting soil aggregates and to improve tobacco-planting soil effectively,by taking soils from Xuchang tobacco fields as the research object,the stability and organic carbon distribution of soil aggregates in 0-10 cm,10-20 cm and 20-30 cm soil layers were analyzed under four treatments:conventional fertilization(CK),conventional fertilization+biochar(T1),conventional fertilization+decomposed straw(T2),conventional fertilization+biochar+decomposed straw(T3).The results were as follows:1)The application of biochar and straw significantly increased the content(mass fraction)of 0.500-1.000 mm aggregates in 0-20 cm soil layer and decreased the content of<0.250 mm aggregates.Among the four treatments,T3 performed the best.2)Compared with the control,the application of biochar and straw significantly increased Mean Weight Diameter(MWD),Geometric Mean Diameter(GMD),>0.250 mm Water-stable Macroaggregate(WR0.25)and Water Stability Coefficient(K),and significantly reduced Percentage of Aggregate Disruption(PAD),Unstable Aggregate Index(ELT)and Fractal Dimension(D)in 0-20 cm soil layer;wherein the MWD,GMD,WR0.25 and K were the highest,while PAD,ELT and D were the lowest in 0-10 cm soil layer under T3 treatment.3)The application of biochar and straw significantly increased the organic carbon content in aggregates of various particle sizes in 0-30 cm soil layer,and the organic carbon content in aggregates of various particle sizes was the highest under T1 treatment.4)The application of biochar and straw improved the contribution rate of organic carbon of large aggregates in 0-30 cm soil layer,and the biochar and straw mixed treatment increased the most.Thereby,the mixed application of biochar and straw can significantly increase the content of macroaggregates and improve the stability of aggregates in 0-20 cm soil layer.The soil total organic carbon content and aggregate organic carbon content in 0-30 cm soil layer can be increased by biochar treatment alone.