紫云英添加对土壤团聚体组成及有机碳分布的影响

以湖北省武汉市稻田土壤为研究对象,分别设置不添加紫云英(CK)、添加2%土壤质量的紫云英(G1)、添加4%土壤质量的紫云英(G2)3个处理,进行干湿交替模拟培养试验,研究培养60、120和180d土壤团聚体组成及团聚体内有机碳的分布特征。结果表明:添加紫云英培养120 d增加了各处理2 mm团聚体含量,培养60 d时G1处理的增幅最大(78.08%),培养120 d时G2处理的增幅最大(77.31%),且显著提高了团聚体的平均重量直径。不同培养时期添加紫云英均提高了土壤的有机碳含量,且G2处理土壤有机碳含量高于G1处理,各处理随着培养时间的增加有机碳含量先增加后降低。团聚体中有机碳含量均随着粒级的减小而降低,紫云英添加培养180 d时团聚体各粒级有机碳含量均有所提升,且2 mm团聚体的有机碳含量增幅最大(17.17%～43.67%)。紫云英添加培养120 d时主要增加大团聚体内各有机碳组分的相对含量,180 d时显著增加了微团聚体内细颗粒有机碳的含量。

Effects of Adding Chinese Milk Vetch on Soil Aggregates Composition and Organic Carbon Distribution

Taking the paddy field soil of Wuhan city, Hubei province as the research object, three treatments were carried out without adding Chinese milk vetch (CK), adding 2% Chinese milk vetch (G1), and adding 4% Chinese milk vetch (G2). The experiment of dry and wet alternate culture was carried out, and the composition of soil aggregates and the distribution characteristics of organic carbon in the aggregates at 60, 120 and 180 days were studied. The results showed that the content of > 2mm aggregates was increased by adding Chinese milk vetch culture for 120 days, the increase of G1 treatment was the largest at 60 days (78.08%), the increase of G2 treatment was the largest at 120 days (77.31%), and the mean weight diameter of the aggregates was significantly increased. The content of organic carbon in soil increased with the addition of Chinese milk vetch in different culture periods, and the content of organic carbon in soil treated with 4% Chinese milk vetch was higher than that of 2%. The content of organic carbon in each treatment first increased and then decreased with the increase of culture time. The content of organic carbon in the aggregates decreased with the decrease of size. The content of organic carbon in each size of the aggregates was increased after the addition of Chinese milk vetch for 180 days, and the organic carbon content of > 2mm aggregates increased the most (17.17% ~ 43.67%). The relative content of organic carbon fractions in macroaggregates was mainly increased after the addition of Chinese milk vetch 120 days, and significantly increased the content of fine particulate organic carbon in microaggregates after 180 days.