添加材料对黄绵土团聚特性的影响

Effects of additives on the aggregation characteristics of loess

探究不同添加材料对黄绵土团聚体数量、水稳性团聚体稳定率、团聚体大小和分形维数等的影响,以期为增加黄绵土土壤团聚体和提高其稳定性提供科学依据。在陕西富平中试基地设置野外培养试验,以黄绵土为研究对象,通过添加材料(玉米秸秆和生物质炭),设置4个试验,分别为对照(零添加,CK)、玉米秸秆(5%,S1)、生物质炭(5%,S2)、玉米秸秆与生物质炭混施(各5%,S3),培养30 d后,采集黄绵土土壤样品,利用团聚体测定常用干法和湿法进行测定稳定性指标。结果表明:在整个培养过程中,添加玉米秸秆的处理较其它处理需水量高。通过干法和湿法测定黄绵土不同粒径的团聚体百分含量,各处理下黄绵土不同粒径团聚体含量呈现相同趋势,>0.25 mm的团聚体含量的大小次序分别为S3>S2>S1>CK。水稳性团聚体稳定率以S3处理最高,在干法和湿法处理下,土壤团聚体平均重量直径和几何平均直径大小顺序趋势一致,均为S3>S2>S1>CK。湿法下,黄绵土土壤团聚体分形维数与>0.25 mm土壤团聚体含量存在良好的负相关线性关系,即R^2=0.9604。综合分析表明,添加材料可有效改善土壤结构,增加其稳定性,并且混合使用材料对土壤团聚体改善效果优于单一添加材料。

To evaluate the effects of different additive materials on the number of aggregates,the stability rate of water-stable aggregates,the size of aggregates and the fractal dimension in loessial soil,hence offer scientific basis for increasing the aggregates and stability of loessial soil.The field experiments were set up at the Fuping pilot plant in Shaanxi Province.Four experiments were set up with loessial soil as the research object and by adding corn stalks and biomass charcoal.Thefourdifferent experiments were control(zero addition,CK),corn stover(5%,S1),biomass charcoal(5%,S2)and corn straw biomass carbon mixed application(5%each,S3),respectively.The samples of loessial soil were collected after 30 days of incubation.Afterwards,the determination of stability indicators were measuring aggregates by dry and wet methods.The results show that:The water requirement of corn straw treatment was higher than that of other treatments in the whole culture process.The aggregate content of different particle size of loessialsoil showed the same trend under each treatment by determining the percentage of aggregates with different particle sizes in loessial soil through dry and wet methods.Additionly,the order of the aggregates larger than 0.25 mm is S3>S2>S1>CK.The stability rate of water stable aggregate is the highest in S3 treatment,the average weight diameter and geometric average diameter of soil aggregate have the same trend under dry and wet treatment,which are S3>S2>S1>CK.There is a good negative correlation between the fractal dimension of soil aggregate and the content of soil aggregate larger than 0.25 mm under dry method,that is R^2=0.9604.Comprehensive analysis shows that the added materials can effectively improve the soil structure and increase its stability.In addition,the mixed materials have better effects on improving soil aggregates than the single added materials.