外源添加物对土壤干缩裂缝特征的影响

Effects of Exogenous Additives on the Characteristics of Soil Dry Shrinkage Cracks

为研究外源添加物对土壤干缩裂缝特征的影响,选取水田、旱田、林地3种土地利用方式,添加生石灰(1 g/kg)、黄腐酸(10 g/kg)、鱼塘底泥(250 g/kg)、生物炭(15 g/kg)4种外源添加物,进行土壤干燥收缩试验。结果表明:除生石灰外,不同土壤外源添加物处理下各用地类型土壤干燥收缩裂缝特征变化趋势非常一致,裂缝面密度、长密度、平均宽度均呈现耕作层水田>旱田>林地、犁底层水田>林地>旱田。生石灰对土壤干燥收缩裂缝特征无显著影响;黄腐酸使土壤干缩裂缝面密度、裂缝平均宽度增加,但对土壤干缩裂缝长密度无显著影响;鱼塘底泥使土壤裂缝面密度、长密度增加,但对干缩裂缝平均宽度无影响;生物炭使土壤裂缝面密度、裂缝平均宽度降低,但使裂缝长密度增加。相对于空白对照,不同外源添加物对于土壤裂缝面密度影响程度表现为耕作层鱼塘底泥>生物炭>黄腐酸>生石灰、犁底层黄腐酸>鱼塘底泥>生物炭>生石灰;对于裂缝长密度影响程度表现为耕作层生物炭>鱼塘底泥>生石灰>黄腐酸、犁底层生物炭>鱼塘底泥>黄腐酸>生石灰。外源添加物对土壤裂缝特征产生重要影响,生石灰对于土壤裂缝发育影响不显著,黄腐酸、鱼塘底泥促进土壤裂缝发育,生物炭可以抑制土壤裂缝的发育。研究结果可为农业生产中使用改良土壤剂改良土壤理化性质提供参考。

To investigate the effect of exogenous additions on the characteristics of soil drying and shrinkage crack.Three utilization types of soil samples were selected for paddy field,dry field and forest land and four exogenous additives including quicklime(1 g/kg),fulvic acid(10 g/kg),fish pond sediment(250 g/kg),and biochar(15 g/kg),were added to conduct soil drying and shrinkage tests.The results showed that,in addition to quicklime,the change trend of soil drying shrinkage crack characteristics of different land types under different soil amendment treatments was very consistent,and the surface density,length density and average width of crack showed the change trend of cultivated layer paddy field>dry field>forest land,and plow bottom paddy field>forest land>dry field.Quicklime has no significant effect on soil dry shrinkage crack characteristics;fulvic acid increased the surface density of soil dry shrinkage cracks and the average width,but had no significant effect on the length density of soil dry shrinkage cracks;fish pond sediment increased the surface density of soil cracks and the length density,but had no effect on the average width of dry shrinkage cracks;biochar reduced the surface density of soil cracks and the average width of cracks,but increased the average length density of cracks.Compared with the blank control,the degree of influence of different exogenous additives on the density of soil fracture surface were as follows:Cultivated layer fish pond sediment>biochar>fulvic acid>quicklime,plow bottom fulvic acid>fish pond sediment>biochar>quicklime;the degree of influence on fracture length density was as follows:Cultivated layer biochar>fish pond sediment>quicklime>fulvic acid,plow bottom biochar>fish pond sediment>fulvic acid>quicklime in the plough bottom layer.Exogenous additives have an important effect on the characteristics of soil cracks.Quicklime has no significant effect on the development of soil cracks.Fulvic acid and fish pond sediment can promote the development of soil cracks,and biochar can inhibit the development of soil cracks.The results can be used to improve the physical and chemical properties of soil using improved soil agents in agricultural production.