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选择紫色土丘陵区5种种植模式,分层(0~20,20~40 cm)采集土壤样品,对土壤团聚体分布、团聚体水稳性和分形特征进行研究.结果表明:不同种植模式下团聚体分布和水稳性差异明显,>0.25 mm水稳性团聚体含量和团聚体稳定性指数(ASI)表明团聚体水稳性从高到低依次为自然生草地,横坡玉米,南方早熟梨+苜蓿,桑基+农作物,柑橘+鸭茅草;0~20 cm土层团聚体水稳性较20~40 cm团聚体高.湿筛后团聚体的分形维数(y2)与>5 mm(x3),>0.25 mm(x4)水稳性团聚体含量回归方程为y2=-1.186x3+0.636x4,相关系数达极显著水平.风干土团聚体分形维数与粉粒和粘粒含量呈正相关,而水稳性团聚体分形维数则与之呈负相关;有机质含量高的土壤结构较好,分形维数较小.因此,可以通过横坡耕作和农林复合经营提高土壤团聚体稳定性,减轻和防治水土流失.
Five planting patterns were selected in purple hilly region, soil samples were stratified (0 ~ 20, 20 ~ 40 cm) to study soil aggregate distribution, water stability and fractal characteristics of aggregates.The results showed that under different planting modes The distribution of aggregates and the water stability are obviously different. The water stable aggregates content and aggregate stability index (ASI) of> 0.25 mm indicate that the water stable of aggregates is natural grassland, corn in horizontal slope, Pear + alfalfa, mulberry + crop and citrus + ductile grass.The water-stability of aggregates in 0-20 cm soil layer was higher than that in 20-40 cm soil aggregates.The fractal dimension (y2) x3) and> 0.25 mm (x4), the regression equation of water-stable aggregates content was y2 = -1.186x3 + 0.636x4, and the correlation coefficient reached extremely significant level.The fractal dimension of dry soil aggregates was positively correlated with the content of silt and clay , While the fractal dimension of water-stable aggregates was negatively correlated with it.The soil structure with high organic matter content was better and the fractal dimension was smaller.Therefore, the stability of soil aggregates could be improved by cross-slope farming and agroforestry, Reduce and prevent soil erosion.