内江市微地形条件影响下土壤团聚体稳定性及分形特征

以季节性干旱区-川中丘陵区-内江市农耕地作为研究对象,选择坡向、坡位、土层厚度作为影响土壤团聚稳定性的作用因子,采用标准化平均质量直径和分形理论,探讨了土壤团聚体的稳定性、分形特征及二者之间的关系.结果表明:研究区土壤团聚体稳定性标准化平均质量直径(NMMD)表现出阳坡>阴坡、下坡>中坡>上坡、15-30cm>30-45cm>0-15cm的特点,说明在坡向上,阳坡的土壤团聚体与阴坡相比较稳定;在坡位变化上,下坡团聚体稳定性最高、中坡次之、上坡最低,在土层深度变化上,15-30cm团聚体稳定性最高,30-45cm次之,0-15cm最低.微地形条件下分形维数的变化特征为:阴坡>阳坡,下坡>中坡>上坡,15-30cm>30-45cm>0-15cm;3个地形因子作用下,分形维数与<0.1mm的粒级质量分布达到极显著正相关,与其他粒级的质量分布相关性呈显著或不显著.研究结果可以为研究区土地利用及农业耕作提供一定的理论依据.

The Soil Aggregates Stability and the Fractal Features as Influenced by Tiny Terrain Conditions in Neijiang City

Agricultural land of Neijiang City, which is seasonal drought area and in the hilly area of central Sichuan, was chosen as the study site. The slope aspect, slope position, soil thickness were chosen as the factors influencing the soil aggregation stability. The stability of soil aggregates, fractal characteristics as well as the relationship between them were discussed by using the method of normal mean mass diameter and fractal theory. The results showed that soil aggregation stability of normal mean mass diameter in this area presented as the sequence of sunny slope>slope, downhill slope>middle slope>uphill slope, 15-30cm>30-45cm>0-15cm. It explained that the soil aggregation stability of sunny slope was higher than that in slope upward, and the soil aggregation stability of downhill slope was the highest, it was the second in middle slope, and was the lowest in uphill in terms of the slope changing, and it was the highest in the layer of 15-30cm, it was the second in the layer of 30-40cm, it was the lowest in the layer of 0-15cm with regard to soil depth. Under the condition of micro-landform, the changing characteristics of fractal dimension was in the order of slope>sunny slope>middle slope>uphill slope, 15-30cm>0-15cm. Affected by the three terrain factors, the partial correlation coefficient between fractal dimension and quality of particle size of <0.1mm was pretty lange or was to be direct proportion. The research result can provide some theoretical evidence for the use of land and agriculture cultivation.