坡耕地整地下农田土壤水分与团粒特征互作关系

    Interaction between soil moisture and aggregate characteristics under slope land preparation

    • 摘要: 土壤团粒是形成土壤结构的基础,从土壤微观角度深入分析土壤团粒与土壤水分之间的作用关系,可为进一步阐明丘陵山区坡耕地整地后土壤结构如何调控田间水肥利用提供理论支撑。该研究将染色示踪试验和扫描电镜实验相结合,利用图像解析、统计分析等方法,探究水平、反坡2种典型整地措施(坡耕地为对照)下田间土壤团粒特征与土壤水分状况之间的互作影响。结果表明:在相同外部供水条件下,整地使田间土壤水分集中分布在0~10 cm土壤浅层空间内,显著小于坡耕地田间土壤水分分布范围,水平和反坡整地后形成的田间土壤水分运动变化程度相比坡耕地分别提高11.09%和7.14%。水平和反坡整地后的土壤团粒相较于坡耕地(平均分形维数为1.19)空间分布均匀程度更高(平均分形维数分别为1.16和1.18),整地使土壤团粒中孔隙大小组成的差异性分别降低5.81%(水平)和10.10%(反坡),且水平台田间土壤团粒中孔隙空间分布方向更复杂(概率熵为0.9578)。水平台土壤团粒特征中的空间分布均匀化程度对其田间土壤水分空间分布和运动的影响程度最大(关联度为0.812),而反坡台和原状坡耕地的土壤团粒大小组成对土壤水分空间分布和运动的影响程度最大(关联度分别为0.708和0.698)。整地措施显著改变坡耕地土壤团粒状况,进而影响田间土壤水分。因此,针对丘陵山区坡耕地选择适宜的整地措施,一定程度上可以有效改善田间土壤结构,进而调控土壤水分状况,促进农业生产。

       

      Abstract: Soil aggregates can often form the basis of soil structure. This study aims to analyze the relationship between soil aggregates and soil water from the microscopic perspective of soil in the hilly and mountainous slopes. Theoretical support was then provided to further clarify how the soil structure regulated the field water and fertilizer use after land preparation. Two typical measures of land preparation were selected as the horizontal and reverse slope, with the slope farmland as the control. A series of experiments were carried out to explore the interaction between soil aggregates and soil water status. The staining tracer test was also conducted on the plots under different measures of land preparation. Imaging and statistical analysis were finally employed using a scanning electron microscope. The results indicate that the staining was characterized by the movement and distribution of water in the soil, particularly in the same conditions of external water supply. The spatial distribution of soil water was concentrated in the shallow space of the 0-10 cm depth of the soil in the field. A significantly smaller range was observed on the distribution of soil water in the slope farmland field. After horizontal and reverse slope preparation, the degrees of change in the spatial movement of soil water in the field were 11.09% and 7.14% higher than those in the slope land, respectively. Microscopic images of soil aggregates were magnified by 1000 times using scanning electron microscopy. Then the quantitative analysis was conducted using pore analysis software. It was found that the spatial distribution of soil aggregates after horizontal and reverse slope cultivation was more uniform (with average fractal dimensions of 1.16 and 1.18, respectively) than that of the slope-cultivated land (with an average fractal dimension of 1.19). Land preparation reduced the difference in the pore size and composition in the soil aggregates by 5.81% (horizontal) and 10.10% (reverse slope), respectively. The complex behavior was found along the spatial distribution direction of pores in the soil aggregates in the horizontal field (with a probability entropy of 0.957 8). The spatial distribution and movement of soil water were analyzed to couple the coordination degree model. A reference value was obtained to determine the correlation degree of soil water. The coupling coordination degrees of the horizontal platform, reverse slope platform, and slope farmland were 0.62, 0.58, and 0.56, respectively. Gray correlation was employed to analyze the reference value of soil water status and various indexes of aggregates. There was the greatest influence of the spatial distribution in the soil aggregates of the horizontal platform on the spatial distribution and movement of soil water in the field (with a correlation degree of 0.812). However, the size of soil aggregates in the reverse and undisturbed slope cultivated land shared the greatest influence on the spatial distribution and movement of soil water (with correlation degrees of 0.708 and 0.698, respectively). Therefore, the land preparation measures can significantly alter the soil aggregate status of slope farmland, and subsequently affect the soil moisture in the field. Therefore, it is highly required to the optimal measures of land preparation for the sloping farmland in the hilly and mountainous areas. The finding can provide a strong reference to effectively regulate the soil structure and soil water during agricultural production.

       

    /

    返回文章
    返回