伊犁新垦区土地利用和地形对表层土壤养分变异性的影响

本文基于野外实测剖面数据,借助于数理统计方法探讨了采样点尺度上土地利用和地形因子（海拔、坡度和坡向）对伊犁新垦区表层土壤有机质、全氮、全磷和全钾含量分布特征的影响。结果表明：①土地利用类型对表层土壤的有机质、全氮和全磷有显著性影响,而对全钾的影响不显著;②不同地形因子对表层土壤养分要素影响的显著性各异。4种养分含量与海拔呈极显著正相关,在500～600m梯度平均含量均最低,600～700m梯度波动范围均最大;有机质、全氮和全钾在高海拔梯度的平均含量高于低海拔的含量,全磷的平均含量随着海拔升高呈倒U型分布;③有机质和全氮与坡度呈显著正相关,3°以上的平均含量显著高于3°以下;在坡度〈1.82°时,4种养分含量的波动范围最大;④全磷与坡向呈显著负相关;阴坡的各种养分因子的平均含量不同程度的高于阳坡的含量;除全钾外,各种养分因子在阳坡的波动范围均大于阴坡的范围;⑤土地利用类型与地形条件的交互作用对表层土壤养分含量存在影响。在不同地形条件下,不同土地利用类型间的表层土壤养分含量高低情况存在差异,表现在较高海拔、较大坡度和阴坡上中覆被草地的有机质含量明显高于农田和低覆被草地,而在较低海拔、较小坡度和阳坡上则情况相反。

Effects of Land Use and Topographic Factors on the Variability of Soil Nutrients in Newly Reclaimed Area in Yili

The spatial variability of soil nutrient may be influenced by environmental factors. Based on the data of measured section in the field and laboratory analysis, this study has explored the effects of land use and topographic factors on the distribution characteristics of surface soil nutrients on the scale of sampling points with the mathematical statistics method. The results show that: 1) Land use types have significant effects on the organic matter, total nitrogen and total phosphorus of the surface soil but have slight effects on total potassium. Saline land contains the most organic matters while sand contains the least. Total nitrogen in wasteland is less than that in farmland. As for the total phosphorus, saline land has the highest average content and moderate coverage grassland has the largest coefficient of variation; 2) Different topographic factors affect the soil nutrients to different degrees. The four soil nutrients are positively correlated with altitude, they have the lowest average content at the altitude gradient of 500～600m and the largest fluctuation range at the altitude gradient of 600～700m. The average content of organic matter, total nitrogen and total potassium at high altitude gradient is higher than that at low altitude gradient. Nevertheless, the average content of total phosphorus presents inverted-U distribution with the rise of the altitude; 3) Organic matter and total nitrogen included in the soil are positively correlated with slope. The average content of them above the slope of 3° is obviously higher than that under the slope of 3°. When the slope gradient is less than 1.82°, the average content of the four soil nutrients shows the largest fluctuation range. 4) Total phosphorus is negatively correlated with the slope direction. The average content of the soil nutrients on the shady slope is higher than that on the sunny slope. However, except total potassium, the other three soil nutrients have larger fluctuation ranges on the sunny slope than they do on the shady slope; 5) The interaction between land use types and topographical factors has effect on the nutrients content of surface soil. Soil organic matter content of moderate coverage grassland is obviously higher than that of farmland and low coverage grassland at places with higher altitude, sharper slope and shady slope, but it is the opposite at places with lower altitude, gentler slope and sunny slope.