伊金霍洛旗不同土地利用方式下的土壤养分特征

Characteristics of soil nutrient under different land use types in Yijinhuoluo County

为分析内蒙古鄂尔多斯市伊金霍洛旗在4类土地利用方式(灌木林地、采矿用地、天然牧草地和农地)下,土壤养分质量分数的差异性,运用野外采样和室内化验、分析相结合的方法,测定4种土地类型在0~30 cm土层的土壤有机质和全量氮磷钾质量分数及pH值。结果表明:1)4类土地在0~30 cm土层的土壤有机质和全氮质量分数存在显著差异,土壤全磷量和全钾量差异不显著(P<0.05),土壤有机质质量分数依次为农地>天然牧草地>灌木林地>采矿用地,土壤全量氮磷钾最大值分别为天然牧草地、天然牧草地和灌木林地,最小值分别为采矿用地、灌木林地和天然牧草地;2)在垂直剖面上,采矿用地和天然牧草地的有机质质量分数随着土层深度的增加逐渐减小,农地和灌木林地的有机质质量分数最大值出现在20~30 cm深度的土层,4类土地的土壤全氮量和全磷量均有随土层深度的增加而下降的趋势,全钾量随土层深度的变化不明显。4类土地的土壤全氮和全钾质量分数整体而言较为理想,全磷和有机质质量分数欠缺。农地全磷质量分数基本能满足主要作物的生长需求,有机质和全氮质量分数不能满足主要作物的生长需求。本研究可为内蒙古中部工矿开采区土地合理利用以及退化的生态环境恢复等提供科学依据。

[Background] Human activities,such as mining,cause the changes nearby environment,especially soil nutrients. The research is to investigate the difference of soil nutrient content among 4 land use types: shrub land,mining land,nature grassland and farmland in Yijinhuoluo County of Ordos,Inner Mongolia. [Methods]Yijinhuoluo County of Ordos is located in E 109°45'-110°40',N 38°50'-39°50',in which there are 3 major types of soil: skeletal soil,aeolian sandy soil and chestnut soil. The sampling sites were determined based on the studied mining area,centered outward in ladder shape,and the proportion of the land use in total area. The soil samples were collected from 3 random soil profiles,each profile was divided into 0-10,10-20 and 20-30 cm layers,three soil samples were collected and mixed from each same layer,the mixed soil sample was divided into four shares equally,and the soilsample shares were packed to the lab. The soil organic matter was analyzed with dilution heat method,and the soil total nitrogen,phosphorus,potassium were analyzed respectively with wet combustion method,Mo-Sb colorimetry and flame photometry. The data was processed by ANOVA. [Results]1)The organic matter content and total N content were significantly different under 4 land use types in the Yijinhuoluo region,while there was no significant difference on total P content and total K content at depth from 0 to 30 cm( P < 0. 05). In the case of organic matter content,4 land use types can be organized from high to low as following,farmland( 7. 63 g/kg) > nature grassland( 4. 91 g/kg) > shrub forest land( 4. 11 g/kg) > land use for mining( 3. 29 g/kg). The highest content of total N,P,and K were 0. 39 g/kg( nature grassland),0. 42 g/kg( nature grassland) and 26. 23 g/kg( shrub forest land).The lowest content of total N,P,and K were 0. 13 g/kg( land use for mining),0. 34 g/kg( shrub forest land) and 21. 59 g/kg( nature grassland) respectively. 2) In soil vertical section,the organic matter gradually decreased with the increase of soil depth on mining land and nature grassland. The maximum organic matter content appeared in the depth of 20 – 30 cm both in farmland and shrub forest land. The total N and total P content of the all land use types had a decrease tendency with the increase of soil depth. There was no obvious change about total K content within different soil layer. [Conclusions]Soil total N and total P content of the 4 land use types are comparatively ideal,and the total N content and organic matter content are deficient. The total P content of farmland can meet the growth needs of main crops; however organic matter and total N content cannot meet the growth needs of major crops.