土壤中的氮、磷元素大都以有机态存在,这是—种养分的保存方式。当这些营养元素自有机物中释放出来成为无机态时易被植物利用,但也容易流失。许多微量元素以与有机物络合的形式保存于土壤中。因此土壤有机物的储量多寡密切关系着作物产量,也影响着土壤结构、水气通透牲等土壤物理牲状;从而也在很大程度上影响着土壤的发生和演变。人们往往以有机物质的质与量作为评定土壤肥瘦和发生、分类的指标。黄土地区的地壤很大部分处于坡陡山高、支离破碎的丘陵沟壑区,土壤遭受到不同程度的侵蚀。本文通过统计分析试图阐明在土壤侵蚀和水土流失作用下黄土地区几种主要土壤有机质含量的变化趋势及其与氮、磷元素的相关性。 Soil nitrogen, phosphorus mostly exist in organic form, which is - the preservation of nutrients. When these nutrients are released from organic matter into inorganic state, they are easily used by plants, but also easily lost. Many trace elements are stored in the soil as organic complexes. Therefore, the amount of soil organic matter closely related to the crop yield, but also affect the soil structure, water and gas permeability and other soil physical sacrificial; thus also largely affect the occurrence and evolution of soil. People tend to use the quality and quantity of organic matter as a measure of soil fat and occurrence, classification index. Most of the loess area is located in a steep hill with high slope and fragmented hill and gully area, so the soil is subject to different degrees of erosion. Through statistical analysis, this paper attempts to clarify the trend of organic matter content in several major soils in the loess area under the action of soil erosion and soil erosion as well as its correlation with nitrogen and phosphorus.