陕北黄土高原土壤有机质分布研究

对陕北黄土高原地区不同年限、不同植被立地土壤有机质含量的分析发现,刺槐、苜蓿、撂荒地土壤有机质含量随植被恢复年限的增加而增大,且呈线性相关;安塞土壤有机质含量随植被逐渐乔木化而增大;0～60cm土层土壤有机质含量随深度的增加而减小;坡面表层土壤有机质分布曲线类似于一个周期的"正弦曲线"或"反弦曲线",但植被生长较好的坡面例外;土壤有机质受地理位置的影响,随纬度的北移而减小,其顺序为:富县>宜川>安塞>神木。

Distribution of soil organic matters on loess plateau of Northern Shaanxi

By analyzing the organic matters content in soils of different vegetations coverings with different restoration time in North of Shaanxi provice,we found that the content of organic matters increased with the increase of re-vegetation time in the soil with Robinia pseudoacacia,Medicago sativa Linn planted and abandoned land,and there was a linear correlation between the content of soil organic matters and restored time;The content of organic matters increased with the coverings turning from grass to arbor in Ansai;The content of soil organic matters reduced with the increase of soil depth in 0-60 cm layers;Though the trend-line was simulated with multinomial,we found that distribution of soil organic matters in slope surface layer soils showed "sinusoid" or "re-sinusoid" in a whole period,except those slopes with well vegetations.Besides,the content of soil organic matters was affected by geographical position,and dropped with the increase of latitude from south to north with a distribution order of Fu county>Yichuan>Ansai>Shenmu.