清水河流域山区坡面土壤养分分布特征

Analysis of the distribution characteristics of soil nutrients of mountain slope in Qingshui river watershed

水土流失作为影响山区河道水质的面源之一,其坡面土壤库中养分(对水质产生影响的主要为有机物、氮和磷)的分布与变化,直接影响植被生长和水土流失物养分含量。本研究基于崇礼县土壤分布图,沿清水河3条主干支流(东沟、中沟和西沟)布设土样采集点位,分析不同坡位土壤养分时空变化特征。结果表明:(1)山区土壤速效磷含量在不同时段变化较大,而有机质和速效氮含量受季节影响较小;(2)坡面0~20cm土层土壤速效磷、有机质和碱解氮含量的变化顺序为上坡位>下坡位>中坡位;(3)随海拔高度的增高,多数样点土壤有机质、速效磷和速效氮含量呈增加趋势。晚秋和早春(采样时间),清水河流域山区坡面中坡位土壤养分平均含量低于上、下坡位;土壤养分在下坡位有一定累积,有利于坡底植被生长,既可减低水蚀,又可发展高效农业。

Soil and water loss is one of the sources affecting the mountain river water quality.The distribution and change of the soil nutrients in slope soil pool（including soil organic matt ers,available nitrogen and phosphorus,which were the main soil materials that influenced river water qualities）directly affected the vegetation growth and soil nutrient loss by runoff.The variation characteristics of soil organic matter,available phosphorus and nitrogen contents,as well as their influencing factors were studied in the case of,slope soil in Qingshui River watershed in order to provide a theoretical basis for soil and water conservation plans.Based on the soil distribution map of Chongli district,are soil sampled at the mountain slope of the three main tributary of Qingshui river,which was Zhong-gou,Xi-gou and Dong-gou river,to analyze the temporal-spatial variation characteristics of the soil nutrient contents.The results showed：（1）The soil available phosphorus content varied greatly in different periods,and the soil organic matter and available nitrogen were influenced less by the change of seasons;（2）The order of soil available phosphorus,organic matter and alkali-hydrolyzale nitrogen contents of 0—20 cm soil layer with different slope positionwas upper slope ﹥lowerslope﹥ middle slope;（3）The contents of soil organic matter,available phosphorus and available nitrogen of most samples increased with the increase of altitude.In late autumn and early spring（sampling time）,the average contents of soil nutrients in middle slope position in the underlying surface of Qingshui river watershed mountain slope were lower than that at upper and lower slope position;soil nutrient in the lower slope had certain accumulation,which was favor able to vegetation growth at the slope bottom,and had the effect of reducing water erosion and developing efficient agriculture.