黄土高原的形成与整治对策

本文以雨土和雨尘等泥质“细粒团”的形成和细小矿粒楔入粗粒等现象,作为只有经过风力吹扬搬运才能形成的“专一”特征,来检查250万年以来黄土高原各期黄土后,发现黄土确系西来黄尘在黄土高原上空与东来湿气相遇不断降落、堆积增厚所成。这样堆积以颗粒支架式接触为主的黄土层,本来就具有良好的通透性能,后来因植被的繁生,尤其是禾本科草本植物根系的作用,而更加提高和巩固。这是在自然环境下,黄土高原堆积厚达100m以上完整的黄土——古土壤系列的唯一背景和根源。目前黄土高原水土流失剧烈进行,其主要原因就是人为活动对天然植被的无情破坏,从根本上破坏了土壤的入渗和抗冲性能。当前黄土高原整治的对策也只有按照“全部降水就地入渗拦蓄”为战略目标,采取“米粮下川上塬;林果下沟上岔;草灌上坡下坬”,并与社会经济需求紧密结合,来安排土地合理利用和具体生产措施。

The Formation of Loess Plateau and Its Harnessing Measures

By taking the formation of mud-rain and dust-rain and other mud "granular fine sand",and the inlaying of fine mineral grain into coarse sand and other phynomena,as the sole characteristic for the formation of loess plateau caused only by the blowing and carrying of wind,and after checking each different periods'loess,which were formated for 2.5million years long,it was believed that the formation of the loess plateau was indeed the causes that the loess dust,which was carried by wind from west,met the moist airflow from east then continuously fell down then accumulated gradually,The loess layer accumulated this way,in which the structure appears frame touch,possessed fine aeration and permeability originally,later it is affected by the reproduction of vegetation,especially by the effect of root system of grass,the character is strengthened.This is the sole background and source for the accumulation of loess up to 100 meters and formulating the complete loess platcau--ancient soil under the natural condition.The soil and water loss violently,the main reason was human's destory on natural vegetation,thus it thoroughly destroyed the permeability and anti-souring of soil.So recent harnessing measures on loess plateau are forced to be"no-site-retain all precipitation"as the strategic goal,and adopt measures as "cereal crops are planted on plain and plateau land,forest and fruit tree are set on gullies,grass and shrub are located on hillside";and combining with the social and economic requirement,to arrange the reasonable land utilization and concrete productive measures.