大学生英语竞赛作文陕西黄土高原人工林土壤干层及形成原因

2021年1月7日发(作者：钟离权)
陕西黄土高原人工林土壤干层及形成原因
赵景波;杜娟;陈宝群


【期刊名称】《地理学报（英文版）》

【年(卷),期】2007(017)001

【摘要】By determining the earth moisture content of artificial
forestland between 0 and 6 m deep in the Loess Plateau of Shaanxi
province, the vertical change of moisture content,distribution and
formation causes of a dried earth layer are researched. The results show
that the average moisture content is 9.3%-9.5% between 2 and 4 m
under artificial forest of over 10 year's growth in Guanzhong Plain, and
chronic weak dried earth layers are developed which show that the
dried earth layers are distributed extensively on the Loess Plateau. The
southern boundary of the dried earth layer has reached the northern
foot of the Qinling Mountains. When precipitation reaches 600 mm,
there are weak dried earth layers between 2 and 4 m under artificial
forest of more than 10 years old. When the precipitation is between 400
and 500 mm, there are moderate dried earth layers. When precipitation
is above 800 mm,there are no dried earth layers. There are no dried
earth layers under meadow land, corn land and less than 5 years old of
artificial forestland in central and southern parts of the Loess Plateau.
The development of dried earth layers under cypress forest is weaker
than broad-leaved forest. Under the same climatic conditions, the