沟谷密度

沟谷系统发展，在沟间地依据沟谷密度分为密集类型、稀疏类型和中间过度类型，发育特点不同，主要受地形因子制约；

The development of gully system may be divided into 3 types including the concentrated , sparsed and transitional in accordance with the gully density and are mainly restricted by topographical factors of the upland plain .

冲沟溯源侵蚀速度加快，如元谋地层上发育的冲沟，年均溯源侵蚀速度50cm左右最大达200cm，沟谷密度一般为3～5km/km~2；

The speed of headward erosion of the gullies has been increased . The erosion speed of the gullies which are developed on the Yuanmou layer is about 50 cm / a , the maximum speed reached 200 cm / a.

研究表明，包括切沟在内的黄土丘陵区的沟谷密度值可高达20km/km~2以上；

Density of gully in this area is so high that it can reach 20km / km2 ;

其中自然因素包括气候因素、植被因素、土壤因素、地形地貌因素、地质因素及水文因素，但起主导作用的是降水、植被覆盖度、土壤质地、地质岩性、地形坡度和沟谷密度等；

Natural factors include climate , vegetation , edaphic factors , terrain , geological and hydrological factors . However , the main factors include rainfall , the degree of vegetation coverage , the soil texture , the terrain gradient and the ditch density geological lithology .