Abstract:

In order to provide scientific referencess for vegetation restoration and reconstruction in semi-arid loess area,the soil nutrients were measured and analyzed in 4 typical land use types(cropland,abandoned cropland,grassland,forestland) and 3 watersheds(Anjiagou,Longtan,Diaogou) in loess hilly area of Longzhong,Gansu Province.Variance analysis indicated that the soil nutrient content had no significant differences(P>0.05) among three watersheds except for total K,but had significant differences among different land use types(P<0.05);there were no significant differences(P>0.05) in soil nutrients between different slope aspects for cropland and abandoned cropland,also there were no significant differences(P>0.05) between different vegetations of forestland,but there were significant differences(P<0.05) between different vegetations of grassland.Variation analysis showed that there were small differences in nutrient variation among different watersheds,but great differences among different land use types.Correlation analysis showed that there was significant correlation among soil nutrients(P<0.05). The comprehensive analysis showed that in semi-arid loess hilly area,the geographical location of the watershed had no obvious influence on the content and distribution of soil nutrients,but the land use type had a great influence on the content and distribution of soil nutrients.Under the same land use type,slope aspect had no obvious influence on soil nutrient content and distribution,but the vegetation type had certain influence on soil nutrient content and distribution.The conversion of cropland to forestland and grassland was beneficial to the recovery of soil nutrients.

Key words: semi-arid loess area, land use type, vegetation type, soil nutrient, distribution of soil nutrient