The efficiency of large-scale afforestation with fish-scale pits for revegetation and soil erosion control in the steppe zone on the hill-gully Loess Plateau

Abstract

To reduce the rate of soil erosion and improve the environment, the Chinese government launched the “Grain for Green” project in 1999, and afforestation with fish-scale pits (FSPs) is one of the main measures of this project in the steppe zone on the Loess Plateau. In this study, tree survival and growth, vegetation recovery and differences in soil erosion between afforestation with FSP slopes (AFS) and natural restoration slopes (NRS) were analyzed, and the suitability of afforestation with FSPs in the steppe zone of the Loess hilly–gully region was assessed by field survey. We found that the average tree survival rate was 37.9% for planted Robinia pseudoacacia and was 58.9% for planted Prunus armeniaca and Prunus davidiana. All three tree species afforested using FSPs exhibited a “small-aged tree” trend due to the poor growth conditions. The coverage of both the herb and litter on NRS was an average of 1.5 and 1.7 times higher than that on AFS, respectively. There was no significant difference with regard to rill erosion between the non-FSP part of the afforestation slopes and NRS. However, the total amount of rill erosion in the upside and downside FSPs was 2.14 times higher than the amount of sediment deposited inside FSPs after 8years. Therefore, we conclude that afforestation with FSPs is not effective in controlling soil erosion and improving vegetation recovery. Large-scale afforestation with FSPs is unsuitable in the steppe zone on the hilly-gully Loess Plateau.