Optimized patterns for intercropping forest and grass and engineering conservation measures for the sloping field converted from farmland in Loess Plateau

The intercropping system of forest and grass with grassland as the main body was presented as a conservation pattern to restore vegetation rapidly and reduce soil and water loess in the sloping fields converted from farmlands in consideration of natural characteristics of different plants combining with different engineering conservation measures. This pattern had successfully solved severe loss of soil and water on bared land in the same year. Results showed that large terraced field+Humulus scandens+non-timber product forest was the optimum conservation pattern for sloping fields with gradient from 15° to 20°, and a vegetation coverage of 47.2% was achieved at the same year and 75.9% four years later and soil erosion was 34.30% lower than control; for sloping fields with gradient from 20° to 25°, sloping terrace+Humulus scandens+arbor ecological forest was the optimum conservation pattern, which led to a vegetation coverage of 33.9% at the first year and 49.4% four years later and 34.30% decrease of soil erosion compared to control; for sloping fields with gradients over 25°, large fish-scale pits+Agropyron cristatum+shrub was advisably used as combination pattern which vegetation coverage reached 28.7% at the same year and 36.3% four years later, and soil erosion could be reduced by 68.17% of that of control. All three patterns could abate the effect of rain splash erosion on loose top soil, enhance soil water content and vegetation coverage and promote the formation of the stable harmonious community of forest and grass.