Background The severe soil erosion on the Loess Plateau results in the ecological balance imbalance, restricting the sustainable development of the social economy. The erosion gully is not only the basic unit of ecological environment management, but also the main source of regional erosion and sediment production. In the research of erosion gully management, the plant measures and the site condition allocation of erosion gully are lack of in-depth theoretical discussion. Therefore, the phenomenon of "small old trees" and "three lows" of plants often occur, which limits the effectiveness of soil and water conservation measures.

Methods The Luoyugou and Lu'ergou watersheds in the third sub-region of the loess hilly and gully region, Anjiagou and Chenggou river watersheds in the fifth sub-region, and the Nanxiaohegou watershed in the loess high plateau gully region were selected as the study areas. Meteorological statistics, spatial interpolation, ecological suitability models, and field survey methods were used to calculate the differentiation law and quantitative characteristics of the environmental factors of the microclimate in different terrain parts of the erosion channel, to analyze the environmental resource level of the gully environment and the ecological demand level of plants, to calculate the ecological suitability of plant species, and to propose a counterpoint configuration model.

Results Erosion gully site conditions were divided into 10 types according to topography, slope direction, slope, soil type and water factor. The site conditions were mainly gully slopes and gully terraces. The air temperature, ground temperature, and water pressure in the erosion gully varied regularly with months in the shady and sunny slopes and the bottom of the gully. The annual sunshine hours and effective accumulated temperature on the sunny slope were significantly higher than that on the shady slope when the slope was the same. In different types of areas, the annual sunshine hours was as: The third sub-regions of the loess > loess sorghum > The fifth sub-regions of the loess. ≥ 10 ℃ effective accumulated temperature was in: The third sub-regions of the loess > the fifth sub-regions of the loess > loess sorghum. Verification of the counterpoint configuration mode found that the same plant growth and development were better under the better site conditions in the same type area, and the suitability index was higher.

Conclusions The counterpoint configuration of environmental resource level and plant ecological demand level of the erosion gully in the loess area was studied, the quantitative study of suitable trees for the site was discussed in depth, and the counterpoint configuration mode of plant measures for soil and water conservation in the erosion gully was proposed. Its application should result in good plant growth and development effects, may provide a theoretical basis for the selection of gully control measures and the scientific configuration of measures, and guide the practice of water and soil erosion and management in small watersheds in the Loess Plateau.