Abstract:

The study aims to analyze the variations in soil nutrient content, soil physicochemical properties and soil microbial quantity across different site types and planting densities during intercropping between forests and grasses, to offer insights for selecting an optimal management approach for intercropping between forests and grasses. With Ophiopogon japonicus planted under poplar forests as the subject of the study, three different afforestation densities and two different land types were established. By measuring, we compared the variations in soil nutrients, soil physicochemical properties and soil microbial quantity under different treatment methods. The results showed that compared to plain land, riverbank land had lower nutrient content in terms of available N, available P, available K, available Fe, available Mn, available Cu, available Zn and organic matter. There were significant variations in these elements among different land types (P<0.05). Additionally, there were extremely significant differences in available N, available K, available Mn and available Cu among various afforestation densities, while no significant differences were observed in other elements and organic matter content (P>0.1). In comparison to riverbank farmland, plain farmland had a greater soil bulk density but lower saturated water content, total porosity, bacteria, fungi, actinomycetes and total microbial content. In plain farmland, among various afforestation densities, all soil physicochemical properties and soil microbial numbers were higher than that in LN2, except for soil bulk density and total soil porosity. The differences in soil bulk density, saturated water content, total porosity, fungi, and actinomycetes were extremely significant (P<0.05). However, the changes in soil physical and chemical properties and soil microbial quantity in riverbank land were not significant. The variations in soil bulk density, saturated water content, total porosity, bacteria, fungi, actinomycetes, and total microbial count between various types of land are highly significant (P<0.05). To sum up, in the long run, forests with a density of 5 m×6 m or 5 m×8 m exhibit excellent tree growth and nutrient levels, making them optimal planting densities.

Key words: poplar, intercropping between forest and grass, soil physicochemical properties, soil microorganism