适宜铝土矿复垦土壤改良的固氮豆科植物筛选及固氮效应研究.

[Objective] The present paper aimed to screen leguminous plants suitable for improving the soil of bauxite mine reclaimed soil and provide a reference basis for sustainable agricultural development in mining areas. [Method] Seven legumes, including Sesbania cannabina, Vicia sativa, Astragalus sinicus, V. villosa, Medicago sativa, Stylosanthes guianensis and Coronilla varia, were planted in the reclaimed soil of the Pingguo bauxite mine in Guangxi, and the biomass, presence of root nodules, nutrient content, nitrogen fixation efficiency, biological nitro- gen fixation, soil nutrients, calcium and magnesium ion content, total aluminum and active aluminum content of each legume were determined. The legumes suitable for planting in bauxite mine reclamation soil were screened through principal component analysis, and a partial least squares path model (PLS-PM) was established to explore the factors that affected the biological nitrogen fixation of legumes in bauxite mine reclamation soil. [Result] Among the seven legumes, A. sinicus had the highest below-ground biomass(1.961 g/pot) and above-ground bio-mass (0.344 g/pot), C. varia had the lowest below-ground biomass (0.387 g/pot) and above-ground biomass (0.099 g/pot) while Sesbania had the highest N(7.98% ), P(2.999 g/kg), and K(19.828 g/kg) contents. In terms of nodulation, only Sesbania, A. sinicus, and C. varia had root nodules, while the rest of the legumes did not nodulate. Among the three nodulated legumes, S. cannabina had the highest nitrogen fixation efficiency (80.01%) and biological nitrogen fixation (0.077 g/pot). Principal component analysis of three leguminous plants based on evaluation factors including plant nutrient content, biomass, biological nitrogen fixation, and nitrogen fixation efficiency as evaluation factors showed that comprehensive score of S. cannabina repens was the highest (2.30 points). PLS-PM pathway analysis showed that the biological nitrogen fixation of legumes in bauxite mine reclamation soil was directly influenced by plant nutrient content and soil active aluminum and pH, soil nutrients, and types of plants indirectly influenced the biological nitrogen fixation of legumes by affecting plant nutrient content and soil active aluminum. [Conclusion] S. cannabina, A. sinicus, and C. varia are capable of nodulating and improving the pH, available K, ac- tive aluminum, organic matter content, and biological nitrogen fixation of the reclaimed soil in bauxite mines. Based on the comprehensive e- valuation, S. cannabina is considered as the most suitable legume plant for planting in the reclaimed soil of bauxite mines and can be promo- ted and applied as a legume plant for nitrogen fixation and soil improvement in bauxite mining areas. [ABSTRACT FROM AUTHOR]