The effect of inoculation of an indigenous bacteria on the early growth of Acacia farnesiana in a degraded area

Abstract

Restoration of native vegetation and fuelwood production are important environmental pending goals for Mexico,where years of wrong management practices resulted in ecosystemic degradation and fuelwood scarcity. In degraded areas, native rhizobial strains are often undetectable, therefore, the restoration of natural vegetation associated with an effective nodulation of the leguminous trees is mostly appropriate. Sinorhizobium americanum is a native nitrogen-fi xing bacteria isolated from nodules of the native Acacia species in the region. Acacia farnesiana is a multipurpose leguminous shrub from Mexican seasonally dry tropical forests (SDTF). In this study we analyzed the effect of inoculation with S. americanum on A. farnesiana growth in a greenhouse and in a very degraded area and compared with non-inoculated seedlings. In a greenhouse, we measured the biomass dry weight of different parts of the plant, using destructive sampling after 15, 20, 30, 45 and 120 days of growth. We also calculated the relative growth rate (RGR) and the resources allocation (root/shoot weight ratio and root length/root dry weight) of seedlings. In a degraded area we measured the seedling length and survival and calculated the RGR. In the greenhouse and in the degraded area, the inoculation positively affected the growth of seedlings. However in the greenhouse, the inoculation did not have effect on resource allocation patterns. Therefore, the inoculation with Sinorhizobium americanum could improve the A. farnesiana growth and the re-establishment of important plant-soil interactions in degraded areas, being a recommendable technique for land restoration and the improvement of fuelwood production.