Sithole, N.; Tsvuura, Z.; Kirkman, K.; Magadlela, A. Altering Nitrogen Sources Affects Growth Carbon Costs in Vachellia nilotica Growing in Nutrient-Deficient Grassland Soils. Plants2021, 10, 1762.
Sithole, N.; Tsvuura, Z.; Kirkman, K.; Magadlela, A. Altering Nitrogen Sources Affects Growth Carbon Costs in Vachellia nilotica Growing in Nutrient-Deficient Grassland Soils. Plants 2021, 10, 1762.
Vachellia nilotica (L.) Willd. Ex Del. is multipurpose leguminous tree which is common in grass-land and savanna ecosystems in southern and eastern Africa. These ecosystem soils are reported to be acidic and nutrient limited, specifically with regards to nitrogen (N) and phosphorus (P). The presence of this plant in these terrestrial ecosystems improves soil fertility benefiting the sur-rounding vegetation due to its ability fix atmospheric N. This study seeks to understand the mi-crobial symbiosis and physiological adaptations of V. nilotica in these acidic and nutrient defi-cient KZN soils. The soils used for this study were collected from the Ukulinga Grassland Nutri-ent Experiment located at the Ukulinga research farm of the University of KwaZulu-Natal, Pie-termaritzburg, South Africa. Due to long-term soil nutrient addition treatments, these soils of-fered a diverse nutrient variation for better understanding the effects of acidity and nutrient var-iation on microbial symbiosis, plant nutrition and biomass accumulation of V. nilotica. V. nilotica was able to maintain growth by relying on both atmospheric and soil derived N across all treat-ments decreasing carbon (C) growth costs. There was an increased reliance on atmospheric de-rived N of un-nodulated high N treated plants. The plants grown in high N+P soils were able to nodulate with various species from the Mesorhizobium genus which resulted in an increased bio-mass compared to other plants. The results of this study show that V. nilotica can alter N sources to reduce C growth costs. Also, free-living N2 fixing bacteria play an important role under P deficient conditions.
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.