Soil acidity and its effects on symbiotic nitrogen fixation on pasture legumes

Leticia Barrientos D.1, Ricardo Campillo R,2 y Edith Méndez A.1

During the 1993 season, a field research trial was carried out in a transitional soil, characterized by high acidity, in the IX Region. The purpose was studying the effects of calcium carbonate over the establishment of lucerne, berseem, crimson, red and white clover and alfalfa and their impact on the symbiotic nitrogen fixation. In absence of lime, the production of dry matter was drastically reduced and a low account and weight of nodules formed on the roots were obtained. Moreover, a low activity ofthe nitrogenase enzyme in the plants nodules was registered. Nitrogenase activity was evaluated through acetylene reduction assay. However, in presence of lime (4 ton/ha), there was an important and significant increase of the parameters referred above, since the toxic aluminium of the soil was neutralized by the carbonate applied through this management practice.

Keywords: pasture legumes, soil, acidity, nitrogen fixation.
1 Estación Experimental Carillanca (INIA), Casilla 58-O, Temuco, Chile.
2 Estación Experimental Remehue (INlA), Casilla 24-D, Osorno, Chile.