Phosphorus fertilization of a grass-legume mixture: effect on plant growth, nutrients acquisition and symbiotic associations with soil microorganisms

MENDOZA, RODOLFO; BAILLERES, MATÍAS; GARCÍA, ILEANA; RUIZ, OSCAR A

JOURNAL OF PLANT NUTRITION

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2016 vol. 39 p. 691 - 701

0190-4167

Adding P on Lotus tenuis and Festuca arundinacea in pure or mixed stands on plant growth, nutrient acquisition and symbiotic associations with soil microorganisms were studied in a field experiment. Moderate amount of triple-superphosphate was applied on a Typic Natraquoll soil where Lotus grows spontaneously. Aboveground biomass, N and P uptake, arbuscular mycorrhizal colonization and rhizobia nodulation were measured in late spring. Lotus achieved the highest aboveground biomass, N and P uptake in fertilized stands, whereas Festuca achieved the lowest in both fertilized and non-fertilized stands. Mycorrhizal colonization decreased with fertilization in roots of both plants. The rhizobia nodules in Lotus roots showed little changes with fertilization. In mixed fertilized stands, Lotus promoted both the growth and the N and P uptake by Festuca compared to non-fertilized stands. The results suggest that P fertilization increases the ability of Festuca to compete with Lotus for the available P in soil. Adding moderate amounts of P to limited N-P environments depress the ability of grasses to compete with legumes for resources and to keep a good proportion of legumes in the grassland. Lotus tenuis improves nutrient cycling in the grassland and maintains high level of rhizobia nodules and arbuscular mycorrhizal colonization in roots.