Soil P Buffer Capacity Effects on Leucaena leucocephala Response to VA Mychorrhizae

Abstract

In two glasshouse experiments, Leucaena leucocephala was grown in different soils adjusted to several levels of available P, with half of the treatments inoculated with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus aggregatum. The first experiment used two soils with different mineralogies but similar P buffer capacities. Each soil was adjusted to three P levels, and half of the treatments were fumigated with methyl bromide. Fumigation decreased plant growth, while VAM inoculation and added P increased it. In the second experiment, four soils were used. The soils were selected to provide a wide range of P buffer capacities. All soils were fumigated and each was adjusted to nine P levels. An equation incorporating soil solution P concentration, soil P buffer capacity, and VAM inoculation accounted for 91% of the variation in plant P uptake.