Interaction of the vesicular-arbuscular mycorrhizae of maize with extractable soil phosphorus levels and nitrogen-potassium fertilizers

Summary A field experiment was conducted for 3 years to determine whether increasing extractable soil P levels would affect vesicular-arbuscular mycorrhizae (VAM) of maize (Zea mays L.) and the subsequent uptake of P and production of dry matter. Five levels of extractable soil P were established on an Aquic Dystrochrept soil with high and low NK fertilization. The results show that as extractable soil-P levels increase the vesicular-arbuscular mycorrhizae of maize decrease, but P concentrations in both leaf and root tissue increase. There was a significant interaction between the extractable soil-P levels and NK treatment. At the low soil-P level NK fertilization increased mycorrhizae, while at the high soil-P levels NK fertilization reduced mycorrhizae. Dry-matter production generally paralleled extractable soil-P levels from 1.0 mg P kg^–1 to a maximum at 10 mg P kg^–1 soil (by ammonium acetate, pH 4.8). The reduction in vesicular-arbuscular mycorrhizae at the highest levels of extractable soil P apparently was not critical to either P uptake or dry-matter production.Scientific contribution No. 1196 Storrs Agricultural Experiment Station