Response of Arbuscular Mycorrhizae to Soil Test Based Phosphorus Fertilization of Corn (Zea mays L.) in Eastern Nebraska.

Abuscular mycorrhizae (AM) in soils and plants are dynamic, responding to environmental factors, crop growth stage, crop rotation and nutrient management. In corn grown at high yield, AM fungi facilitate P acquisition during reproductive growth, a period of high P demand. Thus, is maintaining a high soil test P important to yield in enough years to justify the cost or can AM fungi perform this function without loss of yield. To assess the impact of increasing P rate on the AM community of corn roots, a study was conducted on a silt-loam soil in eastern Nebraska. The three treatments were applied were (1) recommended, < 15 ppm P; (2) Bray-1 P maintained at 25 ppm; and (3) Bray-1 P <15 ppm with no P applied. Roots were sampled in August and analyzed for percent colonization, spore density, phosphatase activity, AM biomass using fatty acid methyl esters (FAMEs) and community composition using PCR-DGGE. In this study, the three soil P treatments affected the root colonized percent of Arbuscular mycorrhizal fungi (AMF) and AMF spore density.