Effect of Liquid Phosphorus (P) Fertilizer on Arbuscular Mycorrhizal Fungi (AMF) Association with Corn (Zea Mays L.) Roots in the Field.

Fertilization practices necessary to maintain current levels of intensive agriculture production are projected to result in eventual depletion of the primary phosphorus (P) fertilizer source, rock phosphate. There is an emerging recognition of the need to investigate techniques that enhance P uptake efficiency by crops. This study focuses on plant root architecture response and AMF root interactions that increase access to plant available soil P in corn. No-till field trials were conducted in the Brazos Bottom Farm (Snook, TX) and Stiles Farm Foundation (Thrall, TX) to assess the effect of banded soluble phosphorus fertilizer on arbuscular mycorrhizal fungi association and root traits such as root length density (RLD) and root length of the corn plant. Plant height, plant biomass, nitrogen and phosphorus status of leaf tissue as well as P uptake and P content on corn grains were also evaluated. A randomized complete block design with 3 application rates (recommended, half and 1.5 times of recommended dose) and 3 depths (surface, 10cm and 20cm) of liquid P fertilizer placement was replicated five times at each site. The previous year’s studies indicate that post-harvest soil test P level were far greater in the root zone of the plants under treatments receiving no P fertilizer than those receiving even small amounts. Fungal infection of roots is known to enhance plant available P in soils, but is also inhibited in the presence of applied P. Therefore, we hypothesize that AMF colonization varies with P levels (i.e. the highest AMF colonization will be observed with lowest P level). Results and conclusions of the current year’s study will be presented.