13-3 Optimizing the Rate of AVAIL® Co-Polymer While Enhancing Phosphorus Availability to Corn (Zea mays).

See more from this Division: Students of Agronomy, Soils and Environmental Sciences (SASES)
See more from this Session: Undergraduate Research Contest - Oral II

Sunday, November 6, 2016: 12:45 PM
Phoenix Convention Center North, Room 225 A

Samantha Jo Croat, Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD, Sarah Doydora, Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, Dean Hesterberg, North Carolina State University, Raleigh, NC and Carl R. Crozier, Soil Science, North Carolina State University, Plymouth, NC
Abstract:
Phosphorus is an essential plant macronutrient, but only a fraction (<40%) of phosphate applied to soils is available to plants. Our objective was to determine the application rate of a polycarboxylic acid co-polymer (AVAIL®) for optimal P uptake and corn growth at a reduced input of P fertilizer. In a greenhouse experiment, corn was grown in a P-deficient Goldsboro soil that was amended with phosphate fertilizer at 50% of the recommended rate in a horizontal band, along with AVAIL® treatments of 25, 50, 100, 150, and 200% of the soil’s estimated polymer sorption capacity. A complementary soil-sorption experiment measured dissolved P for the same P and AVAIL® treatments at pH 5.6. The corn grew for 21 days to a height of 32 ± 3 cm, with all plants showing P deficiency (purpling) after 15 days and no apparent growth trends across AVAIL® treatments. However, the soil-sorption experiment revealed a positive linear relationship (r2 = 0.97) between AVAIL® input rate and dissolved P, with the average P concentration increasing from 0.03 to 0.06 mg/L.  The sustained concentration of dissolved P considered adequate for corn growth is 0.025 mg/L. Total biomass and tissue concentrations of P and other nutrients showed no trend with AVAIL® rate. Although AVAIL® increased dissolved P concentrations in the soil alone, a lack of corn growth response in the greenhouse indicates that the AVAIL® rates need to be optimized at a higher P fertilization rate.

See more from this Division: Students of Agronomy, Soils and Environmental Sciences (SASES)
See more from this Session: Undergraduate Research Contest - Oral II