EVALUATION OF PHOSPHORUS APPLICATION WITH AVAIL ON GROWTH AND YIELD OF WINTER WHEAT IN SOUTHEASTERN COASTAL PLAINS

Abstract

Phosphorus (P) application with Avail may affect pl ant growth and grain yields of winter wheat ( Triticum aestivum L.) under dryland conditions. The objective of this study was to determine the effects of two P application rates (45 and 90 kg ha -1 ) with and without Avail polymer on growth and yiel ds of dryland winter wheat near Blackville, SC from 2010 to 2012. Plant growth measurements included plant biomass, P uptake, Normalized Difference Vegetation Index (NDVI), plant height and grain weight, yield and nutrie nt uptake. Application of P significantly improved whe at biomass production, plant Normalized Difference Vegetation Index (NDVI) at 8, 10 and 12 weeks after planting and grain yields of winter wheat. Plant biomass production improved with addition of Avail polymer by 6.3% at P rate of 45 kg ha -1 and by 4.3% at P rate of 90 kg ha -1 . Additionally, Avail application increased P uptak e by 8% in biomass and improved plant NDVI at high P rates. Compared to untreated control, higher grain yields were obtained from treatments with P application at 90 k g ha -1 with and without Avail and P rate at 45 kg ha -1 with Avail application. Avail improved wheat grain yields by 5.1% at 45 kg P ha -1 and 2.0% at 90 kg P ha -1 and increased grain P uptake by 2.6% at P rate of 45 kg ha -1 . Based on significant linear regression at 20 weeks after planting, increasing p lant NDVI by 0.1 increased grain yield by 0.88 Mg ha -1 . Phosphorus and Avail polymer applications did not affect plant height, grain mass and grain nitrogen uptake compared to the untreated control. Results from this study indicate that growth and yields of winter wheat grown may increase with P ap plication and Avail polymer under dryland conditions with insufficient rainfall in Southeaste rn Coastal Plains.