Sorghum Response to Foliar Application of Phosphorus and Potassium with Saline Water Irrigation

Abstract

Increasing demand for fresh-water resources for urban and industrial uses is leading to limited availability of better quality water for crop irrigation. Therefore, crop response to poor quality irrigation water (e.g., saline water), and strategies to mitigate the negative effects of poor-quality irrigation water on crop yield and/or quality need to be investigated. A greenhouse experiment was conducted in the National Research Centre, Dokki, Cairo, Egypt, during the 2005 summer to evaluate the effects of different salt concentrations (tap water as control, seawater diluted to attain salinity levels of 2,500 and 5,000 ppm) and potassium (K) and phosphorus (P) foliar application (0, 50, and 100 ppm as potassium dihydrogen phosphate) on the growth, grain yield, chemical composition, and anatomical features of sorghum (Sorghum bicolor L.) plants. Increasing irrigation-water salinity adversely affected plant growth characteristics, length and width of the vascular bundles, diameter of xylem vessels, and thickness of leaf blade mesophyl. Foliar application of P and K mitigated some of the negative effects of salinity on plant growth, and increased the concentrations of these nutrients in the leaves and grain.

Keywords:

• Irrigation water quality
• mineral nutrition
• best management practice
• leaf and stem anatomy

Acknowledgments

This study was made possible by funding from Water Relations and Irrigation Department, and Soils and Water Use Department, National Research Centre, Giza, Egypt. We appreciate the excellent assistance of Megan Harrison (USDA-ARS, Prosser, WA) for preparation of this manuscript.