Eco-Physiological Study of the Effect of P Levels and Coated P Fertilizers on the Wheat Grain Yield (Triticum aestivum L.), Dirab, Riyadh, Saudi Arabia

Abstract

The soils in the Kingdom of Saudi Arabia suffer from severe P deficiency. This is attributed to the high soil pH due to the presence of calcium carbonate. Under such conditions, the utilization of fertilizer P by plants is generally very low due to sorption of P by soils. The objectives of this study were to assess the suitability of coating of P fertilizer along with soil P application on available soil P content and wheat yield in calcareous soil. Soil application rates of P (0, 150, 300 and 450 kg ha^-1) as di-Ammonium phosphate (DAP) applied just before sowing. Coating types included (No coated, humic acid with different %, bitumen emulsion and bitumen emulsion+ 5% clay). The results indicated that, application of different rates of soil P has a significant effect on the available P soil content. The available P reached 18.9, 31.0, 36.0 mg kg^-1 under application of 150, 300 and 450 kg DAP ha^-1, respectively. The results showed addition of 300 kg DAP ha^-1 resulted in high content of available soil P and no need for further application of P fertilizer. The coated DAP fertilizer with HA, bitumen emulsion and bitumen emulsion+ clay did not increases the available P in soil compared with no coated. Under current experiment, coating of P fertilizer by HA, bitumen emulsion and bitumen emulsion+5% clay along with medium rates of soil P fertilizer may contribute to improve P fertilizer efficiency and increase wheat grain yield cultivated in calcareous soil.