The interaction effects of phosphorus fertilization, applied at various rates and time intervals, with or without foliar spraying with citrine on the growth and macro- and micronutrient uptake of two new wheat cultivars (Triticum aestivum cv. Sakha 94 and Gmiza 10) in a sandy soil were investigated under greenhouse conditions at the Faculty of Agriculture, Zagazig University. Superphosphate was used at different rates (0, 7.5 and 15 mg P kg−1 soil) and timing: before planting (BP); 1 month after planting (AP) and 50% BP + 50% AP. The results confirmed that phosphorus fertilization and foliar spraying with citrine significantly increased both the straw and grain yield and the nutrient uptake compared with the control. The interaction effect of phosphorus fertilization and foliar spraying with citrine significantly increased Zn and Mn uptake by the straw and grain yield, as well as P and Fe uptake by the straw yield. The addition of 7.5 mg P kg−1 soil (50% BP + 50% AP) gave the highest value of apparent P recovery (APR) when spraying with citrine. APR and P use efficiency (PUE) were markedly decreased at the higher P addition rate, with or without citrine. Treating wheat plants with 7.5 mg P kg−1 soil combined with citrine saved 59% of the P fertilizer, and thus reduced environmental pollution.
The main objective of this work was to study the importance of applying gypsum and sulphur to the soil to inhibit the hazardous effects of soil salinity stress on the vegetative growth and yield quantity and quality of rice plants (Oriza sativa L., cv. Sakha 101) grown on a salt-affected soil irrigated with low quality water from the El-Salam (El-Shikh Zaid) Canal. Two field experiments were carried out during two successive seasons (2011, 2012) at Sahl El-Tina plain, village 4, Gilbana town. Gypsum was applied at a rate of 10.7 Mg ha−1)1 while sulphur was added in two forms, as elemental sulphur at a rate of 4.8 Mg ha−1) or as sulphuric acid at a rate of 1190 L ha−1. The results could be summarized as follows: The highest values of rice yield and its attributes as well as nutrient content and uptake were obtained after treatment with sulphuric acid. The treatment effects decreased in the order: sulphuric acid > sulphur > gypsum > control. The highest proline content (21.3 μmol g−1) was recorded after the gypsum treatment.
Authors:F. I. El-Hosiny, S. A. Abo-El-Enein, I. M. Helmy and Kh. A. Khalil
Portland cement was mixed with rice husk ash (RHA) fired at 450, 700 and 1000‡C, in ratios of 5, 15 and 25% of RHA by mass. Cement-RHA pastes were made by using a water/solid mixture ratio of 0.30 by mass and then cured for various hydration periods within the range 3 to 90 days. The surface properties of the hydrated samples were studied by means of the nitrogen adsorption technique. The results indicated that the hydrated cement-RHA samples made from rice husks fired at 450 and 700‡C gave higher values of surface area than that for the hydrated cement-RHA sample made from rice husks fired at 1000‡C. The surface area and pore volume results could be related to the pore structure of the silica produced in the RHA, as controlled by its predicted degree of crystallinity.