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:Mamdouh R. Rezk, Abd El-Aziz B. Abd El-Aleem, Shaban M. Khalile and Omneya K. El-Naggar
Lavender and rosemary are shrubs that have many medicinal uses. Like any other shrubs, they are susceptible to pest infection which needs pesticides treatment. Residues of pesticides in lavender and rosemary leaves may be hazardous to human health. The main objective of this study was to develop accurate and sensitive methods for the determination of residues of pesticides, namely, diazinon and chlorpyrifos, in lavender and rosemary leaves. Thin-layer chromatography (TLC) fractionation was applied to separate the desired pesticides to be analyzed and to determine the rate of the disappearance of these pesticides from lavender and rosemary leaves. Diazinon and chlorpyrifos were separated from extracts of leaves using silica gel 60 F254 plates. The mobile phase was formed of petroleum ether–ethanol–glacial acetic acid (9.5:0.5:0.1, v/v) and (9.0:1.0:0.1, v/v) as the developing systems for diazinon and chlorpyrifos, respectively, followed by densitometric measurement at 254 nm for both pesticides. The methods were validated over a range of 0.01–l.6 μg band−1 for diazinon and 0.04–2.0 μg band−1 for chlorpyrifos. The detection limits of diazinon and chlorpyrifos were 0.003 and 0.012 μg band−1, respectively. The safe harvest interval (pre-harvest interval; PHI), time in days between the last pesticide application to the crop and the time it can be safely harvested, was suggested to be 21 and 24 days for diazinon and chlorpyrifos, respectively. The developed TLC methods were used for sample cleanup and estimation of the studied pesticides residues in leaves extracts, in addition to the determination of the pre-harvest interval.