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Soil degradation and low productivity are among the major agricultural problems facing farmers of the newly reclaimed agricultural area in the Nile Delta region, Egypt. High content of clay and silt characterizes the soil texture of all farms in the area, while farmers still rely on the traditional mole drainage (MD) system to reduce the salinity of the farm soil. We present a comparison of innovative geo-resistivity methods to evaluate mole drains and the salinity affected clay soils. Geoelectrical surveys were conducted on three newly reclaimed farms to image the subsurface soil drainage conditions and to evaluate the efficiency of using the traditional MD systems in these heavy clay environments. The surveys included measuring the natural spontaneous potential (SP), apparent resistivity gradient (RG), and electrical resistivity tomography (ERT). Integrating the results of the three methods reduced the ambiguous interpretation of the inverted ERT models and allowed us to determine the subsurface soil structure. The inverted ERT models were suitable for locating the buried MDs and delineating the upper surface of the undisturbed clay beds. The proximity of these layers to the topsoil reduces the role played by MDs in draining the soil in the first farm and prevents the growth of deep-rooted plants in the second farm. Time-lapse ERT measurements on the third farm revealed a defect in its drainage network where the slope of the clay beds opposes the main direction of the MDs. That has completely obstructed the drainage system of the farm and caused waterlogging. The presented geo-resistivity methods show that integrated models can be used to improve the assessment of in situ sub-surface drainage in clay-rich soils. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Soil Sciences & Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biochar has not been adequately used by farmers to improve the clay textured soil productivities in the world. Therefore, the objective of this study is to investigate the effect of the co-application of biochar with different rates of phosphorus (P) fertilizer on selected soil physical properties and wheat yield on clay textured soil over two growth seasons. Biochar treatments occupied the main plots at a rate of 0.0 and 10 t ha−1, while the sub-plots were devoted to phosphorus rates at rates of 0%, 50%, 100%, and 150% of recommended P fertilizers. Biochar (10 t ha−1) and P at different rates decreased soil bulk density significantly. Meanwhile, it increased aggregate stability, saturated hydraulic conductivity and soil water retention significantly at (p <.05), and it improved the grain yield of wheat. More grain yields in the soil treated with biochar than untreated soil under all P application rates for both years were probably caused partially by more nutrients (N, P, and K) were applied from biochar itself. Grain yield of wheat in the soil-amended biochar and P did not increase significantly between the application at 50%, 100% and 150% P. The results of this study indicate that phosphorus blends with biochar can be used to decrease the bulk density of clay textured soils and to improve crop production in these soils. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Soil Sciences & Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Menoufia Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Laboratory batch experiments were designed to study the adsorption of cadusafos on two types of soils: clay loamy and sandy, collected from two regions around the Nile Delta in Egypt. The adsorption process is fast reaching equilibrium in 60min, decreases with increasing soil mass and independent on pH in the range 3–11. The experimental results were well fitted to linear partition model, and to a lesser extent to Freundlich non-linear model, Temkin and Dubinin–Radushkevich models. However, the 1/n parameter of Freundlich relation being of value around one supported the linear partition model. The K d values obtained from the linear model were 4.20 and 2.74L/g for sandy and clay soils, respectively. The energy of adsorption calculated from D–R equation was 4.36 and 5.04kJ/mol for clay and sandy soils, respectively, in the range assigned to physical forces. This kind of weak interaction, together with pH-independence implies that for the studied soils the organic content (that is higher in the clay soil) is not a major parameter in the adsorption of cadusafos. Water movement taking place more readily in sandy soil caused increased uptake relative to the case of clay soil. The higher uptake in sandy soil denotes that cadusafos may be mobile with a potential to leach and eventually pollutes ground water and surface water. The kinetics of adsorption was well fitted by the pseudo-second order equation. The intraparticles diffusion is of lower significance in case of sandy soil than in clay soil. Thermodynamic parameters indicated that the adsorption is spontaneous, endothermic accompanied by increase in entropy. [Copyright &y& Elsevier]