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The absence of calcium decreases the production of peanuts compared to any other element. To investigate the influence of calcium (Ca) applications on the production and seed quality of four diverse peanut cultivars from different regions—USA (NC-7), Egypt (Giza-6) and Nigeria (Samnut-23 and Samnut-24)—under clay soil conditions, two experiments were carried out at the Agricultural Experimental and Research Station, Cairo University, Egypt, during the two seasons of 2016 and 2017. The experimental design was a randomized complete block in a spilt-plot arrangement with three replications. The main plots were allocated to four peanut cultivars (Giza-6, Samnut-23, Samnut-24 and NC-7), and the sub-plots were devoted to calcium applications (soil application in the form of calcium sulfate dihydrate, foliar application in the form of calcium oxide and the control treatment of distilled water). Results indicated that all four peanut cultivars responded differently to the application of calcium fertilizers. The calcium application significantly enhanced peanut growth, yield components, biological, pod, seed, oil yields, seed oil, free fatty acids and seed calcium percentages in different cultivars. Soil calcium application significantly improved peanut production compared to foliar calcium application. NC-7 cultivar treated with the soil Ca application resulted in the maximum values of biological yield (92.9-ton ha−1), pod yield (6.8-ton ha−1), seed yield (4.4-ton ha−1), oil yield (2247.0 kg ha−1), pod index (203.2 g) and seed index (84.1 g). The interaction between the NC-7 cultivar and soil calcium applications is recommended to attain the best combination, leading to the highest yield and seed quality of peanuts. [ABSTRACT FROM AUTHOR]

Despite studies focusing on soil substrates (carbon and nitrogen) and heavy metal availability, the impact of diversified parent materials in arid alkaline regions has received little attention. To reveal the influence of parent material, we investigated four different parent materials: fluvio-marine, Nile alluvial, lacustrine, and aeolian deposits. We assessed the effect of soil parent materials through selected soil physical and chemical properties, such as clay content, bulk density, pH, and available phosphorus (AP). The Tukey HSD test (SPSS ver. 23) was used to assess the soils derived from these different sediments. Using the R "glmulti" package, we examined this effect in a model of mixed-effects meta-regression. The sum of Akaike weights for models that contained each element was used to estimate the importance of each factor. The average contents of soil organic carbon (SOC) and total N in alluvial deposits were greater (p < 0.001) than those of marine, aeolian, and lacustrine deposits. A multivariate analysis in arid regions revealed that parent material, soil pH, and the availability of P had the greatest effects on SOC concentration, whereas clay content, available P, soil pH, parent material, and bulk density had the greatest effects on soil total nitrogen. The average content of Fe in the aeolian deposits was greater (p < 0.001) than those of marine, alluvial, and lacustrine deposits, without any significant differences between the latter two deposits. We found that the highest average contents of zinc (Zn), manganese (Mn), and copper (Cu) were recorded in alluvial deposits, with significant differences between other deposits. Soil parent material was the major factor impacting soil iron (Fe) content, along with clay content and soil pH. However, soil bulk density was the most important factor controlling soil Zn and Mn contents, while SOC drove Cu content. This study will help in developing a more accurate model of the dynamics of soil substrates and availability of heavy metals by considering readily available variables, such as parent materials, soil pH, soil bulk density, and clay content. [ABSTRACT FROM AUTHOR]

This paper presents a real case study of a micropiling process that was developed to stop the continuous tilting of a 9-story residential building in Dakahlia, Egypt. Shortly after the construction of the building, the surface raft foundation exhibited severe settlement problems. In order to carry out a geotechnical investigation, boreholes were drilled around the constructed building. It was discovered that in addition to a thick, soft clay layer in the soil profile, there was also a crucial eccentricity between the centroid of the total building loads and the centroid of the raft. The issue needed to be addressed immediately, and a micropiling system was proposed to satisfy the geotechnical and structural conditions associated with the case history. In addition to describing the field measurements, detailed methodology, and micropile installation process, this paper also presents three different design approaches for determining the number and location of the micropiles. Although the underpinning process itself initially induced some settlement, micropiling the raft proved to be an efficient solution to stop the continuous tilting of the building. A micropile load test confirmed the advantageous effect of the grouting technique used for Type B micropiles, where the grout is injected under high pressure. [ABSTRACT FROM AUTHOR]

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]

Water scarcity is becoming a global problem. The shift from traditional irrigation systems to deficit irrigation increased soil salinity, particularly in clay soils. The use of magnetized water (MW) and biostimulants can induce plant resistance to drought and salinity stress. To assess the role of MW and proline (P) on 'Taifi' pomegranate shrubs' growth, productivity, and fruit quality under such conditions, a split-plots experiment was conducted for two seasons using three irrigation levels (100%, 75%, and 50%), based on the crop water requirements (CWR), and four treatments including foliar spray of tap water (control) and P, irrigation with MW, and MW + P. The most pronounced effect was referred to MW + P at 75% CWR that improved shrubs' chlorophyll content and nutritional status, reduced endogenous proline content, and enhanced vegetative growth with minimum consumptive water use (CWU), optimum water use efficiency (WUE), maximum water productivity (WP), utmost yield and average fruit weight, lowest percentage of fruit cracking, and fairly good total soluble solids (TSS), vitamin C and anthocyanin contents. Overall, MW + P at 75% CWR improved the resistance mechanism of pomegranate shrubs in saline clay soils, plus improving the growers' net profit. MW generally reduced soil salinity, expressed as reduced pH, EC, Na+, and Ca2+ values. [ABSTRACT FROM AUTHOR]

Water scarcity and weed infestation are major challenges to soybean production. Therefore, two field experiments were conducted in a strip plot design including three replicates in the 2019 and 2020 summer seasons at Sakha Agricultural Research Station, Agricultural Research Centre, Egypt, to investigate the effect of three irrigation levels (I0 (100%), I1 (90%), and I2 (80%)), and six weed control treatments of pendimethalin (T1), oxyfluorfen (T2), bentazon + clethodim (T3), imazethapyr (T4), hand-hoeing twice (T5), and untreated check (T6) on annual weeds, physiological traits, water relations, and yield and its components of soybean cv Giza 111. Results indicated that intermediate irrigation levels lead to the highest yield and economic return, while the herbicide program that resulted in the greatest weed control gave the highest yield. The rate of weed infestation in field experiments was 19.7 and 21.8 t ha−1 dry weights, which decreased soybean yield by 56.9 and 57.1%, compared to treatment (T4). The interactions between 100 irrigation level (I0) and imazethapyr (T4), bentazon + clethodim (T3), and hand-hoeing twice (T5) gave the highest significant values of the most studied characters. Furthermore, under 90% irrigation, all weed control treatments give the best control of weeds and the highest values of the economic criteria. [ABSTRACT FROM AUTHOR]

There is consensus on the impact of wastewater irrigation on soil properties and heavy metal accumulation. The studies that show the impact of temporal changes as a result of different long-term additions of wastewater on the heavy metal accumulation and degradation of soil are extremely limited. This study was carried out to assess heavy metal contamination in soils irrigated with wastewater for more than 30 years in Egypt. A total number of 12 irrigation water samples and 12 soil profiles were collected during 2020 and were chemically characterized. The results showed that soils irrigated with wastewater over the long term contained significantly higher concentrations of heavy metals compared to fields irrigated with fresh water. Heavy metal levels in water and soil samples were within the permissible limits, with the exception of Cd concentration in water (0.03 mg L−1). Continuous cultivation for a long period of time (30 years) using raw urban wastewater application has led to the adverse effect of increasingly available Pb concentration (5.44 mg kg−1). Similar temporal behavior was seen for Cd and Fe, which increased by 0.98 and 11.2 mg kg−1, respectively, after 30 years. The heavy metals in wastewater-irrigated soils significantly increased in clayey soils, as compared to sandy soils irrigated from the same source. Our findings provide important information for decision makers in Egypt and similar countries for the development of a strategy for the use of wastewater in irrigation for sustainable agricultural management. [ABSTRACT FROM AUTHOR]