Heavy metal contamination in the El-Gharbia Governorate (District) of Egypt was identified by using remote sensing, Geographical Information Systems (GIS), and X-ray fluorescence (XRF) spectrometry as the main research tools. Digital Elevation Model (DEM), Landsat 8 and contour map images were used to map the landforms. Different physiographic units in the study area are represented by nine soil profiles. X-ray fluorescence spectrometry (XRF) was used for geochemical analysis of 33 soil samples. Vanadium (V), nickel (Ni), chromium (Cr), copper (Cu) and zinc (Zn) concentrations were measured and they all exceeded the average global concentrations identified by Wedepohl (1995). Ni and Cr concentrations exceeded recommended values in all soil profile horizons (Canadian Soil Quality Guidelines, 2007), while Cu had a variable distribution. Zn concentrations are under recommended concentration limits in most soil samples. Contamination Factor, Pollution Load Index and Degree of Contamination indices were used to assess the environmental risks of heavy metal contamination from the soils. All analysed metals pose some potential hazard and pollution levels were particularly high near industrial and urban areas

Areas contaminated by heavy metals were identified in the El-Gharbia Governorate (District) of Egypt. Identification used remote sensing and Geographical Information Systems (GIS) as the main research tools. Digital Elevation Models (DEM), Landsat 8 and contour maps were used to map physiographic units. Nine soil profiles were sampled in different physiographic units in the study area. Geochemical analysis of the 33 soil samples was conducted using X-ray fluorescence spectrometry (XRF). Vanadium (V), nickel (Ni), chromium (Cr), copper (Cu) and zinc (Zn) concentrations were measured. V, Ni and Cr concentrations exceeded recommended safety values in all horizons of the soil profiles, while Cu had a variable distribution. Zn concentrations slightly exceeded recommended concentration limits. Concentrations were mapped in each physiographic unit using the inverse distance weighted (IDW) function of Arc-GIS 10.1 software. Pollution levels were closely associated with industry and urban areas.

The use of nano-gypsum in low doses can be an innovative method to mitigate salinity-sodicity effects and enhance spinach growth in saline-sodic soil. We evaluated nano-gypsum in four low doses of 960, 480, 240, and 120 kg ha⁻¹, in addition to the control and the recommended conventional gypsum dose (~ 30 t ha⁻¹), in a randomized complete pot experiment. The pots of soil were incubated in a laboratory for 2 months and leached 5 times for another 2 months. Then, spinach was grown in the soil for 60 days. The nano-gypsum dose of 240 kg ha⁻¹ with leaching was the best at improving the soil and spinach growth characteristics compared with the other doses and both control and conventional gypsum rate. Moreover, it was considered the critical nano-gypsum threshold rate. Compared to control after soil leaching, the critical rate increased the water-stable aggregate index and reduced bulk density by 57.39% and 16.30%, respectively; accordingly, the saturated hydraulic conductivity increased up to 2.34 times. Improved hydraulic conductivity led to a decrease in exchangeable Na ratio by 91% and reduced both soil salinity and pH by 83% and 1 unit, respectively. These great improvements in the soil properties favored the spinach growth indicators, which increased leaf area index, root hair index, and fresh yield by 2.20, 4.41, and 1.29 times, respectively, when compared to the recommended conventional gypsum rate. Accordingly, nano-gypsum in low doses is considered an innovative alternative to high doses of conventional gypsum to mitigate salinity-sodicity effects and enhance spinach growth in saline-sodic soil.

Recycling waste, such as rice straw and water treatment residuals, is important to reduce harmful effects on the environment and to improve canola yield and soil quality in degraded soils. Nanotechnology for the production of nanomaterials from biochar and water treatment residues will be a future revolution for improving soil quality and increasing canola yield in degraded soil. Therefore, this study aims to identify the properties of some recycled nanomaterials, such as nanobiochar (nB) and nanowater treatment residue (nWTR), and their effect on the biological activity and productivity of canola in degraded soils. The results showed that the nWTR and nB contain many functional groups and minerals, and they also have high negative zeta potential. The addition of the studied soil amendments significantly improved microbial biomass carbon (MBC) and biological activity, which played a major role in increasing canola yield. The highest dehydrogenase (DHA) and catalase (CLA) activity was found in nWTR-treated soil at 50 mg kg⁻¹, with increases of 32.8% and 566.7% compared to the control, respectively. The addition of nB greatly improved the growth of canola plants in the soil. This was evident from the increase in the weight of seeds, the weight of 1000 grains, the number of pods per plant, and the highest increase was for nB added at the rate of 250 mg per kg⁻¹ soil. The addition of 50 mg kg⁻¹ of nWTR gave the best results in seed yield by 150.64% compared to the control. These results indicate that recycled nWTR and nB are some of the best waste recycling treatments, in addition to good soil health, in increasing soil biology and canola yield in degraded soils. In the future, research on recycled nanomaterials should examine the residual effect they have on yield, soil quality, and soil fauna in the long term.

Surface irrigation is the traditional irrigation method applied in about 80% of the irrigated area in Egypt with greater water losses leading to profile drainage. The double ridge-furrow planting technique (DRFI) uses a practical way to reduce the applied water quantities. Therefore, field experiments were conducted in 2010 and 2011 (maize growth seasons) to study the effects of DRFI with two irrigation intervals – 7 days and 14 days – on maize yield, water saving, water productivity and some economic parameters such as net return and investment ratio compared with the conventional ridged-furrow planting technique (RFI) with irrigation at 14-day intervals. Optimal irrigation interval for maize under DRFI was also determined. Regardless of irrigation intervals, smaller depth of applied water was observed with DRFI treatments compared to RFI treatment. Consequently, with DRFI treatments, more water could be saved compared with RFI treatment in both seasons. Double ridged-furrow planting with irrigation at 7-day intervals proved superior to increase the grain yield and water productivity compared to the 14-day interval and the conventional treatment. It also increased the investment ratio and net return of maize crop. Therefore, double ridge-furrow planting with irrigation at 7-day intervals will practically be the optimal choice under the conditions of the studied area.