Soil salinity and sodicity are significant issues worldwide. In particular, they represent the most dominant types of degraded lands, especially in arid and semi-arid regions with minimal rainfall. Furthermore, in these areas, human activities mainly contribute to increasing the degree of soil salinity, especially in dry areas. This study developed a model for mapping soil salinity and sodicity using remote sensing and geographic information systems (GIS). It also provided salinity management techniques (leaching and gypsum requirements) to ameliorate soil and improve crop productivity. The model results showed a high correlation between the soil electrical conductivity (ECe) and remote-sensing spectral indices SI_A, SI3, VSSI, and SI9 (R² = 0.90, 0.89, 0.87, and 0.83), respectively. In contrast, it showed a low correlation between ECe and SI5 (R² = 0.21). The salt-affected soils in the study area cover about 56% of cultivated land, of which the spatial distribution of different soil salinity levels ranged from low soil salinity of 44% of the salinized cultivated land, moderate soil salinity of 27% of salinized cultivated land, high soil salinity of 29% of the salinized cultivated land, and extreme soil salinity of 1% of the salinized cultivated land. The leaching water requirement (LR) depths ranged from 0.1 to 0.30 m ha⁻¹, while the gypsum requirement (GR) ranged from 0.1 to 9 ton ha⁻¹.

Two field experiments were conducted at Kafr El Sheikh Gov., Egypt, during two winter growing seasons (2020/2021 and 2021/2022). The objective of this study was to improve some chemical and physical properties of soil and the yield and water productivity of faba beans (Viciafaba L.), Cv. Sakha-4 by application of gypsum, compost, and some nanoparticles in salt-affected soils. The experimental treatments were arranged in a split-plot design with three replications. The main plots had the following soil amendments: T₁: control treatment, T₂: 10 tons compost/hectare, T₃: soil gypsum requirement (GR) of 8.59 ton ha⁻¹, and T₄: GR + 10 tons compost/hectare. The subplots were treated with foliar application as follows: no treatment, manganese nanoparticles (Mn-NPs), selenium nanoparticles (Se-NPs), and Mn-NPs + Se-NPs. According to the findings, the application of compost + GR significantly decreased soil salinity (EC), exchangeable sodium percentage (ESP), and soil bulk density (BD). However soil porosity, soil penetration resistance (SPRa), and basic soil infiltration (IR) were significantly increased. On the other hand, the results revealed significant positive effects onthe 100-grain weight as well as proline, chlorophyll, superoxide dismutase, and catalase contents due to the interaction between gypsum + compost and Mn-NPs + Se-NPs, which enhanced the productivity of both the seed and straw yields of faba beans compared to the alternative treatments. In addition, the seed yield and irrigation water productivity (PIW, kg m³) of faba beans were significantly increased with addition of gypsum and compost and foliar application of nanoparticles. The highest values of these parameters were achieved due to the interaction between gypsum + compost and Mn-NPs + Se-NPs. It can be concluded that application of GR of 8.59 ton ha⁻¹ and 10 ton ha⁻¹ compost as well as foliar application of Mn-NPs and Se-NPs may be a key strategy for improving some chemical and physical properties of soil and the yield and water productivity of faba beans in salt-affected soil under these experimental conditions.

Diagnosis of soil salinity and its spatial variability is required to establish control measures in irrigated agriculture. Soil salinity can vary temporally and spatially due to dynamic nature of soluble salts. For these reasons, practical methods for measuring soil salinity (ECe) are required to achieve faster, cheaper, and reliable surveys. Thus, the bulk soil electrical conductivity (ECa) was measured directly in the field using portable sensors (EM₃₈) in vertical position (EM_V) or horizontal position (EM_H). Therefore, the objective of this research was to develop statistical relations between ECa and ECe and assess whether they could be applied for salinity predicting and mapping. The empirical relations were established to convert EM₃₈ readings (ECa) in mSm^-1 to ECe values in dSm^-1 for different depths. So, ECe was determined in soil samples collected from 33 sites at depths of 0-30, 30-60 and 60-90 cm. Also, 33 EM readings (EM_V and EM_H) taken at soil sampling sites were used to derive equations for salinity prediction. Fifteen quadratic or multiple regression models were established to describe the relations between the original or logarithmic values of both ECa and ECe. The statistical comparison measurements; coefficient of determination (R²), simple correlation coefficient (r) and t-test were also used to evaluate the relationships between the actual and predicted ECe values to select the relevant models. So, two preferable models were chosen and one equation for each soil depth was derived from each selected model to be used for ECe predicting. These equations allow useful prediction of ECe using ECa values, since ECa values are regressed strongly with ECe values (R² > 0.70). Also, the actual and the predicted ECe levels were highly correlated (r > 0.80), in addition to insignificant differences between them according to t-test.

The drought is one of the most important abiotic stresses limiting crop productivity especially in sandy soils in arid and semi-arid areas. So, using soil amendments such as vermicompost (VC), biochar (BC), and polymer (PL) are more important in these areas. Lysimeter experiments with sandy soil were carried out at Sakha Agric. Res. Station, Kafr El-Sheikh, Egypt to study the effect of 0.4% PL, 4.0% VC and 1.0% BC (W:W soil) on productivity of wheat (2018/019) and maize (2019) under tow irrigation levels (irrigation after depletion of 50% and 75% from available water). The obtained results indicated that irrigation at 75% moisture depletion (irrigation deficit) decreased plant height, 100-grain weight, grain and straw yields, water applied to wheat (-16.8%) and maize (-20%) compared to that with higher irrigation level (50% depletion). Also, water productivity was slightly decreased for wheat, but it slightly increased for maize and ECe values were slightly increased due to irrigation deficit. Also, applications of soil amendments and their combinations significantly increased plant height, 100-grain weight, and yield and water productivity of both crops and improved soil porosity and field capacity. The VC was more effective followed by BC and PL, while their interactions were the most effective on these parameters. Moreover, soil amendments alleviated the deleterious effects of irrigation deficit on plant growth and salt accumulation. Finally, applying BC combined with VC and PL could be recommended as a good approach to maintain long-term productivity of sandy soils and mitigate the hazardous effects of drought stresses.

Because of water shortage in North Nile Delta, Egypt, some farmers have to irrigate their crops by saline water. So, soils and/or plants are preferred to be treated by some amendments to alleviate the hazardous effects of salt stress. Two field experiments were conducted at Sakha Agric. Res. Station Farm, Kafr Elsheikh Gov., Egypt, to study the effect of gypsum (50, 75 and 100% of gypsum requirement, 8.2 t ha-1), K-humate (5 and 10 kg ha-1) and inoculation with plant growth-promoting-rhizobacteria (PGPR), (108-109 colony, ml-1) on soil properties and productivity of wheat (2018/19) and maize (2019) irrigated by saline water (0.7 and 2.43 dSm-1). The results revealed that plant height, grain filling, grain and straw yields of wheat and maize were negatively affected by irrigation water salinity. Also, irrigation water salinity clearly affected soil ECe and ESP, while it slightly affected soil bulk density and total porosity. Also, soil ECe, ESP, bulk density and total porosity were slightly affected by application of gypsum, K-humate and PGPR. The biomass yield, plant height and grain filling in both crops were positively affected by gypsum application, whereas it alleviated the adverse effects of salinity on crop growth. Also, K-humate with PGPR positively affected the crop yield and its attributes. The bio amendments alleviated the harmful effects of salinity stress on both crops. Finally, 100% gypsum combined with higher rate of K-humate and PGPR treatments was more effective treatment on plant growth and alleviated the harmful effects of salinity stress on plant growth.