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.

The use of phosphogypsum (PG) and plant growth-promoting rhizobacteria (PGPR) for agricultural purposes are good options to improve soil properties and increase crop yield. The objective of this study was to investigate the effect of different rates of PG (ton ha⁻¹; 0 (PG1), 3 (PG2), 6 (PG3), and 9 (PG4)) combined with PGPR inoculation (Azospirillum lipoferum (control, T1), A. lipoferum + Bacillus coagulans (T2), A. lipoferum + B. circulance (T3), and A. lipoferum + B. subtilis (T4)) on soil properties, plant physiology, antioxidant enzymes, nutrient uptake, and yield of maize plants (Zea mays L., cv. HSC 10) grown in salt-affected soil. Over two growing seasons, 2019 and 2020, field experiments were conducted as a split-plot design with triplicates. The results show that applying PG (9 ton ha⁻¹) and co-inoculation (A. lipoferum + B. circulance) treatment significantly increased chlorophyll and carotenoids content, antioxidant enzymes, microbial communities, soil enzymes activity, and nutrient contents, and showed inhibitory impacts on proline content and pH, as well as EC and ESP, thus improving the productivity of maize plant compared to the control treatment. It could be concluded that PG, along with microbial inoculation, may be an important approach for ameliorating the negative impacts of salinity on maize plants.

Soil salinity and climate change have a negative impact on global food production and security, especially in arid regions with limited water resources. Despite the importance of planting methods, irrigation, and soil amendments in improving crop yield, their combined impact on saline soil properties and cereal crop yield is unknown. Therefore, the current study investigated the combined effect of soil amendments (i.e., compost, C and zeolite, Z) and planting methods such as raised bed (M1) and conventional (M2), and different fractions of leaching requirements from irrigation water, such as 5% (L1) and 10% (L2), on the soil physio-chemical properties and wheat and maize productivity in an arid region. The combined application of C + Z, L2, and M1 decreased soil salinity (EC) and sodicity (ESP) after wheat production by 37.4 and 28.0%, respectively, and significantly decreased by these factors by 41.0 and 43.0% after a maize growing season. Accordingly, wheat and maize yield increased by 16.0% and 35.0%, respectively under such a combination of treatments, when compared to crops grown on unamended soil, irrigated with lower leaching fraction and planted using conventional methods. This demonstrates the significance of using a combination of organic and inorganic amendments, appropriate leaching requirements and the raised bed planting method as an environmentally friendly approach to reclaiming saline soils and improving cereal crop production, which is required for global food security.

Sandy soil covers a significant portion of Egypt’s total land area, representing a crucial agricultural resource for future food security and economic growth. This research adopts the hypothesis of maximizing the utilization of secondary products for soil improvement to reduce ecosystem pollution. The study focuses on assessing the impact of combining phosphogypsum and modified biochar as environmentally friendly soil amendments on loamy sand soil quality parameters such as soil organic carbon, cation exchange capacity, nutrient levels, and wheat yield. The treatments were T₁: the recommended NPK fertilizer (control); T₂: 2.5 kg phosphogypsum m⁻² soil; T₃: 2.5 kg rice straw biochar m⁻² soil; T₄: 2.5 kg cotton stalk biochar m⁻² soil; T₅: 2.5 kg rice-straw-modified biochar m⁻² soil; T₆: 2.5 kg cotton-stalk-modified biochar m⁻² soil; and T₇ to T₁₀: mixed phosphogypsum and biochar treatments. The results revealed that the combined use of phosphogypsum and modified cotton stalk biochar (T₁₀) significantly enhanced soil organic carbon (SOC) by 73.66% and 99.46% in both seasons, the soil available N both seasons by 130.12 and 161.45%, the available P by 89.49% and 102.02%, and the available K by 39.84 and 70.45% when compared to the control treatment. Additionally, this treatment led to the highest grain yield of wheat (2.72 and 2.92 Mg ha⁻¹), along with a significant increase in straw yield (52.69% and 59.32%) compared to the control treatment. Overall, the findings suggest that the combined use of phosphogypsum and modified biochar, particularly cotton-stalk biochar, holds promise for improving loamy sand-soil quality and wheat productivity.

The use of water-efficient soil amendments has gained increasing importance in agriculture, particularly in regions facing water scarcity. So, this study evaluates the impact of silica and nano-silica hydrogels on soil water retention, crop yield, and crop water productivity under variable irrigation regimes. Using a randomized complete block design with furrow irrigation, the experiment tested different hydrogel application rates and irrigation levels in rice (Oryza sativa L.) and clover (Trifolium alexandrinum L.) across two growing seasons. Statistical tests, including ANOVA and t-tests, confirm that nano-silica hydrogel significantly improves soil properties, yield, and crop water productivity (CWP), especially at moderate irrigation levels (70–90% of water requirements). In the first season, nano-silica hydrogel enhanced rice yield, with a maximum yield of 10.76 tons ha⁻¹ with 90% irrigation and 119 kg ha⁻¹ of hydrogel compared with other treatments. In the second season, clover yields were also positively affected, with the highest fresh forage yield of 5.02 tons ha⁻¹ with 90% irrigation and 119 kg ha⁻¹ nano-silica hydrogel. Despite seasonal variation, nano-silica hydrogel consistently outperformed silica hydrogel in terms of improving soil water retention, reducing bulk density, and enhancing hydraulic conductivity across different irrigation levels. Principal Component Analysis (PCA) revealed that nano-silica hydrogel significantly improved soil water retention properties, including the water-holding capacity (WHC), field capacity (FC), and available water (AW), and reduced the wilting point (WP). These improvements, in turn, led to increased crop yield and water productivity, particularly at moderate irrigation levels (70–90% of the crop’s total water requirements. These findings highlight the potential of nano-silica hydrogel as an effective amendment for improving soil water retention, enhancing crop productivity, and increasing crop water productivity under reduced irrigation conditions.

The scarcity of water resources in arid and semi-arid areas is considered a threat to agricultural sustainability. Therefore, approaches are needed to rationalize use of irrigation water without reducing crop productivity or degrading soil properties. The objective of this study was to investigate the effect of different organic amendments (O₁ = control, O₂ = compost, and O₃ = vermicompost) combined with different rates of nano- zinc foliar spraying (Zn₁ = 0, Zn₂ = 1 and Zn₃ = 2 gm/L), under irrigation supplements (I₁ = 100%, I₂ = 85%, and I₃ = 65% of water requirements) on clay soil characteristics, on the production of Egyptian barley Giza 126. Over two successive winter growing seasons, 2018/2019 and 2019/2020, field experiments were conducted as a split-split plot design with three replications. The results show that using vermicompost is an appropriate organic amendment to improve the physical and chemical properties of soils as compared with compost. Application of vermicompost led to a reduction in soil salinity (ECe), exchangeable sodium percentage (ESP), and soil bulk density (BD), of −5.67%, −5.44%, and −2.21%, respectively; there was a significant increase in soil organic carbon (SOC), available nitrogen (A.N), and field capacity (F.C.), of 43.75%, 14.37%, and 18.65%, respectively, compared with unamended soil (O₁). The maximum values for grain yield were increased by 13.2% and 14.9% in both seasons, respectively, and the irrigation water productivity of barley was increased more than compost and control. Vermicompost increased the irrigation water productivity for grain (1.69 and 1.69 kg grain m⁻³) and straw (1.23 and 1.17 kg straw m⁻³) in the first and second season, respectively. Similar trends were also observed from treatments on the water applied, stored water, and water application efficiency. Application of vermicompost and nano-Zn foliar spraying could be exploited for the development of barley growth and yield, which are enhanced under water-saving irrigation strategies.