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.

Calcareous soils, prevalent in arid and semi-arid regions, often limit agricultural productivity due to their alkaline nature and poor nutrient availability. This study assessed the effects of mineral sulfur (312 kg ha⁻¹), nano-sulfur (12, 24, and 36 kg ha⁻¹), and compost (4.8 tons ha⁻¹) on the physical and chemical properties of saline calcareous soils and their impact on maize and wheat yields. The field experiment on new extended agriculture in Mallawy, Egypt, utilized a randomized complete block design. The results showed that nano-sulfur treatments outperformed mineral sulfur. Specifically, the combination of 36 kg ha⁻¹ nano-sulfur with 4.8 tons ha⁻¹ compost improved key soil physical properties, including bulk density, porosity, and hydraulic conductivity. This treatment also significantly reduced soil pH, electrical conductivity, and exchangeable sodium while enhancing the availability of essential nutrients such as nitrogen (N), phosphorus (P), potassium (K), and total sulfate (SO₄²⁻). These enhancements in soil health led to notable increases in both maize and wheat yields, as well as better crop nutrient uptake. The findings suggest that nano-sulfur, when used in conjunction with compost, is a highly effective amendment for improving the health of saline calcareous soils, enhancing crop productivity, and promoting sustainable agricultural practices in arid and semi-arid regions. This combination provides a promising alternative to excessive chemical fertilizers, fostering soil health and long-term agricultural sustainability.

The present study aimed to investigate the occurrence of eight potentially toxic elements (PTEs) in selected varieties of watermelon (Citrullus lanatus var. Arka Shyama and Crimson Sweet) and muskmelon (Cucumis melo var. Cantaloupe and Kajri) grown near riverbanks in the Yamuna and Ganga River basins of Northern India. For this purpose, samples of melon fruits were collected from ten sampling sites from May to June 2024 and analyzed using ICP-OES. The results showed that the levels of PTEs varied significantly across the sampling sites, with muskmelons exhibiting slightly higher concentrations compared to watermelons. Specifically, the concentration (mg/kg dry weight) ranges for the watermelon varieties were Cd (0.05–0.20), Cr (0.40–1.10), Cu (1.50–4.90), Pb (0.01–0.11), As (0.01–0.08), Fe (80.00–120.00), Mn (9.00–15.80), and Zn (5.00–18.00). For muskmelons, the ranges were Cd (0.05–0.23), Cr (0.40–1.00), Cu (2.40–4.80), Pb (0.01–0.08), As (0.02–0.08), Fe (80.00–120.00 g), Mn (9.00–15.00), and Zn (8.00–18.00). In particular, the variability coefficients (CV%) indicated differential contamination in Crimson Sweet. On the other hand, Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) tools facilitated the identification of sites of significant contamination and their respective interactions. The health risk studies using the health risk index (HRI), dietary intake modeling (DIM), and the target hazard quotient (THQ) also revealed no significant health risk of eight PTEs in melon fruits. Therefore, this study provides valuable insights into the biomonitoring of PTE contamination in widely consumed summer fruits of Northern India and the subsequent health risk assessment.

Soil salinity poses a significant challenge to agricultural productivity, particularly in arid and semi-arid regions. This study explores the effect of compost, elemental sulfur (ES), sulfur nanoparticles (SNPs), and their combinations, i.e., compost + ES and compost + SNPs, to improve soil properties and maize productivity across a range of salinity levels (EC1 = 3.68, EC2 = 6.15, EC3 = 8.34, and EC4 = 12.18 dS/m). We hypothesized that integrating compost with ES or SNPs would enhance soil quality and maize performance more effectively than individual treatments. Results validated this hypothesis, showing that compost increased soil organic matter (SOM) by 1.33 times, reduced sodium adsorption ratio (SAR) by 33%, and boosted maize grain yield by 40% in moderately saline soils (6.15 dS/m). ES and SNPs lowered soil pH by 0.8–1.2 units and improved phosphorus availability by 25–30%. The compost–SNP combination delivered the most significant improvements, enhancing infiltration rate by 60%, total porosity by 15%, and straw yield by 50% in highly saline soils (12.18 dS/m). Additionally, plant height, cob length, and chlorophyll content increased by 20%, 22%, and 40%, respectively, with combined treatments. These findings highlight the efficacy of integrated amendments in alleviating salinity stress, offering a promising strategy for sustainable agriculture in saline environments.

Aims: Saline sandy soils severely constrain sugar beet ( Beta vulgaris L.) productivity due to low nutrient retention, high salinity, and micronutrient imbalances, particularly boron deficiency. Although humic substances, glauconite, and boron fertilization have individually or pairwise improved crop performance, no previous field study has evaluated their ternary, dose-optimized integration as a multifunctional soil–plant management strategy under saline sandy conditions. Methods: This study investigated, for the first time, the combined application of soil-applied humic acid (600 kg/ha), glauconite (1100 kg/ha), and graded foliar boric acid (0, 1900, and 3800 g/ha) to test the hypothesis that their complementary physicochemical and physiological mechanisms would generate synergistic improvements in soil quality, crop performance, and sugar productivity beyond additive effects. Field experiments were conducted over two consecutive growing seasons (2021–2022) in West Minya, Egypt, using a split-plot design. Results: The integrated high-dose treatment (HG3800) significantly enhanced leaf area index (by 75%), chlorophyll content (46–71%), and net photosynthetic rate (40–128%) relative to the control. Root yield increased by 27% (reaching 56.7 ton/ha), while sugar yield rose by up to 79% (11.5 ton/ha). Sucrose concentration reached 20.4%, with reduced impurity indices and improved extractable sugar percentage (up to 90%). Based on fermentable sugar yield, the HG3800 treatment corresponded to a substantial increase in theoretical bioethanol output potential per hectare. Concurrently, soil electrical conductivity declined by 24%, soil organic matter increased, and bulk density decreased, reflecting improved soil structure and salinity mitigation. Conclusions: The ternary, dose-optimized integration of humic acid, glauconite, and foliar boron represents a novel agronomic strategy that simultaneously enhances soil physicochemical properties, physiological efficiency, and fermentable sugar production. By directly linking yield gains to increased bioethanol feedstock potential, this approach offers a scalable and multifunctional pathway for sustainable bioenergy-oriented sugar beet production in salt-affected sandy soils.

Biogas slurry contains high levels of organic matter and essential nutrients, which enhance soil fertility and structure. Although it can reduce the uptake of heavy metals by plants, improper application may result in soil contamination. This research evaluated the effects of applying semi-solid biogas slurry (SSBS) at 72 or 96 m3/ha, either on its own or combined with a foliar spray of liquid biogas slurry (LBS) at 48 L/ha or a recommended NPK fertilizer on spinach growth. Results showed that all SSBS treatments, whether individually or combined with NPK or LBS, improved growth traits such as plant height and total leaf area. They also increased chlorophyll content (chlorophyll a, b, and total), vitamin C, total phenolic compounds in leaves, and concentrations of nitrogen, phosphorus, potassium, iron, and zinc, along with enhanced nitrate reductase activity. Furthermore, these treatments boosted leafy yield and lowered levels of lead (Pb), cadmium (Cd), nitrate, and oxalate content in spinach leaves. The most pronounced positive effects on growth and physiological-biochemical parameters occurred when SSBS was applied at 96 m3/ha along with either the recommended NPK dose or LBS. These findings indicate that biogas slurry could serve as a sustainable alternative to chemical fertilizers in agriculture.