Water scarcity and the rising cost of chemical fertilizers pose major challenges to sustainable crop production in Egypt, particularly in sandy soils with low fertility. This study was conducted during the winters of 2022–2023 and 2023–2024 to investigate the combined effects of different irrigation levels and Nostoc algae extract on soil properties and wheat (Triticum aestivum) productivity. Three irrigation levels (100%, 80%, and 60% of crop evapotranspiration [ETc]) were evaluated with and without added algae. To analyze our data, we performed an analysis of variance (ANOVA) to evaluate differences among the treatments; correlation analysis was conducted to assess the relationships among soil properties and plant properties. The results showed that application of algae significantly increased soil organic matter under all irrigation treatments. In contrast, soil pH decreased in response to addition of algae, with the greatest reduction observed under the 60% ETc treatment (0.29 and 0.31 units in the first and second growing seasons, respectively). Water productivity differed significantly among treatments, following the order: 80% ETc > 100% ETc > 60% ETc (p ≤ 0.05). The application of algae under the 80% ETc regime increased water productivity by 12.01% and 12.19% in the first and second seasons, respectively, compared with the treatment without algae. Moreover, organic matter exhibited a strong positive correlation with N, P, and K contents in both straw and grain. The total yield reached its greatest level at 100% ETc with algae (5,526.43 ± 61.30 kg feddan⁻¹), whereas the lowest value was reported at 60% ETc without algae (2,880.97 ± 37.81 kg feddan⁻¹). Overall, application of algae contributed to improved soil properties, enhanced soil nutrients, structure and moisture retention, and mitigated yield losses associated with reduced irrigation. These findings suggest that integrating algae biofertilizers with deficit irrigation strategies can serve as a sustainable approach to improve wheat production in sandy soils under water-limited conditions.

Lime application represents an established approach for ameliorating soil acidity, and understanding its effects on the interactions between aluminum (Al) and iron (Fe) oxides and soil organic carbon (SOC) fractions is essential for promoting sustainable agricultural practices that enhance carbon sequestration. This investigation examined the interactions among Al and Fe oxides and SOC fractions under long-term fertilization and liming. A long-term field experiment was implemented with five treatments: CK (no fertilizer), N (nitrogen fertilizer), NCa (N plus lime), NPK (nitrogen, phosphorus, and potassium fertilizer), and NPKCa (NPK plus lime). Soil samples were obtained from three depths: 0–10, 10–20, and 20–30 cm. The findings revealed that lime application increased SOC by 20.84% under the N treatment but decreased SOC by 9.97% under NPK. At the 0–10 cm depth, dissolved organic carbon (DOC) was substantially higher under NCa (410.51 mg kg^–1) and NPKCa (372.83 mg kg^–1) compared with CK. Particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) demonstrated consistent enhancement under NPK and NPKCa across all soil depths compared with CK. DOC exhibited significant positive correlations with both aluminum (Ald), reactive aluminum (Alo) and aluminum (Alp), indicating a key role of organically bound and reactive Al in carbon dynamics. Compared to the CK treatment, SOC stock increased significantly by 43.49% under NPK and by 36.82% under NPKCa. Structural equation modeling demonstrated that lime application mitigated the negative effects of free Al (Ald) on carbon sequestration, while Fe oxides (Fed) contributed positively to SOC stabilization. DOC showed no significant impact on carbon sequestration rate (CSR), while easily oxidizable carbon (EOC) negatively affected CSR directly. These results highlight the crucial role of lime in improving acidic soil conditions and enhancing the stability and sequestration of soil organic carbon.

Green manure and rice straw recycling is widely practiced in paddy soils of southern China to enhance soil fertility and crop productivity; however, its environmental consequences remain lacking. Here, we used a long-term field experiment to quantify greenhouse gas (GHG) emissions and associated microbial functional genes, energy-use efficiency, carbon footprint, and net ecosystem economic benefit to assess the sustainability implications of this practice. The treatments consisted of conventional chemical fertilizers (CK), CK + green manure recycling (M), CK + early-season rice straw recycling (ERS), CK + ERS + late-season rice straw recycling (DRS), CK + ERS + M (ERSM) and CK + DRS + M (DRSM). Compared with ERS, DRS and DRSM, the ERSM significantly reduced the annual cumulative methane (CH₄) emissions by 24.3 %, 33.9 % and 22.1 %, respectively. Similarly, ERSM significantly reduced nitrous oxide (N₂O) emissions by 18.5 %–34.2 % compared to the other treatments, except for DRS. However, compared with all the other treatments, the ERSM treatment increased annual grain yield by 6.0 %–67.6 %, energy-use efficiency by 6.8 %–68 %, and net ecosystem economic benefit by 10.9 %–112.1 %. Optimizing carbon-to-nitrogen ratio lowers direct GHG emissions through balancing CH₄-related gene activity (mcrA and pmoA) and by promoting ammonia-oxidizing genes (amoA), which in turn reduced carbon footprint. Soil organic carbon storage and CH₄ via direct-GHG emissions and chemical nitrogen via indirect-GHG emissions were the major contributors to carbon footprint. In conclusion, ERSM is an effective strategy to promote sustainable rice production in rice-rice cropping systems and it has the potential to support carbon neutrality efforts.

This research evaluated the potential of black soldier fly larvae meal (BSFLM) as a partial substitute for soybean meal (SBM) in broiler diets, for their health and optimum performance. To this end, a total of 360 one-day-old male Cobb500 broiler chicks were randomly allocated to 36 floor pens and fed on basal starter (0-7 days) and grower (8-21 days) diets. During the finisher phase (22-35 days), chicks were randomly assigned to six treatment groups (six replicate pens of 10 birds per treatment) in which SBM was substituted with BSFLM at 0, 10, 20, 30, 40, or 50%, respectively. Growth performance traits were determined as pen averages for each treatment group (n=6). At the end of the trial, blood samples were randomly collected from two birds per replicate pen (n=12) to determine the plasma metabolites, antioxidant status, cytokine indices and immune responses. Additionally, jejunum and ceca specimens were obtained from two birds per replicate (n=12) to assess the jejunum histomorphology and cecal microbiota. Data was analysed through one-way ANOVA and Tukey’s post hoc test for comparison of mean differences. Results showed that including BSFLM up to 30% optimized feed conversion efficiency and maximized productive performance indices (P<0.05), including final BW (R²=0.724), BW gain (R²=0.729), and the European broiler index (R²=0.699). Intermediate inclusion levels (20-30%) were associated with alterations in the overall endocrine and physiological systems, characterized by higher thyroid activity (R²=0.608, P<0.001), enhanced antioxidant potential (R²=0.732, P<0.001) and lower proinflammatory cytokine interleukin-1 (R²=0.631, P<0.001). Immunological parameters, including leukocyte viability, antibody titers and lymphocyte proliferation, were also maximised at 20-30% replacement (R²=0.608-0.703, P<0.001). The intestines significantly (P≤0.001) exhibited better histomorphological features and a more balanced microbial composition in response to the 30% BSFLM treatment compared with other treatments. In conclusion, BSFLM can effectively substitute up to 30% of SBM in broiler finisher diets without adverse effects on productive performance and physiological status, offering a sustainable and effective protein alternative supplement for poultry production

Co-exposure to insecticides and heavy metals alters the way the chemicals affect the aphid. This interaction can induce synergism through enzymatic inhibition of the insect, increasing mortality, or antagonism through competition for cellular receptors. The aim of this study was to determine the synergistic or antagonistic effect of four insecticides and five heavy metals on the median lethal concentrations (LC₅₀ and LC₉₀) and their toxic efficiency between 24 and 48 h post-exposure to the bird cherry–oat aphid under laboratory conditions. The four pesticides were acetamiprid, imidacloprid, emamectin benzoate, and thiamethoxam. The five heavy metals were Cr, Ni, Pb, Cd, and Cu. The results revealed LC₅₀ and slope values for all four tested insecticides against the aphid. After 24 and 48 h from treatment, acetamiprid was the most toxic compound according to LC₅₀ values, followed by emamectin benzoate, thiamethoxam, while imidacloprid was the least toxic one. The results indicated that thiamethoxam was synergized by Cr, Cu, Cd, Ni, and Pb by 18.31, 5.36, 74.12, 4.58, and 225.46-fold, respectively, as compared with LC₅₀ values of thiamethoxam alone. This finding indicated that Pb was the most effective heavy metal in synergizing thiamethoxam. The results indicated that the toxicity of imidacloprid increased by adding each of the tested heavy metals except for Cu as compared with LC₅₀ of imidacloprid alone. Results showed that LC₅₀ value of each insecticide decreased with Cd as compared with LC₅₀ value of the insecticide alone at both 24 h and 48 h. Under the conditions of this study, it can be concluded that the Cd acted as a synergist for all tested insecticides.