Agronomy

Brazil is the world’s largest producer of sugarcane, and its processing residues have potential as feed for ruminants; however, treatments are required to improve their digestibility. This study evaluated the chemical composition, carbohydrate fractionation, and ruminal degradability of sugarcane silages from two genotypes treated with alkaline additives—calcium oxide (CaO) and sodium hydroxide (NaOH). A 2 × 4 factorial design was used, comprising two genotypes and four treatments (no additives, 1% CaO, 1% NaOH, and 0.5% CaO + 0.5% NaOH). A significant interaction (p < 0.05) between genotype and additive was observed for dry matter, ether extract, fiber components, lignin, cellulose, non-fiber carbohydrates, total digestible nutrients, and phosphorus. The IAC-862480 genotype without additives exhibited higher values for most variables compared with CTC-3. Interactions were also detected for total carbohydrates and fractions A + B1 and C, except in silages treated with 1% CaO or the combined 0.5% CaO + 0.5% NaOH, where genotypes did not differ. Overall, alkaline additives improved the nutritional quality of sugarcane silages. Treatments with 1% CaO or 0.5% CaO + 0.5% NaOH were the most effective in hydrolyzing structural carbohydrates and enhancing dry matter and neutral detergent fiber degradability, especially in the CTC-3 genotype.

Water scarcity in Mediterranean regions such as Morocco makes treated wastewater a strategic alternative for irrigation. This field study evaluated the effects of two treated wastewater sources, membrane bioreactor T2 and activated sludge T3, compared with groundwater (T1, control) on growth, yield, and fruit quality of two tomato cultivars (Solanum lycopersicum L., Bobcat and Galilia). Irrigation with activated sludge effluent T3 significantly improved agronomic performance relative to both MBR-treated water and groundwater. Under T3, plant height reached 158 ± 3.5 cm in Galilia and 150 ± 3.2 cm in Bobcat, while fruit yield increased to 9.93 ± 0.38 kg plant⁻¹ in Bobcat and 7.12 ± 0.25 kg plant⁻¹ in Galilia, more than double the yield recorded under T2. Physiological parameters such as chlorophyll a, proline, and soluble sugars increased markedly under T3, indicating enhanced photosynthetic activity and improved stress tolerance. Fruit quality was enhanced under T3, with higher soluble sugar and protein levels, while lycopene and acidity were greatest under groundwater irrigation. Overall, the results demonstrate that secondary treated wastewater, particularly from activated sludge processes, can sustainably improve tomato yield and quality while conserving freshwater resources in arid regions. These findings demonstrate the potential of treated wastewater as a sustainable irrigation source for water-scarce Mediterranean agriculture.

Annually, up to 15 million tons of coffee production waste are produced worldwide. Among them are spent coffee grounds (SCG), which have the potential to be recycled and used as organic fertilizers. However, their direct application to soil is limited due to the presence of ecotoxic compounds (phenols, tannins, and caffeine). Composting is a promising approach; however, the highly variable properties of the raw coffee materials require the selection of optimal production and application modes. In this study, we performed two composting methods for SCG, i.e., vermicomposting and microbial composting, in mixtures with co-composting substrate at five SCG/substrate ratios (0, 25, 50, 75, and 100% SCG). First, the acute toxicity of raw SGC and its mixtures to earthworm Eisenia andrei was evaluated. After 30 days of composting, chemical and microbiological properties, including pH, RedOx potential (Eh), organic carbon (C_org), lignin content, bacteria count, diversity, and potential metabolic activity, were determined in the end products. As composting went on, the pH increased from 5.6–6.2 to 6.0–7.3 and 7.4–7.7 under microbial composting and vermicomposting, respectively. RedOx potential levels achieved 142–166 mV for microbial composting and 73–113 mV for vermicomposting. Organic matter (OM) content reached 86–94%, with an increasing proportion of lignin, demonstrating the decomposition of more readily accessible organic matter. Vermicomposting and microbial composting produced chemically safe and microbiologically highly active composts. An initial SCG content of 25–50% of the compost mixture’s weight yielded the most favorable properties for the resulting compost (high organic matter content and optimal pH levels). Due to the high biological activity of both composting methods, the resultant composts are likely to have a positive effect on plant growth and development and soil health when used as organic nutrient resources.