Comprehensive evaluation of cow dung digestate composition for potential soil fertilization: Advanced analytical techniques
Cow dung digestate, a nutrient-rich byproduct of anaerobic digestion, offers a sustainable alternative to synthetic fertilizers, aligning with the United Nations Sustainable Development Goals (SDGs), particularly Goal 2 (Zero Hunger) and Goal 13 (Climate Action). This study aims to evaluate the physicochemical composition, nutrient bioavailability, and agronomic potential of CDD (Cow Dung Digestate) in South African agriculture, focusing on its impact on soil fertility, microbial activity, and environmental sustainability. A multi-faceted analytical approach was employed, incorporating pH measurement, gravimetric moisture determination, and UV-VIS spectroscopy for organic matter analysis. Advanced techniques, including FT-IR, ICP-OES, GC-MS, and UHPLC-QTOF-MS, characterized functional groups, elemental composition, volatile organic compounds, and metabolomic profiles. Multivariate data analysis provided a comprehensive assessment of nutrient interactions and biochemical complexity. Results indicate that CDD maintains a moisture content of 45.95%–48.72% and an alkaline pH range of 7.73–8.62, conditions that promote microbial proliferation and nutrient solubilization. Spectroscopic analyses confirm the retention of nitrogenous compounds, humic substances, and bioactive metabolites, contributing to both immediate and long-term soil fertility. Metabolomic profiling highlights the presence of oxaluric acid, proline, and nopaline compounds associated with stress tolerance, nitrogen metabolism, and plant-microbe interactions emphasizing the bio-stimulatory potential of digestate. Structural and elemental analyses reveal strong organic-mineral interactions that enhance soil moisture retention and nutrient stability. Compared to synthetic nitrogen fertilizers, digestates particularly UD, exhibit higher levels of potassium, calcium, magnesium, and iron. Elevated sodium and chromium concentrations in certain digestates necessitate careful application strategies to mitigate salinity and toxicity risks. Additionally, lipid-derived compounds enhance microbial activity, while volatile organic compounds suggest the need for optimized composting strategies to minimize gaseous emissions. This study establishes CDD as a scientifically validated biofertilizer that reduces reliance on synthetic fertilizers while enhancing soil health, microbial diversity, and crop productivity. However, precise application protocols must be developed to balance nutrient delivery with potential ecological risks.
Digestate, Anaerobic digestion, Fertilizer, UHPLC-QTOF-MS, UV-VIS Spectroscopy, SEM, Gravimetric analysis, Multivariate data analysis, PH - Measurements, Organic compounds, Nutrients, Agricultural benefits, UCTD
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