Enhancing aerobic composting of cow dung and wheat straw with nanobubble water: Improved lignocellulose degradation and nutrient enrichment for increased crop biomass

Abstract

Cow dung and wheat straw are rich in lignocellulose, which has a complex structure, making it difficult to biodegrade. This study investigated the promotion of composting effectiveness and product fertility by adding nanobubble water (Air, CO₂, He, and N₂) during aerobic composting of cow dung and wheat straw. Nanobubble water prolonged the high-temperature period by 1–2 days, increased the activity of soil urease and soil ligninase, reduced the lignocellulose content by 1.4 %–6.1 %, and increased the total potassium/total phosphorus ratio of the final compost products by 1.8 %–3.5 %/31.6 %–43.0 %. Nanobubble water of N₂ significantly increased the total nitrogen of final compost products by 8.3 %. The lignocellulose content was significantly positively correlated with the moisture content, but significantly negatively correlated with the relative abundances of Georgenia and Marinimicrobium. The final compost products of the nanobubble water groups significantly increased the total biomass of cabbage by 37.1 %–195.3 %. The results showed that adding nanobubble water to aerobic compost of cow dung and wheat straw improved the biodegradation of lignocellulose and enriched the nutrient elements (total nitrogen, total phosphorus, and total potassium) of the final compost products. Among the four types of nanobubble water, N₂-containing nanobubble water is the most promising.