Moisture-Induced Effects on Lignocellulosic and Humification Fractions in Aerobically Composted Straw and Manure

Abstract

Humic substances affect compost stability and maturation. However, the intricate structure of lignocellulosic materials hinders the biodegradation of cellulose, hemicellulose, and lignin, often promoting the use of synthetic additives which results in microbial inactivation and death. Therefore, this study examined the effects of optimal moisture levels (MC1 = 45%, MC2 = 55%, and MC3 = 65%) on lignocellulosic and humification fractions in aerobically composted straw and manure. The study showed that 65% moisture content was more efficient in decomposing cellulose, hemicellulose, and lignin, with hemicellulose (115.3% w/w ≈ 47.1%) degrading more than cellulose (76.0% w/w ≈ 39.5%) and lignin (39.9% w/w ≈ 25.9%). However, in compost heaps with 45% moisture, the humic acid concentration increased significantly by 12.4% (3.1% w/w) and 17.3% (4.3% w/w) compared with 55% and 65% moisture, respectively. All moisture levels increased the mineralization of humic substances, but the index measured was highest at 65% MC (23.8% w/w) and lowest at 45% MC (18% w/w). In addition, the humification rate showed the trend: 0.083% w/w > 0.087% w/w > 0.100% w/w for MC1, MC2, and MC3, respectively. Overall, the results indicate that an initial moisture content of 65% is aerobically efficient for the conversion of corn straw and cow manure into stable and mature compost.

Comparing bacterial dynamics for the conversion of organics and humus components during manure composting from different sources

“…At the end of composting, the hemicellulose content of PM, CD, SM, and CM decreased by 12.35, 8.51, 7.46, and 3.38%, respectively, and the degradation of hemicellulose in PM was significantly higher than other composts ( p < 0.05), while the ratio of hemicellulose in dry matter of DM increased by 2.46% ( Figure 2D ). Ghanney et al (2023) found that when the initial content of hemicellulose in the compost was higher than that of cellulose, hemicellulose was more likely to be degraded than cellulose and lignin. The above results showed that the degradation of cellulose in composting from cow manure and sheep manure was obvious and the degradation of hemicellulose in composting from pig manure and chicken manure was prominent, indicating that the degradation of organic components might be related to its initial content.…”

Grape Skin Composting Process to Recycle Food Waste: Kinetics and Optimization

“…Compost’s maturity and stability are connected to its quality. While maturity refers to a product’s ability to be utilized effectively in agriculture and is related to features of phytotoxicity and plant growth, stability relates to a product’s organic matter’s resistance to extensive degradation or higher microbiological activity [ 13 ]. In order to obtain high-quality compost, it is necessary to optimize composting process conditions [ 14 ].…”