Nutrient production from Korean poultry and loading estimations for cropland

Dynamics of microbial functional guilds involved in the humification process during aerobic composting of chicken manure on an industrial scale

Proper composting treatment of poultry manure waste is recommended before its use as a fertilizer. This involves many bioprocesses driven by microorganisms. Therefore, it is important to understand microbial mechanisms behind these bioprocesses in manure composting systems. Many efforts have been made to study the microbial community structure and diversity in these systems using high-throughput sequencing techniques. However, the dynamics of microbial interaction and functionality, especially for key microbial functional guilds, are not yet fully understood. To address these knowledge gaps, we collected samples from a 150-day industrial chicken manure composting system and performed the microbial network analysis based on the sequencing data. We found that the family Bacillaceae and genus Bacillus might play important roles in organic matter biodegradation at the mesophilic/thermophilic phases. Genera Virgibacillus, Gracilibacillus, Nocardiopsis, Novibacillus, and Bacillaceae_BM62 were identified as the key ones for humic acid synthesis at the mature phases. These findings improve our understanding about the fundamental mechanisms behind manure composting and can aid the development of microbial agents to promote manure composting performance.

Multi-omics analysis provides insight into the phytotoxicity of chicken manure and cornstalk on seed germination

To minimize environmental risks and the phytotoxic influence of organic materials on crop growth, it is necessary to test their phytotoxicity and maturity when they were used in farmland. However, the stress response of seed germination to chicken manure and cornstalks is not clear. This study used multi-omics analysis to investigate the inhibition mechanism of seed germination by chicken manure and cornstalk. Chicken manure caused destructive inhibition of seed germination with higher phytotoxicity (GI = 0). Cornstalk also had a low GI (8.81 %), while it mainly inhibited radicle growth (RL = 9.39 %) rather than seed germination (GR = 93.33 %). The response of radish seed germination to chicken manure and cornstalk phytotoxic stresses was accompanied by metabolic adjustments of storage substance accumulation, antioxidant enzyme activity change, phytohormone induction, and expression of specific proteins and gene regulation. Combined transcriptomic and proteomic analysis revealed that differential expression of 13,090 (5944 upregulated/7146 downregulated) and 3850 (2389 upregulated/1461 downregulated) genes (DEGs), and 1041 (82 upregulated/932 downregulated) and 575 (111 upregulated/464 downregulated) proteins (DEPs) at chicken manure and cornstalk treatment, respectively. Most down-regulated genes and proteins were involved in phenylpropanoid biosynthesis under chicken manure stress, which caused irreversible inhibition of seed germination. Down-regulation of phytohormone signal transduction-related genes under cornstalk stress resulted in inhibition of radicle growth, but the inhibitory stress was restorable. These findings provide new insight into the phytotoxicity of livestock manure and cornstalk on seed germination.

Spatial Suitability Evaluation of Livestock and Poultry Breeding: A Case Study in Wangkui County, Heilongjiang Province, China

With the development of animal husbandry, environmental pollution caused by livestock and poultry breeding (LPB) has become a major problem faced by environmental protection departments. In response to this problem, this study established a spatial suitability evaluation system for LPB. According to the particularity of the indicators, there is a nonlinear relationship after quantification and not all elements in the matrix presented by the indexes and evaluation units have an ‘order’ relationship. Therefore, this study selects a method of combining a self-organising map network. The Hasse diagram technique and geographic information system were used to evaluate the suitability of LPB. Practical application research was conducted in Wangkui County. Most regions of Wangkui County are unsuitable for LPB, accounting for 81.23% of the total area of the county. A small part of a suitable region (434.76 km2) was determined to be a potential site for LPB. According to the results of suitable breeding regions, 17 existing large-scale livestock and poultry farms (LPFs) with unreasonable distribution were optimised for space, which are located in an urban construction area. Spatial optimisation was performed using GIS buffer and overlay analyses, providing the best relocation plot for these 17 LPFs. The results provide a scientific basis for the utilisation of livestock manure and spatial layout planning for LPB.

Effect of biochar amendment on compost quality, gaseous emissions and pathogen reduction during in-vessel composting of chicken manure

Because of rapid development in the livestock industry, the production of chicken manure has subsequently increased, which may contribute to environmental pollution. In this regard, in-vessel composting of biochar amended chicken manure and sawdust mixtures was investigated to find out the effect of biochar at the ratios of 0% (control), 3% (T1), 5% (T2), and 10% (T3) on ammonia and greenhouse gases (GHGs) emission, compost quality, pathogenic contaminants and phytotoxicity. The composting process was performed in 100-L, pilot-scale, plastic, cylindrical vessels for 50 days. The addition of biochar (3%, 5%, and 10%) increased the thermophilic temperature with a significant reduction in gaseous emissions (ammonia and CO₂), microbial pathogens (Escherichia coli and Salmonella sp.), and phytotoxicity (Lepidium sativum seed germination assay) compared with that of the control compost products. However, according to the obtained results with in-vessel composting, the amendment of 10% biochar showed the most significant effects concerning the quality of the compost nutrients. The study reveals that the addition of biochar during in-vessel chicken manure composting is beneficial in the reduction of gaseous emissions and pathogenic microorganisms apart from improvement in plant nutrients.