Specialized Microbes Found to Enhance the Composting Process of Agricultural Waste

Every year, the world produces around 1 billion tons of agricultural waste (1). While this form of organic waste has the potential to be renewable, its sheer volume presents challenges for disposal and recycling. One major contributor to agricultural waste is spent mushroom substrate (SMS), the byproduct of edible mushroom cultivation. China, the largest producer of mushrooms, creates about 50 million tons of SMS annually. This material, along with chicken manure, which is abundant due to the poultry industry, can overwhelm waste management systems if not handled properly. With limited disposal methods, these materials can lead to environmental hazards if they are not recycled in a timely manner. Fortunately, SMS and chicken manure can be transformed into valuable compost that enriches the soil and returns nutrients back to agricultural systems.

A recent study has found that microbial inoculums, mixtures of beneficial bacteria and fungi, can optimize the composting process. By accelerating the breakdown of these forms of organic matter, these microbes significantly shorten the composting time and improve the quality of the final composting product. This enhanced approach will allow farmers and agricultural producers to create a more efficient cycle of nutrient recycling, which is essential for sustainable agriculture.

A better means of composting

The study employed a controlled experiment setup involving three different treatment groups: one with a microbial inoculum (MI), another with a commercial inoculum (CI), and a control group (CK) that received no inoculum. Each group used a mixture of SMS and chicken manure, allowing researchers to directly compare the effects of the microbial treatments against the natural composting process. 

Researchers found that the microbial inoculum significantly accelerated the decomposition of the organic materials, evident by a quicker rise in compost temperature, which is a common indicator of increased microbial activity. Compared to both the CI and CK groups, the MI group demonstrated a more rapid breakdown of complex organic compounds, indicating that the specific blend of microbes in the MI was more effective at enhancing the composting process. Furthermore, the study found that the quality of the compost produced with MI was superior to that of other groups. In fact, the compost from the MI group had higher levels of essential nutrients like nitrogen, phosphorus, and potassium, which are crucial for plant growth. The MI compost also had better structural properties, such as increased porosity and moisture retention, which are beneficial for soil health.

The use of microbial inoculums also presented environmental benefits since the enhanced composting method led to a decrease in the greenhouse gas emissions typically released during the breakdown of organic matter. Notably, the levels of methane emissions were lower in the MI group, contributing to a reduction in the overall carbon footprint associated with the composting process (2).

Future applications for sustainable agriculture practices

 By making the composting process more efficient and producing a higher quality compost, microbial inoculums help create a more sustainable cycle of nutrient recycling. Such enhancements can lead to reduced reliance on chemical fertilizers, lower production costs for farmers, and improved soil health across agricultural lands. 

Furthermore, the environmental impact of using microbial inoculums in composing goes far beyond waste reduction. By improving the efficiency of composting, these inoculums also help conserve soil and water resources, mitigate the release of harmful gases, and enhance biodiversity in agricultural soils – benefits crucial for the long-term sustainability of farming ecosystems, which face increasing pressures from climate change and growing global food demands.

While this method was only tested on chicken manure and SMS, it holds potential for broader application across various types of agricultural and organic waste and allows a more adaptive and comprehensive approach to recycling organic materials.

References

1. Peng, Xiaoxuan, Yushan Jiang, Zhonghao Chen, Ahmed I. Osman, Mohamed Farghali, David W. Rooney, and Pow-Seng Yap. 2023. “Recycling Municipal, Agricultural and Industrial Waste into Energy, Fertilizers, Food and Construction Materials, and Economic Feasibility: A Review.” Environmental Chemistry Letters, January. https://doi.org/10.1007/s10311-022-01551-5.

2. Li, Haijie, Zihe Yang, Chuanyu Zhang, Weiwei Shang, Tianlin Zhang, Xiaojian Chang, Zhansheng Wu, and Yanhui He. 2024. “Effect of Microbial Inoculum on Composting Efficiency in the Composting Process of Spent Mushroom Substrate and Chicken Manure.” Journal of Environmental Management 353 (February): 120145–45. https://doi.org/10.1016/j.jenvman.2024.120145.