Simulation of cattle stomach processes applied to the fermentation of mixed manure and straw

Abstract

The cattle stomach was considered as the basis for simulating a proposed operation. Microenvironmental degradation mechanisms are understood to be key to the efficient utilization of straw and other resources. Through dynamic tracking of the change law of heat generated by microbial degradation of straw in the cattle stomach, this study used an orthogonal test to explore the optimal ratio of feeding feed, the degradation mechanism in the microenvironment, and the characteristics of cattle manure and straw anaerobic fermentation. The results showed that the number of days of fermentation and the ratio of straw and cattle manure had a significant impact on methane gas production, and the mixture ratio was 1:3, at 26 °C; within 20 days, the cumulative gas production was up to 78.9 L. The results also showed that rumen microorganisms, cattle manure, and mixed straw fermentation can be used at different ratios to obtain the change of methane production, and determine the best ratio to achieve the maximum gas production.

A Comprehensive Assessment of Rice Straw Returning in China Based on Life Cycle Assessment Method: Implications on Soil, Crops, and Environment

“…(1) Soil Fungus: As shown in Figure 4d. Compared to non-straw-returning modes, the fungal abundance in direct modes had significantly increased; the ploughing mode having the highest (5.26%), followed by the mulching mode (4%), due to the large amount of inert carbon brought to the soil, which helps the growth and abundance of soil fungi [55]. However, the abundance in other modes decreased significantly.…”

“…As for climate warming, greenhouse gases were the key factors, and the source of their emissions was mainly from energy consumption, processing, and straw returning. The feeding mode had the highest potential (495.13 gCO 2 e; higher than the burning straw mode), mainly due to the large amount of greenhouse gases, such as CH 4 , produced by the straw passing through the stomach of cows during overfeeding [55]. Interestingly, the potential values of the composting and burning modes were similar (351.24 gCO 2 e), possibly due to the large amount of greenhouse gases generated during the straw composting process [56].…”