Evaluation of composting of several plant biomass wastes with different types of starters

Purpose: This study aimed to evaluate the effectiveness of starters made from cattle rumen and EM 4 on the decomposition of agricultural biomass wastes (rice straw, corncobs, and coffee husks).Method: Three types of starter i.e. starter from local cattle rumen (grass/straw feed), starter from the rumen of cattle farms (concentrate feed), EM 4 (factory product), and control (water) applied to three types of biomass waste (rice straw, corncob, and coffee husk) to observe the decomposition process using the litterbag method. An evaluation was carried out on the rate of decomposition of biomass. Parameters evaluated include decomposition rate, C and total-N content, as well as the C/N ratio.Results: The starter made from the rumen of grass-fed cows could decompose rice straw and coffee husks at an average that was not significantly different from using EM 4 starter with the speed ratio (k=-0.0852 vs. k=-0.0924) and (k=-0.0832 vs k=-0.0908) respectively. In corncobs, the decomposition speed with a starter of the rumen of cattle farms-concentrate feed was not significantly different from using EM 4 (k=-0.0916 vs. k=-0.1067). The decrease in the C/N ratio is also in line with the decomposition process and was faster with the adding of the starter.Conclusion: The starter made from the rumen of local cattle (grass feed) and from company cattle (concentrate feed) could decompose plant biomass waste (rice straw, corncobs, and coffee husks) with an average speed that was not significantly different from a starter from factories (EM 4).