Effects of Different Mixed Ratio of Maize Straw and Cabbage Wastes on Silage Quality

Ensiling, a wet preservation method, is an appropriate method of storing feedstock for biogas production. Fresh maize straw, contain enough water-soluble carbohydrates, is the prevailing material producing biogas, but research on preservation and storage of maize straw as feedstock for anaerobic digestion is still in its infancy. Generally in China, the free sugars are consumed, the water evaporates during wilting and field drying, giving rise to fail to achieve the demand of good-quality silage. In view of strong complementary in terms of physical structure, nutrient/moisture content of maize straw and vegetables, this paper propose a hypothesis of trans-seasonal mixed ensiling for biogas production. The objective of the current work was to evaluate effects of different mixed ratio of maize straw (MS) and cabbage wastes (CW) on silage quality, taking into account the silage quality, chemical composition and structural properties of feedstock. Mixed ensiling of maize straw and cabbage waste were prepared in 1.6-L plastic silos at 25 degrees C. The mixed mass ratios (MMR) of MS and CW were 19:29, 21:27, 23:25, 25:23, 27:21 and 29:19, respectively. The results show that the content of cellulose and hemicellulose after ensiling were increased, achieving the goal of seasonal storage for MS. When the MMR was 27:21, that is, the moist content was 73% (MEMS73), the pH value had a minimum and the content of lactic acid was highest after mixed ensiling for 30 days. Therefore, the optimum MMR of MS and CW was 21:27 for storage of maize straw. The microtoporaghy of SEM indicated that the cracks and ruleless pores were taken on the surfaces of maize straw silage, compared to the compact lignocellulosic matrix before ensiling. The crystalline degree of cellulose was decreased after ensiling. In a word, ensiling is an appropriate feasibly storage method to preserve MS and should be considered a promising method for stable storage of biogas feedstock.