Abstract:

To realize the harmless treatment and resource utilization of corn straw, wheat straw, mushroom residue and the mixture of sawdust, kitchen waste oil and cow dung, and find out the law of their decomposition, the aerobic composting experiment was carried out. The results showed that the four materials all experienced heating, high temperature and cooling phases, and the peak temperature reached 74.7, 63, 58.5 and 64.1℃, respectively. The high temperature phase of the four materials lasted for 24, 20, 16 and 22 days, respectively. Water was not needed in the whole decomposition process of corn straw and the mixed material. It was very difficult for wheat straw to absorb water before stacking, but water absorption became easy after the first pile-turning. Mushroom residue absorbed water easily, but it lost water quickly, and needed water adding when the piles were turned. After decomposition, the volume of mushroom residue and the mixed material changed little, and more products were obtained. Corn straw needed at least 2 weeks of decomposition, while wheat straw, the mixed material and mushroom residue needed at least 3 weeks of decomposition before they could be used as substrate. The contents of nutrient elements and heavy metals of the substrates after decomposing were different, but all could be used safely. This experiment finds out the decomposition law and composting method of various materials, and lays a foundation for the production of efficient and stable bio-fertilizer substrates.

Key words: corn straw, wheat straw, mushroom residue, the mixed material, aerobic composting