الفهرس 
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Abstract
The experimental work was carried out in the wastes treatment laboratory of the Agricultural Engineering Department, Faculty of Agriculture, Mansoura University to assess the optimal aeration rate and mechanical stirring in order to produce compost from some field residues using a stainless-steel horizontal unit. Carbon to Nitrogen ratio (C/N ratio) of the examined raw materials was calculated to find out the mixing ratios of the correct ingredients. The composting of digested buffalo dung (slurry) and maize stover has been investigated in a forced-aeration composting system at three different aeration rates (0.0003, 0.0005 and 0.0007 m3/s) and two different levels of mechanical stirring (Once and twice a week for 30 minutes at 25 rpm) to specify the optimal aeration rate and mechanical stirring system. The obtained optimum aeration rate and mechanical stirring obtained was used with fresh buffalo dung and maize stover. Two controls (traditional system) experiments were performed, the first (control1) was digested buffalo dung and maize stover while the second (control2) was the fresh buffalo dung and maize stover during this work. Temperatures of ambient air, in the bioreactor vessel, (control1) and (control2) were measured and recorded. The moisture content of the mixed materials was about 65% w.b. Chemical analysis for the raw materials (buffalo dung and maize stover) and the final compost was also carried out. The obtained results of this experimental work indicated that, The buffalo dung (digested or fresh) can be mixed with shredded maize stover together at a ratio of two part of buffalo dung to one part of maize stover (by weight) in order to produce compost. It is recommended to use aeration rate of 0.0005 m3/s at once a week mechanical stirring to produce compost with good properties inside the bio-reactor vessel. According to the physical and chemical analysis, the produced compost from different experiments could be used as a good organic soil conditioner. It contains suitable concentration of plant nutrient elements (N, P and K) and it has tendency to increase soil microbial activity and fertility. According to the biological analysis, the produced compost from the digested buffalo dung is better than that from the fresh buffalo dung because it does not contain pathogenic bacteria such as Escherichia coli and Salmonella spp.