[Nitrogen transformation during co-composting of flower wastes and cattle manure]

Nitrogen transformation during co-composting of flower wastes and cattle manure were studied in pilot scale. The first stage was aerobic static bed of composting based on temperature feedback and control via aeration rate regulation, which lasted about 20d. The second stage was window composting, with a period of about 40d. Changes of composting of total nitrogen (TN), organic nitrogen, inorganic nitrogen, NH4(+)-N and NO3(-)-N were studied. Results show that ammoniation and denitrifcation were serious at the beginning of first stage. The total nitrogen losses was about 41.98% during 60 days of composting, most of which was losses of organic nitrogen contributing about 99.95% at first stage. Losses of N were governed mainly by volatilization of ammonia as the pile temperatures and pH values were high. It is hoping to reduce nitrogen losses by effective aeration rate regulation, improving C/N of raw materials and addition of acidic amendment. On the part of material of low C/N and high nitrate, it is not appropriate for NH4(+)-N < or = 0.04% and NH4/NO3 < or = 0.16 as maturity indicators.