Study On The Nutrient Loss And Control Measures Of Poultry Manure Compost

A series of experiments were carried out aiming at aerobic compost of poultry manure and straw, when the windrows were covered by tarpaulin, straw and clay or mixed with zeolite. In order to find the compost method which not only decrease the nutrient loss but also enhance the compost quality, differences of compost effect and nutrient loss among different treatments were measured during composting. The results are as follows.1. There was so much of salt, especially NH4+, accumulated in the covered treatments during composting that the EC and pH value of these treatments were higher than uncovered treatments. The ammonia volatilization was measured by a chamber where the air was replaced 15-20 times per minutes. This method can be used to measure the intensity of NH3 emission among treatments, but not suitable for calculating total net NH3 volatilization in the compost period.2. Nutrient losses through runoff took up only a small part of the whole loss in composting. The windrow covered had smaller nutrient loss than uncovered, while the zeolite mixed in the windrow did not decrease nutrient loss significantly. About 50% of the nitrogen in the runoff is organic nitrogen, while most part of the phosphorus and potassium in the runoff is mineral, the concentration of nutrient of runoff is N>P>K.3. Most part of the nutrient losses leached into soil, the concentration of nutrient is decreasing with the soil depth, and most is in the 0-60 cm soil.4. The recovery of the nutrient losses is about 60-70%, most part of the phosphorus and potassium is through leaching, and only a small part is through runoff. The leached nitrogen took up about 40-60% part of total net nitrogen loss, while only about 3-6%o was lost through runoff, so we must take good methods to stop the nutrient losing though leaching.5. The windrows covered had a very low rate of heat and water release compared with uncovered treatments. The water content of the windrow covered by clay was higher than the others significantly from the middle compost period. The higher water content is not good for the compost which can decrease the content of oxygen in the windrow, leads to anaerobic compost.6. The content of oxygen and carbon oxidize in the windrows have the absolutely opposite trend during composting. The concentration of carbon-oxidize in the windrows covered by tarpaulin, straw and clay or mixed with zeolite is higher than the check treatment, for the air change is very low in these treatments.7. The germination index was increasing in the compost time. The germination of the check treatment is the best, while the compost covered by clay had a very low germination index.