Composting Efficiency of Urban Forest Litter and River Sediment at Different Proportions

城市林木枯落物和河道底泥不同配比的堆肥效果(英文)

In order to explore a technology for producing organic fertilizer by composting urban forest litter and river sediment passivated by fly ash, an experiment was conducted to study dynamic changes of several parameters including temperature, pH, organic matter, C/N and germination index （GI） during high-temperature composting of urban forest litter and river sediment at five different proportions （1：1 （Ⅰ）, 1：2 （Ⅱ）, 1：3 （Ⅲ）, 2：1 （Ⅳ） and 3：1 （Ⅴ））. Results showed that the temperature and pH increased first and then decreased; at the proportion of 3：1, the temperature increased rapidly and the high-temperature duration was longest （5 d）; at the end of the composting, all the treatments reached the decomposed status, the pH ranged from 7.47 to 8.87, and the organic matter content was reduced by 36%, 38%, 42%, 33% and 29%, respectively, indicating that increasing the proportion of urban forest litter was conducive to reducing the loss of organic matter. Due to low C/N ratio of river sediment, increasing the proportion of urban forest litter was helpful to improve the efficiency of composting. The GI of treatments I, IV and V reached 80% on day 26, 18 and 19 respectively, but the GI of treatments II and III did not reach this level until the end of composting. Considering the quality of fertilizer and efficiency of composting for large-scale production, the proportion between urban forest litter and river sediment is suitable to be set as 3：1 for production of organic fertilizer.

为利用城市林木枯落物和河道底泥堆肥生产有机肥,设计城市林木枯落物和经加粉煤灰钝化处理的河道底泥5种不同比例(1∶1、1∶2、1∶3、2∶1和3∶1)的高温堆肥试验,测定堆肥过程中堆温、pH、有机质和C/N的动态变化,以及这5种配方堆肥产物的种子发芽指数。结果显示,堆温和pH均呈先升高后下降的趋势,3∶1配比的升温迅速、高温期维持时间最长(5d);堆肥结束时,各处理均达到腐熟,pH值在7.47~8.87,有机质分别下降了36%,38%,42%,33%和29%,城市林木枯落物比例增加有利于减少有机质损失;由于底泥的C/N较低,增加枯落物有助于提高堆肥效率;处理组1、4和5的种子发芽率分别在26、18和19 d达80%以上,而处理组2和3直至堆肥结束其种子发芽率仍小于80%。综合考虑堆肥质量和效率,底泥和城市林木枯落物3∶1的处理为规模化生产有机肥的适宜原料比例。