干污泥和堆肥污泥施用于红壤中N素的释放特性

Nitrogen Release Characteristics of Dry Sludge and Composted Sewage Sludge Applied in Red Soil

在红壤自然状况下,模拟了施肥沟,对红壤不同污泥施肥处理的N素释放特性进行了研究。试验结果表明,干污泥配比在10%~20%时,碱解氮、铵态氮和硝态氮累计释放量分别为：25.71%~33.48%,9.57%~14.85%和4.08%~7.65%。堆肥污泥配比在20%~33%时,其累计释放量分别为13.55%~15.65%,2.03%~4.23%和3.11%~5.37%。干污泥处理的释放量大于堆肥污泥处理的释放量,释放过程变化较堆肥污泥剧烈,铵态氮和硝态氮均有明显峰值,铵态氮最大含量532.98±10mg/kg,释放量最大达10.95%;硝态氮含量最大为149.2±14mg/kg,释放量最大时为3.32%。无论是从氮的肥效角度,还是氮释放的环境风险角度考虑,污泥堆肥处理后施肥方式均优于干污泥处理施肥方式。

The nitrogen release characteristics of dry sludge and composted sewage sludge applied in red soil was studied by determining the hydrolyzable N, NH4＋--N and NO3--N of the different treated and control red soil. The results showed that the accumulative released amounts of hydrolyzable N, NH4--N and NO;---N were 25.71%-33.48%, 9.57%-14.85 %, and 4.08% ~7.65%, respectively by the 10%-20% dry sludge addition. Meanwhile, the corresponding accumulative released amounts were 13.55%-15.65%, 2.03%-4.23%, and 3.11%-5.37%, respectively when 20%-33% dry sludge was used. Moreover, the dry sludge treatments released greater amounts of nitrogen than composted sewage sludge treatments. In the incubation period, the variation of released N of dry sludge treatments is more than composted sludge treatments, and the peak contents and release amounts of NH4＋--N and NO3--N were 532. 98±10 mg/kg （10.95%） and 149.2±14 mg/kg（3.32%）, respectively. Overall, the composted sewage sludge treatments are better than the dry sludge treatments considering whether the N fertilizer effects and the environment risk of N release.