干污泥和堆肥污泥施用于红壤中N素的释放特性

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±10 mg/kg,释放量最大达10.95%;硝态氮含量最大为149.2±14 mg/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。

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

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 NO₃^--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.