乙炔抑制方式对潮土硝化和矿化作用的影响

The Effects of Methods of Exposure to Acetylene on Nitrification and Mineralizationin in the Fluvo-aquic Soil

在土壤最大持水量60%和温度28?C的实验室培养条件下,研究了乙炔的不同抑制方式(短时前期暴露/连续灌注法)对潮土硝化、矿化作用的影响。结果显示,连续14天灌注10 ml/L或100 ml/L浓度乙炔完全抑制了供试潮土的硝化作用,而将土样短时前期暴露于乙炔12 h后驱散乙炔,仅能保持48 h的抑制效果,驱散乙炔后第3天土样的硝化作用开始恢复,培养结束时土样的硝化率仍可达到99%。本研究的结果还显示,培养结束时,加入乙炔的4个施N处理其净矿化量为负值,乙炔连续抑制方式下土样净矿化量低于乙炔短时前期暴露方式下土壤的净矿化量。因此,采用乙炔抑制技术进行研究时应当考察所采集的供试土壤在乙炔抑制方式下的硝化活性恢复速率和矿化过程,以保证相关试验方法设计的合理性。对培养期较长的试验,采用连续灌注乙炔,并将通风时间控制在硝化活性恢复点以前的方式是区分硝化类型较为适用的实验室方法。

The effect of long-term or short-term exposure method on the nitrification in the fluvo-aquic soils incubated at 60% water-holding capacity and 28℃ was firstly studied using acetylene as nitrification inhibitor. The results showed that nitrification in the fluvo-aquic soils were completely or nearly completely inhibited during the long-term exposure （14 d） to 10 ml/L or 100 ml/L acetylene. However, after short-term （12 h） exposure, partial inhibition of nitrification by acetylene was observed. The nitrification reoccurred on 3 d after the acetylene was removed and the nitrification ratio still reached high up to 99% at the end of the incubation, the results indicated that the net mineralization in the treatments of adding acetylene were negative value. The net mineralization in the treatment of the long-term exposure was lower than that of in the treatment of short-term exposure. Therefore, for ensuring the experiment design reasonable, it should be noticed that the recovery rate of nitrification and the changes in the mineralization in the sampled soil treated with acetylene inhibitor. For long incubation, it is a better method that long-term exposure to acetylene with periodically adding fresh air to soil, strictly controlling the aerobic time before the recovery of nitrification.