Increase in concentrations of various greenhouse gases and their possible contributions to the global warming are becoming a serious concern. Anthropogenic activities such as cultivation of flooded rice and application of waste materials, such as sewage sludge which are rich in C and N, as soil amendments could contribute to the increase in emission of greenhouse gases such as methane (CH_4) and nitrous oxide (N_2O) into the atmosphere. Therefore, evaluation of flux of various greenhouse gases from soils amended with sewage sludge is essential to quantify their release into the atmosphere. Two soils with contrasting properties (Candler fine sand [CFS] from Florida, and Ogeechee loamy sand [OLS] from Savannah, GA) were amended with varying rates (0, 24.7, 49.4, 98.8, and 148.3 Mg ha~(-1)) of 2 types of sewage sludge (industrial [ISS] and domestic [DSS] origin. The amended soil samples were incubated in anaerobic condition at field capacity soil water content in static chamber (Qopak bottles). Gas samples were extracted immediately after amending soils and subsequently on a daily basis to evaluate the emission of CH4, CO_2 and N_2O. The results showed that emission rates and cumulative emission of all three gases increased with increasing rates of amendments. Cumulative emission of gases during 25-d incubation of soils amended with different types of sewage sludge decreased in the order: CO_2 > N_2O > CH_4. The emission of gases was greater from the soils amended with DSS as compared to that with ISS. This may indicate the presence of either low C and N content or possible harmful chemicals in the ISS. The emission of gases was greater from the CFS as compared to that from the OLS. Furthermore, the results clearly depicted the inhibitory effect of acetylene in both soils by producing more N_2O and CH_4 emission compared to the soils that did not receive acetylene at the rate of 1 mL g~(-1) soil. Enumeration of microbial population by fluorescein diacetate (FDA) and most probable number (MPN) procedure at the end of 25-d incubation demonstrated a clear relationship between microbial activity and the emission of gases. The results of this study emphasize the need to consider the emission of greenhouse gases from soils amended with organic soil amendments such as sewage sludge, especially at high rates, and their potential contribution to global warming.
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机译：各种温室气体的浓度增加及其对全球变暖的可能作用正成为一个严重的问题。人为活动，例如种植水稻和使用富含碳和氮的废料（例如污泥），因为土壤改良剂可能有助于增加甲烷（CH_4）和一氧化二氮（N_2O）等温室气体的排放。 ）进入大气层。因此，对土壤中各种温室气体通量进行污水污泥改良的评估对于量化其向大气中的排放至关重要。修改了两种具有相反特性的土壤（佛罗里达州的坎德细砂[CFS]和佐治亚州萨凡纳的Ogeechee壤土砂[OLS]），并分别以不同的速率（0、24.7、49.4、98.8和148.3 Mg ha〜（-1）进行了修正。 ）两种类型的污水污泥（工业[ISS]和生活用[DSS]来源）。将修改过的土壤样品在厌氧条件下在田间持水的情况下在静态室（Qopak瓶）中进行含水培养，在修改土壤后立即提取气体样品结果表明，三种土壤的CH4，CO_2和N_2O的排放量均随着修正量的增加而增加，土壤25d温育过程中的累积气体排放量经修正后被修正。不同类型的污水污泥的排放顺序依次为：CO_2> N_2O> CH_4。用DSS改良土壤的气体排放量比采用ISS的排放量大，这表明存在低C和N含量或可能存在国际空间站中的有害化学物质。与OLS相比，CFS的气体排放量更大。此外，结果清楚地描述了乙炔在两种土壤中的抑制作用，与未以1 mL g〜（-1）的速率接受乙炔的土壤相比，会产生更多的N_2O和CH_4排放。在第25天孵育结束时，通过二乙酸荧光素（FDA）和最可能数（MPN）程序对微生物种群进行计数，表明微生物活性与气体排放之间存在明显的关系。这项研究的结果强调，必须考虑经过有机土壤改良剂（例如污水污泥）修正的土壤中温室气体的排放，特别是高排放量，以及它们对全球变暖的潜在影响。
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