Temperature and duration of extraction affect the biochemical composition of soil water-extractable organic matter
Temperature and duration of extraction affect the biochemical composition of soil water-extractable organic matter
复制标题
DOI：
10.1016/j.soilbio.2014.04.011
复制
发表时间：
2014-08-01
影响因子：
9.7
通讯作者：
Beare, Mike
中科院分区：
文献类型：
--
作者：
Chantigny, Martin H.;Harrison-Kirk, Tina;Beare, Mike
水溶性有机质被认为是土壤微生物最易利用的基质。然而，很少有人知道的影响，提取温度和时间对其生化组成。采用新西兰和加拿大东部的4种农业土壤，研究了温度（20 ℃和80 ℃）和浸提时间（1-24 h）对土壤中水溶性有机碳（WEOC）、水溶性有机氮（WEON）、碳水化合物、酚类物质、茚三酮反应性有机氮（NRON）和矿质氮含量的影响。更多的WEOC和WEON提取在热水中比在冷水中，并发现同样的所有生化化合物测试。生化成分在80 ℃下提取的前4小时内迅速增加，此后以较慢的速度增加。相反，在20 ℃下，所有测量组分的浓度在1小时后达到或接近其最大值，此后几乎没有变化。20 ℃提取物中的葡萄糖和硝酸盐在1至24小时之间均大幅下降，可能是由于微生物活性。此外，葡萄糖的消失导致碳水化合物-C与酚-C的比率下降。在两种温度下的水浸提液中测得的碳水化合物在1 h后主要来自微生物。而在80 ℃下，从1 ~ 24 h，微生物碳水化合物的比例逐渐下降，植物碳水化合物的比例逐渐上升。基于这些发现，我们建议将浸提时间限制在20 ℃下1小时或更短，80 ℃下4小时或更短，以尽量减少在较长浸提时间内可能发生的成分变化。皇冠版权所有（C）2014由爱思唯尔有限公司出版。保留所有权利。
Water-extractable organic matter is regarded as readily available substrate for soil microbes. However, little is known about the influence of extraction temperature and duration on its biochemical composition. The effect of temperature (20 vs. 80 degrees C) and extraction duration (1-24 h) on the amounts of water-extractable organic C (WEOC), water-extractable organic N (WEON), carbohydrates, phenolics, ninhydrin-reactive organic N (NRON), and mineral N were evaluated using four agricultural soils from New Zealand and eastern Canada. More WEOC and WEON were extracted in hot than in cold water, and the same was found for all biochemical compounds tested. Biochemical components increased rapidly during the first 4 h of extraction at 80 degrees C, and at a slower rate thereafter. In contrast, at 20 degrees C, concentrations of all measured components were at or close to their maximum after 1 h and showed little change thereafter. Glucose and nitrate in the 20 degrees C extracts both declined substantially between 1 and 24 h, likely due to microbial activity. Moreover, the disappearance of glucose induced a decline in the ratio of carbohydrate-C to phenolic-C. The carbohydrates measured in water extracts at both temperatures were predominantly of microbial origin after 1 h. However, the proportion of microbial carbohydrates gradually declined and the proportion of plant carbohydrates increased from 1 to 24 h at 80 degrees C. Based on these findings, we recommend limiting extractions to 1 h or less at 20 degrees C and to 4 h or less at 80 degrees C to minimize compositional changes that may occur during longer extraction periods. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.