提取方法对土壤可溶性有机碳测定结果的影响  

Effects of Extraction Conditions on the Test Results of Soil Dissolved Organic Carbon

作　　者：李太魁[1,2,3] 郭战玲 寇长林[1,2,3] 吕金岭 张香凝[1,2,3] 杨小林 

机构地区：[1]河南省农业科学院植物营养与资源环境研究所,河南郑州450002 [2]农业部原阳农业环境与耕地保育科学观测实验站,河南郑州450002 [3]河南省农业生态环境重点实验室,河南郑州450002 [4]河南理工大学安全与应急管理研究中心,河南焦作454000

出　　处：《生态环境学报》2017年第11期1878-1883,共6页Ecology and Environmental Sciences

基　　金：国家重点研发计划项目(2017YFD0801403);国家科技重大水专项(2012ZX07205-001);国家科技支撑计划项目(2012BAD15B02)

摘　　要：为验证浸提条件对土壤可溶性有机碳(DOC)浸提量的影响,选择具有代表性的3种土地利用方式的土壤进行实验,研究土样处理方式、提取时间、水土比、提取剂种类和振荡次数等提取条件对DOC浸提量的影响。结果表明:土样处理方式影响DOC浸提量的大小顺序为:风干过2 mm筛>鲜样过1 mm筛>过2 mm筛>过5 mm筛>不过筛,风干过2 mm筛的DOC提取量是鲜样不过筛的2.4倍,且各处理之间DOC浸提量差异性达显著水平(P<0.05);DOC的浸提量随振荡时间变化不是特别明显,振荡4 h后基本达到平衡;土壤DOC浸提量随水土比的增加而增大,呈显著的线性关系;浸提剂种类对土壤DOC浸提量影响显著,4种提取剂提取出来的DOC量的大小顺序为:DOC(80℃,H_2O)>DOC(25℃,0.5 mol·L^(-1) NaHCO_3)>DOC(25℃,0.5 mol·L^(-1) K_2SO_4)>DOC(25℃,H_2O);单次提取量随提取次数增加而降低,累积提取量随浸提次数增加而升高,且累积提取的DOC量与浸提次数呈极显著正相关。建议采用过2 mm筛的土壤鲜样,提取剂用25℃去离子水,水土比采用5∶1,连续振荡4 h后一次过滤测定土壤DOC含量。本研究有助于增强不同研究结果之间DOC数据的可比性,也有利于推动土壤DOC测定标准的完善。In order to confirm the effects of extraction methods on the concentration of soil dissolved organic carbon （DOC） andselect representative soils from three land use types were used by measuring the concentration of DOC extracted with different soilsieving, shaking time, water-to-soil ratios, extractants and frequency of extraction. The results showed that there was markeddifference in the concentration of DOC extracted among 5 kinds of soil sieving, with the following order： 2 mm sieved of air-dryingsoils〉1 mm sieved〉2 mm sieved〉5 mm sieved〉unsieved, air-drying caused a 2.4-fold increase in the extraction of DOC from soil incomparison to soils extracted in a field moist state; The amount of DOC extracted from the soil gradually increased over a 4 hextraction period;The amount of DOC extracted from soil presented a positive linear relationship significantly with water-to-soilratio; The types of soil extractants also had influence on amount of DOC in soil to some degree, with the following order： DOC（80 ℃, H2O）〉DOC （25 ℃, 0.5 mol·L-1 NaHCO3）〉DOC （25 ℃, 0.5 mol·L-1 K2SO4）〉DOC （25 ℃, H2O）; DOC from a single eventdecreased with the frequency of the extraction and cumulative DOC increased with the extracting time. There was a significantpositive correlation between cumulative DOC and the frequency of the extraction in three types of soils. We therefore propose theintroduction of a standardized extraction procedure： Replicate samples of 2 mm sieved, field-moist soil extracted as soon as possibleafter collection with distilled water, at a 5∶1 （V/W） water-to-soil ratio for 4 h at 25 ℃. This research is useful in enhancing thecomparability of soil DOC data from different studies and improving the standard of soil DOC measurement.

关 键 词：可溶性有机碳(DOC) 振荡时间 水土比 提取剂 提取次数 

分 类 号：X132[环境科学与工程—环境科学]