温室土壤酸化评估的不同pH测定方法比较研究  

Comparative Study of Different pH Determination Methods for Assessing Soil Acidification in Greenhouse System

作　　者：王嫒华[1,2] 段增强[1] 董金龙[1,2] 赵宇[1] 汤英[1,2] 李汛[1] 

机构地区：[1]中国科学院南京土壤研究所,南京210008 [2]中国科学院大学,北京100049

出　　处：《农业环境科学学报》2014年第11期2164-2170,共7页Journal of Agro-Environment Science

基　　金：国家科技支撑计划(2014BAD14B04);国家自然科学基金(41401257);江苏省自然科学青年基金(BK20141054)

摘　　要：为筛选出适合于温室土壤酸化评估的pH测定方法,以温室中常见的褐土、潮土和水稻土为研究对象,设置不同的KNO3和复合肥（N-P2O5-K2O,15%-15%-15%）梯度,用五种方法：水浸提测定pH（pHw）、0.01 mol·L^-1CaCl2浸提测定pH[pH（CaCl2）]、饱和泥浆测定pH（pHw）、田间浓度模拟测定pH[pH（salt）]以及石灰位（pHw-0.5pCa）,测定各处理土壤的pH值,并对添加KNO3和复合肥后土壤的酸化状况进行评估。结果表明,KNO3累积在土壤中,虽然没有引入H＋,却使pHw下降0.34～1.41个单位,盐分含量越高,pH下降程度越大;复合肥施入土壤中,氮肥转化过程中净释放H＋,加之盐分积累的影响,导致pHw下降0.78～2.01个单位。对于其余四种pH测定方法,KNO3使pH（CaCl2）、pHw”、pH（salt）、pHw-0.5pCa分别下降了0～0.06、0.36～0.64、0.17～0.74、0.07～0.19个单位,复合肥使pH（CaCl2）、pHw”、pH（salt）、pHw-0.5pCa分别下降了0.28～1.49、0.51～1.87、0.57～1.89、0.53～1.56个单位。因此,温室中有盐分积累时,若用pHw作为酸化评判标准,计算质子引入量,不考虑盐分的影响,会高估土壤的酸化速率。五种pH测定方法中,pH（CaCl2）与pHw-0.5pCa值比较稳定,受土壤盐分含量影响较小。考虑到盐分积累对pH测定的影响、土壤酸化评估的准确程度以及测定的简易程度,认为pH（CaCl2）与pHw-0.5pCa是用于温室土壤酸化评估的最佳选择。Five methods for pH determination were compared to seek an optimal assessment method of greenhouse soil acidification. Various amounts of KNO3 were added to obtain soils with a series of salinity without introducing foreign H, while compound fertilizer（ N-P2O5-K2O2 15%-15%-15% ） was applied to get soils with a series of salinity with foreign H＋ inputs, These soils were subjected to incubation in green- house for three months. After that, soil pH was determined in distilled water without CO2（pHw）, 0.01 mol. L^-1 CaCl2 solution[pH （CaCl2）], saturated paste （pHw）, various concentrations of CaClz solution equal to salt concentration in field moist soil solution[pH （ salt ）], and lime potential （pHw-0.5pCa）. The pHw, pH （CaCl2）, pHw＂, pH （salt）, and pHw-0.5pCa values dropped by 0.02-1.41, 0～0.06, 0.36-0.64, O. 17-0.74, and 0.07～0.19 unit by KNO3 addition, and by 0.78-2.01, 0.28-1.49, 0.51-1.87, 0.57-1.89, and 0.53-1.56 unit by compound fertilizer addition, respectively. Hence, the pHw method over-estimated net acid addition and aeidification in greenhouse systems. pH （CaCl2） and pHw-0.5pCa would be the best methods for assessment of greenhouse soil acidification.

关 键 词：PH 测定 酸化评估 设施土壤 盐分积累 次生盐渍化 

分 类 号：S153[农业科学—土壤学]