Relationship between spatio-temporal evolution of soil pH and geological environment/surface cover in the eastern Nenjiang River Basin of Northeast China during the past 30 years

To illuminate the spatio-temporal variation characteristics and geochemical driving mechanism of soil pH in the Nenjiang River Basin,the National Multi-objective Regional Geochemical Survey data of topsoil,the Second National Soil Survey data and Normalized Difference Vegetation Index(NDVI)were analyzed.The areas of neutral and alkaline soil decreased by 21100 km^(2)and 30500 km^(2),respectively,while that of strongly alkaline,extremely alkaline,and strongly acidic soil increased by 19600 km^(2),18200 km^(2),and 15500 km^(2),respectively,during the past 30 years.NDVI decreased with the increase of soil pH when soil pH>8.0,and it was reversed when soil pH<5.0.There were significant differences in soil pH with various surface cover types,which showed an ascending order:Arbor<reed<maize<rice<high and medium-covered meadow<low-covered meadow<Puccinellia.The weathering products of minerals rich in K_(2)O,Na_(2)O,CaO,and MgO entered into the low plain and were enriched in different parts by water transportation and lake deposition,while Fe and Al remained in the low hilly areas,which was the geochemical driving mechanism.The results of this study will provide scientific basis for making scientific and rational decisions on soil acidification and salinization.

Effects of Straw and Biochar Returned to the Soil on Soil Physical Properties and pH Value in Cold Rice Region

[Objectives]In order to explore the feasibility of using straw and biochar returned to the soil to improve soil physical properties and pH value in cold rice regions of China.[Methods]the effects of straw directly returned to the soil and charred straw(biochar)returned to the soil on soil bulk density,porosity,temperature and pH value of cold paddy soil were studied in this paper.[Results]The results showed that compared with conventional production,straw(6 t/ha),a small amount of biochar(2 t/ha)and a large amount of biochar(40 t/ha)returned to the soil reduced paddy soil bulk density at different growth stages by 6.02%-11.86%,2.69%-6.67%and 8.58%-11.32%,respectively,increased total porosity by 7.41%-14.93%,3.19%-8.38%and 9.81%-14.27%,respectively,and increased aeration porosity by 22.28%-192.11%,17.80%-92.11%and 52.44%-157.11%,respectively.Straw and a small amount of biochar returned to the soil had no significant effect on soil temperature and pH value of paddy field,but a large amount of biochar returned to the soil could significantly increase soil temperature by 5.13%-8.79%and pH value by 3.15%-5.96%in the later stage of rice growth.[Conclusions]The straw and biochar returned to the soil could reduce soil bulk density,increase total porosity and aeration porosity,and only a large amount of biochar returned to the soil could significantly increase soil temperature and pH value.

Effects of Soil pH on Growth and Dry Matter Accumulation of Tobacco Plants

In order to clarify the relationships between soil pH and flue-cured tobacco growth and dry matter accumulation, effects of soil pH on root morphology and vigor, aboveground agronomic traits and dry matter accumulation of flue-cured tobacco were investigated by pot experiment. The results showed that on the whole, the intensity of soil pH on flue-cured tobacco growth and dry matter accumulation ranked as pH=6＇s 〉 pH=7＇s 〉 pH=5＇s 〉 pH=4＇s 〉 pH=8＇s. Acidic soil （pH=4） was not conducive to the early growth of tobacco plants, reduced root vigor and affected dry matter accumulation; and alkaline soil （pH=8） was not conducive to the growth of tobacco roots and shoot, reduced root vigor and affected dry matter accumulation. In conclusion, the suitable pH of soil for growth of flue-cured tobacco in Xiangxi is 5-7, but weakly acidic soil is the best.

Soil pH Dynamics and Nitrogen Transformations Under Long-Term Chemical Fertilization in Four Typical Chinese Croplands

Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical （1990-2005） observations on four agricultural long-term experiments in China （Changping, Chongqing, Gongzhuling and Qiyang） under four different fertilizations, i.e., no-fertilizer （control）, sole chemical nitrogen fertilizer （FN）, sole chemical phosphorous and potassium fertilizers （FPK） and chemical nitrogen, phosphorous and potassium fertilizers （FNPK）. The significant decline in topsoil pH was caused not only by chemical N fertilization （0.29 and 0.89？pH at Gongzhuling and Qiyang, respectively） but also by chemical PK fertilization （0.59？pH at Gongzhuling）. The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P （168-599%）〉available K （16-189%）〉available N （9-33%）. The relative rate of soil pH decline was lower under long-term judicious chemical fertilization （-0.036-0.034 ？pH yr-1） than that under long-term sole N or PK fertilization （0.016-0.086 ？pH yr-1）. Long-term judicious chemical fertilization with N, P and K elements decreases the nutritional limitation to normal crop growth, under which more N output was distributed in biomass removal rather than the loss via nitrate leaching. We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.

A novel strategy for quantitative analysis of soil pH via laser-induced breakdown spectroscopy coupled with random forest

pH is one of the significant properties of soil,and is closely related to the decomposition of soil organic matter,anion-cation balance,growth of plants and many other soil processes.In the present work,laser-induced breakdown spectroscopy(LIBS) technique coupled with random forest(RF) was proposed to quantify the pH of soil.First,LIBS spectra of soil was collected,and some common elements in soil were identified based on the National Institute of Science and Technology database.Then,in order to obtain a better predictive result,the influence of different input variables(full spectrum,different spectral ranges,the intensity of characteristic bands and characteristic lines) on the predictive performance of RF calibration model was explored with the evaluation indicators of root mean square error(RMSE) and coefficient of determination(R2),the characteristic bands of four elements(AI,Ca,Mg and Si) were determined as the optimal input variables.Finally,the predictive performance of RF calibration model was compared with partial least squares calibration model with the optimal input variables and model parameters,and RF calibration model showed a better predictive performance,and the four evaluation indicators of R_p^2,RMSEP,mean absolute error and mean relative error were 0.9687,0.1285,0.1114 and 0.0136,respectively.It indicates that LIBS technique coupled with RF algorithm is an effective method for pH determination of soil.

Effect of Long-term Drip Fertigation on Root Growth of Lychee and Soil pH

Through field experiment,we explore the impact of long-term drip fertigation on growth and distribution of lychee root and changes of soil pH in different layers of soil in lychee garden.The results show that drip fertigation can significantly promote the growth of lychee roots,and increase the contact area of root and soil;if it experiences six years of drip fertigation successively,the dry weight of root,root length and surface area of root in soil in drip fertigation area,will be 2.29 times,2.17 times and 2.25 times that in non-drip fertigation area,respectively.The lychee root is mainly distributed in 0-40 cm layer of soil,but there is conspicuous difference between drip fertigation area and non-drip fertigation area in terms of root distribution in 0-20 cm and 20-40 cm layer of soil.Drip fertigation is more favorable for the root to go deep inside the soil.Under long-term drip fertigation,the soil acidification in lychee garden is prominent,and in comparison with non-drip fertigation area,there is the greatest decline in soil pH in 10-20 cm layer of soil in drip fertigation area,reaching 1.47 units.

Threshold of Soil pH for Occurrence of Tobacco Bacterial Wilt in Henan Province

[Objective]The paper was to study the relationship between spatial distribution characteristics of soil p H and bacterial wilt in tobacco-growing area in Henan Province.[Method]The 21 tobacco-growing fields infected by bacterial wilt and 91 tobacco-growing fields with no cases were selected from Henan Province,and the pH of fields was determined.[Result]Bacterial wilt mainly occurred in the tobacco-growing fields in Luoshan,Pingqiao,Queshan,Biyang,Suiping,and Xiping,and the soil pH mainly ranged from 5.5 to 6.5(accounted for 84.75%of total surveyed tobacco fields);bacterial wilt had not been found in tobacco-growing fields in Tanghe,Zhengyang,Shangcai,Sheqi,Wuyang and Chenqu,and the soil pH mainly ranged from 6.5 to 7.0(accounted for 81.25%of total surveyed tobacco fields).There were significant differences in soil pH between the fields with and without bacterial wilt,and soil pH 6.5 could be regarded as the threshold for the occurrence of tobacco bacterial wilt in Henan Province.There was extremely significantly positive linear correlation between soil p H and latitude(y=0.7375 x-17.799,R2=0.386,P<0.01).The geographical boundary of soil pH 6.5 was roughly 33°N,and bacterial wilt was less likely to occur in the north tobacco-growing areas of the boundary.[Conclusion]The study will provide a scientific basis for the prevention and control of tobacco bacterial wilt in Henan.

Soil pH and phosphorus drive the canonical nitrifiers and comammox Nitrospira communities in citrus orchards with different cultivation ages

Comammox Nitrospira clade A and B showed contrasting responses to citrus planting.54d9-like AOA and Nitrobacter-NOB dominated in the 5Y and 10Y soils.Nitrososphaera-like AOA and Nitrospira-like NOB dominated in the 20Y and 30Y soils.Soil pH and P content were the major factors shaping nitrifying communities.

两种调理剂对水稻土pH值和重金属吸收的影响

探明两种调理剂对近中性水稻土pH值、重金属有效性和水稻吸收的影响,及其与土壤性质的关系,为调理剂的科学开发及合理施用提供科学依据。选取水淬高炉渣源调理剂(T1)及其腐殖质改性调理剂(T2),分别设置2个施用量梯度(T1L、T1H和T2L、T2H),通过盆栽试验分析了两种调理剂及不同用量对土壤pH值、有效硅、镉、锌、铜含量,以及水稻籽粒和秸秆镉、锌、铜含量的影响。与对照(CK)相比,2个施用T1调理剂处理土壤pH值分别升高0.64和1.02,2个施用T2调理剂处理pH值分别升高0.27和0.56(P<0.05),土壤pH值随调理剂施用量的增加而增加。T1L和T1H处理土壤有效硅含量与CK相比分别提高5和22倍(P<0.05),且显著高于施用T2调理剂处理。与CK相比,T1H处理土壤有效镉、锌、铜含量分别降低37.21%、45.57%和95.30%(P<0.05);T2L和T2H处理土壤有效锌含量分别降低31.55%和30.67%,有效铜含量分别降低6.53%和19.32%(P<0.05)。与CK相比,T1L和T1H水稻籽粒锌含量分别降低23.44%和18.12%(P<0.05);施用T2调理剂后,籽粒和秸秆锌、铜含量无显著变化。土壤pH值、有效硅含量与土壤有效镉、锌、铜含量呈显著或极显著负相关,土壤有效硅含量与籽粒、秸秆镉含量呈显著负相关。研究表明,在近中性水稻土上施用富含硅的强碱性调理剂,既有利于提高土壤p H值和有效硅含量,又可有效降低土壤重金属有效性及其水稻吸收量。

转基因抗虫耐除草剂大豆JD321对根际土壤含水量和pH值的影响

为了评价转基因抗虫耐除草剂大豆JD321对土壤生态系统的影响,该实验研究了其对土壤主要理化性质的影响。在大豆苗期、花期、鼓粒期和成熟期,分析了转基因大豆JD321对根际土壤含水量和pH值的影响。与其对应的非转基因大豆相比,转基因大豆JD321的根际土壤含水量和pH值没有明显变化,除草剂处理转基因大豆也没有对土壤含水量和pH值产生明显影响,但土壤含水量和pH值在不同生育期间存在明显差异。研究结果为转基因大豆JD321的环境安全性提供了新的支撑。

秸秆还田对苏打盐碱土pH、电导率及玉米生长的影响

通过田间试验,分析玉米秸秆不同还田方式对苏打盐碱土pH、电导率及玉米生长的影响。结果表明,在作物整个生长阶段内,处理HCS与FCS中0~20 cm土壤pH均低于CK,但30~50 cm略高于CK;处理HCS与FCS中各层土壤EC均低于CK;相比CK,处理HCS与FCS玉米株高、茎粗、穗位高、穗长、穗粗均增加;二者产量分别比CK高6.70%和18.25%。综上,秸秆还田可有效减轻苏打盐碱土的碱害和盐害,促进玉米生长,提高产量,玉米秸秆还田量为1.2 t/hm^(2)的作用效果优于还田量为0.6 t/hm^(2)。

基于Meta分析研究毛竹入侵致土壤pH提升及养分和微生物群落结构的变化

诸多研究发现毛竹入侵周围林分提高土壤pH,但未见统计性描述报道。为此,本研究将通过大数据分析证实此现象的普遍性以及探究伴随的土壤养分和微生物变化。本研究收录包含毛竹入侵有关土壤pH变化的42篇文献总计101组数据,采用整合分析方法(Meta-analysis)进行深入探讨。在研究土壤养分变化时,本文还结合了团队采集的12个毛竹入侵带的样地数据总计92个样品18组数据进行分析。结果表明,在所有的数据组中,84.9%的土壤在经过毛竹入侵后其pH有不同幅度的提升,说明毛竹入侵周围林分普遍提高土壤pH;土壤pH增加幅度随入侵阶段、毛竹纯林时间增加而增加,随土层深度增加而降低;入侵针叶林致土壤pH增加的幅度高于阔叶林。入侵的毛竹纯林与原生林相比,总体上显著降低(P<0.05)了土壤全氮(–15.9%)、硝态氮(–21.7%)、全碳(–2.0%),却增加(P<0.05)了土壤有效磷(+54.9%)、铵态氮(+14.7%)和碱解氮(+8.2%)。对27篇包含微生物数据的文献进行整合分析,结果表明毛竹入侵改变了微生物群落结构,增加(P<0.05)了放线菌门相对丰度(+25.86%),而降低(P<0.05)了酸杆菌门(–15.49%)、浮霉菌门(–26.66%)、拟杆菌门(–22.58%)的相对丰度。本研究通过Meta分析证明毛竹入侵周围林分提高土壤pH为普遍自然现象,结合土壤硝态氮和铵态氮指标的变化推测了导致土壤pH提升的可能机制,毛竹入侵提高了土壤细菌和真菌多样性,表明入侵对土壤微生物具有正反馈效应。

湖南省柑橘园土壤pH值空间变异特征、成因及养分有效性

[目的]研究湖南省柑橘园土壤pH值的空间变异特征、影响因素及主要养分的有效性,为减缓柑橘园土壤酸化,提升土壤肥力提供科学依据。[方法]本研究以湖南省38个柑橘重点县的15722个柑橘园土壤为对象,利用地统计学、相关性分析、结构方程模型等方法,探究了湖南省柑橘园土壤pH值的空间变异特征,分析了土壤pH值对地理、气候、土壤性质等因子的响应,并研究了土壤pH值对土壤氮、磷、钾有效性的影响。[结果]湖南省柑橘园土壤pH值范围为3.00~8.50,均值为5.58,变异系数为18.06%,空间变异为中等程度。最适合柑橘生长的弱酸性土壤面积占44.35%,而酸性、强酸性、中性和碱性土壤分别占48.92%、1.69%、4.95%和0.08%。通过Pearson相关性分析发现,土壤pH值与降水量呈显著正相关(P<0.05),与速效钾含量呈极显著正相关(P<0.01),而与气温、碱解氮和有效磷含量呈极显著负相关(P<0.01)。结构方程模型模拟结果表明,土壤类型与成土母质是解释土壤pH值空间变异的主导因子。除少量强碱性土壤中碱解氮和有效磷含量处于较低水平外,柑橘园土壤各酸度等级土壤中的碱解氮、有效磷和速效钾含量皆处于适宜水平。[结论]由于特有的土壤类型和成土母质,湖南省柑橘园超过一半(50.61%)的土壤处于过酸状态(酸性和强酸性)。湖南省柑橘园土壤速效氮、磷、钾养分含量基本处于适宜水平,因此,应重视改善土壤酸性。

近30年四川省土壤pH时空变化特征研究

【目的】酸碱性(pH)是重要的土壤化学指标,影响着土壤质量和土壤健康状况。研究土壤pH的时空变化特征为农业生产和耕地质量管理提供借鉴。【方法】研究数据包括1979—1985年(1980s)全国第二次土壤普查和2005—2014年(2010s)测土配方施肥项目期间四川省土壤pH的调查数据。利用ArcGIS 10.2软件中“Spatial Analyst”模块和反距离权重(inverse distance weighted,IDW)插值方法对土壤pH进行空间插值,获得土壤pH空间分布图;利用ArcGIS 10.2软件中栅格计算器获得两个时期的土壤pH变化状况,并统计分析不同土壤pH分级空间和面积变化。【结果】四川省土壤pH平均值由1980s的7.0降低至2010s的6.54。1980s时期四川省土壤pH在强酸性(pH≤4.5)、酸性(4.5<pH≤5.5)、弱酸性(5.5<pH≤6.5)、中性(6.5<pH≤7.5)、弱碱性(7.5<pH≤8.5)和碱性(8.5<pH≤9.0)的面积占比分别为0.09%、14.58%、53.17%、12.57%、19.58%和0.01%。2010s时期,以上7个土壤pH分级的面积占比分别为0.06%、4.45%、30.41%、48.65%、16.40%和0.04%。从1980s到2010s期间,四川省土壤pH值升高的面积比例为49.63%,主要分布在四川西部地区,土壤pH值降低的面积比例为20.13%,主要分布在川中丘陵区。成都平原区各分级pH土壤面积变化较少,弱酸性土壤面积略增加,碱性土壤面积略减少。川中丘陵区酸性土壤面积占比增加,碱性土壤面积减少。盆周山区酸性和碱性土壤面积减少,中性土壤面积增加;川西南山地区各土壤pH分级面积变化比例较小,其酸性面积比例略减少,中性土壤面积增加;川西北高原山地区酸性、弱酸性土壤面积分别降低了9.00%、23.67%,中性土壤面积增加29.96%,碱性土壤面积略增加。【结论】从1980s到2010s的近30年间,四川省酸性土壤面积减少,中性土壤面积增大,然而在川中丘陵区有一定比例的土壤酸化,需引起重视。

高原山区茶园土壤pH和重金属铬的空间异质性研究——以贵州省贵定县为例

【目的】探究高原山区茶园土壤pH及重金属铬(chromium,Cr)含量的空间异质性及其驱动因素,为茶树高产优质栽培提供科学依据。【方法】采集贵州省贵定县423个茶园土壤样品,采用地统计学和半方差函数模型法探究茶园土壤pH和Cr的空间异质性,并利用随机森林算法研究不同pH下Cr含量变化的驱动因素。【结果】高原山区茶园土壤pH值为4.5~6.0的样品占74%,适宜茶树生长。研究区域内土壤Cr含量处于安全水平。土壤pH值自西南向东北逐渐减小,呈明显的带状分布。土壤重金属Cr含量的空间分布呈现自北向东南逐渐降低的趋势,低值斑块多出现在东南区域,高值斑块集中在中西部。【结论】不同土壤pH值对Cr含量的影响不同。在pH≤5.5的茶园土壤中,土壤pH对Cr含量影响最大;在5.5<pH≤6.5的茶园土壤中,土壤颗粒对Cr含量影响最大。

普洱市茶园土壤pH、有机质和中微量养分分析及肥力综合评价

【目的】采用土壤肥力综合评价指数法对普洱市茶园土壤pH、有机质和中微量元素含量进行综合评价,为普洱市茶园土壤养分管理和茶叶品质提升提供科学指导。【方法】采集普洱市4个典型茶叶种植区的40个茶园土壤样品,测定土壤pH、有机质及中微量元素(钙、镁、铁、锰、铜、锌)有效含量,采用隶属度函数模型计算土壤肥力综合指数,综合评价普洱市茶园土壤养分特征和肥力质量。【结果】普洱市茶园土壤总体呈酸性,pH为4.0~5.8,平均值为4.8。土壤有机质、有效钙、有效镁、有效铁、有效锰、有效铜和有效锌含量为4.9~41.6 g/kg、87.7~2351.9 mg/kg、56.9~272.2 mg/kg、40.3~107.3 mg/kg、2.8~64.8 mg/kg、0.3~2.9 mg/kg和0.5~5.2 mg/kg,平均值为23.4 g/kg、853.8 mg/kg、134.5 mg/kg、77.8 mg/kg、38.3 mg/kg、1.2 mg/kg和2.7 mg/kg,平均含量均达适宜水平,但不同茶园空间分布差异较大。其中,95.0%茶园表层土壤有机质含量、55.0%茶园土壤有效钙含量、62.5%茶园土壤有效镁含量达适宜及以上水平,95.0%以上茶园土壤的微量元素有效铁、有效锰、有效铜和有效锌含量适宜茶树生长。茶园土壤肥力综合指数为0.59~1.00,平均值为0.83,土壤营养状况总体较好。土壤肥力综合指数与有机质、有效镁、有效锰、有效铜和有效锌含量呈极显著正相关(P<0.01)。【结论】普洱市茶园土壤pH、有机质含量适宜高产优质茶树种植,针对土壤有效钙和有效镁等中量元素含量不足,铁、锰、铜、锌等微量元素含量过高及养分空间分布不均衡现状,需进行优化施肥和科学精准施肥,适当控制微量元素投入,加强茶园土壤测土配方工作,以维持普洱市茶园的高产优质生产。

土壤改良剂施用量对锥栗园土壤pH和养分含量的影响

为探究土壤改良剂施用量对锥栗果园酸性土壤环境的改良效果和对土壤养分含量的影响,以福建省建瓯市某锥栗园为研究对象,设置施入土壤改良剂0(CK)、373.13(A)、746.27(B)、1119.40(C)和1492.54 kg·hm^(−2)(D)5个浓度梯度,研究不同土壤改良剂施用量对锥栗园土壤pH和养分含量(有机质、全氮、全磷、钙、镁、钾、硅)的影响。结果表明:与CK相比,D组显著提高了0~20 cm土层中镁、硅的含量,分别提高了35.3%、33.6%。B组显著提高了21~40 cm土层中有机质、全氮、全磷和硅的含量,分别提高了171.9%、52.4%、41.4%、23.1%;D组显著提高了21~40 cm土层中有机质、钾和硅的含量,分别提高了203.1%、54.8%、35.9%,同时pH值上升,有效改良土壤酸性环境。B组显著提高了41~60 cm土层中全氮、全磷、有机质的含量,分别上升了93.5%、41.7%、440.5%;D组显著提高了41~60 cm土层中有机质、全磷的含量,分别上升了297.3%、200%。不同浓度的酸性改良剂对锥栗土壤养分含量都有一定的改善效果,综合考虑土壤改良剂最适宜施加量为1492.54 kg·hm^(−2)。

永州植烟土壤pH分布特征及其影响因素初探

研究永州植烟土壤pH分布状况,为永州烟区土壤pH调节提供科学理论依据。在永州产烟区采集土壤样品689个,利用多元统计学和逐步回归方法分析了永州土壤pH空间变异及其主要驱动因素。结果表明,永州植烟土壤pH均值为6.95,仅有25.84%的植烟土壤pH处于“适宜”水平内,3.34%的植烟土壤pH处于“极低”(≤5.0)水平,51.52%的植烟土壤pH位于“极高”区间(≥7.5),存在偏碱性的问题。影响因素的分析结果显示,交换性钙、交换性镁、有机质、速效钾、全钾、全氮、有效硫、阳离子交换量8个指标对pH的累计解释能力达到了82.2%,交换性钙对永州植烟土壤pH的空间变异影响能力最大,可独立解释其变异的79.5%。各基础设施配套情况、各轮作制度、各成土母质下的pH均存在显著或者极显著差异。

典型工矿区小流域土壤pH值空间分布特征及其影响因素

[目的]揭示南太行典型工矿区土壤pH值的空间分布规律及影响过程,为该典型工矿区复杂环境下土壤环境质量评估及污染防治提供科学支撑。[方法]以南太行典型工矿区蟒河小流域为研究区,采集121个土壤表层(0—20 cm)样品和部分辅助样品,综合应用3S技术、地统计学及地理探测器等模型方法,对研究区土壤表层pH值空间分布特征及影响因素展开研究。[结果]研究区土壤pH值范围在6.40~8.53之间,均值为7.82,低于黄河流域河南段背景值(背景值为8.46),与其他时期相比,土壤pH均值下降,存在土壤酸化趋势。土壤pH值呈弱空间变异,受地形等因素影响大,当间隔距离小于1905 m时,空间分布连续,具有较强空间自相关性。基于经验贝叶斯克里金的土壤pH值空间插值效果更优,土壤pH值空间上呈梯度分布,由中西部向东北和南部递增。低值区主要在中部和西部的河谷及山前平原地带;单个因子对pH值解释力不明显,坡向、土地利用等叠加其他因子后对流域内土壤pH值空间分布解释程度显著增强。[结论]自然条件及人类活动等多要素叠加作用是区域土壤pH值空间分布的主要驱动因素,也是区域土壤环境评估与污染修复重点关注的内容。

电位法测定土壤pH值不确定度评定

土壤pH值是土壤分析中的一项重要指标,许多土壤分析项目需要根据土壤的pH值进行选择相应的分析方法,检测结果也都与土壤pH值有关联,是审核其他项目结果的重要依据。本文根据测量不确定度评定理论,结合电位法对土壤pH值测量不确定度进行全面分析。从测定的重复性、样品称重、浸提前处理、仪器示值误差、仪器校准5个方面归纳不确定度来源,对各不确定度分量详细评定,并由各不确定度分量合成得到土壤pH值测定的相对标准不确定度及扩展不确定度,得出土壤pH值的测量不确定度为8.24±0.03。在分析过程中,对比各个不确定度分量对土壤pH值测定不确定度的贡献大小,其中pH标准缓冲溶液校准引入的不确定度分量最大。