Regional pH in Five Agricultural Soil-Types – Associations with Temperature and Groundwater Si in Continental Finland

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Regional pH in Five Agricultural Soil-Types – Associations with Temperature and Groundwater Si in Continental Finland

Journal Title: Biomedical Journal of Scientific & Technical Research (BJSTR) - Year 2019, Vol 14, Issue 1

Abstract

The role of weathering in carbon sequestration has not got attention enough. This study is assessing regional factors: annual temperature (Temp), groundwater (gw) Si, agricultural total (tot) and soil-type pH´s and soil-type proportions (Prp) of moraine (mor), sand, silt, clay and mull soils in order to clarify whether weathering could be associated with pH variation in different soil-types. [mor + sand soils are labeled as coarse mineral soils (coms), respectively coms + silt + clays as mineral soils (miner). 1 – Prp.miner = Prp organic (org). Moraines, sands and clays include several subclasses]. Materials and Methods: Regional soil pHs, soil-type Prps, Si.gw and Temp are from old sources. N of regions in statistical survey was 15 (after combining 2 and excluding 4 of them – Åland + 3 continental regions - because of carbonate soil prominence or statistical inadequacy). N of soil-samples was ca 570,000 and gw samples 596. Results: Regional pH´s ranged from 5.35 to 6.20 in different soil-types. Temp associated significantly positively with pH´s, Si.gw and Prp.miner. Si.gw-pH associations [(Pearson/ Spearman): pH.mor (0.42 / 0.37) + , pH. sands and silts [( 0.53, 0.52) / ( 0.58, 0.55)] ++ ++ , pH.clays [( 0.74 / 0.77)] + + seemed to increase from coarse towards finer mineral soils. Represented soil-type pH´s associated significantly with pH.tot. Conclusion: Regional pH.mor, pH.sands, pH.silt and pH.clays associated significantly with pH.tot and Temp, as well as obviously with soil weathering status. pH associations with Si.gw seemed to increase towards finer mineral soils. This phenomenon is possibly related to carbon silicate cycle.Dissolved silica (SiO2 ) is known as a product carbonate silicate cycle [CaSiO3 + 2CO2 + H2O ↔ Ca + 2HCO3 - + SiO2(dissolved silica)] [1]. Weathering is associated with temperature (Temp) [2], soiltype [3] and soil ageing [3,4]. Silicate slags [5] and granite powder [6] can be used for pH elevation of acid soils. Inter-regional relative pH stability during three decades (1961 – 1990) and pH asso ciation with Temp and Si.gw is suggesting on pH association with soil weathering [7]. Association of pH.tot with Si.gw is interestingly mirror-like when the regions were arranged by Temp [8]. Inter-relations between soil-type pH´s, Temp and Si.gw after [7,8] need somewhat clarification. The aim of this survey is to clarify whether regional Temp, Si.gw and soil-type pH variations could support the role of weathering in soil pH regulation.Available data concerning regional Temp, Si, pH and soil-type proportions are first collected per 21 Rural Centers (RC, earlier Agricultural Advisory Centers). Regional Si.gw values, means, median and N of samples, are from Groundwater database © Geological Survey of Finland 2017 [9]. pH values and soil-type proportions of cultivated fields per RC´s, concerning period 1986-90 are provided by Eurofins Viljavuuspalvelu Oy [10]. Average annual temperatures of RCs from 1981-2010 are visually approximated by combining map of Finnish Meteorological Institute [11] and map of RC´s [12]. Regional values for “VarsinaisSuomi” are got by weighting RC values of “(03). Varsinais-Suomen” and “(4b). FinskaHushållningss.” by their arable land areas [13] and respectively values for “Uusimaa” by weighting RC values of “(01). Uudenmaan” and “(02).Nylands Svenska” by their arable land areas. After this RC values were given for respective Regions [14]. Åland has been excluded because its pH is in the “carbonate buffer” range, where the soil pH regulation (and Si availability) seems not to be associated with Si.gw [15]. Lapland has been excluded because of missing clay soil samples, Kainuu with only one clay soil sample. Si.mean/Si.median ratio in gw of Ostrobothnia was 1.62 (i.e. ca mean + 4*SD – can be calculated by data in Table1). This is a sign of statistical inadequacy, why Ostrobothnia has been excluded from calculations. Northern Karelia, with two and Central Finland with three clay soil samples included to this study. The boundaries, names and numbers of RCs and Regions deviate slightly from each other [14]. Number of included soil samples was 565,558 and gw samples 596. Numerical data from included and excluded regions are in Table 1, where excluded data are over-lined.

Authors and Affiliations

Töysä T

Keywords

pH; Groundwater; Agriculture; Silicon; Temperature; Geography; Soil-Type; Töysä T Scientific Research Articles on Biomedical; Biomedical Open Access Journals; Biomedical Science Articles; Journals on Medical Research

EP ID EP587626
DOI 10.26717/BJSTR.2019.14.002505
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