Regional pH Change in Groundwater Between Field and Laboratory Analyses, Temperature, Groundwater Silicon, Agricultural Soil pH and Soil-Type Distribution in Finland

Töysä T*

Received: December 02, 2018;   Published: December 20, 2018

DOI: 10.26717/BJSTR.2018.12.002509

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Abstract

Objective: Silicates are a part of carbonate-silicate cycle, but the role of silicon (Si) in pH regulation of groundwater and agricultural soil (soil) is not as well clarified. Groundwater (gw) pH is different in immediate analysis on the field (pH.gw.field) to the laboratory survey (pH.gw.lab). The purpose of this manuscript is to describe regional associations between temperature (Temp), Si.gw, pH.soil, pH. gw´s and their difference (Δ. pH.gw), as well as proportion of organic (Prp.org) and coarse mineral soil-types sine silt (Prp. coms) and suggest explanations.

Materials and Methods: Regional values of pH’s, soil-type distribution, Si.gw and Temperature are from old sources. Regional values for Uusimaa and Varsinais-Suomi are formed of their Rural Center (RC) parts as earlier presented. Statistical analyses are from continental Finland. In grapHics whole Finland is represented,

Results: Mean Δ. pH.gw was 0.31 (+/- 0.21) (Table 1) Only in one region of 19 (Ostrobothnia) pH.gw.field value was higher to its pH.gw.lab value. pH ´s of Ostrobothnia are associated with special local factors. Correlations of pH.gw.field/ pH.gw.lab with Si.gw were +0.64**/-0.11 and oppositely with Δ. pH.gw (-0.56*/+0.63**) and soil pH values. (Combined regression by) [Temp; Δ. pH.gw] explained pH.soil variation 79.4 % (r = 0.89, p < 0.001),with coefficient directions (+/+). [Prp.coms;Prp.org] explained trend-like Δ. pH.gw, coefficient directions were (+/-).

Conclusion: Regional Δ. pH.gw was associated inversely with Si.gw. Combined Temp and Δ. pH.gw explained ca 80 % of agricultural soil pH variation. Δ. pH.gw can be associated with silicate carbonate interactions. (CO2 sequestrating by silicates - weathering - can be seen as a pH stabilizing process, which could be supported by silicate liming agents and fertilizers, e.g. industrial slags and stone meals)

Keywords :pH; Groundwater; Agriculture; Silicon; Temperature; GeograpHy; Soil Type

Abbreviations : C: Carbon; Continental Finland: Finland Without Åland; Correlation: Pearson Correlation; GW: Ground Water; H: Hydrogen; O: Oxygen; Prp.org: Proportion of Organic Soiltypes; Prp.coms: Proportion of Coarse Mineral Soiltypes Sine Silt; pH.gw.field: pH of the Fresh Groundwater, pH.gw.lab: pH Studied in Laboratory. Δ. pH.gw = pH.gw.lab minus pH.gw.field; RC: Rural Center (earlier Agricultural Advisory Center); Si: Silicon; Silanol - Si-O-H-group; Temp: Temperature