scholarly journals SOIL pH MEASUREMENT AND ITS APPLICATION TO ORGANIC SOILS

1977 ◽  
Vol 57 (1) ◽  
pp. 55-64 ◽  
Author(s):  
WM. van LIEROP ◽  
A. F. MacKENZIE

The average soil pH of 10 organic soils was significantly influenced by drying and the salt concentration of the suspending media. Accordingly, mean soil pH of field-moist and oven-dried soils was pH 5.0 and 4.5, 4.1 and 3.9, and 3.8 and 3.6 for soils suspended in water, 0.015 M CaCl2 and 1 M KCl. A significant treatment–soil interaction indicated that the soils responded differently to the treatments. No junction potentials were found when the ionic strength of the solution was 0.01 M CaCl2 equivalent or greater. Milli-equivalents exchangeable hydrogen (−0.984**), percent hydrogen saturation (−0.966**) milli-equivalents extractable bases (0.937**) and percent base saturation (0.957**) were more closely correlated with 1 M KCl pH values than with values in the other media. Liming influenced soil pH significantly on all field sites and within 8 h after application on two field sites. The influence of liming on soil pH tended to diminish the year after applications were made. Measured soil pH variability among treatments and replicates at various sampling dates ranged up to 1 pH unit during the growing season. However, it was about 0.2 pH unit on the control treatments with undetectable quantities of residual limestone. The quantity of reacted limestone was established at 25 and 40%, between 23 May and 31 July, on two sites (J.I.V. and S.B.). The reacted limestone was found to be proportional to the application rate.

1970 ◽  
Vol 75 (3) ◽  
pp. 571-576 ◽  
Author(s):  
A. Islam ◽  
J. Bolton

Ryegrass was used to remove potassium from two acid soils limed to different pH values. Most non-exchangeable potassium was removed from the unlimed soils (pH 4·5) but differences in removal between pH 5·5 and 7·0 were small. Air-drying the soils after cropping released further potassium into the exchangeable form in amounts independent of soil pH.Equilibrium potassium activity ratios (ARK) after each out declined to small constant values characteristic of the soils. A sandy soil (Woburn) initially contained less exchangeable potassium than a soil with more clay (Sawyers), but after a few crops, ARK, % K in the grass and K uptakes per cut were larger from Woburn soil, showing that non-exchangeable potassium was being released faster than in the other soil.


1981 ◽  
Vol 61 (4) ◽  
pp. 577-579 ◽  
Author(s):  
W. VAN LIEROP

Regression equations were derived for converting pH values of organic soils determined by five procedures. Data were obtained by measuring the pH of 30 soils using the following volumetric ratios and solutions: 1:1, soil to water; 1:2 and 1:4, soil to 0.01M CaCl2; and 1:2 and 1:4 soil to 1N KCl. Average pH values measured in 0.01M CaCl2 and 1N KCl were 0.44 and 0.70 pH units lower than those measured in water (pH 5.21). Converting data by merely adding or subtracting the average difference between methods was not as accurate as using appropriate regression equations. These equations are provided in the text and indicated that differences between soil pH values measured by different procedures increased as soil pH increased. Similar pH values were found with the 1:2 and 1:4 soil to 0.1M CaCl2 solution ratios, though a small dilution effect was observed when 1N KCl was used at these ratios.


Weed Science ◽  
1971 ◽  
Vol 19 (3) ◽  
pp. 233-239 ◽  
Author(s):  
F. T. Corbin ◽  
R. P. Upchurch ◽  
F. L. Selman

The influence of soil pH (4.3 to 7.5) on the phytotoxicity of herbicides incorporated into high organic soils was studied. Phytotoxicity increased as the soil pH increased and reached a maximum at pH 6.5 for the weak aromatic acids 3,6-dichloro-o-anisic acid (dicamba) and (2,4-dichlorophenoxy)-acetic acid (2,4-D) and the weak bases 2,4-bis(isopropylamino)-6-methoxy-s-triazine (prometone) and 3-amino-s-triazole (amitrole). Conversely, phytotoxicity increased as soil pH decreased and reached a maximum at pH 4.3 for the weak aliphatic acid 2,2-dichloropropionic acid (dalapon), the cationic herbicides 6,7-dihydrodipyrido[1,2-a:2′,1′-c]pyrazinediium ion (diquat) and 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat), and a nonionic herbicideS-propyl dipropylthiocarbamate (vernolate). Soil pH levels between 4.3 and 7.5 had no effect on the phytotoxicity of (a) the weak aromatic acids 3-amino-2,5-dichlorobenzoic acid (chloramben) and 4-amino-3,5,6-trichloropicolinic acid (picloram); and (b) the nonionic herbicides 2,6-dichlorobenzonitrile (dichlobenil), 5-bromo-3-isopropyl-6-methyluracil (isocil), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), and 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin). A change of one pH unit decreased the phytotoxicity of 2,4-D, dicamba, dalapon, prometone, amitrole, paraquat, and vernolate by a factor of two to four depending on the particular herbicide and the pH values considered.


2020 ◽  
Author(s):  
Jelena Popović-Djordjević ◽  
Zoran Broćić ◽  
Mirjana Kresović ◽  
Jelena Mutić

<p>Potato is currently the third most significant crop culture in the world, with the production of over 388 million tons in 2016. This crop is present on the tables of Serbian consumers throughout the year because of the tradition and its affordable price. Serbia has relatively good climatic conditions for potato production, which are defined by the temperature regime and the amount and frequency of precipitation. The nutritive value of the potato is mainly attributed to the chemical composition of the tuber. The element composition of tubers depends on many factors, such as: genotype, developmental phase of the plant, agroecological conditions, chemical properties of soil, fertilization and irrigation. On the other hand, geochemical origin of trace elements in the soil, the intensive agriculture production, use of contaminated soil and irrigation water may increase their toxic levels in tubers.</p><p> Potato tubers of five varieties were produced on commercial farms at two locations in Western Serbia (Guča and Sjenica), with favorable agroecological conditions for potato production. Tuber samples of studied varieties from each location were collected at the end of growing seasons at the stage of physiological maturity. Soil samples were collected from several sites at each production location at the depth of 0–30 cm. Basic agrochemical properties of the soil samples were determined. Content of toxic (As, Cd, Pb) and potentially toxic (Al, Ba, Ni, V) elements in fresh tubers (peel and core) and soil samples was established by inductively coupled plasma–optical emission spectrometry (ICP–OES). Bioaccumulation factor (BAF) of each studied element, as the ratio between its content in the peel and in the core of the tuber and the soil, was calculated.</p><p> According to pH values, 4.77 and 6.80, soils were clasified as very acidic (Guča location) and slightly acidic (Sjenica location), respectively. Content of studied trace elements in soils, with the exception of Ni, was within the allowable limits. Tuber peel of all studied varieties grown on both soil types was characterized with the higher content of Cd, Al, Ba and Ni, compared to the relevant core. Consenquently, the higher values of BAF were observed in the peel of tubers. Average values of BAF for the studied elements in the peel for both soil pH values 4.77 and 6.80 (Guča and Sjenica, respectively) were in the following order: Cd>Ba>Pb>As>Ni>Al=V. On the other hand, average BAF values for the core of the tuber samples were in a slightly different order, depending on the soil pH; Cd>Pb>As>Ba>Ni>Al=V (pH 4.77) and Cd>Pb>As>Ba=Ni>V (pH 6.80). The highest/lowest BAFs were calculated for Cd (0.339) in the peel and Al (0.0002) in the core, respectively. Content of As and Cd did not exeed the maximum allowed concentrations set by the national and European Union regulations, but it should be pointed out that Cd content was close to the upper limit. Also, it was noticed that the content of Pb exceeded the safe limit set for these elements according to both regulations.</p><p>Keywords: potato tuber, soil, toxic elements, ICP</p><p>Acknowledgement: This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Research grant No. 46009).</p>


1975 ◽  
Vol 55 (2) ◽  
pp. 205-212 ◽  
Author(s):  
WM. VAN LIEROP ◽  
A. F. MACKENZIE

The effects of lime and gypsum applications were determined on lettuce yields, soil pH and extractable aluminum for 10 organic soils. No increase in yield attributable to liming was found beyond pH 4, and a significant yield depression occurred with gypsum treatments. Further, the more acid soils outyielded the less acid but denser cultivated soils. Although the limestone applications increased soil pH significantly, significant treatment–soil interaction effects were found, and were ascribed to lower soil-limestone reactivities of the denser, less acid organic soils. Consequently, soil pH change upon liming was significantly correlated with bulk density and percent ash. Maximum yields were obtained at extractable aluminum levels lower than 0.1 meq/100 g soil. Further, potentially toxic levels of extractable aluminum disappeared at the same pH as maximum attainable lettuce yields; consequently, its possible toxicity was associated with pH effects in these soils. Field experiments with radishes grown on two organic soils gave initial increases in yields. This effect was surmised to be due to increased N-mineralization, because subsequently the controls outyielded the liming treatments.


1969 ◽  
Vol 43 (4) ◽  
pp. 255-267
Author(s):  
Julián Roldán

A general literature review on formation, subsidence, water table, and chemical properties of organic soils has been presented and discussed. Soil samples from a virgin peat soil of Puerto Rico were analyzed by rapid microchemical soil tests and, from them, the general fertility level of the area sampled was evaluated. The relation of the different soil types to the soil-test data has been presented. From the preceding investigation the following conclusions were drawn: 1. The virgin peat soils from Puerto Rico are low in phosphorus and potassium. 2. No significant correlation was found between manganese values by soil test and soil pH values. 3. A probable manganese deficiency is seen in spots where the pH of the soils is above 6.0, and the presence of free calcium carbonate has been detected. 4. A highly significant negative correlation was found for iron values by soil test and soil pH values. 5. A highly significant negative correlation was found for aluminum values by soil test and soil pH values. 6. In areas where the pH was lower than 6.0 the iron and aluminum values obtained are often high enough to render growth of crops unsatisfactory. 7. Salinity is not a problem in the area studied if correct soil-management practices are used.


2005 ◽  
Vol 53 (11) ◽  
pp. 1311-1321 ◽  
Author(s):  
Katsura Emoto ◽  
Shuji Yamashita ◽  
Yasunori Okada

We investigated the effects of pH and ionic strength of solutions used for antigen retrieval to elucidate the mechanism of heat-induced antigen retrieval (HIAR) in immunohistochemistry. The immunostaining intensity of nuclear, cytoplasmic, cell membrane, and extracellular matrix antigens with 17 different antibodies was evaluated in formaldehyde-fixed and paraffin-embedded mouse and human tissues. Deparaffinized sections were autoclaved for 10 min in buffers with different pH values ranging from 3.0 to 10.5. To test the influence of ionic strength on immunoreactions, the sections were autoclaved for 10 min in 20 mM Tris-HCl buffers (TB) at pH 9.0 and 10.5 with or without 25, 50, and 100 mM NaCl. There were two immunostaining patterns for pH dependency of HIAR. First, the majority of antibodies recovered their antigenicity when heated in the buffers with both acidic pH (pH 3.0) and basic pH (pH 9.0 and 10.5). Second, some antibodies showed strong immunostaining only at basic pH values (pH 9.0 and 10.5). When the sections were autoclaved in TB at pH 9.0, immunostaining of all eight antibodies examined decreased as the NaCl concentration increased. On the other hand, when the sections were treated with TB at pH 10.5, all antibodies yielded stronger reactions in the buffer containing NaCl than in the buffer without NaCl; five antibodies exhibited the strongest immunoreaction at concentrations from 25 to 50 mM. These results suggest that the extended polypeptides by heating are charged negatively or positively at basic or acidic pH, and that an electrostatic repulsion force acts to prevent random entangling of polypeptides caused by hydrophobic attractive force and to expose antigenic determinants, during cooling process of HIAR solution.


HortScience ◽  
2002 ◽  
Vol 37 (6) ◽  
pp. 890-893 ◽  
Author(s):  
Terence R. Bates ◽  
Richard M. Dunst ◽  
Theodore Taft ◽  
Michael Vercant

One- and 2-year-old 'Concord' (Vitis labruscana L.) grapevines were used to study the effect of soil pH on vegetative growth and nutrition. Ninety-eight, own-rooted, 'Concord' grapevines were planted in 94.6-L pots containing vineyard soil adjusted to seven soil pH levels ranging from 3.5 to 7.5. After the first growing season, seven vines from each soil pH treatment were randomly selected, destructively harvested, and measured for root and shoot growth. The remaining 49 vines over-wintered in the pots, were defruited in year two, and were destructively harvested at the end of the second growing season. There was a reduction in root biomass below soil pH of 4.5 and a greater reduction in shoot biomass leading to a higher root: shoot ratio. There were no significant differences in vegetative growth of young 'Concord' vines from a soil pH of 5.0-7.5. However, there was a trend toward lower shoot biomass and higher root: shoot ratio at the highest soil pH level. Phylloxera nodosities on roots were present in equal densities at all soil pH values. However, the negative impact of phylloxera on vine dry mass was greater on vines under nutrient stress at the highest and lowest pH treatments than on those with adequate nutrition at the mid-range soil pH values.


1992 ◽  
Vol 57 (10) ◽  
pp. 2089-2094 ◽  
Author(s):  
Ladislav Svoboda ◽  
Leona Čáňová

The effect of pH and ionic strength on the exchange capacity of sorbents based on modified bead cellulose was examined for the sorption of Pb2+ and Cd2+ ions. Ion exchange of these cations in aqueous solutions is nonselective on Ostsorb SA-5, which is cellulose containing functional groups based on H-acid. The medium acidic Ostsorb P cation exchanger with functional groups formed by the phosphoric acid fragment, on the other hand, sorbs lead, and to a lesser extent also cadmium, also at high ionic strengths of the medium even at low pH values.


1982 ◽  
Vol 47 (10) ◽  
pp. 2716-2723 ◽  
Author(s):  
Lubomíra Rexová-Benková ◽  
Jiřina Omelková ◽  
Vladimír Kubánek

Endo-D-galacturonanase of Aspergillus sp. was irreversibly adsorbed on polyethyleneterephthalate in an acetate 0.1 mol l-1 buffer solution of pH 4.2. Immobilization of the enzyme resulted in lowering of its activity, the measure of which depended on the amount of the enzyme fixed on the carrier. The highest relative activity (42.4%) had the preparation containing 5.25 mg of the enzyme per 1 g of the carrier. The velocity and intensity of the sorption of the enzyme depended on the ionic strength of the medium, whilst pH, on the other hand, was of no influence. Endo-D-galacturonanase immobilized in a 0.1 mol l-1 buffer was characteristic a) of its fixation strength in salt solutions of various ionic strength and pH, in a 3 mol l-1 guanidine solution, and also in sodium pectate and pectin solutions, b) of its high stability during a long-lasting storage at 4 °C, c) of its operational stability. The immobilization led to a partial change of the action pattern onto the high-molecular substrate, manifested in lowering the decrease of viscosity to degradation degree ratio.


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