Soil acidity in New-South-Wales - Current pH values and estimates of acidification rates

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 523 ◽  
Author(s):  
KR Helyar ◽  
PD Cregan ◽  
DL Godyn
Keyword(s):  
Soil Ph ◽  
Buffer Capacity ◽  
Sandy Loam ◽  
Low Ph ◽  
Ph Values ◽  
Acid Addition ◽  
South Wales ◽  
Addition Rate ◽  
The Mean ◽  
Ph Buffer

An estimate has been made of the mean pH of the surface soils (0-10 or 0-15 cm) of New South Wales by mapping the soil pH (1:2, soil: 0.01 M CaCl2) values of soil samples analysed by the NSW Agriculture & Fisheries soil testing service. Within mapped classes the soil pH values vary around the mean by about 20.4 units for low pH soils (3.8-5.0) to about 20.9 units for high pH soils (>6.0). It is estimated that the areas of surface soils within agricultural holdings in NSW in the pH classes <4.5, 4.51-5 0, 5.01-5 5 and 5.5 1-6.0, are 5 3, 8.4, 5 7 and 5.1 million ha respectively. In general, pH values in the higher rainfall coastal and tablelands areas in the east are below 5.0, with the most acid areas being below 4.25. The latter are usually in the high rainfall zones (>1000 mm) and on low pH buffer capacity soils (sand to sandy loam texture). In the south of the state the area of low pH soils is broader, and extends into lower rainfall zones. Within the mapped pH classes the higher pH buffer capacity clay soils had pH values 0.83 (s.e. 0.6) units higher than the mean, whilst sands and sandy loams had pH values 0.34 (s.e. 0.1) units lower than the mean. Data on the acid addition rates for a number of agricultural systems in NSW and adjacent areas were collated and show net rates of acid addition to the soil profile from near zero to rates of 3-5 kmoles H+ ha-l year-1 over extensive areas. High acid addition rates, of 10-20 kmoles H+ ha-1 year-1, have been measured in some exploitative systems. These acid addition rate values can be used in association with soil pH buffer capacity data to estimate the rate of pH change in the future. At an acid addition rate of 4 kmol H+ ha-1 year-1, the soil pH can decline by one unit, in the surface 30 cm within 30 years for sandy loam soils, and within 120 years for clay soils.

Response of Weeds to Soil pH

Weed Science ◽  
1975 ◽  
Vol 23 (6) ◽  
pp. 473-477 ◽  
Author(s):  
G. A. Buchanan ◽  
C. S. Hoveland ◽  
M. C. Harris
Keyword(s):  
Soil Ph ◽  
Sandy Loam ◽  
Plantago Lanceolata ◽  
Warm Season ◽  
Amaranthus Retroflexus ◽  
Low Ph ◽  
Sandy Loam Soil ◽  
Weed Species ◽  
Stellaria Media ◽  
Loam Soil

Ten warm-season and six cool-season weed species were grown in the glasshouse on Hartsells fine sandy loam soil and Lucedale sandy loam soil at pH levels from 4.7 to 6.3. Growth of species varied widely in response to soil pH as measured by herbage yield. Showy crotalaria (Crotalaria spectabilis Roth), coffee senna (Cassia occidentalis L.), and large crabgrass (Digitaria sanguinalis (L.) Scop.] were highly tolerant to low pH soils. Sicklepod (Cassia obtusifolia L.), annual bluegrass (Poa annua L.), Carolina geranium (Geranium carolinianum L.), and buckhorn plantain (Plantago lanceolata L.), were medium to high in tolerance. Jimsonweed (Datura stramonium L.), tall morningglory [Ipomoea purpurea (L.) Roth], crowfootgrass [Dactyloctenium aegyptium (L.) Richter], and prickly sida (Sida spinosa L.) were medium to low in tolerance to low soil pH. Growth of Florida beggarweed [Desmodium tortuosum (Sw.) DC], redroot pigweed (Amaranthus retroflexus L.), chickweed [Stellaria media (L.) Cyrillo], common dandelion (Taraxacum officinale (Weber), and wild mustard [Brassica kaber (DC.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler] was severely reduced in soils with low pH.

The effect of valence and Ionic-strength on the measurement of pH buffer capacity

Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 975 ◽  
Author(s):  
RL Aitken ◽  
PW Moody
Keyword(s):  
Ionic Strength ◽  
Titration Curve ◽  
Buffer Capacity ◽  
Experimental Conditions ◽  
Linear Portion ◽  
Titration Curves ◽  
Addition Rate ◽  
Ph Buffer ◽  
Buffer Capacities ◽  
Linear Regressions

Although the measurement of pH buffer capacity (pHBC) is used to determine lime requirement and acid addition rate in acidification studies, the experimental conditions under which pHBC is determined have not been studied. The effect of valence and ionic strength on the measurement of pHBC was investigated on a range of soils. The effect of the monovalent or divalent accompanying ion was examined by establishing separate titration curves for each of 100 soils by adding incremental amounts of either Ca(OH)2, NaOH, HCl or H2SO4 to soil suspended (1 : 5) in water. Linear regressions were fitted to the linear portion of each titration curve and the slopes of these lines were used as a measure of pHBC. For each soil, the pH buffer capacities were statistically compared. The pHBC determined with Ca(OH)2 was significantly (P = 0.05) greater than that determined with NaOH in 92 soils and, on average (all soils), was 2.2 times the pHBC in NaOH. The effect of ionic strength on pHBC was investigated in each of 20 soils by titrating with HCI in water and suspensions at nominal ionic strengths of 0.006, 0.03 and 0.3 m. In all soils there was a trend for increasing pHBC with increasing ionic strength (I) and, for I < 0.03 m, there was a marked increase in pHBC with increasing I. The results are discussed in relation to the effect of valence and ionic strength on pH buffer capacity mechanisms, and the implications with respect to calculating acidification rates and lime requirements.

scholarly journals Carbon dioxide and pH affect sperm motility of white sturgeon(Acipenser transmontanus)

2002 ◽  
Vol 205 (18) ◽  
pp. 2885-2890 ◽  
Author(s):  
R. L. Ingermann ◽  
M. Holcomb ◽  
M. L. Robinson ◽  
J. G. Cloud
Keyword(s):  
Sperm Motility ◽  
Marked Decrease ◽  
Time Frame ◽  
Low Ph ◽  
Buffering Capacity ◽  
White Sturgeon ◽  
Physiological Adaptation ◽  
Ph Values ◽  
Partial Pressures ◽  
Ph Buffer

SUMMARYMaintenance of sperm at pH values less than approximately 7.5 inhibited the onset of motility when sperm were subsequently diluted with water; maintenance at pH values above approximately 8.2 was associated with maximal motility upon dilution with water. Within 5∼min of exposure to low pH buffer (pH 6.9),there was a 50% decline in sperm motility upon dilution with water suggesting that exposure to low pH interferes with motility within a time frame that may affect fertilization. In most instances, maintenance of sperm under CO2 at a pressure of 4-5 kPa almost completely blocked their capacity for motility. Furthermore, exposing semen to increasing partial pressures of CO2 up to about 1 kPa resulted in a marked decrease in semen pH. These observations are consistent with the findings that the buffering capacity of semen is particularly low at physiological pH, and that this low buffering capacity corresponds to the highest pH sensitivity of the capacity for sperm motility. The low seminal buffering capacity may represent a physiological adaptation in the control of sperm function. It may also represent a vulnerability to environmental hypercapnia or metabolic acidosis.

Copper and zinc species in the soil solution and the effects of soil pH

Soil Research ◽  
1983 ◽  
Vol 21 (4) ◽  
pp. 479 ◽  
Author(s):  
JJ Jeffery ◽  
NC Uren
Keyword(s):  
Soil Solution ◽  
Soil Ph ◽  
Sandy Loam ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Metal Species ◽  
Ph Values ◽  
Chelex 100 ◽  
Copper And Zinc ◽  
Free Metal

A scheme to distinguish various species of trace metals in the soil solution has been used to study the forms of copper and zinc in the soil solution of a sandy loam that had been limed to give a range of soil pH values. The scheme is based on the lability of the metal species and involves the use of anodic stripping voltammetry, atomic absorption spectroscopy, and equilibration with Chelex-100 exchange resin. The solubility of zinc in this soil decreased markedly with increasing soil pH, with most of the zinc being present as free metal ions or as labile complexes. In contrast, copper species were largely moderately labile and non-labile and the solubility of copper varied only slightly with soil pH. The effects of enriching the soil with the metals and organic matter on the species present were also investigated.

Soil properties in and around acid sulfate soil scalds in the coastal floodplains of New South Wales, Australia

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 595 ◽  
Author(s):  
Mark A. Rosicky ◽  
Leigh A. Sullivan ◽  
Peter G. Slavich ◽  
Mike Hughes
Keyword(s):  
Sulfur Content ◽  
Surface Soil ◽  
New South ◽  
New South Wales ◽  
Low Ph ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Soil Layers ◽  
Ph Values ◽  
South Wales

Soil profiles in 10 persistently bare areas (i.e. scalds), mainly located in coastal backswamps of New South Wales, Australia, were examined for chromium-reducible sulfur content and selected chemical properties. At 5 of the sites, the adjacent paddocks with vegetation cover were also examined. All of the tested sites had been affected by the extensive drainage of the surrounding acid sulfate soil (ASS) landscapes and the consequent oxidation of pyrite. All sites had low pH values in the surface soil layers and these low pH values extended for up to 150 cm into the underlying unoxidised blue/grey pyritic estuarine gels. This can be attributed to the downward diffusion of acidity, either produced in the overlying oxidised zones of these soils or transported laterally across the landscape to these low-lying areas. Acidified unoxidised pyritic zones 120 cm thick can evidently form within several decades after drainage disturbance. At the scalded sites the depth from the soil surface to the main pyritic zone varied from the surface to >200 cm depth, indicating that this variable is not critical to ASS scald formation. For most of the sites examined, the chromium-reducible sulfur contents in the surface soil layers were appreciably higher than those in the immediately underlying soil layers. In most of the vegetated sites the chromium-reducible sulfur content in the surface layers was considerably higher than for the adjacent scalded site. The conditions necessary for pyrite formation (i.e. adequate supplies of organic matter, soluble iron, sulfate, and waterlogging) were found to exist at all sites, and the pyrite accumulations in these surface soil layers are considered to be neo-formed. The vegetated soil-profile pyrite and pH results were very similar to their scalded counterparts except that they had an extra 20–40 cm layer of vegetation and mulch that was missing from the scalded profiles. This indicates that there is considerable potential for more extensive scalding in these ASS areas.

scholarly journals On the determination of soil pH

1965 ◽  
Vol 37 (1) ◽  
pp. 51-60
Author(s):  
Ritva Ryti
Keyword(s):  
Soil Ph ◽  
Salt Content ◽  
Soil Samples ◽  
Liquid Ratio ◽  
Ph Values ◽  
Water Suspensions ◽  
The Mean ◽  
The Difference ◽  
Soil Groups

In the present paper the routine determination of soil pH in the laboratory was studied using a material of 15 soil samples of various kind and in addition, two larger soil groups, consisting of 80 and 406 samples respectively. In comparing the pH values determined in water and in 0.01 M CaCl2 suspensions, the latter proved to be almost independent of the soil/liquid ratio between 1: 2.5 and 1: 10, that markedly affected the pHH2O values. The change with time from the pH values measured after the first hour showed less variation in CaCl2 suspensions than in water suspensions; the constancy observed in pHCaCl2 values indicating that a relatively short equilibration period of 1—2 hours would be sufficient. To sum up these results, the use of 0.01 M CaCl2 would mean easy and accurate measurements well suited to mass pH determinations. A linear relationship and a highly significant positive correlation was found between pHH2O and pHCaCl2 values in a material of 406 soil samples. The difference between the two values, which largely depends on the soils’ own salt content, ranged from 0 to 1.1 pH units, with the mean difference of 0.49. Therefore, the suggested use of a constant correction factor to bring the pHCaCl2 values to the level of the pH measured in water, is not recommendable. The main advantage of using 0.01 M CaCl2 would be the concealing of differences in salt content of a soil. The use of pHCaCl2 values would also offer new ways for getting more information about a soil’s exchange capacities, as it provides the center point for TERÄSVUORI’s (13) soil curve.

Differential tolerance of genotypes of Medicago truncatula to low pH

1992 ◽  
Vol 43 (3) ◽  
pp. 731 ◽  
Author(s):  
M Bounejmate ◽  
AD Robson
Keyword(s):  
Medicago Truncatula ◽  
Soil Ph ◽  
Acid Soils ◽  
Acid Tolerance ◽  
Dry Weight ◽  
Low Ph ◽  
Commercial Cultivar ◽  
Ph Values ◽  
Shoot Dry Weight

Growth and nodulation of five Moroccan ecotypes of Medicago truncatula Gaertn. Collected from soils of different pH, Medicago truncatula cv. Cyprus and Medicago murex Willd. cv. Zodiac, were compared in soil and solution at different pH values. The seven genotypes tested varied greatly in their ability to grow and nodulate on acid soils. Increasing soil pH from 4.5 to 5.4 increased the shoot dry weight of Cyprus and three M. truncatula ecotypes but not Zodiac and two M. truncatula ecotypes. Cultivar Cyprus, with a shoot dry weight at pH 4.5 only 58% of that at pH 5.4, was the most affected by acidity. Nodulation was the most sensitive step as nodule numbers decreased with increasing acidity for sensitive genotypes. Several genotypes were more able to nodulate at low pH than the commercial cultivar Cyprus. Acid tolerance was not restricted to genotypes occurring naturally in acid soils.

A study of inoculation and sowing methods for Trifolium subterraneum in New South Wales

1973 ◽  
Vol 13 (62) ◽  
pp. 284 ◽  
Author(s):  
RJ Roughley ◽  
MH Walker
Keyword(s):  
Soil Ph ◽  
New South ◽  
New South Wales ◽  
Previous History ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Positive Effects ◽  
Ph Values ◽  
South Wales ◽  
History Of

The effects of treatments known to influence the nodulation of subterranean clover (Trifolium subterraneum) were tested at 32 sites in New South Wales. The influence of the treatments varied but where positive effects were obtained the results generally corroborated earlier findings. At soil pH values below 5.5, lime pelleting was generally superior to slurry inoculation without lime but still better nodulation resulted from drilling inoculated seed with equal parts of lime and superphosphate. The results highlighted the difficulty of predicting the need to inoculate seed to achieve effective nodulation. The soil texture and pH, presence of the host plant and the previous history of the site were not reliable guides. Nodulation was generally improved by separating seed and superphosphate and by drilling seed rather than broadcasting it even if covered later.

EFFECTS OF pH AND NITRIFIER POPULATION ON NITRIFICATION OF BAND-APPLIED AND HOMOGENEOUSLY MIXED UREA NITROGEN IN SOILS

1975 ◽  
Vol 55 (1) ◽  
pp. 15-21 ◽  
Author(s):  
P. C. PANG ◽  
C. M. CHO ◽  
R. A. HEDLIN
Keyword(s):  
Soil Ph ◽  
Sandy Loam ◽  
Silty Clay ◽  
Clay Loam ◽  
Nitrate Accumulation ◽  
Soil Suspension ◽  
Soil Nitrification ◽  
Ph Values ◽  
Effects Of Ph ◽  
The Difference

Two soils, Keld silty clay loam (pH 5.4) and Wellwood clay loam (pH 6.6), were used to investigate the effects of modifying soil pH upon the nitrification of band-applied urea at 20 C. The pH of the Keld soil was adjusted to 6.5 and 7.3 with Ca (OH)2, whereas the Wellwood soil was adjusted to 5.6 with H2SO4. In addition, nitrification of nitrogen in a homogeneously mixed soil–urea suspension at 20 C was studied using the two soils mentioned and also Morton very fine sandy loam (pH 8.2). There were marked differences in the rate of oxidation of NH4 between the natural Keld and acidified Wellwood soils at comparable soil pH values. The oxidation was found to be very slow in the Keld soil at all pH values and no appreciable nitrite was formed. In the Wellwood soil, nitrification was more rapid and was accompanied by nitrite formation. However, the rate of oxidation was temporarily retarded by decreasing the pH of the Wellwood soil, but the oxidation of band-applied urea in the Keld soil remained unchanged with modified pH of 6.5 and 7.3. Increase in nitrification and nitrate accumulation occurred when the limed Keld soils (pH 7.3) was inoculated with Nitrosomonas europaea. Soil suspension studies confirmed that the difference in nitrifying capacity among the soils was related to the initial nitrifier numbers whose activities were affected by the initial soil pH.

The effect of pH, liming, moisture and temperature on the activity of nitrifiers in a soil under pasture

Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 711 ◽  
Author(s):  
RGV Bramley ◽  
RE White
Keyword(s):  
Moisture Content ◽  
Soil Temperature ◽  
Soil Ph ◽  
Marked Change ◽  
Quadratic Equation ◽  
Ph Optimum ◽  
Ph Values ◽  
Significant Relationships ◽  
The Mean ◽  
The Relationship

A short-term nitrification assay (SNA) was used to measure the activity of soil nitrifiers in the field in relation to soil pH and seasonal changes in soil temperature and moisture content. At roughly two-monthly intervals over two successive years, samples of the Tokomaru Silt Loam which had been limed in 1982 and/or 1987 were analysed in addition to an unlimed control. The SNA analysis was carried out for a range of pH values between 4.5 and 7.5, obtained by amending the incubation medium with small amounts of HCl or KOH. A quadratic curve was fitted to a plot of SNA value v, incubation pH. The fitted equations were used to calculate the pH optimum for nitrification (pHopt), the SNA value at pHopt (SNAopt) and the SNA value at the soil pH at sampling (SNApH). Values of pHopt and the mean soil pH over the year were higher in soil limed in 1982 than control soil; neither variable showed marked change in either soil over the first 320 days of observation. The addition of lime in 1987 raised the mean soil pH and pHopt in unlimed soil, but had negligible effect on either variable in soil limed five years previously. A covariance-type analysis demonstrated that the same quadratic equation could be fitted to each plot of SNA v. incubation pH for each soil treatment by changing the intercept parameter (C), i.e. the relationship between nitrifier activity and pH in the four soils remained constant over the year. No significant relationships could be found for the four soils between soil pH, pHopt, SNA, soil moisture content, soil temperature and C. However, the slight fluctuation in pHopt tended to follow the variation in soil pH. Values of SNAopt and SNApH showed a more obvious seasonal trend and showed a 1 : 1 relationship over a range of values from 0.015 to 0.110 �mol g-1 h-l; i.e. the nitrifier activity in the soil, irrespective of variations that were random (unknown influences) or associated with seasonal variables (temperature and moisture), was near the optimum with respect to pH. Nitrification activity is dynamic and changes quickly in response to changes in the soil environment. The implications of this with respect to nitrate leaching models include the likelihood that it may not be possible to produce a definitive model which works for all soil types.

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