Journal articles on the topic 'Soil pH'
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1
Aitken, RL, and PW Moody. "Interrelations between soil pH measurements in various electrolytes and soil solution pH in acidic soils." Soil Research 29, no. 4 (1991): 483. http://dx.doi.org/10.1071/sr9910483.
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Ninety soil samples (81 surface, 9 subsurface) were collected from eastern Queensland and soil pH (1:5 soi1:solution) was measured in each of deionized water (pH,), 0.01 M CaCl2, 0-002 M CaCl2 and 1 M KCl. Soil solution was extracted from each soil after incubation for 4 days at the 10 kPa matric suction moisture content, and pH (pHss) and electrical conductivity were measured. The objectives of this work were to investigate interrelationships between soil pH measurements in various electrolytes and soil solution pH in a suite of predominantly acidic soils. Although the relationships between pHw and pH measured in the other electrolytes could be described by linear regression, the fitting of quadratic equations improved the coefficients of determination, indicating the relationships were curvilinear. The majority of soils exhibited variable charge characteristics (CEC increases with soil pH) and the curvilinear trend is explained on this basis. At low pH, the difference between pH, and pH measured in an electrolyte will be small compared with the difference at higher pH values because, in general, at low pH, soils will be closer to their respective PZSE (pH at which electrolyte strength has no effect). Of the electrolytes used, pH measured in 0.002 M CaCl2 gave the closest approximation to pHs,. However, when soils with ionic strengths greater than 0.018 M were selected (predominantly cultivated surface soils), pH in 0.01 M CaCl2 gave the best approximation to pHss. For predicting pHss, the ionic strength of the electrolyte will need to be matched to that of the soils studied. For a suite of soils with a large range in soil solution ionic strength (as in this study), it is preferable to measure pHss directly.
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Hsu, Shih-Lin, Joe Hung, and Arthur Wallace. "Soil pH Variation Within a Soil. III. pH Variation in Limed Soil." Communications in Soil Science and Plant Analysis 35, no. 3-4 (December 31, 2004): 337–44. http://dx.doi.org/10.1081/css-120029716.
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Al-Busaidi, A. S., and P. Cookson. "Salinity–pH Relationships in Calcareous Soils." Journal of Agricultural and Marine Sciences [JAMS] 8, no. 1 (January 1, 2003): 41. http://dx.doi.org/10.24200/jams.vol8iss1pp41-46.
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Soil pH is the most commonly requested analysis undertaken during farm advisory work. Determination of pH assists in understanding many reactions that occur in soil. Variations in pH between soils have been related to a number of other soil parameters. In this study thirty different soils were collected from agricultural areas to have a wide range of pH, salinity, and texture. The objective was to study the relationship between soil pH and salinity. A negative relationship was found between soil salinity and pH. The main factor contributing to this relationship was probably the presence of soluble Ca2+ ion in soil. Variations in soluble Ca2+ ion concentrations between soils were negatively related to soil pH and positively related to soil salinity. Other soil properties that may affect pH, including CEC, CaCO3, clay content, gypsum and sodium adsorption ratio (SAR), were also determined.
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Brouder, S. M., B. S. Hofmann, and D. K. Morris. "Mapping Soil pH." Soil Science Society of America Journal 69, no. 2 (March 2005): 427–42. http://dx.doi.org/10.2136/sssaj2005.0427.
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Ahern, CR, MMG Weinand, and RF Isbell. "Surface soil-pH map of Queensland." Soil Research 32, no. 2 (1994): 212. http://dx.doi.org/10.1071/sr9940213.
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Surface soil pH can influence biological activity, nutrition and various chemical processes in the soil. Low pH or acidity is causing major concern in southern Australia, prompting requests for details on the extent, severity and distribution of acidic soils in Queensland. By creating a soil pH database, using an appropriate base map, rainfall isohyets and GIS technology, a coloured pH map of surface soils was produced at a 1:5000000 scale for the entire State. As most samples were from virgin or little disturbed sites, the map generally reflects naturally occurring soil pH. Developed horticultural, agricultural and fertilized pastoral areas are likely to have lower pH than that mapped. About two thirds (63.1%) of Queensland's soils have acidic surfaces, 9.5% neutral and the remaining 26.9% are alkaline. The major proportion (74%) of the > 1200 mm rainfall zone is strongly acid, and the remainder is medium acid or acid. Much of the sugar growing areas occur in this zone. Surface soil pH generally decreases as rainfall increases and to a lesser extent from subtropical to tropical climate. In addition to climate, identification of the soil type assists with predicting pH, as the organic, coarse and medium textured soils and massive earths are more likely to be acid and have low buffering capacity. Depending on the land use, such soils may require regular liming or minimizing of net acidifying practices for long term sustainability.
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Crawford, DM, TG Baker, and J. Maheswaran. "Soil pH changes under Victorian pastures." Soil Research 32, no. 1 (1994): 105. http://dx.doi.org/10.1071/sr9940105.
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The severity and extent of surface soil acidification was assessed at 107 pasture sites across Victoria. At each site, soil samples (0.20 cm depth) were taken from the pasture area and an adjacent reference (undisturbed) area for analysis of soil pH (1:5 0.01 m CaCl2 or water). Acidification was evident in the 0.10 cm depth of sites with moderately and slightly acid (pH [water] 5.5-7) reference soils, while alkalinization was evident in the 0.20 cm depth of sites with strongly acid (pH [water] <5.5) reference soils. Causes of pH changes were not clearly evident from the relationships between site factors and changes in soil. It was evident that site factors were confounded since sites that had acidified often supported subterranean clover and had slightly to moderately acid reference soils, while sites which had alkalinized often supported white clover-based pastures under higher rainfall and had more acidic reference soils. An understanding of the causes of acidification in pasture-based agricultural ecosystems will only be gained through more fundamental studies at individual sites.
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Slattery, WJ, and VF Burnett. "Changes in soil pH due to long term soil storage." Soil Research 30, no. 2 (1992): 169. http://dx.doi.org/10.1071/sr9920169.
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Soil pH measured in 0.01 M CaCl2 was found to increase by up to 0.23 of a unit due to long term (7 years) storage of dried surface soil. In comparison, pH measured in water was found to increase by up to 0.55 of a unit after the same time of storage. Soils with the highest ionic strength were found to have the largest pH change. There appeared to be no relationship between soil type and pH change due to storage of soils. We suggest that caution be exercised when re-analysing soils that have been stored for long periods, for water and CaCl2 pH.
8
Strong, D. T., P. W. G. Sale, and K. R. Helyar. "Initial soil pH affects the pH at which nitrification ceases due to self-induced acidification of microbial microsites." Soil Research 35, no. 3 (1997): 565. http://dx.doi.org/10.1071/s96055.
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The existence of microsites of low pH around active colonies of nitrifying soil bacteria has previously been suggested but has been difficult to verify. A study was undertaken to examine whether observed decreases in bulk soil pH that occur during nitrification are in accordance with the theory of acidified nitrification microsites. A red earth soil (sieved <2 mm) was retained at a pH of 5·3 or amended with KHCO3 to achieve a pH of 6·3. Ammonium [(NH4)2SO4] was added to the soils and they were incubated for 35 days. In both soils the pH dropped rapidly and severely limited further nitrification. The soil with the higher initial pH experienced limitations to nitrification at a pH which was 0·2 units higher than that of the soil with the lower initial pH. The explanation for this result is in terms of acidified nitrification microsites. It is suggested that an active nitrifying colony may lower the pH within its immediate vicinity to a critical pH at which nitrification almost ceases. This critical pH achieved at the nitrification microsite is probably unrelated to the initial pH of the soil, but the pH of the soil matrix which is distant from the immediate influence of the nitrification microsite would remain at a pH closer to that of the soil initially. This less acidified region of the soil matrix would have an overriding influence on the measured pH of the bulk soil and account for the discrepancy between the measured pH of the two soils at the end of the incubation. These data provide further evidence that acidified nitrification microsites exist in soil, and that the measured soil pH is a poor estimate of the pH experienced by the microbial biomass.
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Hiller, E., and M. Šebesta. "Effect of temperature and soil pH on the sorption of ibuprofen in agricultural soil." Soil and Water Research 12, No. 2 (April 10, 2017): 78–85. http://dx.doi.org/10.17221/6/2016-swr.
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Besides many natural factors, soil pH and temperature can have significant effects on the sorption of pharmaceuticals in soils. This is the first study, which aimed to evaluate the effect of soil pH and temperature on the sorption of ibuprofen in soil. Sorption–desorption experiments at 20°C indicated weak retention of ibuprofen in the soil. Sorption of ibuprofen in the soil was affected by both temperature and pH with the latter showing much greater effect. The extent of ibuprofen sorption increased with decreasing pH mainly due to the change of ibuprofen speciation from negatively charged ions at high pH to the neutral form at low pH. At pH 4, the distribution coefficient K<sub>d</sub> was 1.30 l/kg, whereas at pH 8, it was only 0.42 l/kg. When temperature increased, the sorption of ibuprofen decreased, showing that its sorption was exothermic.
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Heckman, J. R., G. C. Pavlis, and W. L. Anastasia. "Lime Requirement for New Jersey Blueberry-producing Soils." HortTechnology 12, no. 2 (January 2002): 220–22. http://dx.doi.org/10.21273/horttech.12.2.220.
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In New Jersey, the major soil series (Sassafras, Pocomoke, Berryland, Atsion, and Downer) used for blueberry (Vaccinium corymbosum L.) production often have soil pH levels much lower than the soil pH range of 4.0 to 5.2 that is considered satisfactory for blueberry. The lime requirements for these soils to achieve a target soil pH of 4.8 has not been established. Soils with current soil pH levels in the range of 3.3 to 3.9 were collected from eight New Jersey sites used for blueberry production. The soils were treated with various application rates of calcium carbonate (CaCO3) and incubated in a green-house to estimate the lime requirement of each soil. After 70 days of incubation with CaCO3, results show that a general lime recommendation of 100 lb of calcium carbonate equivalent (CCE)/acre (112 kg·ha-1) for each one tenth of a soil pH unit increase desired would elevate pH of each of the soils to within a range (pH 4.3 to 5.0) that brackets the target pH of 4.8 without causing serious risk of overliming.
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Brautigan, D. J., P. Rengasamy, and D. J. Chittleborough. "Amelioration of alkaline phytotoxicity by lowering soil pH." Crop and Pasture Science 65, no. 12 (2014): 1278. http://dx.doi.org/10.1071/cp13435.
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Highly alkaline soils (pH >9) may adversely affect agricultural crop productivity. At pH >9.2, aluminium (Al) phytotoxicity may further retard plant development. Most alkaline soils have little alkaline buffering capacity, making it feasible to use acid to lower soil pH to <9.2. Many methods of lowering soil pH have been trialled; however, little research has been done on their relative effectiveness and longevity. Methods trialled in this study as means of lowering soil pH were chemical additives (gypsum), organic additives (glucose, molasses, horse manure, green manure, humus) and leguminous plants. Gypsum was also used in conjunction with plants to determine any synergistic effects of combining treatments. All ameliorants trialled except humus and horse manure proved effective at lowering soil pH to <9.2. The reduction achieved with biological amendments was temporary, with pH returning to pre-amendment levels over the course of the study. Gypsum was most effective amendment for lowering soil pH and sustaining the lowered pH level. The use of plants to lower soil pH, in conjunction with gypsum to sustain the lowered pH, may be an effective and economic method of remediating Al phytotoxicity in alkaline soils.
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Wei, Hui, Jiayue Yang, Ziqiang Liu, and Jiaen Zhang. "Data Integration Analysis Indicates That Soil Texture and pH Greatly Influence the Acid Buffering Capacity of Global Surface Soils." Sustainability 14, no. 5 (March 4, 2022): 3017. http://dx.doi.org/10.3390/su14053017.
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Soil acidification is a global environmental issue that decreases soil functions, and it has been significantly accelerated by anthropogenic activities in recent decades. Soils can resist acidification upon receiving acid inputs due to the resistance or/and resilience capacity of soils, which is termed the acid buffering capacity of soils, and it is often indicated by the soil pH buffering capacity (pHBC). An increasing number of studies have been conducted to quantify soil pHBC at various sites, but to date, integration of global data is lacking; therefore, the variations in large-scale soil pHBC and the factors that influence these variations are still unclear. In this study, we collected previously published data on soil pHBC to analyze its variations on a large scale, as well as investigate the underlying factors influencing these variations. The results showed that soil pHBC varied substantially from site to site, with a mean of 51.07 ± 50.11 mmol kg−1 pH−1. Soil texture and pH, separately or collectively, explained a considerable proportion of the total variation of global soil pHBC. It is well-established that a series of processes contribute to the soil acid buffering capacity in different pH ranges, and the global data analyses showed that pH 5.5 could be a key threshold value; different buffering systems may be active at pH > 5.5 and pH < 5.5. Moreover, tropical soils were more acid-sensitive than temperate and subtropical soils, and forest soils had significantly lower soil pHBCs than grassland and cropland soils. This could be attributed in part to the different soil properties, such as soil texture or pH, among the different climatic zones and ecosystems.
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Wei, Hui, Yalan Liu, Huimin Xiang, Jiaen Zhang, Saifei Li, and Jiayue Yang. "Soil pH Responses to Simulated Acid Rain Leaching in Three Agricultural Soils." Sustainability 12, no. 1 (December 30, 2019): 280. http://dx.doi.org/10.3390/su12010280.
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Soil has the nature of acidity and alkalinity, mostly indicated by soil pH that could greatly affect soil ecological processes and functions. With exogenous inputs of acidic materials (such as acid rain), soils may more or less resist to maintain their pH levels within specific thresholds by various buffering processes. It has been well established that soil properties such as cation exchange capacity (CEC), soil organic matter (SOM), and clay content play important roles in mitigating the effects of acid inputs, but the factors varied across soils. This microcosm experiment was conducted to investigate changes in the soil pH and quantitatively estimate the critical pH threshold of simulated acid rain for three highly weathered soils (red soil, lateritic red soil, and latosol) that are typical soil types widely distributed across the world’s subtropical and tropical climatic zones, as well as important influential factors, after continuously adding different levels of simulated acid rain on the surface of soil cores. The results showed that the change in the soil pH was not significantly different among the three soils, although it was exponentially related to soil CEC and clay content. Resultantly, the latosol that had high soil CEC and clay content was more resistant to simulated acid rain, especially when relatively weak simulated acid rain treatments were applied. The lateritic red soil that contained the lowest soil CEC and clay content showed the greatest decline in the soil pH under the strongest simulated acid rain treatment of pH being 2.5. Furthermore, we estimated the critical pH threshold of simulated acid rain for the three soils and observed that it was considerably different among the soils. Surprisingly, the pH threshold of simulated acid rain was also positively related to the soil CEC and clay content, therefore making the highest pH threshold in the latosol. Our results imply that soil CEC and clay content may play critical roles in the soil acid-buffering processes from two aspects; it could not only contribute to the soil acid-buffering capacity, but also affect the threshold of acidity of acid rain below which abrupt soil acidification may occur.
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Magdoff, F. R., and R. J. Bartlett. "Soil pH Buffering Revisited." Soil Science Society of America Journal 49, no. 1 (January 1985): 145–48. http://dx.doi.org/10.2136/sssaj1985.03615995004900010029x.
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Morgan, Kelly. "Citrus Soil pH Management." EDIS 2019, no. 6 (December 10, 2019): 2. http://dx.doi.org/10.32473/edis-ss666-2020.
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Management of both soil pH and nutrients is required to maintain soil fertility levels and ensure economic agricultural production. Maintaining soil in the 6.0-6.5 pH range is best for most crops including citrus. This new two-page publication of the UF/IFAS Department of Soil and Water Sciences, written by Kelly Morgan, explains the effects of soil pH on citrus as well as options for management.https://edis.ifas.ufl.edu/ss666
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Thunjai, Taworn, Claude E. Boyd, and Karen Dube. "Poind Soil pH Measurement." Journal of the World Aquaculture Society 32, no. 2 (June 2001): 141–52. http://dx.doi.org/10.1111/j.1749-7345.2001.tb00365.x.
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Lee, S. Z., L. Chang, C. M. Chen, Y. I. Tsai, and M. C. Liu. "Predicting soil-water partition coefficients for Hg(II) from soil properties." Water Science and Technology 43, no. 2 (January 1, 2001): 187–96. http://dx.doi.org/10.2166/wst.2001.0089.
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The metal adsorption characteristics for fifteen Taiwan soils by Hg(II), were evaluated using pH as the major variable. The soil samples were thoroughly characterized for their physical chemical properties and composition, particularly organic matter and metal oxides. The adsorption of Hg(II) increased with increasing pH between pH 2.5 and 5.5, whereas the adsorption significantly decreased above around pH 5.5. Below pH 5.5, greater adsorption was found for soils with a higher organic matter content at constant pH and metal concentration. To better understand the mechanism of adsorption, the experimental results for Hg (II) were tested in a partition coefficient model to relate the adsorption of the Hg(II) by the different soils with soil components: organic matter, iron oxide, aluminium oxide and manganese oxide. This model was not successful when applied to measurements at the differing natural soil pHs because of the importance of pH. At pH greater than 5.5 the model fails because of the complexation of Hg by the dissolved organic matter. However, partition coefficients obtained from experimental data were highly correlated with those calculated for a partition coefficient between mercury and organic matter alone at lower pH. Normalization of the partition coefficients, Kd, for the organic matter content of the soils, Kom, greatly improved the correlation between the partition coefficient and pH under pH 5.5 (R2 increased from 0.484 to 0.716). This suggests that the surficial adsorption sites are principally due to organic matter for pH less than 5.5. For the 24-hour equilibration period employed, diffusion of Hg through this superficial organic matter coating to underlying sorptive materials, including metal oxides, is not important in the partitioning of Hg. At pH above 5, a decrease of mercury adsorption with increasing solution pH was also found. This result may be explained in part by the complexation of mercury by soil dissolved organic matter whose concentration increased with increasing pH.
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Neilsen, Denise, Paul B. Hoyt, Peter Parchomchuk, Gerald H. Neilsen, and Eugene J. Hogue. "Measurement of the sensitivity of orchard soils to acidification." Canadian Journal of Soil Science 75, no. 3 (August 1, 1995): 391–95. http://dx.doi.org/10.4141/cjss95-056.
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The pH buffer curves for 45 surface soils from apple (Malus domestica Borkh.) orchards in southern British Columbia were determined. Buffer curve shape differed according to the initial soil pH and incubation treatment. Soils with initial pHw < 7.4 and incubated with either H2SO4 or CaCO3 had typically sigmoid or modified sigmoid buffer curves. Non-calcareous soils with initial pHw > 7.4, incubated with H2SO4 were far less buffered above pH 6.5–7.0 than soils with initial pH < 7.4. Thus, non-calcareous neutral to alkaline soils may be more susceptible to acidification than buffer curves derived from liming acid soils might predict. A new measure of soil susceptibility to acidification, the acidification resistance index (ARI), was derived from buffer curves. It is defined as the amount of acid (cmol (p+) kg−1) required to reduce soil pH from its initial level to pH 5.0. Best-fitted multiple regression equations between ARI and soil properties routinely measured in soil test laboratories determined that 79% of the variation in ARI could be explained by a combination of extractable cations and initial soil pH. This regression model could be used to provide an inexpensive measure of soil susceptibility to acidification for orchards where acidifying fertilizers are applied through drip irrigation systems. Key words: Soil acidification, pH buffer curves, Malus domestica Borkh, drip irrigation
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Keeley, Helen C. M. "Report on the buried soil." Proceedings of the Prehistoric Society 53, S2 (1987): 32. http://dx.doi.org/10.1017/s0079497x00078713.
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Present-day soils in the Borwick area form the Carnforth Association, i.e. freely drained gravelly brown earths, some calcareous brown earths and peaty gleys and peaty soils in hollows. pH is normally 6 to 7, with some soil pH higher than 7.The buried soil beneath the cairn was a truncated stagnopodzol with a pH of 7.35. The Eag, Bf and Bs horizons were present but the lack of a topsoil and relatively high pH suggested that pollen analysis of the soil would be unproductive. Similarly, detailed soil analysis was unlikely to add to the interpretation of the site and was therefore not pursued. The development of podsolised soils on such gravels is not unusual and may indicate that the vegetation at the time the cairn was constructed was acid grassland or moorland. The soil pH would have been on the acid side at this stage, rising subsequently due to downward leaching of the calcium carbonate from the overlying limestone of the enclosure.
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Brockwell, J., A. Pilka, and RA Holliday. "Soil pH is a major determinant of the numbers of naturally occurring Rhizobium meliloti in non-cultivated soils in central New South Wales." Australian Journal of Experimental Agriculture 31, no. 2 (1991): 211. http://dx.doi.org/10.1071/ea9910211.
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Measurements were made of soil pH, frequency of occurrence of annual species of Medicago (medics) and populations of Rhizobium meliloti at 84 sites on 7 dominant soil groups of the Macquarie region of central-western New South Wales. Over all sites, soil pH (0-10 cm; 1:5 soil: water) ranged from 5.26 to 8.07, medic frequency from 0 to 100% and most probable numbers of R. meliloti from undetectable to 675 000/g soil. There was a highly significant (P<0.001) relationship between soil pH and number of R. meliloti. Above pH 7.0, the mean soil population of R. meliloti was 89000/g; below pH 6.0, it was 37/g. Medics occurred most frequently on the more alkaline soils and with least frequency on the more acid soils, but the relationship between soil pH and medic frequency was weaker than between pH and R. meliloti number. Medics were more tolerant of low soil pH than their rhizobia were; at 2 sites, of pH 5.49 and 5.35, medics occurred at 100% frequency but R. meliloti was undetected. There was an indication of some acidification in these soils over a period of 35 years but this remains to be confirmed.
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Shaw, David R., and Glen P. Murphy. "Adsorption and relative mobility of flumetsulam." Weed Science 45, no. 4 (August 1997): 573–78. http://dx.doi.org/10.1017/s0043174500088846.
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Laboratory studies were conducted to evaluate flumetsulam adsorption and mobility in seven Mississippi soils of different organic matter content, pH, and texture. Adsorption isotherms were determined for all soils using a 1:1 (soil: water) technique. In six of seven soils, Freundlichnconstants were close to unity, suggesting a partitioning-like adsorption mechanism for flumetsulam. Mobility was examined using packed soil columns.14C-flumetsulam recoveries in leachate ranged from 1 to 70% and were influenced by both organic matter content and soil pH. However, the effects of organic matter content and soil pH were not independent. Consequently, clear relationships between flumetsulam mobility and either organic matter content or soil pH were not established across all soils. However, among soils of similar pH (7.5 ± 0.3), mobility decreased linearly (R2= 0.75) as organic matter content increased from 0.7 to 3.6%. Across soils with similar organic matter content (3.9 ± 0.3%), mobility increased linearly (R2= 0.98) as soil pH increased from 5.3 to 7.2. Net adsorption constants (Kd) provided a more accurate assessment of flumetsulam mobility across all soils thanKoc.
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Zhang, Xiaolan, Xuan Shan, Hongdan Fu, and Zhouping Sun. "Effects of artificially-simulated acidification on potential soil nitrification activity and ammonia oxidizing microbial communities in greenhouse conditions." PeerJ 10 (October 3, 2022): e14088. http://dx.doi.org/10.7717/peerj.14088.
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Background Nitrification can lead to large quantities of nitrate leaching into the soil during vegetable production, which may result in soil acidification in a greenhouse system. A better understanding is needed of the nitrification process and its microbial mechanisms in soil acidification. Materials and Methods A simulated acidification experiment with an artificially manipulated pH environment (T1: pH 7.0; T2: pH 6.5; T3: pH 6.0; T4: pH 5.5; T5: pH 4.5) was conducted in potted tomatoes grown in greenhouse conditions. The abundance and community structures of ammonia oxidizers under different pH environment were analyzed using q-PCR and high-throughput sequencing methods, respectively. Results and discussions Soil acidification was accompanied by a reduction of soil organic matter (SOM), total nitrogen (TN), NH3 concentration, and enzyme activities. The abundance of ammonia-oxidizing archaea (AOA) in the soil was higher than that of ammonia-oxidizing bacteria (AOB) in soils with a pH of 6.93 to 5.33. The opposite trend was observed when soil pH was 4.21. In acidified soils, the dominant strain of AOB was Nitrosospira, while the dominant strain of AOA was Nitrososphaera. The abundance and community structure of ammonia oxidizers were mainly affected by soil pH, NH4+ content, and microbial biomass. Soil nitrification activity (PNA) has a relationship with both AOA and AOB, in which the abundance of AOA was the crucial factor affecting PNA. Conclusions PNA was co-dominated by AOA and AOB in soils with simulated acidification. Changes of soil pH, NH4+, and microbial biomass caused by acidification were the main factors for the differences in the ammonia-oxidizing microbial community in greenhouse soils. Under acidic conditions (pH < 5), the pH significantly inhibited nitrification and had a strong negative effect on the production of tomatoes in greenhouse conditions.
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Turner, Benjamin L. "Variation in pH Optima of Hydrolytic Enzyme Activities in Tropical Rain Forest Soils." Applied and Environmental Microbiology 76, no. 19 (August 13, 2010): 6485–93. http://dx.doi.org/10.1128/aem.00560-10.
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ABSTRACT Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.
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Ila'ava, Vele P., Pax Blamey, and Colin J. Asher. "Effects of lime and gypsum on growth of sweet potato in two strongly acid soils." Australian Journal of Agricultural Research 51, no. 8 (2000): 1031. http://dx.doi.org/10.1071/ar00043.
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There were strong relationships between exchangeable aluminium (Al) and relative top yield, and between soil pH and relative top yield in the Garret and Bisinella soils. Sweet potato plants produced maximum top yields at soil exchangeable Al <3.0 cmol ((+)/kg, with a 10% yield reduction coinciding with a value of approximately 5.0 cmol (+)/kg. The value was lower for the Bisinella soil than the Garret soil. In the case of pH, maximum yield in both soils was evident at a soil pH of 5.0 with 90% of maximum yield being achieved at about pH 4.7. These results suggest that soil pH would be a good index for Al toxicity. The close relationships between sweet potato growth and both exchangeable Al and soil pH need to be explored further to determine whether it will hold across a wide range of acid soil groups.
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Dong, Jing, Qi Sun, Xue Zhang, Yuan Zhou, Longchao Xia, and Jin Yuan. "Effect of Soil Washing with Ferric Chloride on Cadmium Removal and Soil Structure." Applied Sciences 11, no. 22 (November 19, 2021): 10956. http://dx.doi.org/10.3390/app112210956.
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In China, arable soils contaminated with cadmium (Cd) threaten human health. Ferric chloride (FeCl3) is a highly efficient agent that can remove Cd from contaminated soils. However, it is unknown whether FeCl3 damages the soil structure and consequently affects crop growth. In this study, we investigated the impacts of Cd extraction by FeCl3 on the structure of a paddy soil on the basis of comparisons of control (without washing agents) and hydrochloric acid (HCl) treatments. According to our results, the removal efficiency increased with the decrease in soil initial pH, as adjusted by FeCl3. However, the low pH of 2.0 caused a partial loss of soil mineral components, with an Al release of 4.4% in the FeCl3-treated soil versus 1.3% in the HCl-treated soil. In contrast, the amount of released Al was less than 0.2% in the control and in the FeCl3 treatments with initial pH values of 3.0 and 4.0. The washing agents caused soil TOC loss of 27.1%, 17.5%, and 2.76% in the pH 2.0, 3.0, and 4.0 FeCl3 treatments, compared with 15.5% in the initial pH 2.0 HCl treatment. The use of FeCl3 represents an optimum tradeoff between removal efficiency and the loss of soil components to restore Cd-polluted soils by adjusting the initial pH to 3.0 with the addition of FeCl3. Under this condition, the amount of Al loss was less than 0.2%, and the extraction efficiency reached 40.3%, compared to an efficiency of 39.7% with HCl at an initial pH of 2.0. In conclusion, FeCl3 could effectively remove Cd from contaminated soil.
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Helyar, KR, PD Cregan, and DL Godyn. "Soil acidity in New-South-Wales - Current pH values and estimates of acidification rates." Soil Research 28, no. 4 (1990): 523. http://dx.doi.org/10.1071/sr9900523.
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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.
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Li, Ying, Zhi-Yong Dong, Dong-Zi Pan, Cun-Hong Pan, and Lai-Hua Chen. "Effects of Termites on Soil pH and Its Application for Termite Control in Zhejiang Province, China." Sociobiology 64, no. 3 (October 17, 2017): 317. http://dx.doi.org/10.13102/sociobiology.v64i3.1674.
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Soil dwelling termites dig nests in the ground that have a significant impact on the soil environment. Activities of termites can result in accumulation of organic matter and enrichment of nutrients and minerals in the soil. Samples from the nest/surrounding soils of two termite species (Odontotermes formosanus (Shiraki) and Reticulitermes flaviceps (Oshima)) and termite non-invaded soils in the seawall of the Qiantang River, Zhejiang Province, China were collected and analysed for soil pH. The results show that the observed termites prefer an acidic environment and that their activities elevate the pH of termite mound soil compared with surrounding soil. Considering the differences in the distribution areas, termite species, and properties of termite mounds and surrounding soils, this paper also examines the literature concerning the effects of termites on soil pH. After summarizing the pH of the termite survival soil environment, the feasibility of termite control by modifying the soil pH is addressed. Finally, some topics for future research are discussed.
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Goetz, Andrew J., Glenn Wehtje, Robert H. Walker, and Ben Hajek. "Soil Solution and Mobility Characterization of Imazaquin." Weed Science 34, no. 5 (September 1986): 788–93. http://dx.doi.org/10.1017/s0043174500067862.
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Imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} sorption and mobility were studied in five Alabama soils ranging from sandy loam to clay. Techniques included thinlayer soil chromatography, batch equilibrium, and soil solution recovery. Imazaquin was mobile in all soils with Rfvalues of 0.8 to 0.9. Sorption based on batch equilibrium was minimal with Kdvalues ranging from 0.001 to 0.21. The soil solution recovery technique was used to evaluate imazaquin sorption in each soil as influenced by imazaquin concentration, wetting and drying, and pH. As herbicide concentration added to the soils was increased from 0.1 to 10 mg/kg, the amount of14C-imazaquin in soil solution increased. Temporarily drying each soil to 25 or 50% of field capacity resulted in maximum sorption of imazaquin. Lowering the pH enhanced sorption in all soils such that the amount of imazaquin in solution ranged from 38 (low pH) to 100% (high pH). Soil sorption appeared to be governed by the pH-dependent charge surfaces from aluminum and iron oxyhydroxides (specifically hematite and gibbsite) and kaolinite.
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Jansen, Gisela, Hans-Ulrich Jürgens, Edgar Schliephake, and Frank Ordon. "Effect of the Soil pH on the Alkaloid Content ofLupinus angustifolius." International Journal of Agronomy 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/269878.
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Field studies were conducted in growing seasons 2004, 2005, and 2010 to investigate the effect of different soil pH values on the alkaloid content in seeds ofLupinus angustifolius. Two-year experiments with eleven cultivars were carried out in acid soils with an average ofpH=5.8(Mecklenburg-Western Pomerania) and on calcareous soils with an average pH of 7.1 (Bavaria), respectively. In addition, in 2010, eight cultivars were grown in field experiments in soils with pH values varying betweenpH=5.3andpH=6.7. In all experiments conducted on soils with a higher pH (pH=6.7andpH=7.1), a significantly lower alkaloid content was detected in allLupinus angustifoliuscultivars than on soils with a lower pH (pH=5.3andpH=5.8). Results clearly show that the alkaloid content is significantly influenced by the soil pH but genotypic differences regarding the reaction to different pH values in the soil were observed.
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Li, Guohua, Haigang Li, Peter A. Leffelaar, Jianbo Shen, and Fusuo Zhang. "Dynamics of phosphorus fractions in the rhizosphere of fababean (Vicia faba L.) and maize (Zea mays L.) grown in calcareous and acid soils." Crop and Pasture Science 66, no. 11 (2015): 1151. http://dx.doi.org/10.1071/cp14370.
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The dynamics of soil phosphorus (P) fractions were investigated, in the rhizosphere of fababean (Vicia faba L.) and maize (Zea mays L.) grown in calcareous and acid soils. Plants were grown in a mini-rhizotron with a thin (3 mm) soil layer, which was in contact with the root-mat, and considered as rhizosphere soil. Hedley sequential fractionation was used to evaluate the relationship between soil pH and P dynamics in the rhizosphere of fababean and maize. Soil pH influenced the dynamics of P fractions in both calcareous and acid soils. Fababean and maize roots decreased rhizosphere pH by 0.4 and 0.2 pH units in calcareous soil, and increased rhizosphere pH by 1.2 and 0.8 pH units in acid soil, respectively, compared with the no-plant control. The acid-soluble inorganic P fraction in the rhizosphere of calcareous soil was significantly depleted by fababean, which was probably due to strong rhizosphere acidification. In contrast, maize had little effect on this fraction. Both fababean and maize significantly depleted the alkali-soluble organic P fractions in calcareous soil, but not in acid soil. Fababean and maize utilised different P fractions in soil, which was partly due to their differing abilities to modify the rhizosphere. This study has decoupled successfully the effects of chemically induced pH change from plant growth effects (such as mineralisation and P uptake) on P dynamics. The effect of soil pH on plant exudation response in P-limited soils has been demonstrated in the present study.
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DIONNE, J. L., and A. R. PESANT. "EFFETS DES REGIMES HYDRIQUES ET DES pH DU SOL SUR LA REPONSE AU MOLYBDENE DE LA LUZERNE." Canadian Journal of Soil Science 66, no. 3 (August 1, 1986): 421–35. http://dx.doi.org/10.4141/cjss86-044.
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The objectives of this study were to determine the changes in response of alfalfa (cv. Saranac) to molydbenum applications from variations in soil pH and soil moisture. To achieve these ends the test crop was grown on three replicates of the following treatments: Three soils (Ste Rosalie clay, Greensboro loam and Danby sandy loam) adjusted to approximately pH 5.0, 6.5, and 7.5 fertilized at 0.0, 0.1, 0.2 and 0.3 mg Mo kg−1 of soil and maintained at three moisture levels: dry, optimal and saturated. Yields were not affected by molybdenum applications regardless of soil type, soil pH or soil moisture regimes. Mo content of alfalfa increased linearly with rates of Mo from 0.2 ppm to 23 ppm Mo. Liming soil to pH 7.2 produced the same increase of Mo content in alfalfa as applying Mo at the rate of 0.2 mg kg−1 to acid soils. Mo content of alfalfa was also slightly increased by soil moisture. A Mo content of 20 ppm or more was obtained as a result of the combined effect of molybdenum application, liming and soil moisture regimes. The exchangeable Mo content found in soils after the experiment increased with rate of Mo but decreased with increasing soil pH. The uptake of molybdenum was increased so much by liming that the Mo left in soil after cropping was decreased as soil pH increased. Key words: Mo content of soil, Mo content of alfalfa, soil pH, soil moisture, alfalfa
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Niskanen, Raina. "Extractable aluminium, iron and manganese in mineral soils: III Comparison of extraction methods." Agricultural and Food Science 61, no. 2 (March 1, 1989): 89–97. http://dx.doi.org/10.23986/afsci.72357.
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The extractability of soil Al, Fe and Mn were studied in 102 mineral soil samples. The extractants were 0.05 M oxalate (pH 2.9), 0.05 M K4P2O7 (pH 10), 0.02 M EDTA (pH 5.3) and 1 M CH3COONH4 (pH 4.8). In the group of clay and silt soils (n = 51), the Al extracted by the four extractants correlated closely; the r values ranged from 0.91*** to 0.96***; in coarser soils (n = 51) the r values ranged from 0.42* to 0.82***. In clay and silt soils, the organic carbon content and soil pH together explained 50 % of the variation in oxalate-extractable Al, 70 % of the variation in pyrophosphate-extractable Al, 53 % of the variation in pyrophosphate-extractable Fe and 56 % of the variation in acetate-extractable Al. The clay and organic carbon contents together with soil pH explained 77 % of the variation in EDTA-extractable Al in clay and silt soils. In coarse soils, the extractable metals were not closely related to the soil characteristics.
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Hsu, Shih-Lin, Joe Hung, and Arthur Wallace. "Soil pH Variation Within a Soil. II. pH Variation in a Neutral and an Alkaline Soil." Communications in Soil Science and Plant Analysis 35, no. 3-4 (December 31, 2004): 331–36. http://dx.doi.org/10.1081/css-120029715.
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Butchee, Katy, Daryl B. Arnall, Apurba Sutradhar, Chad Godsey, Hailin Zhang, and Chad Penn. "Determining Critical Soil pH for Grain Sorghum Production." International Journal of Agronomy 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/130254.
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Grain sorghum (Sorghum bicolorL.) has become a popular rotation crop in the Great Plains. The transition from conventional tillage to no-tillage production systems has led to an increase in the need for crop rotations. Some of the soils of the Great Plains are acidic, and there is concern that grain sorghum production may be limited when grown on acidic soils. The objective of this study was to evaluate the effect of soil pH for grain sorghum production. Potassium chloride-exchangeable aluminum was also analyzed to determine grain sorghum’s sensitivity to soil aluminum (Al) concentration. The relationship between relative yield and soil pH was investigated at Lahoma, Perkins, and Haskell, Oklahoma, USA with soil pH treatments ranging from 4.0–7.0. Soil pH was altered using aluminum sulfate or hydrated lime. Soil acidity reduced grain sorghum yield, resulting in a 10% reduction in yield at soil pH 5.42. Potassium chloride-exchangeable aluminum levels above 18 mg kg−1resulted in yield reductions of 10% or greater. Liming should be considered to increase soil pH if it is below these critical levels where grain sorghum will be produced.
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DIONNE, J. L., and A. R. PESANT. "EFFETS DES DOSES DE MANGANESE, D’ALUMINIUM, DES REGIMES HYDRIQUES ET DU pH DES SOLS SUR LES RENDEMENTS DE LUZERNE ET SUR L’ASSIMILABILITE DU MANGANESE ET DE L’ALUMINIUM." Canadian Journal of Soil Science 65, no. 2 (May 1, 1985): 269–82. http://dx.doi.org/10.4141/cjss85-031.
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Alfalfa (Medicago sativa L. ’Saranac’) was grown on Ste. Rosalie clay, Greensboro loam and St. Jude sand adjusted to about pH 5.0, 6.5 and 7.5 in a greenhouse experiment, to determine the changes in response of alfalfa to aluminum and manganese resulting from variations in soil pH and soil moisture. Rates of Mn were equivalent to 0 and 200 kg∙ha−1 and rates of Al were 0, and 100 kg∙ha−1. Three soil moisture regimes were used: (1) Optimum with soil moisture between field capacity (FC) and 70% of this value. (2) Wet: with soil moisture between saturation point (SP) and FC. (3) Very wet: with soil moisture between saturation point and a value half way between SP and FC. Manganese applied on acid soils (pH 5.2) under optimum soil moisture regimes decreased alfalfa yields by 3% only, compared to a 62% decrease in alfalfa yields by Mn applied on acid soils of the two high soil moisture regimes. This was due to a high level of Mn in alfalfa on the wet acid soils. A large quantity of aluminum was also found in alfalfa grown in acid soils along with a high concentration of "extractable" aluminum. This resulted in a 54% reduction of alfalfa yields. Content of Al and Mn in alfalfa top and in soils was decreased sharply by liming soils at pH of 6.5 or 7.5. On soils limed to a pH of about 7.0 alfalfa survived at high levels of Mn and Al such as frequently encountered in some acid and very wet soils. Key words: Soil Mn, soil Al, soil pH, soil moisture, alfalfa
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Islam, A., R. E. White, and D. Chen. "Nitrification activity in acid soils of north-eastern Victoria, Australia, as affected by liming and phosphorus fertilisation." Soil Research 44, no. 8 (2006): 739. http://dx.doi.org/10.1071/sr06058.
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A short-term nitrification assay (SNA) was used to measure the activity of soil nitrifiers and their response to pH change in acid pasture soils (pH 4.8–5.3 in water) at the sites of Maindample and Ruffy in north-eastern Victoria, Australia. Changes in soil pH associated with lime applications in the field resulted in a change in the optimum pH (pHopt) of the nitrifying organisms in the range 4.93–6.94. Nitrification in these soils was predominantly autotrophic, and rates increased from 0.18 to 0.93 μg NO3–-N/g.h with increasing pH. The strong positive correlation between field soil pH and the respective pHopt values suggested that the indigenous nitrifier population had adapted to the change in soil pH. SNA measurements within 6 months of lime application to Maindample soil showed that the soil nitrifying organisms had rapidly adapted to the pH change. However, the residual effect of lime on nitrifier activity was long-lasting (up to 8 years) and may involve more than a simple effect on soil pH. Repeat application of lime further enhanced nitrification activity on an already elevated activity, but only if sufficient time was allowed (>3 years) after the earlier application. Phosphate applications to these soils did not affect the general pH response in nitrifier activity. Both soils had considerable capacity for nitrification, even at pHs much lower than the commonly accepted range for autotrophic nitrifiers.
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Wang, Yajing, Wenchao Cao, Jingheng Guo, and Minghu Zhang. "Effects of Increasing pH on Nitrous Oxide and Dinitrogen Emissions from Denitrification in Sterilized and Unsterilized Forest Soils." Forests 13, no. 10 (September 29, 2022): 1589. http://dx.doi.org/10.3390/f13101589.
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Denitrification, as an important part of the soil nitrogen cycle, is widely considered to be a major source of nitrous oxide (N2O). Both biotic and abiotic denitrification processes contribute significantly to soil N2O emission, especially under acidic conditions. Increasing soil pH was found to suppress N2O emissions from denitrification, while the underlying mechanism remains uncertain. In this study, we incubated fresh forest soil anaerobically after increasing soil pH and adding nitrate (NO3−) under both sterilized and unsterilized conditions. The dynamic changes of NO3−, nitrite (NO2−), N2O and dinitrogen (N2) were monitored continuously during the 15 days of incubation. The results showed that nitrate reduction rates increased with soil pH in both sterilized and unsterilized soils, with the former having higher rates. The obvious production and consumption of nitrite were found at pH 7.1, rather than at pH 5.5, especially in sterilized soils. In both sterilized and unsterilized soils, accumulative emission of N2O and N2O-N/(N2O+N2)-N product ratios decreased significantly with increasing pH, while N2 showed the opposite trend. In sterilized soils, N2O was the dominant end gas product, accounting for 40.88% and 29.42% of the added nitrate at pH 5.5 and 7.1, respectively. In unsterilized soils, N2 was the only final gas product at pH 7.1 (59.34% of the added nitrate), whereas N2O dominated at pH 5.5 (26.67% of the added nitrate). Our results here showed that increasing soil pH promoted the conversion of N2O to N2 under both sterilized and unsterilized conditions, and highlighted the potential importance of abiotic denitrification on N2O emission.
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Moir, J. L., and D. J. Moot. "Medium-term soil pH and exchangeable aluminium response to liming at three high country locations." Proceedings of the New Zealand Grassland Association 76 (January 1, 2014): 41–46. http://dx.doi.org/10.33584/jnzg.2014.76.2963.
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Acid soil conditions and associated aluminium (Al) toxicity pose a serious impediment to legume establishment, persistence and productivity in high country. However, data that report soil exchangeable Al concentrations in response to lime applications are scarce. Three historical (3-8-year-old) lime trial soils were sampled for soil pH and exchangeable aluminium (Al). Soil pH ranged from 4.8 to 7.5, with exchangeable Al concentrations (CaCl2 extraction) of 0.2 to 24 mg Al/ kg. Soil pH and exchangeable Al changed significantly when lime was applied, but the shape of the response differed between the three site locations. The soil pH changes (0-7.5 cm horizon) were 0.16, 0.10 and 0.20 pH units/t lime applied. Critical research needs to be conducted to investigate the key soil factors and mechanisms that result in Al toxicity in high country soils to enable development of mitigation strategies. On-farm decisions on lime rates and legume species suitability need to be based on soil pH and Al testing from individual farm blocks rather than using "rule of thumb" approaches. Keywords: soil pH, soil exchangeable aluminium, lime, pasture legumes
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Hochman, Z., DC Edmeades, and E. White. "Changes in effective cation exchange capacity and exchangeable aluminum with soil pH in lime-amended field soils." Soil Research 30, no. 2 (1992): 177. http://dx.doi.org/10.1071/sr9920177.
Full textAbstract:
Eleven acidic soils from northern N.S.W., having a wide range of values for ECEC, A1 and soil organic carbon (%C), were treated in the field with five rates of lime. The relationships between soil pH and the effective cation exchange capacity (ECEC), and between pH and exchangeable aluminium (Al), were investigated for the top 10 cm of these soils. Increases in the total exchangeable cations (TEC) calculated as ECEC-Al, were shown to be madelup almost entirely by increases in exchangeable calcium. There were no consistent changes in the amount of exchangeable magnesium, potassium or sodium due to liming these acidic soils. Formulae used to predict changes in A1 and ECEC with pH in the 'Lime-it' model were tested and modified on the 11 soils from northern N.S.W. A strong linear relationship was observed in each soil between Al and pH (transformed to hydrogen ion concentration x 103). The slope of this relationship (SALs) can be predicted from the pH and A1 values of unlimed soils. Strong linear relationships were also observed between pH and TEC, for each of the 11 soils. The SL, (the slope of the linear relationship TEC/pH for any soil 's') was shown by multiple regression analysis to be a function of TECi/pHi (where TECi is the sum of exchangeable cations of unlimed soil 's'; and pHi is the pH value of unlimed soil 's'), %C of the unlimed soil, and SALs. By using the measured values of pH, ECEC, Al and %C of unlimed soils, the values of Al, and TEB can be predicted for any pH value that may be measured (or predicted) after liming. The predictive relationships developed on N.S.W. soils were tested against independent data from New Zealand. The results confirmed the Al/pH predictions (R2 = 0.955), while the TEC/pH predictions were less well matched (R2= 0.62) possibly due to unusual clay mineralogy or organic matter fractions of 3 of the 18 soils tested.
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Mattiazzo, M. E., and N. A. da Glória. "Effect of Vinasse on Soil Acidity." Water Science and Technology 19, no. 7 (July 1, 1987): 1293–96. http://dx.doi.org/10.2166/wst.1987.0035.
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The effects of microbiological activity on soil acidity components in soils previously treated with vinasse are determined. These soil acidity components were interpreted through the measurement of pH, exchangeable aluminium and titratable acidity. The results showed that there was no rise in soil pH when microbiological activity was absent, through periodic application of methyl bromide. It was concluded that organic matter oxidation is responsible for the rise in soil pH and microbiological activity is responsible for this oxidation. Thus, microbiological activity is necessary to raise the soil pH.
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Huang, Xueru, Xia Zhu-Barker, William R. Horwath, Sarwee J. Faeflen, Hongyan Luo, Xiaoping Xin, and Xianjun Jiang. "Effect of iron oxide on nitrification in two agricultural soils with different pH." Biogeosciences 13, no. 19 (October 7, 2016): 5609–17. http://dx.doi.org/10.5194/bg-13-5609-2016.
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Abstract. Iron (Fe) affects soil nitrogen (N) cycling processes both in anoxic and oxic environments. The role of Fe in soil N transformations including nitrification, mineralization, and immobilization, is influenced by redox activity, which is regulated by soil pH. The effect of Fe minerals, particularly oxides, on soil N transformation processes depends on soil pH, with Fe oxide often stimulating nitrification activity in the soil with low pH. We conducted lab incubations to investigate the effect of Fe oxide on N transformation rates in two subtropical agricultural soils with low pH (pH 5.1) and high pH (pH 7.8). 15N-labeled ammonium and nitrate were used separately to determine N transformation rates combined with Fe oxide (ferrihydrite) addition. Iron oxide stimulated net nitrification in low-pH soil (pH 5.1), while the opposite occurred in high-pH soil (pH 7.8). Compared to the control, Fe oxide decreased microbial immobilization of inorganic N by 50 % in low-pH soil but increased it by 45 % in high-pH soil. A likely explanation for the effects at low pH is that Fe oxide increased NH3-N availability by stimulating N mineralization and inhibiting N immobilization. These results indicate that Fe oxide plays an important role in soil N transformation processes and the magnitude of the effect of Fe oxide is dependent significantly on soil pH.
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Gray, C. W., R. G. McLaren, A. H. C. Roberts, and L. M. Condron. "Sorption and desorption of cadmium from some New Zealand soils: effect of pH and contact time." Soil Research 36, no. 2 (1998): 199. http://dx.doi.org/10.1071/s97085.
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The effects of soil pH on the desorption of native soil cadmium (Cd), and on the sorption and desorption of added Cd at low concentrations, have been examined for 6 New Zealand soils ranging from pH 4·9 to 6·2. The effect of contact time with added Cd on subsequent desorption from soil has also been studied. Cadmium desorption was determined by repeated equilibrations in 0·01 М Ca(NO3)2 solution. Cadmium sorption ranged between 38% and 96% from an initial addition of 2 µg Cd/g soil. The effect of increasing soil pH was to increase substantially the amount of Cd sorbed. Sorption isotherms were all linear, with a negative intercept on the y-axis. Sorption data also fitted a linearised Freundlich sorption equation. Cadmium desorption was also very sensitive to pH, with a dramatic reduction in the amount of native Cd desorbed from the soil as pH increased, as was observed for samples where Cd was added. The cumulative amounts of native Cd desorbed represented only a relatively small proportion (0–22%) of total soil Cd concentrations. Added Cd desorption ranged between 22% and 99% of the Cd initially sorbed on the soil at varying pH. Organic matter appeared to be the most important soil component controlling both sorption and desorption in the soils studied. In the contact period experiment, the proportion of Cd desorbed was decreased by increasing initial contact time to 70 days before desorption for all 4 soils studied. Contact time had the greatest effect on Cd desorption in soils with the highest amounts of soil oxide components. Implications of the study are that, for the soils studied, soil pH, Cd contact time, and soil organic matter content are controlling factors on Cd desorption into soil solution, and are therefore likely to play an important role in Cd phytoavailability.
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Rizwan, Saman. "Effect of Titania (TiO2) Nanoparticles on the Growth of Spinach (Spinacia oleracea) Under Differing Soil Conditions." Pakistan Journal of Analytical & Environmental Chemistry 22, no. 1 (June 23, 2021): 60–73. http://dx.doi.org/10.21743/pjaec/2021.06.08.
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Nanotechnology has widely been used in a variety of fields including agriculture, since the last few decades. The aim of the present study was to assess the effect on the growth of Spinach (Spinacia oleracea) under exposure of 0, 100, 200, 250, 300, 400, 500 mg TiO2 nanoparticles (TNPs) kg-1 of soil. TNPs in anatase form with a size of 74 nm, complex and spherical in shape were synthesized. Two different soils 1) Loamy Soil and 2) Sandy Soil were used under low pH (about 6.5) and high (original) pH of the soils. The effects of TNPs were investigated on plant lengths, total fresh and dry biomass. The plants were exposed to TNPs for about 3 months. It was observed that TNPs had a generally negative impact on the length of plants grown in sandy soil (both low and original pH) and loamy soil with low pH. The measurements of samples with the original pH of loamy soil showed a positive relationship with increased TNPs concentration. Overall the dry biomass of plants grew in (both low and original pH) loamy soil and sandy soil with low pH had increased with increase in concentration of TNPs, while in sandy soil with original pH, the biomass of plants decreased with increased concentration of TNPs. Phosphorous analysis on rhizosphere soil showed correspondence with biomass results. Generally, it was observed that type of soil and pH of soil affected the growth of spinach plants under applied TNPs.
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Benke, Mônica B., Tee Boon Goh, Rigas Karamanos, Newton Z. Lupwayi, and Xiying Hao. "Retention and nitrification of injected anhydrous NH3as affected by soil pH." Canadian Journal of Soil Science 92, no. 4 (May 2012): 589–98. http://dx.doi.org/10.4141/cjss2011-108.
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Benke, M. B., Goh, T. B., Karamanos, R., Lupwayi, N. Z. and Hao, X. 2012. Retention and nitrification of injected anhydrous NH3as affected by soil pH. Can. J. Soil Sci. 92: 589–598. Anhydrous ammonia is an economical and extensively used fertilizer, yet loss after injection can reduce its agronomic efficiency. A laboratory experiment was conducted to examine how soil properties affect ammonia retention and nitrification following anhydrous NH3injection using 10 different Canadian prairie soils. Soils were also injected with atmospheric air for comparison. Following injection, soils were incubated for up to 216 h at field capacity. Among the soil properties studied [pH (1:2 water), clay, total N, and organic C contents], only pH was negatively related (R2=0.55, n=10, 24 h incubation) to percentage injected N retained by soil. The amount of N retained by soil 24 h following injection was 92±2% (mean±SEM) when pH <6, compared with 64±2% when pH>7.5. Rate of nitrification increased (P<0.001) about 48–96 h following injection and was greater in pH>7.5 than pH<6 soils. There was no difference (P>0.05) in bacterial diversity between ammonia- and air-injected soils. The slower nitrification rates suggest that potential leaching and denitrification losses in acid soils could be smaller than in alkaline soils.
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Marsh, Brian H., and Randy W. Lloyd. "Soil pH Effect on Imazaquin Persistence in Soil." Weed Technology 10, no. 2 (June 1996): 337–40. http://dx.doi.org/10.1017/s0890037x00040057.
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Field studies were conducted to determine the effect of soil pH ranging from 5.1 to 7.1 on imazaquin persistence on a Grundy silty clay loam (2.8% OM). Imazaquin residues were equivalent at pH 5.5 or higher but persisted longer at pH 5.1. Corn shoot growth was not different at any soil pH. Corn grain yields in 1993 were lower in imazaquin-treated plots than in the check plots at the lowest pH (5.1), where initial imazaquin soil concentrations were between 10 and 13 μg/kg across all pH levels. Corn grain yields were not affected by herbicide carryover in 1994 where soil imazaquin residues were well below critical levels at planting. Yields were lower where soil pH was less than 5.5.
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Whalen, Joann K., Chi Chang, and George W. Clayton. "Cattle manure and lime amendments to improve crop production of acidic soils in Northern Alberta." Canadian Journal of Soil Science 82, no. 2 (May 1, 2002): 227–38. http://dx.doi.org/10.4141/s01-030.
Full textAbstract:
Crop production on acid soils can be improved greatly by adjusting the pH to near neutrality. Although soil acidity is commonly corrected by liming, there is evidence that animal manure amendments can increase the pH of acid soils. Fresh cattle manure and agricultural lime were compared for their effects on soil acidity and the production of canola (Brassica napus L.) and wheat (Triticum aestivum L.) in a greenhouse study. Canola and wheat yield, the nutrient content of grain and straw, and selected soil properties were determined on a Gray Luvisol (pH 4.8) from the Peace Region of Alberta. Soil pH increased with lime and manure applications, and canola and wheat yields were higher in limed and manure-amended soils than unfertilized, unlimed soils. Macronutrient uptake by canola and wheat was generally improved by liming and manure applications, and micronutrient uptake was related to the effects of lime and manure on soil pH. An economic analysis compared the costs of using cattle manure and lime to increase soil pH to 6.0. The costs of applying lime and fresh cattle manure to increase soil pH were compared, based on the fees for purchasing and applying lime or loading, hauling and applying manure. The nutrient value of manure was calculated based on the quantities of plant-available N, P and K in fresh manure. At distances less than 40 km, it is economical to substitute fresh cattle manure for agricultural lime to increase soil pH of acidic soils. However, good manure management practices should be followed to minimize the risk of nutrient transport and environmental pollution from agricultural land amended with cattle manure. Key words: Agricultural economics, canola production, cattle manure, lime, soil pH, wheat prodution
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Zhang, Hao-Qing, Ren-Fang Shen, and Xue-Qiang Zhao. "Nitrogen Source Preference in Maize at Seedling Stage Is Mainly Dependent on Growth Medium pH." Agronomy 12, no. 9 (September 9, 2022): 2149. http://dx.doi.org/10.3390/agronomy12092149.
Full textAbstract:
To improve crop nitrogen recovery efficiency (NRE), plants must be supplied with their preferred form of nitrogen (N). However, whether pH affects crop N-form preference remains unclear. Here, we aimed to explore how maize (Zea mays L.) preference for NH4+ and NO3− is affected by pH and to determine the critical pH controlling this preference. Maize plants were grown with NH4+ or NO3− in different soils (pH 4.32–8.14) and nutrient solutions (pH 4.00–8.00). After harvest, plant dry weights, N content, N uptake, NRE, soil pH, and exchangeable aluminum (Al) were measured. Compared with the effect of NO3−, NH4+ decreased maize dry weight, N uptake, and NRE by 28–94% at soil pHs of 4.32 and 4.36 and a solution pH of 4.00, whereas it increased these parameters by 10–88% at soil pHs of 6.52–8.02 and solution pHs of 7.00 and 8.00. NO3− increased soil pH and decreased soil exchangeable Al content at soil pHs of 4.32–6.68. Critical soil and solution pHs for changing plant growth and N uptake preference for NH4+ vs. NO3− ranged from 5.08 to 5.40 and from 5.50 to 6.59, respectively. In conclusion, the preference of maize seedling growth and N uptake for NH4+ vs. NO3− mainly depends on the pH of the growth medium, and maize seedlings generally prefer NO3− in strongly acid soils but NH4+ in neutral to alkaline soils.
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Aitken, RL, RA Stephenson, and EC Gallagher. "Effect of lime application to strongly acidic soils on the growth of macadamia seedlings." Australian Journal of Experimental Agriculture 30, no. 3 (1990): 421. http://dx.doi.org/10.1071/ea9900421.
Full textAbstract:
Glasshouse experiments were undertaken to evaluate the effects of soil pH on macadamia (Macadamia integrifolia Maiden and Betche) seedlings and to examine seedling growth in relation to soil chemical properties in acidic soils. In one experiment, in which 13 rates of CaCO3 (0 to the equivalent of 12 000 kg/ha) were applied to a strongly acidic (pH 3.9, 1:5 in water) sandy loam, optimum seedling growth was obtained in the pH range 4.0-5.9. A second experiment, in which seedlings were grown in each of 3 strongly acidic soils amended with various rates of CaCO3, also showed that macadamia seedlings could grow satisfactorily at pH values of 4.0 (2 soils) and 4.5 (1 soil). Increased seedling growth on 2 soils (silty clay loam, experiment 1; sandy loam, experiment 2) treated with lime was due to amelioration of aluminium and/or manganese toxicity and not to the alleviation of calcium deficiency. The results indicate that soil pH measurement alone would not be a good indicator of seedling growth. In some soils, seedling growth was optimum at pH 3.9, whereas at pH 4.0 in another soil, growth was well below the maximum which was attained at pH 4.5. The significant (P<0.05) growth reductions that occurred on all soils limed to pH values >6.0 were attributed to induced micronutrient deficiencies.
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Lefroy, RDB, SSR Samosir, and GJ Blair. "The dynamics of sulfur, phosphorus and iron in flooded soils as affected by changes in Eh and pH." Soil Research 31, no. 4 (1993): 493. http://dx.doi.org/10.1071/sr9930493.
Full textAbstract:
The dynamics of Fe, P and S were studied in three soils (prairie, podzolic and krasnozem) with varying S sorption capacity (13, 32 and 132 �g S sorbed g soil-1 at 5 �g S mL-1). The soils were incubated as suspensions for 14 days at 25�C and the pH and Eh adjusted independently to four levels in the range of pH 4-8-70 and Eh from + 350 to -150 mV. In the prairie and krasnozem soils, the concentration of S in the soil solution at high pH increased as Eh was lowered to +200 mV and then decreased as Eh was lowered further. At low pH, Eh changes did not affect the concentration of S in the soil solution. The changes in the concentration of sorbed S extracted by KH2PO4 were generally similar to those for S in the soil solution. Sulfate sorption increased with a decrease in pH, with the pH effect being greater at higher Eh. At high pH and Eh, the soils released S into the solution but sulfate sorption capacity increased when Eh was lowered. At low pH, the sulfate sorption capacity of the prairie soil first increased with a lowering in Eh from +350 to about +200 mV, but then decreased with a further lowering of Eh. In the krasnozem soil, sulfate sorption capacity increased with a lowering in Eh from the highest (+350 mV) to the lowest (-150 mV) level only at the lowest pH (4.8). In the podzolic soil, the effect of pH on sulfate sorption capacity was similar at all Eh levels. The Eh effects on sulfate sorption capacity of the three soils were different.
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Baker, Scott R., Shaun A. Watmough, and M. Catherine Eimers. "Phosphorus forms and response to changes in pH in acid-sensitive soils on the Precambrian Shield." Canadian Journal of Soil Science 95, no. 2 (May 2015): 95–108. http://dx.doi.org/10.4141/cjss-2014-035.
Full textAbstract:
Baker, S. R., Watmough, S. A. and Eimers, M. C. 2015. Phosphorus forms and response to changes in pH in acid-sensitive soils on the Precambrian Shield. Can. J. Soil Sci. 95: 95–108. Soil acidification may explain declines in total phosphorus (TP) levels that have been observed in surface waters in central Ontario, Canada, but much of the research on phosphorus (P) mobility in pH manipulated soils has been performed at high P concentrations (i.e., >500 µM). This study investigated P fractionation in acidic (pH≤4.6) soils in south-central Ontario and relationships between soil pH and P sorption at relatively low P concentrations to test whether long-term declines in soil pH could have increased soil P sorption. Soils from three forested catchments that vary naturally in soil pH and outlet stream [TP] (0.1–0.4 µM in 2008) had very similar soil P concentrations and distributions (Hedley fractionation). Only hydrochloric-acid extractable P (i.e., apatite) differed amongst catchments and was greatest at the catchment with the highest stream [TP]. The fraction of P present as labile/soluble P did not decline with pH as expected and experiments indicated that P sorption at P concentrations between 4.52 and 452.1 µM was insensitive to manipulated solution pH. Soils were, however, able to sorb >90% of P added in sorption experiments at [P]≤452.1 µM. These results suggest that acidification-induced P sorption in upland soils has not contributed to observed decreases in surface water TP concentrations.