Fluid and pelletized lime are excellent sources of lime to be used under certain circumstances such as: Correction of a low soil pH condition after a crop is planted; A rapid change in soil pH if liming is delayed to just before planting a crop; For maintaining pH in the optimal range for plant growth and yield. However, these two liming materials should not be depended upon to maintain the soil pH during the full crop-growing season if applied at one-fourth of the recommended lime rate.
Lime quality is measured by how effectively it neutralizes soil acidity. This is determined largely by its chemical purity and size of particles. The purity of lime is expressed as calcium carbonate equivalent CCE. This is a measure of how much of the material can react with the soil to neutralize acidity under ideal conditions compared to pure calcium carbonate.
Limestone should have a neutralizing value of at least 90 percent. Even if the CCE of lime is satisfactory, it will not neutralize soil acidity unless the limestone is finely ground.
In an attempt to arrive at a more accurate lime rating to measure liming material effectiveness, some states' soil test laboratories have adopted effective calcium carbonate content for rating liming materials.
An efficiency rating is arrived at by multiplying the calcium carbonate equivalent times the effective calcium carbonate content, which is based on the fineness of the liming material.
The following example of the "effective neutralizing value" ENV calculation, used by the University of Illinois, serves to illustrate the importance of lime particle size in potential soil acidity neutralization. Assume that a liming material has a 96 percent calcium carbonate equivalent. After screening, the liming material is found to have the following particle size distribution:.
The total fineness efficiency factor may be calculated as follows for the example material:. These calculations enable a grower to determine the shorter- and longer-term value of the liming material being considered for purchase. Most Midwestern states use the Bray I solution for extracting P. For K, Mg and Ca, ammonium acetate is used. In regions having calcareous soils, such as the western Corn Belt and Great Plains, the Olsen test is used to extract P.
For crop rotations that include legumes like alfalfa or clovers, lime should be applied to allow enough time for reaction with the soil before the legumes are planted. Ideally, lime should be applied three to six months ahead of seeding the targeted crop.
Applications as late as just before planting, with good soil incorporation, can still be beneficial on strongly acidic soils. Some reduction in soil acidity will still occur, although maximum pH increases are not normally reached until about one year after application of typical agricultural limestone. Placement is just as important as lime quality. Maximum contact with the soil is essential for neutralization of soil acidity. Most common liming materials are only sparingly soluble in water.
For example, ammonium nitrate is about 84, times more soluble than pure calcium carbonate. Even if lime is properly mixed into the plow layer, it will have little reaction if the soil is dry. Moisture must be available for the lime-soil reaction to occur. Perhaps the best way to incorporate lime or any other material with the plow layer is to use two perpendicular passes of a combination disc, followed by a chisel plow.
Deep plowing of lime does not achieve desirable mixing in the upper 6 to 8 inches of soil. However, because the plow or a heavy breaking disc inverts the lime, it can help to distribute the lime in the upper portion of the subsoil. Choice of tillage equipment will depend on the depth at which soil acidity neutralization is most needed.
Good horizontal and vertical mixing of the lime provides the best results. In some cropping systems, like established perennial sods or established no-till crop production, mixing lime with the plow layer is not possible. Lime should be incorporated to adjust the pH in the plow layer before the establishment of these cropping systems.
Once the desired pH is reached, it can be maintained by surface applications in these no-tillage systems. Surface-applied lime reacts more slowly than lime that is mixed with the soil, and usually only affects pH in the upper 2 to 3 inches of soil.
Research at Pennsylvania State University indicated that surface applications of limestone in no-till crop production can begin to influence soil pH below the 2-inch depth after the fourth year, if lime is applied about every third year.
The more intensive the crop production, the higher the nitrogen fertilizer or manure use, and the greater the crop yields and nutrient removal , the greater and more frequent the need will be for lime.
Soil sampling is the best way to evaluate soil pH levels and the need for lime. Many soils in the semi-arid and arid regions of the United States have a naturally high pH. They may contain significant quantities of "free calcium carbonate.
In areas of the mid-South for example, some irrigation well water contains in excess of 3 to 5 milliequivalents of bicarbonate per liter and 3 to 5 milliequivalents of calcium. Sprinkler irrigation systems tend to deliver the lime in the water uniformly across the field. If "flood" or furrow irrigation systems are used, much of the lime from the water may precipitate in the upper regions of fields nearest the water delivery inlets and in the water flow path. In effect, the soil is limed by the irrigation water.
If the water distribution and delivery are the same over several years, the soil may become alkaline, with soil pH levels rising to 7. Soil pH increases may approach 0.
Such soil pH increase will occur more rapidly on coarse and medium-textured soils than on clays, which are more highly buffered. If the well water contains significantly more sodium compared to calcium or magnesium, there may be a risk of sodium buildup on soils that do not readily leach.
This is more often a greater concern in arid regions than in humid regions. Soils with naturally high sodium levels, or those that have received large quantities of sodium bicarbonate through irrigation, may have pH levels as great as 8.
Theoretically, if sodium is not a factor, even if large quantities of calcium or magnesium carbonate are applied, the soil pH will not exceed 8. At pH 8. Irrigation water quality should also be periodically monitored. Elemental sulfur may be used to acidify alkaline soil to the desirable pH range.
It may also be used to maintain pH in the desirable range, on soils that tend to become alkaline with management. Slot blot technique was applied to assess the whole allergenicity of pollen collected from the different racemes, using commercial certified pollen of A.
Soluble protein extracts were prepared according to Aina et al. Equal volumes of these extracts, containing an identical amount of proteins, were bound to nitrocellulose membrane and first stained with Ponceau S staining solution [0. Membranes were then used to evaluate the immunoreactivity of the different pollen extracts to a pool of sera from ragweed allergic patients, previously selected Asero et al.
Image analysis was applied to quantify reactivity signals. At least three different samples for each racemes were analyzed. The final ratio of germinated seeds between each pH was compared using analysis of variance ANOVA test, followed by post-hoc Tukey multiple comparison test.
We used the FlexParamCurve v. This package provides tools that facilitate fitting parametric curves in nonlinear modes, which is computationally efficient and allows the estimation of parameters of biological significance even on relatively small datasets Oswald et al. In detail, the four-parameter generalized logistic curve is described by the equation.
Where y is the estimated value at time t, A is the asymptote of the growth trajectory, k is the rate at which the slope of the curve changes with time, i is the inflection point, corresponding to the time at which the growth is fastest, and m is the shape parameter of the generalized logistic curve.
We used the nlme procedure in the nlme package Bates, to fit nonlinear mixed modes NLMMs for investigating whether values of the A, k, i , and m parameters of the curve were affected by soil pH. NLMMs allow for a large flexibility in the parameterization of both the fixed and the random part of the model, but this flexibility also makes it hard to assess the optimal structure of the model. Following a similar procedure described in Sicurella et al.
These preliminary analyses were run by first interpolating logistic curves to data of each plant separately and noting the estimated value of individual parameters. Then, we used ANOVA models, corrected for inhomogeneity of variance whenever necessary, to test for variation in each parameter according to pH. When these analyses revealed significant variation, the effect of pH was maintained in the final NLMM, while it was excluded otherwise.
For instance, ANOVA models showed that parameters A, k and i from individual plant height model significantly varied among pH levels, while m parameter did not.
We also plotted the range of parameters from curves fitted to individual plants and, in the NLMMs, allowed for random variation in those parameters which, at a visual inspection, showed large heterogeneity see also Sicurella et al. Finally, we controlled for heteroscedasticity by assuming a variation of the variance with time according to an exponential function, as suggested in Oswald et al. Differences in plant dry weight, number of inflorescences, inflorescence size including only plants that did produce inflorescences , and time to pollen emission between plants grown at different pH were tested in ANOVA models, generalized linear models assuming a Poisson distribution and corrected for overdispersion, linear mixed models and parametric survival regression models assuming a negative exponential distribution Kleinbaum and Klein, Plant dry weight was entered as a covariate in all the other models.
Plant identity was included as a random grouping factor in the mixed model of inflorescence size to account for repeated measures taken on the same plant. This model was also corrected for heteroscedasticity by assuming that variance increased exponentially with plant dry weight.
Time to pollen emission was considered an interval censored variable Kleinbaum and Klein, as pollen production was evaluated only during periodic visits. Intervals where therefore considered right censored, but not left censored Kleinbaum and Klein, Analyses where run in R 3. Under the simulated conditions significant differences in the germination percentage were observed between the tested pH values.
These values of pH were retained for further analyses regarding the growth rate of plant traits and allergenicity. Figure 1. We collected 11 measures for 15 plants. One plant, grown at pH7, lost leaves before the last measure, thus we could not measure lateral spread, leaf length and width, but we measured height because the plant was still alive. Sample size is therefore measures for plant height and measures for the other parameters.
Final NLMM of common ragweed height indicated that at pH7 plants were shorter than those grown at pH5 and pH6 as suggested by the significant difference in A parameters of the generalized logistic curves Table 1. In addition, plants grew faster at pH5 than at pH6 and pH7 as indicated by the difference in k parameters of the growth curves. Overall, growth trajectory of plants grown at pH5 and pH6 were similar, while that of plants grown at pH7 differed Figure 2A. Figure 2.
Generalized logistic growth curves of vegetative traits [plant height A , lateral spread B , leaf length C and leaf width D ] of A. Common ragweed plants grown at different pH showed similar final lateral spread and final size of leaves, as suggested by the fact that A parameter did not differ among pH levels in all models.
However, leaf development was slower at pH7, as indicated by the fact that i parameter, indicating when curves reach the inflection point, was larger for plants grown at pH7 than at lower pH in all models Table 1 , Figures 2B—D. At pH6, however, plant leaves seemed to grow more quickly than at pH5, as indicated by a significantly lower value of i parameters of models of leaf length and width Table 1.
In contrast, no significant difference was observed in i values of the model of lateral spread Table 1. Leaves seem also to increase in size at different rates at different pH, as suggested by the significant interaction between k parameter and pH. However, post-hoc tests could not identify any significant pairwise difference in these parameters after Bonferroni correction Table 1. Overall, growth curves showed that common ragweed canopies grew at similar rate at pH5 and pH6.
Table 1 , Figure 1B , but more slowly at pH7. Figure 3. No significant differences were detected among the treatments. Figure 4. Means number of inflorescences and inflorescence size of A.
At pH7 the plants did not produce any inflorescences. Pollen from plants grown at pH 5 and 6 was assessed by slot blot technique in order to preserve protein conformation, on which IgE binding may depend. Identical amount of proteins from pollen extracts were bound on a nitrocellulose membrane and subjected to immunoreaction with a sera mix from selected ragweed allergic patients.
The Figure 5A shows a representative membrane after immunodetection. At least three protein extracts from each plant were analyzed and the mean results of five independent experiments were calculated and statistically elaborated Figure 5B.
Figure 5. A Representative slot blot membrane probed with a pool of selected patient sera showing the total allergenicity of pollen samples collected from plants grown in soils at pH5 and pH6. Pollen proteins obtained from single plants by independent extractions were loaded. S Standard protein extract from commercial pollen, Allergon ; B Mean total allergenicity of pollen collected from plants grown at pH5 and pH6.
On average, all the pollen samples collected from plants grown at pH5 showed a statistically higher IgE-binding signal, ranging from 1. This study demonstrates for the first time that growth and reproductive performances of the IAP A.
Specifically, results confirm that A. On the contrary, the total pollen allergenicity was lower at pH6 than pH5, the only two pH values at which plants produced flowers and then pollen. Since, there is a number of important environmental factors that may control the distribution of common ragweed i.
Despite this, we would point out that: a soil pH is known to control the uptake of macro- and micronutrients N, Mg, and so on from soil so it is a quite important factor to be monitored, especially for invasive plants; b we used natural soil for growing plants and measuring the pH; this choice made experimental conditions more close to those of field conditions and then the subsequent results useful for future field experiments regarding the species' control; c we observed in a crop field as specified in the introduction that the amendment of soil using calcium hydroxide highly reduced the species growth.
The method we used in our test to modify the original reaction condition of soil, which implies the addition of calcium hydroxide to increase pH value, can have changed the original quantity of calcium. Thus, calcium could act as confounding factor in understanding the effect of pH on plants.
Although calcium is not a major nutrient, it plays a key role in many physiological processes such as the stabilization of cell wall structures, the function of a major secondary-messenger molecule in plants under different developmental cues, the participation in mechanisms of water and nutrient uptake, etc. White and Broadley, As a consequence, the addition of calcium hydroxide were intended to reproduce conditions similar to field ones in which calcium is generally the most representative cation in soil exchange complex and to simulate the actual system regulating pH values.
The germination rate of A. These results are in accordance with those of Sang et al. In general, among the intermediate values of pH tested in this study for the subsequent analyses growth curve and reproductive investment , plants grown at pH5 and pH6 performed better than those grown at pH7.
With regard to vegetative traits, the shortest height as well as the slowest growth rate for all vegetative traits were recorded at pH7. This results are in disagreement with those of an old work of Turner reporting that A.
Tessmer et al. Nevertheless, in our results although A. Physiological mechanisms of adaptation of plants to non-optimal soil pH are well-known in literature. This behavior is consistent with observations we made in our study, since the pH of soil conspicuously decreased over time at all the pH values monitored data not shown.
However, observing the whole dataset of vegetative plant traits, plants grown at pH7 exhibited the lowest absolute value of biomass even if not significantly different from pH5 and pH6 , in addition to the lowest values of plant height and velocity of growth in addition to the lack of male inflorescences. Likely a trend, not captured by our data, indicating less vigor of the species at pH7 can be invoked and should be taken into account. In any case, these results should be carefully evaluated considering some confounding factors relating to the soil ecosystem: a soil pH is known to influence the availability and uptake of a micronutrient like Mg that is implicated in the plant's photosynthetic efficiency Dighton and Krumins, For instance, at high pH, Ca, and Mg tend to form less or not available compounds when reacting with P and many micronutrients Barber, ; b complex interactions between biotic i.
Key elements of soil useful for plants growth are nitrogen N , potassium K and phosphorous P that different plants species can preferentially absorb according to pH.
Since A. However, Leskovsek et al. With regards to reproductive investments, at pH6 and pH5 A. This behavior of the plants at pH7 could also be due to the effect of an excess of calcium hydroxide after the manipulation of the natural soil we used in our experiment. With regards to time to pollen emission it significantly decreased with plant dry weight shorter at pH5 than pH6 , as expected.
The influence of pH on the reproductive investment has been already observed for other species no literature information were found for A. For instance, in a work on the effect of different pH values from 4. Plants growing in too acid or too calcareous i. Consequently, a non-optimal soil pH condition for a plant can affect its growth and reproductive performances, as we have observed in this study for A.
In any case, also reproductive investment in response to different pH ranges is species-specific as a result of evolutionary history and adaptation ability to environment of each species Ware, ; Zeng and Clark, ; Offord et al.
In this work, the soil pH at which a plant was grown affected common ragweed pollen allergenicity, which, in our experimental condition, was lowest at pH6. Unfortunately, no specific studies on the effects of soil pH on pollen allergenicity were performed to date.
For instance, Ghiani et al. Climate change was indicated to affect pollen allergenicity determined by a higher concentration of the Amb a 1 allergen in pollen of plants exposed to higher temperatures and drought El Kelish et al. Cloutier-Hurteau et al. They found positive relationships between the concentration of some trace elements Cd Ni and Pb in pollens and in soil or roots. Unfortunately, they did not measure the allergenicity of those pollen grains; moreover they did not find any relation of the trace elements concentration in pollen grain with soil pH probably due to the limited pH range of the investigated soils 7.
In our experiment, we can suppose that the addition of calcium hydroxide to soil in order to increase pH from 5 to 6 interfered with pollen allergenicity.
Indeed, we noticed a higher amount of flavonoids in pollen extracts from plant grown at pH6 probably produced to face the presence of calcium. This higher amount of secondary metabolites likely affected the IgE binding explaining the lower allergenicity detected for pH 6 pollen. Despite the fact that our results in controlled conditions indicate better performances of A. In contrast, other authors found that the presence of A. However, it should be noted that in such studies the vegetative vigor and the reproductive performances of the plant in the growth sites were not reported.
The inconsistency of field studies on pH preference of weeds has been related to the covariation of pH range with climatic gradients annual rainfall and temperature; Pinke et al. In our study, a neutral soil, obtained after the addition of calcium hydroxide to a natural acid soil, inhibited the emission of flowers besides the plant height during the observation period.
This result supports field observations by Italian farmers working on croplands highly invaded by A. In the management of IAPs, manipulating the soil attributes is one of the strategies to achieve a successful control, especially in agricultural environments. Particularly, nutrient and soil nitrogen management, highly dependent on soil pH values, or the addition of activate carbon have been used to achieve desired soil properties, and thus plant communities resistant to invasion Kulmatiski and Beard, ; Vasquez et al.
Although we acknowledge the limitations of only testing the effects of soil pH in controlled conditions, our study suggests that further in-field research on the effects of liming on the growth and performances of A. Species-specific approaches, may be implemented by applying soil liming methods that may have management problems and high costs also tested in combination with other restoration methods such as N management, plowing, herbicide application, etc.
In fact, it is surprising that the effect of invasive plants on soil pH has been investigated in numerous circumstances Ehrenfeld, , but not the opposite. Interesting findings of our experimental study are that: a in not optimal pH conditions pH7 in our study A.
These factors should be considered and may have possible implications during the evaluation of health risk linked to pollinosis. RG and SaCi conceived and designed the experiments. CM and SaCa conducted laboratory analyses. RG and RA analyzed the data and wrote results.
RG and SaCi wrote the manuscript Introduction and Discussion ; all authors provided editorial advice and revised manuscript.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Abbasi, H. Check the soil pH annually especially if you use wood ashes.
Avoid using large amounts of wood ashes because excessively high pH values and subsequent nutrient deficiencies may result. Coal ashes do not have any lime value and may actually be acidic dependent on the source. Many ornamental plants and some fruit plants such as blueberries require slightly to strongly acid soil. These species develop iron chlorosis when grown in soils in the alkaline range. Iron chlorosis is often confused with nitrogen deficiency because the symptoms a definite yellowing of the leaves are similar.
Iron chlorosis can be corrected by reducing the soil pH value. Two materials commonly used for lowering the soil pH are aluminum sulfate and sulfur. These can be found at a garden supply center. Aluminum sulfate will change the soil pH instantly because the aluminum produces the acidity as soon as it dissolves in the soil. Sulfur, however, requires some time for the conversion to sulfuric acid with the aid of soil bacteria. The conversion rate of the sulfur is dependent on the fineness of the sulfur, the amount of soil moisture, soil temperature and the presence of the bacteria.
Depending on these factors, the conversion rate of sulfur may be very slow and take several months if the conditions are not ideal. For this reason, most people use the aluminum sulfate.
Both materials should be worked into the soil after application to be most effective. If these materials are in contact with plant leaves as when applied to a lawn, they should be washed off the leaves immediately after application or a damaging leaf burn may result. Take extreme care not to over-apply the aluminum sulfate or the sulfur. You can use the following tables to calculate the application rates for both the aluminum sulfate and the sulfur. The rates are in pounds per 10 square feet for a loamy soil.
Reduce the rate by one-third for sandy soils and increase by one-half for clays. This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named.
All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies.
Follow all directions, precautions and restrictions that are listed. Join our mailing list to receive the latest updates from HGIC. More Information » Close message window. Factors Affecting Soil pH The pH value of a soil is influenced by the kinds of parent materials from which the soil was formed. Increasing the Soil pH To make soils less acidic, the common practice is to apply a material that contains some form of lime.
Decreasing the Soil pH Many ornamental plants and some fruit plants such as blueberries require slightly to strongly acid soil.
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