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The acidic soils of western Newfoundland require liming for successful production of most crops. Locally sourced paper mill waste wood ash (WA) and paper sludge (SL) have potential as cheaper alternatives to limestone (LIME). Two greenhouse experiments evaluated WA and SL as liming and soil conditioning amendments for annual ryegrass (Lolium multiflorum) production. At 55 days after seeding, soil pH in WA (6.2 and 6.3) and wood ash and paper sludge (WASL) (6.0 and 6.3) were not different from that in LIME (6.0 and 6.5) for Experiments 1 and 2, respectively. However, pH in SL was 0.4 and 0.3 points lower than in LIME. Compared to LIME, WA, SL, and WASL produced 31%–52% and 57%–74% greater biomass yield in Experiments 1 and 2, respectively. N uptake was greater in WA (60 and 129 kg N ha−1) and WASL (51 and 97 kg N ha−1) compared to LIME (40 and 85 kg N ha−1), in Experiments 1 and 2, respectively. SL did not differ from LIME in Experiment 1, but reduced N uptake by 57% in Experiment 2. The results show significant potential of WA as an alternative amendment for liming and yield improvement of annual ryegrass grown in NL podzolic soils. However, SL has limited potential due to the risk of increasing N immobilization and residual soil mineral N when growing conditions are limiting. Combining SL with WA or biochar seemed to alleviate these risks. Overall, the adoption of these amendments for field production systems warrants serious consideration, following supplemental field studies to determine optimal application rates and timing. Core Ideas: The podzolic soils of Newfoundland have low pH and fertility, hence require liming.Locally sourced wastes, such as paper mill wood ash (WA) and sludge (SL), could be used as liming and nutrient sources.WA was equivalent to limestone (LIME) in improving and sustaining optimal soil pH.WA produced 52% and 74% greater annual ryegrass yield than conventional LIME application in podzolic soils. [ABSTRACT FROM AUTHOR]

Background: Liming agricultural land is essential to optimise crop yield and soil nutrients. Despite the importance of pH management in agricultural soils, liming applications have been decreasing in the United Kingdom for decades. There is no comparison of contemporary and historical liming requirement (LR) methods for Northern European, temperate climate mineral soils high in organic matter (OM). Aims: The aims of this research were to thoroughly comparatively analyse current methodologies and to ascertain which soil characteristics contribute to LR reactions. Methods: Analysis compared methods for determining liming values common in the United Kingdom (Scottish Agricultural College [SAC] look‐up chart, RothLime model), Europe and the United States (Shoemaker–McLean–Pratt, Sikora, Modified Mehlich buffers), and the 30‐min calcium hydroxide titration developed by the University of Georgia. Results: RothLime and SAC highly underestimated the LR value in acidic soils. The buffers highly over or underestimated LRs. The UGA titration method is a cheap, easy and accurate method which could be utilised for high OM soils but requires further calculation development. The characteristics most associated with soil–lime reactions in this experiment were measures of exchangeability (cation exchange capacity and loss on ignition, and by proxy, lime buffering capacity). Conclusions: There is an opportunity to create buffer calculators and titration equations adapted to high OM soils. These are suggested for further development, through a larger diversity of UK soil types grouped by buffering capacity ranges. Including soil exchangeability factors in lime management calculations may contribute to more accurate values and therefore better resource management. Increasing LR accuracy for site‐specific soil pH management, used in precision agriculture technologies, is a necessary tool for the conservation of natural resources like limestone, managing resource use efficiency, and for optimising yields. [ABSTRACT FROM AUTHOR]

Ureolytic microbes are abundant in broiler litter (BL), and previous research indicates that microbially induced calcium carbonate precipitation via urea hydrolysis occurs in gypsum‐amended litters. Given that calcium carbonate (CaCO3) is used to correct soil acidity, we hypothesized that the soil‐liming potential of BL + gypsum is greater than that of unamended litter. First, an experiment was conducted to isolate ureolytic bacteria from BL and confirm their ability to precipitate CaCO3. To determine the effects of calcium on urea hydrolysis, six isolates were identified from screenings of 30 colonies collected from different BL sources. Calcium increased the ureolytic rate by 29%–160% and the precipitation of CaCO3 by ~1500% in solution. The 16S rRNA of the isolate with the greatest rate of urea hydrolysis was sequenced and belong to Lysinibacillus macroides. Broiler litter amended with gypsum was inoculated with L. macroides and found to precipitate significantly more CaCO3 than inoculated litter without gypsum. Finally, over the course of a 28‐day incubation, the pH and inorganic‐N of soil, soil + BL, and soil + BL + gypsum were measured. Surprisingly, soil + BL + gypsum was found to have a significantly lower pH than soil + BL for the first 21 days. We propose that the decreased liming ability of BL + gypsum is due to a combination of pH buffering mechanisms and increased nitrification. Although gypsum is a useful litter amendment, it cannot be used to increase the liming ability of litter, despite the fact that gypsum‐amended litter has more CaCO3. Core Ideas: Calcium ions increase the rate of urea hydrolysis by poultry litter‐derived ureolytic isolates.Inoculating gypsum‐amended litter with ureolytic bacteria increases the CaCO3 and NH4+ content of litter.The soil liming potential of gypsum‐amended litter is not greater than the liming potential of unamended litter, even though treated litter contains more CaCO3. [ABSTRACT FROM AUTHOR]

The use of acid soil‐tolerant annual legume pasture species and liming to raise soil pH can have legacy effects that improve subsequent wheat crop growth in acid soils. We established a two‐year experiment in a semi‐arid environment with and without historical lime application to investigate how acid soils (±lime) influence the legacy effects of annual legume pastures. We measured legume and cereal growth and yield, soil‐borne disease incidence, rhizosheath organic acid type and amount, legume biological nitrogen fixation (BNF) and soil moisture in Year 1, and soil microbial biomass carbon (MBC) and wheat yield and quality in Year 2. Minor differences in soil moisture and soil‐borne diseases occurred between cereals and legumes, and the poor BNF contribution of all pasture legumes improved in lime treatments. Pasture legumes produced more organic acids than cereals, which increased in limed treatments. Soil MBC in Year 2 was greater following legumes than cereals. Year 2 wheat grain yield increased following pasture legumes, more so in limed treatments. The contribution of organic acid exudation by annual legume pastures to microbial community legacy effects warrants further scrutiny in semi‐arid environments, particularly when acid soils limit typical rotational benefits. [ABSTRACT FROM AUTHOR]

The effects of biochar on karstic lime soil physicochemical properties, soil microbial community diversity and plant physiology are poorly understood. To clarify these effects of biochar application, we applied biochar on the soil surface of Sichuan pepper (Zanthoxylum schinifolium) stands. One year later, leaf gas exchange and chemicals as well as soil physicochemical properties and microbial community composition were assessed. Biochar significantly increased photosynthesis, stomatal conductance, transpiration rate and total nitrogen and phosphorus in leaves, but it did not significantly affect total chlorophyll content and malondialdehyde. Total nitrogen and phosphorus as well as available phosphorus and potassium in the soil were significantly increased by biochar. However, soil pH, water content, bulk density, abundance of soil microbes (actinomycetes, bacteria, fungi and Gram negative and positive bacteria), and soil microbial community structure did not exhibit significant increases. Soil total phosphorus, available nitrogen, available phosphorus and available potassium positively correlated with the abundance of soil bacteria, fungi and actinomycetes. These results indicate that biochar enhanced main plant nutrients and improved gas exchange of pepper plants and physicochemical properties of karstic lime soil. [ABSTRACT FROM AUTHOR]

Soil liming to lower cadmium (Cd) bioavailability is challenged in perennial cacao orchards by the low penetration of lime in soils, not reaching deeper roots. Some studies suggest that gypsum (CaSO4) could reduce Cd uptake by enhanced Ca2+:Cd2+ competition at the root surface. A pot experiment was conducted to identify soil conditions affecting gypsum efficacy in cacao plantlets (5‐month‐old CCN‐51). Plants grew for 115 days in soils sampled from six locations with variable cation exchange capacity (CEC, 6–50 cmolc.kg−1) and soil solution Ca2+ (1.3–17 mM). Soils were either mixed or not mixed with a dose equivalent to 4.0 Mg gypsum ha−1. Leaf Cd concentration in plants grown on gypsum applied soils was statistically lower compared to unamended soils in only one of the six soils. The reduction factor of leaf Cd concentrations due to gypsum (RF = control/amended Cd concentration ratio) ranged from 2.32 (high effect) to 0.76 (no effect), and it was positively correlated with the Ca2+ in the solution of the unamended soil (R2 = 0.58) and with increasing CEC (R2 = 0.52), that is, gypsum only reduced Cd bioavailability in high CEC soils, confirming a trend found in earlier publications. Soil solution analyses showed that gypsum application enhanced total dissolved Cd by forming CdSO40 complexes with, in some cases, even enhanced Cd2+ ion activities, likely related to Ca2+‐induced Cd2+ mobilisation. Data suggest that Ca2+ derived from gypsum has counteracting effects on Cd mobilisation and ion competition at the root surface. The former reactions are less pronounced in high CEC soils. More research is needed to unravel gypsum effects on high Ca2+ soils to corroborate our findings. Highlights: The effect of soil properties on the efficacy of gypsum to reduce Cd uptake in cacao was studied.Gypsum only reduced Cd uptake in cacao in the soil sample with highest CEC and highest Ca in solution.This finding implies a possible competition between Ca2+ and Cd2+ for root uptake in cacao. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pH adjustment of acidic red soils with lime materials is beneficial for the reduction of phosphorus (P) fixation. However, the reasons for varying levels of P activation after adding different lime materials have not been fully investigated. Therefore, this study examined changes in soil labile P and P forms after phosphate application to calcium carbonate (CaCO3) and dolomite amended red soil during a 120‐day incubation period. Also change of P sorption properties in the amended soil samples from day 120 were examined through a sorption–desorption experiment. RESULTS: The increase of soil H2O‐P and NaHCO3‐P in the CaCO3 and dolomite amended soil treatments was mainly ascribed to the decline of the NaOH‐P. However, when compared with the control treatment after 120 days, soil Olsen‐P significantly increased by 34% and 66% in the CaCO3 and dolomite treatments. The Hedley P fractionation results demonstrated that the CaCO3 application caused a notable increase of HCl‐P (stable Ca–P), which was 88.4% higher than that in the dolomite treatment. However, the formation of stable P was strongly suppressed in the dolomite treatment due to the presence of magnesium (Mg), which was identified by the negative relationship between M3‐Mg and HCl‐P. In line with these findings, P sorption–desorption work showed weaker P binding energy in the dolomite treatment relative to the CaCO3 treatment. CONCLUSION: In terms of increasing P availability in red soil, this study suggests that dolomite should be used to substitute CaCO3 in order to reduce the soil P fixation. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Soil acidity causes an increase in the solubility of toxic aluminium (Al), inhibiting root growth and limiting plant access to soil water and nutrients. Toxicity of Al decreases growth and development more in Al-sensitive than Al-resistant wheat (Triticum aestivum L.) genotypes. Applying magnesium (Mg) may alleviate Al toxicity in acidic soil. It is unclear if growing Al-resistant wheat, coupled with Mg application, will enhance wheat growth and physiological responses in acidic soil. Wheat was grown in the reconstituted acidic soil profile in a three-factor glasshouse experiment comprising foliar Mg at [Mg] = 0 and 200 mg L-1 (using magnesium sulfate), wheat genotypes ES8 (Al sensitive) and ET8 (Al resistant), and four soil treatments [nonamended soil (pH0.1 M CaCl2 4.0); 100% of the recommended lime dose in subsoil to raise pH to 6.0; or 20 mg Mg kg-1 soil to the whole soil profile (as magnesium sulfate or magnesium chloride)]. RESULTS: Applying foliar Mg to Al-resistant wheat significantly increased shoot dry weight (24%), subsoil root dry weight (12%), subsoil coarse (>0.2 mm in diameter) root length (12%), net photosynthetic rate (28%), and total leaf area (10%) compared with plants not treated with foliar Mg. Combining foliar Mg application with subsoil liming increased the subsoil total root length by 1.3-fold compared with zero foliar Mg. Without foliar Mg, subsoil liming and soil Mg amendment significantly (by 10%) enhanced shoot growth and total leaf area compared with non-amended soil. CONCLUSION: Growing an Al-resistant genotype coupled with applying Mg foliarly and to soil improved wheat growth in an acidic soil. [ABSTRACT FROM AUTHOR]

Globally, about 50% of all arable soils are classified as acidic. As crop and plant growth are significantly hampered under acidic soil conditions, many farmers, but increasingly as well forest managers, apply lime to raise the soil pH. Besides its direct effect on soil pH, liming also affects soil C and nutrient cycles and associated greenhouse gas (GHG) fluxes. In this meta‐analysis, we reviewed 1570 observations reported in 121 field‐based studies worldwide, to assess liming effects on soil GHG fluxes and plant productivity. We found that liming significantly increases crop yield by 36.3%. Also, soil organic C (SOC) stocks were found to increase by 4.51% annually, though soil respiration is stimulated too (7.57%). Moreover, liming was found to reduce soil N2O emission by 21.3%, yield‐scaled N2O emission by 21.5%, and CH4 emission and yield‐scaled CH4 emission from rice paddies by 19.0% and 12.4%, respectively. Assuming that all acid agricultural soils are limed periodically, liming results in a total GHG balance benefit of 633−749 Tg CO2‐eq year−1 due to reductions in soil N2O emissions (0.60−0.67 Tg N2O‐N year−1) and paddy soil CH4 emissions (1.75−2.21 Tg CH4 year−1) and increases in SOC stocks (65.7–110 Tg C year−1). However, this comes at the cost of an additional CO2 release (c. 624–656 Tg CO2 year−1) deriving from lime mining, transport and application, and lime dissolution, so that the overall GHG balance is likely neutral. Nevertheless, liming of acid agricultural soils will increase yields by at least 6.64 × 108 Mg year−1, covering the food supply of 876 million people. Overall, our study shows for the first time that a general strategy of liming of acid agricultural soils is likely to result in an increasing sustainability of global agricultural production, indicating the potential benefit of liming acid soils for climate change mitigation and food security. [ABSTRACT FROM AUTHOR]

Lime is a common amendment to overcome soil acidity in agricultural production systems. However, plant root effects on lime and soil carbon (C) dynamics in acidic soils under varied temperature remain largely unknown. We monitored root effects of soybean on the fate of lime applied to an acidic soil at 20 and 30°C in growth chambers. Soil respired CO2 was continuously trapped in columns without and with plants until the final stage of vegetative growth. Lime‐derived CO2 was separated from total respired CO2 based on δ13C measurements in CO2. Leaching was induced at early and late vegetative growth stages, and the leachates were analysed for dissolved organic (DOC) and inorganic C (DIC) concentrations. Soil respiration significantly increased with lime addition at both temperatures (p < 0.001). The presence of soybean doubled the recovery of lime‐derived CO2‐C at 20°C at the early growth stage; however, by the end of the experiment, the contribution of lime‐derived CO2‐C to soil respiration was negligible in all treatments, indicating that the contribution of lime to soil respiration was shortlived. In contrast, DIC and DOC concentrations in leachates remained elevated with liming and were greater in the presence of soybean. We observed no main temperature effects and no interactive effects of temperature and soybean presence on lime‐derived CO2‐C, DIC and DOC. These results highlight the role of plant‐modulated processes in CO2 release and C leaching from lime in acidic soils, whereas an increase in temperature may be less important. Temperature and plant roots alter the rate of key processes controlling C dynamics in a limed acidic soil. Lime‐derived CO2‐C, DIC and DOC increased more in the presence of plants than with increased temperature. Root effects are more important than temperature for inorganic and organic carbon dynamics in limed acidic soils. [ABSTRACT FROM AUTHOR]

Mid‐infrared spectroscopy (MIRS) has proven to be a cost‐effective, high throughput measurement technique for soil analysis. After multivariate calibration mid‐infrared spectra can be used to predict various soil properties, some of which are related to lime requirement (LR). The objective of this study was to test the performance of MIRS for recommending variable rate liming on typical Central European soils in view of precision agriculture applications. In Germany, LR of arable topsoils is commonly derived from the parameters organic matter content (SOM), clay content, and soil pH (CaCl2) as recommended by the Association of German Agricultural Analytical and Research Institutes (VDLUFA). We analysed a total of 458 samples from six locations across Germany, which all revealed large within‐field soil heterogeneity. Calcareous topsoils were observed at some positions of three locations (79 samples). To exclude such samples from LR determination, peak height at 2513 cm−1 of the MIR spectrum was used for identification. Spectra‐based identification was accurate for carbonate contents > 0.5%. Subsequent LR derivation (LRSPP) from MIRS‐PLSR predictions of SOM, clay, and pH (CaCl2) for non‐calcareous soil samples using the VDLUFA look‐up tables was successful for all locations (R2 = 0.54–0.82; RMSE = 857–1414 kg CaO ha−1). Alternatively, we tested direct LR prediction (LRDP) by MIRS‐PLSR and also achieved satisfactory performance (R2 = 0.52–0.77; RMSE = 811–1420 kg CaO ha−1; RPD = 1.44–2.08). Further improvement was achieved by refining the VDLUFA tables towards a stepless algorithm. It can be concluded that MIRS provides a promising approach for precise LR estimation on heterogeneous arable fields. Large sample numbers can be processed with low effort which is an essential prerequisite for variable rate liming in precision agriculture. [ABSTRACT FROM AUTHOR]

Sugar maple (Acer saccharum Marsh.) decline disease, decreased growth, and regeneration failure have been related to a low supply of Ca and Mg. There is increased interest in augmenting cation availability via liming, but there is little information on the amounts of lime required and the longevity of the lime treatment. A single application of 22.4 Mg ha-1 of dolomitic limestone in 1985 at four forested sites in Potter County, PA has shown that soil, soil water, and sugar maple foliage chemistry are significantly altered by liming and the changes in soils and foliage persist as long as 21-yr post-treatment. By 2001, only 3 kg ha-1 of lime remained undissolved while increases in exchangeable Ca and Mg, and pH continued through 2006 at depths up to 35 to 45 cm. Exchangeable Mn and Al concentrations were significantly reduced by lime application, though effects were slower to develop at deeper depths. Soil solution chemistry from 1996 was highly variable but reflected the changed soil nutrients. On limed plots, sugar maple foliage had elevated concentrations of Ca and Mg in 2006 samples, indicating the persistence of the lime treatment. Comparison of Ca/Al ratios in soil solution, soils, and foliage show inconsistencies from previous published risk thresholds. Species-specific thresholds of Ca and Mg availability in soil and foliage have better potential management application and should be more rigorously tested as stress indicators. [ABSTRACT FROM AUTHOR]

Physiological constraints from harsh environmental conditions, such as from calcium limitation on acidic soils, is expected not only to affect species richness, but also species abundance distributions. Also, the effects of amendments by calcium addition (soil liming) on these assemblage characteristics are poorly understood. Because of their sensitivity towards calcium availability, we use snails as model organisms and integrate field surveys and literature data. Temperate forest snail data supported a rule-of-thumb calibration with pH measurements in water being one unit higher than in KCl buffer. The resulting large data set suggests stepwise changes in snail richness that occur at transitions in soil buffer systems, especially at pH 3.2. Species abundance distributions follow the logseries model in most soil buffer systems, except for the iron buffer range (pH ≤3.2) where they swap to the geometric model. Our findings thus suggest several smaller soil pH thresholds for snail assemblages associated with shifts between soil buffer systems, and a tipping point at the threshold to pH ≤3.2. Liming with ground carbonate rocks is a technique to temporarily increase soil pH and calcium availability in forest soils, but its effects on snail assemblages produced inconsistent results that did not meet expectations from the ameliorated soil pH and might warrant a re-evaluation of liming applications. [ABSTRACT FROM AUTHOR]

Agricultural liming materials are used to lower soil acidity and to improve microbial functionality and plant growth. A brownish colored agricultural lime was found to contain up to 180 mg kg-1 Cu, an amount well above any fertilizing materials code threshold. The dark color of the milled material was due to ample black and brown dendrites consisting of the tectomanganate mineral romanechite (ideally (Ba,H2O)2(Mn4+,Mn3+)5O10) and a mixture of the two nanocrystalline Fe oxides ferrihydrite and goethite. A four-step sequential extraction analysis of the lime powder was not sufficient to argue whether the Cu load was contained in the carbonate matrix or in the oxide dendrites, or, in the latter case, in which of the three oxide phases identified. Electron microprobe analysis confirmed that the manganate dendrites were responsible for elevated Cu concentrations in the limestone. Focused micro-x-ray absorption spectroscopy (μ-XAS) revealed the bonding environment of Cu in the romanechite dendrites to be octahedrally coordinated as the Jahn-Teller cation Cu2+ bound into lattice sites of the tectomanganate phase. The Mn-Cu, Cu-Mn, and Cu-Cu shell distances indicated a substitution of the Mn3+ tectomanganate tunnel edge sites by the Cu2+ cations. This structural intercalation of Cu is clearly more stable than Cu cations bound as surface adsorbate complexes. The Cu contained in the liming material is therefore not likely to be mobilized and bioavailable, and therefore the lime poses little threat to agricultural soils. [ABSTRACT FROM AUTHOR]

The effect of surface liming on herbage production in permanent grasslands is rather uncertain. To better understand the effect of liming on the grassland, a study was made with a field experiment and a pot experiment with soil from the same field. In the field, the effects of liming and NPK fertilization on the production and composition of the vegetation were studied. In pots, the effects of liming and phosphate fertilization on different grass species were analysed. The effect of NPK fertilization (+3·96 t ha−1) on the production of the original grassland was greater than that of liming (+0·68 t ha−1), which was only observed ( P < 0·05) on the unfertilized plots. Liming increased the total number of species and the proportion of dicotyledons. After replacing the semi-natural community with Dactylis glomerata L., the effects of liming (+2·37 t ha−1) and fertilization (+6·52 t ha−1) were increased. These results, together with those of the pot trial, show the important role of phosphorus in the fertilization effect, and are interpreted as a protective effect of P against aluminium toxicity. [ABSTRACT FROM AUTHOR]

Aluminum toxicity is one of the major soil factors limiting root growth in acidic soils. Because of the increase in organic matter content in the upper few centimeters of soils under no-till systems (NTS), most Al in soil solution may be complexed to dissolved organic C (DOC), thus decreasing its bioavailability. The aim of this study was to evaluate the effects of surface liming on Al speciation in soil solution in Brazilian sites under NTS. Field experiments were performed in two regions with contrasting climates and levels of soil acidity: Rondonopolis, Mato Grosso State, on a Ithodic Haplustox, and Ponta Grossa, Paraná State, on a Typic Hapludox. The treatments consisted of a control and three lime rates, surface applied to raise the base saturation to 50, 70, and 90%. Soil solution was obtained at soil water equilibrium (1:1 w/w soil/water ratio). The effects of surface liming on soil chemical attributes and on the composition of the soil solution were dependent on weather conditions, time under NTS, and soil weathering. Most Al in soil solution was complexed to DOG, representing about 70 to 80% of the total Al at pH <5.0, and about 30 to 40% at pH >5.0. Under pH 5.5, the results were closely correlated with the solubility line for amorphous Al. Organic complexes may control Al3+ release into soil solution at pH <5.5. Results suggest that in areas under NTS for a long period of time, Al toxicity might decrease due to its complexation to high-molecular-weight organic compounds. [ABSTRACT FROM AUTHOR]

More and more agricultural land in the Netherlands is becoming available for ecological restoration projects. However, nutrient levels in the top layer of the soils are high because the agricultural lands have been heavily fertilized for decades. As drainage ditches are no longer maintained when agricultural use ends, the agricultural lands usually become much wetter. As a result, former agricultural soils tend to develop extensive monotonous stands of Juncus effusus, which have little value from an ecological point of view. In this article, we present the results of field measurements/observations and experiments to examine the relationship between nutrient availability and J. effusus growth. In addition, we present and discuss results of experiments to study the potential beneficial effects of liming. Our findings show that the growth of J. effusus on moist or wet soils seems to be strongly determined by the Olsen-P concentration in the soil. The restoration of diverse, species-rich vegetation types on former agricultural lands with a noncalcareous sandy soil will in most cases not be possible within a reasonable time span without topsoil removal. Liming might be a valuable additional measure to enhance the quality of the soil after topsoil removal, and to prevent mobilization of P to groundwater or surface water. If removal of the topsoil is considered to create P limitation, it is important to study P concentrations at various depths to establish the amount of soil that has to be removed. [ABSTRACT FROM AUTHOR]

Accurately estimating lime requirements (LR) of acidic soils has been a concern since liming practices began. The objectives of this study were to: (i) determine if the Shoemaker-McLean-Pratt (SMP) buffer is accurately predicting the LR of Kansas soils, (ii) calibrate the SMP and Mehlich buffers to accurately estimate the LR of Kansas soils to specific target pH values, and (iii) compare the effectiveness of 60-d incubations vs. field-observed lime response in determining LR. Kansas soils were used to evaluate the current LR according to the SMP buffer and calibrate SMP and Mehlich methods. Slope values (SMP LR vs. 60-d LR) <1 andy intercepts >0 indicated that the SMP either overestimated the LR at low values or underestimated the LR at relatively high LR values compared with 60-d incubations with CaCO3. Calibration of the Mehlich buffer to a target pH of 6.8 provided a better fit than the SMP buffer but the opposite was true at target pHs of 5.5 and 6.0. Titration with 0.022 MCa(OH)2 resulted in a LR (target pH 6.8) 55% less than that measured by the 60-d incubation. Evaluation of the SMP buffer, Mehlich buffer, and Ca(OH)2 titration method on 12 soils indicated that the LR estimated by the Mehlich buffer was not significantly different than the LR from the 60-d incubation. Comparison of the LR from 60-d incubations with field-observed lime response showed that the actual LR in the field was greater than that predicted by the 60-d incubation, which warrants further investigation. [ABSTRACT FROM AUTHOR]

The potential effect of acidification of contaminated sandy soils on Cd transport in the unsaturated zone was assessed. Forty-eight soil profiles were sampled at five depths in a polluted field that was set aside in 1992. The Cd concentration in the top 30 cm of this field was, on average, 10 mg kg−1. A column experiment was carried out with one of the topsoil samples. Homogeneously packed columns were leached with 0.001m CaCl2, adjusted to pH 3 or pH 5.7, at a pore water velocity of 6 cm day−1. The Cd and proton transport was predicted with coupled transport equations. The Cd transport was modelled by assuming local equilibrium and by using sorption parameters derived from batch experiments, while acidification was modelled with a kinetic approach, on the assumption that proton buffering was due to cation exchange and mineral weathering. Organic matter was the main contributor to the cation exchange capacity of these soils. Observed and predicted pH and Cd profiles in the columns agreed well. With the same model, the proton and Cd transport at field scale was calculated for each of the 48 profiles sampled (‘grid model’). It was predicted that the field-averaged Cd concentration in the seepage water will increase from 6 μg litre−1 at present to 200 μg litre−1 over 260 years, which greatly exceeds the maximum permissible concentration (MPC) in groundwater of 5 μg litre−1. Predictions of Cd transport using field-averaged soil properties yielded a later breakthrough time and a larger peak Cd concentration than predicted with the grid model, which illustrates the impact of spatial variability on solute transport. Continuation of liming practices is a possible solution to prevent breakthrough of Cd at concentrations far in excess of the MPC. [ABSTRACT FROM AUTHOR]

The influences of thinning (50% of standing density) and liming (Ca+Mg, 2 Mg ha−1) on soil chemical properties were investigated for 2 years (2001, 2002) in 40-year-old pitch pine ( Pinus rigida Mill.) and 44-year-old Japanese larch ( Larix leptolepis Gord.) plantations established on similar soils. In general, soil properties varied significantly among plantations and treatments. For both plantations, thinning significantly increased soil organic C (SOC) concentrations whereas there were no significant changes in soil pH and Ca and Mg concentrations. In addition, thinning increased total soil N and Na concentrations for the pitch pine plantation and available P concentration for the Japanese larch plantation in the second year after the treatment. Liming did not affect soil chemical characteristics for the pitch pine plantation except for Na concentration. However, for the Japanese larch plantation, liming significantly increased soil pH and K, Ca and Mg concentrations and decreased SOC and total soil N concentrations. For both plantations, soil Al concentration did not change after thinning and liming and decreased exponentially with increased pH values. The increases in SOC and total soil N concentrations after thinning were possibly due to increases in decomposition of organic matter and root death. Although differences were not statistically significant, soil available P concentration tended to increase at early stages of liming for both plantations. These results suggested that thinning and liming seemed to regulate soil chemical properties for pitch pine and Japanese larch plantations established on similar soils. [ABSTRACT FROM AUTHOR]

Denuded landscapes adjacent to big polluters represent an extremely harsh environment for plants due to a unique combination of soil toxicity and physical stress. In a 5-year experiment we tested whether survival and performance of seedlings of Mountain birch ( Betula pubescens ssp. czerepanovii) planted in two barren sites around the nickel–copper smelter at Monchegorsk, northwestern Russia, can be enhanced by physical sheltering and how large the supposed benefits to survival and performance are in relation to liming. Seedling performance was assessed by measuring growth parameters and chlorophyll fluorescence. Physical sheltering was found to be beneficial in some conditions: when soil characteristics were not so harsh as to cause 100% mortality, sheltering increased both survival and performance of birch seedlings. Although the benefits of liming on seedling performance and survival were stronger than the benefits of sheltering, sheltering may still have its uses in restoration when large-scale liming is not applicable, for example, when the ecological side effects of liming are to be avoided. [ABSTRACT FROM AUTHOR]

Direct titration of acid surface soils is often used to measure soil acidity. However, titration has not been used for routine determination of the lime requirement (LR) in soil testing laboratories, because it is too time-consuming, requiring multiple additions of base and long equilibration times between additions. Since soil pH as a function of added base can be described well by a linear equation, titration may be adopted by soil testing laboratories using a minimum number of base additions. Our objective was to evaluate the accuracy of a simplified titration procedure, based on an initial pH reading and a second reading following the addition of one dose of Ca(OH)2, followed by extrapolation to the target pH. Seventeen soils were titrated with Ca(OH)2 in both water and 0.01 M CaCl2 with a 30-min interval between additions. The slopes from the first two data points of the titration in water were frequently in error for estimation of the slopes regressed by all data points to pH 6.5. However, the first two data points in the 0.01 M CaCl2 titration were found to be more reliable for estimating the slopes. Both the initial pH in water and in 0.01 M CaCl2 were used to calculate the LR with the two-point slope in 0.01 M CaCl2. The LR predicted using the initial pH in 0.01 M CaCl@ gave better estimates of the LR than the initial water pH when compared with the standard 3-d Ca(OH)2 incubation. A linear regression of LR by the single addition method in 0.01 M CaCl2 (Y) on LR determined with the 3-d Ca(OH)2 incubation (X) gave the linear equation Y = 0.88 X, r² = 0.93. It is concluded that the LR predictions with the single addition method in 0.01 M CaCl2 are sufficiently accurate to justify further evaluation under routine laboratory conditions. [ABSTRACT FROM AUTHOR]

Odonate assemblages were compared between replicate sets of shallow lakes that had been created and acidified by open-cast mining across a large area (2,451 ha) of southwest France (Arjuzanx, Landes); one set of lakes ( n = 5) was experimentally restored by liming with calcium carbonate, whereas another group ( n = 5) was left as untreated reference lakes. Both odonate adults and exuviae were sampled bimonthly during May–August 1998. Elevated turbidity and conductivity in limed lakes were the only physicochemical measures differing between restored and reference lakes, because deacidification occurred naturally, even in reference lakes during the 17 years after the onset of restoration. Restoration by liming can apparently lead to effects on lake turbidity that might be considered adverse. Twenty-four and 19 odonate species occurred among adults and exuviae, respectively, but there were no significant differences in richness between restored and reference sites. However, significantly, more exuviae were collected from the reference sites (588 vs. 180), where exuvial diversity and rank abundance indicated more evenly structured assemblages than those in restored lakes. Ordination showed that adult assemblages differed significantly between restored and reference lakes, and varied highly significantly with lake turbidity. This effect occurred because a small group of generally scarce adults were characteristic of reference sites ( Chalcolestes viridis, Lestes virens, Cordulia aenae, Leucorrhinia albifrons, and Sympetrum sanguineum). Exuviae of these same species were less abundant at restored sites, but exuvial assemblages overall did not discriminate between restored and reference lakes. We conclude that lake restoration by liming can reduce diversity and larval numbers among odonates and subtly affects adult assemblages. In this case study, adult assemblages discriminated best between the lake types involved in the experiment, but important additional information arose from exuvial abundance and structure. This study indicates that natural recovery processes after acidification in formerly open-cast areas––rather than chemical intervention through liming––might lead to preferable conservation outcomes. [ABSTRACT FROM AUTHOR]

Liming has been mooted as a mitigation option for lowering soil N2O emissions. This study investigated the effect of soil pH and soil water content on N2O and N2 emissions following the addition of synthetic urine (500 kg N ha-1) containing 15N-labeled urea-N. Soil pH treatments ranged from 4.7 to 7.2 with either saturated or field capacity soil. Dinitrogen and N2O fluxes were measured from soil cores kept on water tension tables for 85 d following urine-N addition. Soil inorganic N transformations were also monitored over time by destructively sampling soil cores on five occasions over the 85 d. At field capacity, soil pH affected the N2O fluxes with the lowest cumulative N2O fluxes at soil pH ≥ 5.9. Nitrous oxide losses ranged from <0.1 to 0.4% of 15N applied in the field capacity treatment but this increased to be 0.4 to 1.7% of the 15N applied in the saturated treatment. Dinitrogen fluxes were low (<23 ng N2-N cm-2 h-1) at field capacity but exceeded 4000 ng N2-N cm-2 h-1 under saturated conditions. Cumulative N2 fluxes increased with increasing soil pH in the saturated soil. The flux ratio of N2O-N/(N2O-N + N2-N) remained high (0.68–0.71) under the field capacity treatment but decreased with time from 0.64 to 0.16 in the saturated treatment. This study suggests that while the use of soil liming has merit for lowering N2O emissions from urine patches where soils are at field capacity, the resulting NO3-N will be susceptible to enhanced rates of N2O and N2 loss if the soils are wetted up beyond field capacity. [ABSTRACT FROM AUTHOR]

Assesses the effect of lime and phosphorus (P) on soluble cations by measuring the composition of saturated paste extracts. Properties of the soil used; Increases in soil P availability due to liming; Laboratory evaluation of lime effects on P chemistry; Supply of P to plants; Magnitude of hydrogen-ion concentration effect on P desorption.

Examines the effect of grid sampling at various scales on the efficacy of site-specific lime management on soil pH and the yield of corn and soybean in two fields with variable soil pH. Comparison of the kinetics of granulated (pelletized) lime with agricultural lime to confirm field observations of slow rates of reaction of granulated lime in field experiments.

We have examined the effect that acid deposition and other sources of acidity have had over the last 110–140 years on soil under woodland (Broadbalk and Geescroft Wildernesses) and grassland (Park Grass) comprising some of the Classical Experiments at Rothamsted Experimental Station. Changes in soil chemistry have been followed by analysing some of the unique archive of stored samples for pH, water-soluble and exchangeable base cations, aluminium, iron and manganese, exchangeable acidity, cation exchange capacity (CEC) and soluble anions. Proton balances and historical data show the importance of acid deposition to acidification and concomitant changes in the chemistry of the soil. The pH of the surface soil of Geescroft Wilderness has fallen from 6.2 to 3.8 since 1883. The decrease in the pH of the unlimed, unfertilized plot on Park Grass was less over a similar period (from pH 5.2 to 4.2), illustrating the significant effect of the woodland canopy on the interception of acidifying pollutants. The effect of increasing acidity on the soil chemistry of Geescroft Wilderness is seen in its decreasing base saturation and CEC, with base cations moving down the soil profile. Clay minerals are being irreversibly weathered, and Mn and Al progressively mobilized, so that today Al occupies 70% of the exchange complex in the surface soil. Even with present reductions in sulphur deposition critical loads for sulphur, nitrogen and acidity are still exceeded. Such semi-natural ecosystems are unsustainable under the current climate of pollution. [ABSTRACT FROM AUTHOR]

Investigates the lime-induced loss of soil organic carbon in New South Wales. Effect of the carbon loss to the aggregate stability of the soil; Increased aggregate stability in limed soils suggested formation of bonding involving calcium bridges.

The degradation of chlorsulfuron was studied in laboratory experiments in three oxisols from south and south-east Brazil. Three soil profiles were sampled by horizon, and classified according to USDA soil taxonomy and the Brazilian system. Degradation assays were made to evaluate the influence of temperature, humidity and liming on chlorsulfuron decomposition. Further experiments were set up to study enhanced biodegradation. Abiotic degradation was also studied in sterile soils, to evaluate, by comparison with non-sterile soils, the role of microorganisms in degradation. The degradation always followed first-order kinetics and was generally faster in samples from A than B horizons. An increase in temperature (from 25 to40°C) increased chlorsulfuron degradation. Further, an increase in moisture content increased chlorsulfuron degradation in samples from the A horizons of all soils, whereas for two out of three soils, degradation in samples from the B horizon was greater at lower water content. The biotic contribution to degradation was significant only for the soil with higher fertility. Soil liming significantly increased chlorsulfuron half-life in all samples. Significant enhancement of degradation (decrease in half-life on reapplication) was observed only in soil from A horizons, where a higher microbial activity was likely. [ABSTRACT FROM AUTHOR]

he percentage colonization of roots by arbuscular mycorrhizal fungi was measured in the field in two crops of spring oats (Arena sativa L.) and one of maincrop potatoes (Solanum tuberosum L.), successively grown over a period of 3 yr on the long-term liming experiments at Rothamsted and Woburn. In both crops, all years, both phosphorus treatments and at both sites, percentage colonization was little affected by soil pH from over a range approximately 4.5 to 7.5. There was little effect of pH on crop yields. Up to nine species of coarse endophyte could be identified from spores (> 50 μm diameter) in plots of pH 5.5 and above. There were markedly fewer spores at (approximately) pH 5.5 and none in the most acid plots. [ABSTRACT FROM AUTHOR]

1. North Halfmoon Lake and Lofty Lake (Alberta, Canada) were chosen for whole‐lake liming experiments as a new restoration technology to enhance calcite precipitation and reduce eutrophication. During a 3‐year study (1991–93) the relationships between zooplankton and phytoplankton were assessed, together with the effects of lime additions. 2. Zooplankton communities were numerically dominated by rotifers, while the major contribution to biomass was due to large filter‐feeding Daphnia during the first half of the summer season. In Lofty Lake, cladocerans made up to 93% of biomass, whereas in North Halfmoon Lake both cladocerans and calanoids were strongly represented. 3. Total zooplankton and cladoceran biomasses were inversely correlated with chlorophyll a (chl a). The same relationship was found between large Daphnia (≥ 1 mm) and chl a. These relationships suggest that the decline in Daphnia may have been caused by an increase in cyanobacteria biomass during bloom events. 4. There were minor changes in rotifer populations after liming; however, these changes have been caused by natural year‐to‐year variation rather than liming. In general, cladocerans showed an increase in body size and population biomass when pre and post‐treatment data were compared by means of ANCOVA. Statistical analysis showed that there were more cladocerans per unit of chl a after liming; however, further research is needed to relate these patterns unambiguously to the application of lime as a restoration technology. [ABSTRACT FROM AUTHOR]

Two oil-contaminated sites were bioremediated by stimulating indigenous microbes by tilling, liming, and fertilizing; the hydrocarbon contents were reduced by 84% in 7 weeks at one site and by 83% in 56 weeks at the other site. The process was monitored by measuring the most probable number (MPN) of oil-degrading microbes and the total petroleum hydrocarbon (TPH) concentration in soils. Bioremediation occurred at MPNs of 10 5 to 106 cells g-1 soil, mean water-holding capacities of 54–82% and mean soil pH values of 4.75–5.97. The initial control TPH concentrations remained unchanged at the end of the study at both sites. Bioremediation was not required at depths greater than 6 in except at one location; tilling at 18 in was necessary and remediation took 19 weeks longer than the surface remediation of 56 weeks. As revealed by gas chromatographic analyses of soil extracts before and after bioremediation, the diversity and amounts of hydrocarbons were substantially reduced during bioremediation. There were 10 oil-degrading bacteria isolated from the sites, representing the following genera: Alcaligenes, Actinomyces, Bacillus, Citrobacter, Corynebacterium, Enterobacter, and Pseudomonas. [ABSTRACT FROM AUTHOR]

Liming (at 2.5 or 10t ha−⊃1) of peat taken from under a Picea sitchensis stand reduced mortality and weight-toss of five earthworm species, measured over 8 weeks in the laboratory. In the limed treatments, least population biomass was lost by Aporrectodea caliginosa, A. longa and Lurnbricus terrestris. A. caliginoxa was the only species to gain any weight in any treatment. All earthworm species increased the amount of N released in leachates from limed and unlimed peat. Nitrate-N release was substantially greater (by up to 50fold) in treatments with lime and earthworms than with earthworms alone. Aporrectodea caliginosa was the most suitable species of those tested for inoculation into limed deep peat soils under P. sitchensis to improve rates of N mineralization. Aporrectodea caliginosa was successfully introduced into limed peat profiles in field lysimeters under a stand of N-deficient P. sitchensis. Total earthworm biomass was sustained over the 12 months of the experiment in the limed treatments, whereas only 4% remained in the treatment without lime. Earthworm cocoons were produced in the limed treatments only. Aporrectodea caliginosa in limed soil significantly increased leachate N release (to 60 kg ha−⊃1 year−⊃1) compared with untreated ( 19 kgha−⊃1 year−⊃1). and limed soils (36 kg ha−⊃1 year−⊃1). Nitrogen release was mainly as NO3−-N. Ammonium-N and NO3−-N mobilized by addition of earthworms plus lime appeared to be taken tip by living roots of P, sitchensis. This increased mineralization can be expected to lead to enhanced tree growth. [ABSTRACT FROM AUTHOR]

Plots in a beech-forest in southern Sweden were artificially limed with 2, 5 and 10 tonnes of dolomite lime ha-&sup-1;. Snail populations were sampled. The population increases correlated with lime dosages. In plots treated with 10t ha-¹, mean densities increased 4–40 times, depending on the species (5 years after liming). There were highly significant correlations between snail density and pH, Ca concentration, base cation concentration and base saturation; however, the correlations between nitrogen, phosphorus and potassium were very low. The results indicate that liming positively effects land snail population densities in relatively nutrient-poor deciduous forests. [ABSTRACT FROM AUTHOR]

Laurel Branch (Tennessee, U.S.A.), an acid-sensitive stream in the southern Appalachian Mountains, was limed as a part of the Acid Precipitation Mitigation Program funded by the U.S. Fish and Wildlife Service. Objectives were (1) to evaluate the effectiveness of stream liming by means of a hydropowered doser design, and (2) to monitor stream response(s) to in- creased pH and alkalinity. Precipitation in the region was documented to be acidic, with a mean pH of 4.54 in 1987. Preliming evaluations conducted from 1986 through 1988 depicted Laurel Branch as soft (hardness less than 5 mg/L CaCO[SUB3], pH 6.2-6.6), dilute (ionic strength less than 400 μeq/L), and lightly buffered (alkalinity less than 100 μeq/L). Because of the apparent relationship between flow and water chemistry, Laurel Branch was considered susceptible to episodic acidification caused by storms. In June 1989, a hydro- powered limestone doser was installed to treat the lower 3 km of the stream. Approximately 8.2 tonnes of crushed limestone were added during an 18-month treatment phase that concluded in December 1990. Technical and design problems with the doser reduced efficiency and limited the scale of liming through much of the first 6 months of operation. Design modifications and equipment upgrades in late 1989 corrected most of the problems and improved doser performance in 1990. No substantial chemical or biological changes were detected within the treated reach of Laurel Branch as a result of liming. Time- series statistical analyses showed small but significant changes in total alkalinity (10 μeq/L average increase) and dissolved calcium at all limed sites. pH (as hydrogen ion) increased 0.16 and 0.13 units at two limed sites that were 1 km and 2 km below the doser, respectively. At the lowermost limed site 3 km below the doser, a significant decrease in pH was detected which was probably flow-related. Mean length of age-0 (juvenile) and age-1 rainbow trout increased marginally during liming, suggesting improved fish growth, but increases were not significant. Densities of an acid-sensitive macrobenthic taxon (Baetis spp.) increased during liming, whereas densities of an acid- tolerant taxon (Leuctra spp.) remained unchanged. In general, observed biological changes were considered minimal; they were judged unrelated to liming but rather of seasonal and/or spatial origin. The regional drought of 1987 and 1988 was considered a confounding factor. With most of the baseline data collected during these years, vastly differing hydrology in 1989 and 1990 ("wet" years regionally) became problematic and may have distorted some responses and masked others. It is also possible that biological responses may have been delayed because of the small magnitude of chemical changes, particularly pH and alkalinity. A calcium mass budget estimated that up to 62% of the calcium added was accounted for in chemistry data from limed sites, with increases most visible in the spring and summer of 1990. Results indicated that, although the Laurel Branch watershed does receive acidic precipitation, current biological communities show high levels of integrity and little apparent degradation related to acidification. If watershed buffering capabilities are depleted from continued acidic deposition, however, stream biota may be at risk in the future. [ABSTRACT FROM AUTHOR]

Studies the effect of organic matter addition to soil in relation to soil pH. Mechanism that explain decreases and increase in soil pH after organic matter addition; Reproduction of the effects of organic materials; Comparison of liming ability of mineral and organic molecules.