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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]

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]

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]

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]

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]

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]

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]

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.

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.

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.