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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]

Earthen sites (i.e., ancient earthen buildings) with important historical, cultural, artistic, social, and scientific value have been seriously damaged. Soil treatment with chemical additives can decrease the degradation rate of earthen sites. In the past, polyvinyl alcohol (PVA) and quicklime as chemical additives were studied separately for the protection of earthen sites. In arid and semi-arid northwest China, the early strength of the lime-treated soil may be insufficient due to an inappropriate reaction environment, and the PVA as the additive can quickly increase the soil strength. However, calcium carbonate has been proven to not be decomposed for hundreds of years, while there is still a lack of experimental evidence to show that the PVA cannot be decomposed in decades. The PVA and lime as the additives show the potential to make up for the defects each other. Therefore, the physical and mechanical properties of the PVA and lime composite soil are analysed, and the microscopic properties of the composite soil are discussed in this study. The results show that the addition of the PVA decreases water vapour permeability and pore size, which causes a delay in the carbonization reaction of lime, but it acts as a cementing agent to improve soil strength before the lime appropriately reacts. The addition of quicklime can decrease the hydrophobicity of the PVA-treated soil. The mixing of these two materials is conducive to the colour control of the sample. For the composite soil applied to earthen sites in northwest China, the optimal ratio is 10% lime and 1.0% PVA. [ABSTRACT FROM AUTHOR]

Accurate predictions of the short-term reactivity of liming products are needed for situations where rapid soil pH adjustment is desired. Lime efficiency (LE) describes the capacity of a liming material to neutralize soil acidity in comparison with a finely ground CaCO3 standard (LE = 100%). Our objectives were to evaluate LE for calcitic liming materials varying in particle size at 1–12 months after soil incorporation using pH change (LEpH) and CO2 evolution (LECO2) as response indicators, and to evaluate a 15-min citric acid (CA) test as a predictor of LE. We evaluated LE for lime particle size separates from 10 to 200 USA mesh (< 2000 µm to 75 µm) and for three commercial liming products (65, 25 and 11 µm average particle size) in a sandy loam soil. In field microplots, it took 6 months to achieve LE of > 80% with lime particles of <60 mesh (< 250 µm). LEpH was linearly related to LECO2 at one month following lime incorporation into soil. Both LEpH and LECO2 increased as a function of CA test values, as described by logarithmic equations. Lime particle size, CO2 evolution, and CA test values were all useful indicators of short-term LE. [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]

The cropping systems of northern Idaho and eastern Washington are dominated by a cereal-based (winter wheat) rotation that is exclusively rainfed. Following the green revolution, the productivity of wheat increased dramatically with semi-dwarf varieties and inexpensive synthetic fertilizers. However, long-term and frequent use of ammonium-based nitrogen fertilizers has resulted in the gradual acidification of fields in the region, with reduced productivity and symptoms of aluminum toxicity in some locations. A micronized liquid formulation of lime (calcium carbonate) was evaluated at three locations to mitigate soil acidification in comparison to a no-lime control. To examine how liming affects bacterial community structure, soil samples were taken in the spring in wheat and pea rotations 7 and 19 months after lime application, DNA was extracted and the V1-V3 portion of the 16S rRNA gene was amplified and sequenced with Illumina MiSeq. pH was only increased ∼0.2–0.3 units in most locations, and liming only had a significant effect on bacterial community composition at one location (Pullman). Liming had no consistent or significant effect on community richness or diversity. Location had a stronger effect on communities than liming or crop rotation, but some specific taxa increased in relative abundance in response to liming, including the families Cytophagaceae and Flavobacteriaceae (Phylum Bacteroidetes), A4b (Phylum Chloroflexi), and Opitutaceae (Phylum Verrucomicrobia). A number of operational taxonomic units (OTU) in Chitinophagaceae and Xanthomonadaceae were increased by liming at the Pullman location, which had 3–4 X more OTUs affected by liming than the other locations. Streptomycetaceae and Oxalobacteraceae were more abundant in root zone soil of wheat than pea. In conclusion, there was a strong interaction between liming and location in determining soil bacterial composition, but specific components of the bacterial community responded to even minimal increases in soil pH. [ABSTRACT FROM AUTHOR]

• Accurate and rapid method to measure low concentrations (>0.5%) of inorganic carbon established. • Detection and prediction of inorganic carbon can be used to measure agricultural lime in soils. • Various lime sources can be detected and measured in different soil types and depths. • This method can be used to monitor lime movement and assist with management of acidic soils. • Infrared Spectroscopy approach is a viable alternative to traditional laboratory methods. Globally, surface and subsurface soil acidity pose a serious threat to crop production and require effective management to prevent yield losses. The application of lime (calcium carbonate, CaCO 3) is a well-recognised remediation technique for surface soil acidity. However, for subsurface acidity, improved application and detection methods are required to manage acidity due to the stratification of acidic layers. Mid infrared (MIR) spectroscopy has potential as a rapid, cost effective and accurate method of CaCO 3 detection in soils. However, for this technology to be valuable in an agricultural context, there is a need to develop MIR spectroscopy methods for the detection of CaCO 3 at agriculturally relevant concentrations of <1%, which was the aim of this study. MIR Partial Least Square Regression (PLSR) carbonate prediction models were developed using carbonate-specific spectral regions to predict CaCO 3 concentrations in soil. Prediction models were initially developed using a single soil type spiked with reagent grade CaCO 3 and were tested further with soils collected from field trials that had been treated with various rates and sources of lime. Prediction models using specific carbonate peak regions were established and compared with models using the entire MIR spectrum to assess the model performance. Models built using a single peak range at 2560–2460 cm−1 gave the best results (highest R2 values and lowest RMSE values) followed by the single peak range at 1840–1760 cm−1. Specifically, model performance was improved when developed with a single soil type and reagent grade CaCO 3 in the 2560–2460 cm−1 spectral region, with PLSR R2 of 0.834 and RMSE of 0.030. Performance was reduced but still satisfactory (R2 of 0.735 and RMSE of 0.069) when applied to field trial soils using a range of different lime sources, including dolomitic lime. The MIR method enabled accurate prediction of carbonate concentrations and had a detection limit of 0.05% CaCO 3 , similar to what can be achieved using a pressure calcimeter. Findings suggest that MIR spectroscopy measurements of agriculturally applied CaCO 3 in soils may provide valuable insights into monitoring the movement and efficacy of lime treatments and will enable more informed lime applications in the future. The method may also be used to detect naturally-occurring carbonates at low concentrations and may be useful for rapid isolation of inorganic carbon from organic carbon in soil carbon measurements and carbon accounting. [ABSTRACT FROM AUTHOR]

Liming increases soil negative charges and thus affects the chemical equilibrium of cations between the solid phase and the soil solution with consequences for the mobility of cations. The effects of lime and potassium chloride (KCl) addition on the vertical movement of potassium (K), calcium (Ca), and magnesium (Mg) were investigated in two Brazilian soils. The experiment was carried out in leaching columns. Treatments included a combination of rates of KCl (0, 50, 100, and 200 mg kg−1 K) and acidity levels (without and with liming). Seven water percolations (400 mL per column) were performed at weekly intervals, totaling an equivalent to 357 mm of rain. Raising the soil pH decreased the leaching of K, in both soils, up to 50% because of the increase of its electrostatic adsorption on created negative charges. Addition of KCl increased the percolation of K, Ca, and Mg proportionally to the rate applied, and it was more efficient than calcium carbonate to percolate Ca in both soils. Liming must be taken into consideration when K leaching or plant needs of K are estimated in predominantly variable-charge soils. [ABSTRACT FROM AUTHOR]

Faba beans (Vicia faba L) are grown in northern Tunisia where annual rainfall approaches 1200 mm and where the soil acidity is the most limiting factor for plant growth. Aluminum (Al) and manganese (Mn) toxicities provide a hostile environment to root growth. To alleviate such a problem, farmers use selected acid-tolerant species. However, crop yields remain far below their optimal levels. Liming, a practice to eliminate acidity, has never been tried in this area before. This research aimed to evaluate the impact of lime and mineral fertilizers on root nodulation, plant uptake and yield of faba beans using a pot experiment. Treatments were combinations of two rates of calcium carbonate with three rates of superphosphate and three rates of potassium sulfate. Liming produced significantly higher number and weight of nodules on roots as well as higher nitrogen, phosphorus, and potassium contents in plant tissue. Liming also increased shoot growth and bean yield. [ABSTRACT FROM AUTHOR]

The application of lime or liming materials to acid-soil grasslands might help mitigate soil acidity, a major constraint to forage productivity in many temperate mountainous grasslands. Nowadays, in these mountainous grasslands, it is essential to promote agricultural practices to increase forage yield and nutritive value while preserving biodiversity and agroecosystem functioning. Two different field experiments were conducted in the Gorbeia Natural Park, northern Spain: (i) one in a calcareous mountainous grassland (Arraba) and (ii) the other in a siliceous mountainous grassland (Kurtzegan) to study the effects of a single application of two liming products, i.e. 2429kg lime (164.3% CaCO3) ha−1 and 4734kg calcareous sand (84.3% CaCO3) ha−1, applied one month before the beginning of the sheep grazing season (May–October), on soil chemical (pH, organic C, total N, C/N ratio, %Al saturation, Olsen P, exchangeable K+ and Ca2+) and biological parameters (dehydrogenase, β-glucosidase, urease, acid phosphatase and arylsulphatase activity) as well as on botanical diversity (graminoids, forbs, shrubs) and forage yield and nutritive value (crude protein, modified acid detergent fibre, digestibility). Untreated control plots were also included in the experiment. Soil sampling was carried out at the end of the sheep grazing season (6 months after liming treatment), while botanical composition was determined one year after treatments application. Although no increase in soil pH was observed in Arraba, liming significantly increased dehydrogenase activity (an indicator of soil microbial activity) by 30.4 and 86.7% at Arraba and Kurtzegan site, respectively. Liming treatments significantly improved forage yield and nutritive value in Arraba but not in Kurtzegan. Furthermore, no differences in soil biological quality, evaluated using the “treated-soil quality index” as proposed in this work, were observed between treated and untreated soils, and between the two different lime treatments (lime, calcareous sand). It was concluded that, in acid-soil temperate mountainous grasslands, moderate liming treatments have no negative short-term effects either on soil quality or botanical composition, while resulting in improvements in forage yield and nutritive value under some conditions. [Copyright &y& Elsevier]

An 8-year field study measured soil pH changes annually at various depth increments. Limestone was applied to tilled and untilled field strips annually for 8 years at either a 2.0 Mg/ha rate (100% calcium carbonate efficiency) and once every 4 years at the 8.0 Mg/ha rate (100% calcium carbonate efficiency), or as a water-treatment-plant limestone by-product in two replicated field trials. Liming materials increased soil pH in the 0- to 5-cm and 5- to 10-cm depths with time in untilled soils. Incorporated liming materials increased soil pH faster at the 5- to 10-cm depth and increased soil pH at the 10- to 15-cm depth. Mean maize and soybean grain yields increased for all liming materials, and maize ear leaf P and soybean shoot P and Ca increased after liming at the last year of the study. Consistent surface applications of liming materials without incorporation can mitigate acidification and improve crop yields in highly buffered soils. [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 is an effective method of correcting soil acidity, but the cost and other factors, such as sub-soil acidity, topography, and nutrient availability may limit its benefits. An alternative option is to grow acid tolerant plants. Pot experiments are an effective way of identifying plants with the genetic potential to grow in acidic soils. These experiments require a range of acidity levels. The soil used in this study was a sandy loam. Increments of aluminum sulfate [Al2(SO4)3.18H2O] and calcium carbonate (CaCO3) were added to derive dose-pH response relationships. The derived relationships were used to estimate the quantity of aluminum sulfate and lime required to change the pHCa (1:5, w:v, soil:10 mM CaCl2) of the soil from 4.4 to 3.89 and 4.4 to 5.2, respectively. The estimated quantities of aluminum sulfate (380 g) and calcium carbonate (48 g) were thoroughly mixed through 100 kg batches of the soil, which was potted (2 kg/pot). Then the acidified soils were leached to remove excess salts. The initial pHCa achieved was 3.86 and rose to 3.94 after leaching. A wide range of soluble aluminum (Al) concentrations (1:5, w:v, soil:10 mM CaCl2) was obtained from this study, e.g., 52 mg Al/kg soil in acidified soil and 1.8 mg Al/kg soil in limed soil. The variation in pH and EC between replicate pots was negligible (range 0.05 pH and 0.02 dS/m) and these remained relatively unchanged after six months. During the next six months some pots were held in the laboratory with 3 wetting/drying cycles; however, most were placed outdoors where they were sown with seed of Austrodanthonia spp. During this time, the pHCa of the acidified soils increased slightly to: 4.10 (laboratory), 4.18 (outdoors without plants), and 4.20 (outdoors with plants). A similar increasing trend was also observed in limed soils. It was concluded that adding aluminum sulfate and calcium carbonate followed by washing with water are quick and convenient methods for adjusting soil pH for pot experiments. [ABSTRACT FROM AUTHOR]