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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]

Limestone is the most widely used agricultural input for soil acidity correction and calcium (Ca) and magnesium (Mg) fertilization. However, other materials have the potential to fulfill these purposes, such as steel slags, also known as silicates. Silicates have higher solubility than limestone, serving as agents for increase pH in no‐till, in addition to being a source of Ca, Mg, and silicon (Si). This study aimed to compare the effects of surface application of dolomitic lime and calcium magnesium silicate on soil chemical properties, soybean [Glycine max (L.) Merr.] nutritional status, and grain yield under no‐till. The experiment was installed in the northwest Paraná State, Brazil, on a Rhodic Eutrustox. Lime and silicate rates were applied by broadcasting before the sowing of soybean. Silicate treatment increases soil Ca2+, pH, and base saturation up to a depth of 0.10 m. By contrast, liming effects on soil chemistry were restricted to the 0.05 m top layer after 24 months of application. The acidity correction and Ca2+ supply to greater soil depths and the increased leaf Si as a beneficial element provided by silicate treatment contributed to increasing soybean yield in the 2018/2019 and 2019/2020 seasons. Lime application, regardless of the rate, did not improve soybean yield. Waste from the steel industry can be used as acidity correctives and source of Si, Ca, and Mg, improving the agronomic performance of soybean. Core Ideas: Silicate is more efficient in maintaining soil fertility compared to lime.Changes in soil fertility were observed up to a depth of 0.10 m after 24 months.Silicate increases silicon content in soybean leaf.Surface application of silicate increased soybean yield up to 43%.Soybean yield did not improve with lime. [ABSTRACT FROM AUTHOR]

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]

This present study investigates the recovery of wood biomass ash (WBA) as chemical stabilize in compacted earth bricks. The specimens were tested for compressive and thermal properties in dry state. The tests were performed at 7 and 28 days of age in order to evaluate the effect of the partial substitution of soil with WBA on the mechanical and thermal properties of the compressed earth bricks. The results indicate that bricks manufactured with 20% of partial substitution showed better performance than those containing only soil. Nevertheless, the use of WBA as source of lime improved the compressive strength and the thermal conductivity of the bricks stabilized with different proportions (5, 10, 15 and 20% wt) when compared with bricks fabricated with 100% soil. This improvement is owing to the pozzolanic reaction produced between the soil components and the WBA as well as the soil microstructure. It was also concluded that the combination of the soil components and lime containing in WBA in the stabilization of compressed earth bricks seems to be a promising alternative when considering issues of energy consumption and pollution. [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]

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]

Combining deep tillage (DT) with lime application at greater depths may improve sugarcane yield. The objective of this study was to evaluate the impact of conventional tillage (CT) and DT systems and liming on sugarcane productivity and soil physical attributes. The experiment was conducted in a clayey‐textured Rhodic Hapludox soil cultivated with sugarcane for two growing seasons (first and third ratoons) using a randomized block design with four treatments and four repetitions. The treatments consisted of DT without liming (DT0), DT with liming (DT2), CT without liming (CT0) and CT with liming (CT2). In addition to sugarcane stalk and sugar yields, macroporosity (MA), microporosity (MI), total soil porosity (TP), weighted average diameter (WAD), aggregate stability index (ASI), soil penetration resistance (SPR), pH, potential acidity (H + Al), total soil organic carbon (SOC), particulate organic carbon (POC), mineral‐associated organic carbon (MOC), calcium (Ca) and magnesium (Mg) were analysed. DT2 promoted the best soil conservation effect on sugarcane. In general, DT, regardless of lime application, reduced SOC and POC in soil surface layer. Nevertheless, in the long term, localized lime addition resulted in significant reductions in compaction, reaching values below 2 MPa. The soil fertility improvement provided by DT2 promoted increased sucrose concentrations and stalks yield. Considering that there was an improvement in the physical quality and fertility of soil for better plant development, the deep tillage with localized lime addition can be considered an effective alternative for sugarcane cultivation. [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]

Aluminum toxicity, nutrient imbalance, and reduced microbial activity are the most limiting factors for optimum agronomic productivity in acid soils. A field study was conducted to investigate the impact of micronutrient and liming on soil properties and productivity of groundnut‐rapeseed system in an acidic Inceptisol. The impact of six micronutrient (control or no micronutrient, Zn at 5 kg ha−1, B at 1 kg ha−1, Mo at 0.5 kg ha−1, Zn + Mo, and Zn + B + Mo) and two soil amendment (furrow liming at 500 kg ha−1 and no lime addition) treatments were first tested in groundnut and theirs residual effects were assessed on soil properties of succeeding rapeseed crop. Results indicated that liming significantly improved soil pH, soil organic carbon (SOC), available N, P and K, and diethylene triamine penta acetate (DTPA)‐extractable micronutrients, soil microbial biomass C and dehydrogenase activity as compared to no‐lime. After harvesting groundnut, Mo + Zn + B treated plots maintained the highest SOC content, whereas sole B and Mo treatment had the highest SOC content after harvesting rapeseed. Further, Mo + Zn + B treated plots showed higher contents of soil DTPA‐extractable micronutrients as compared to others. The highest groundnut equivalent yield (GEY) of the cropping system (pooled data of 2 years) was obtained with Mo + Zn + B (2.12 Mg ha−1) but remained at par with Zn + Mo (2.02 Mg ha−1). Multivariate principal component analysis indicated that available P was the most prominent soil nutrient with a strong effect on GEY. The results indicated that integrated application of Zn + B + Mo along with liming improves soil properties and agronomic productivity of groundnut‐rapeseed cropping system. [ABSTRACT FROM AUTHOR]

Land degradation has severely affected soil health and agricultural productivity in the Sasiga district of western Oromiya, Ethiopia, demanding urgent and extensive solutions. Integrated soil management in particular is a comprehensive approach that could mitigate the multifaceted effects of land degradation. Hence, a field experiment was conducted on degraded farmers' land to assess the potential of lime, organic amendments, tillage, and soil–water conservation (SWC) in improving the productivity of soil and Brachiaria (Mulato II). The experiment employed 15 treatments, which were systematically formulated from lime, organic amendments (compost and cattle manure), the SWC method (constructed soil bunds and no soil bunds), and tillage practices (ploughing and no‐ploughing). The study showed that applying lime with tillage or both tillage and SWC and organic amendments alone improved soil pH from very strongly acidic to moderately acidic. The combined application of lime, SWC, and tillage also enhanced the organic carbon, organic matter, total nitrogen, and moisture contents of the soil. Besides, the integrated use of cattle manure, SWC, and tillage practices boosted plant cover, tillering, plant height (PH), and dry biomass of Brachiaria (Mulato II). Consequently, the physicochemical properties of the degraded soil and the agronomic performance of Brachiaria can be improved by amending with combinations of lime or cattle manure with SWC and tillage. In general, integrating multiple soil management practices, including lime, organic amendments, SWC, and tillage, offers a whole‐system approach to rehabilitating degraded soil and improving its physicochemical properties and productivity of Brachiaria grass. Core Ideas: Land degradation is a serious impediment to improving soil health and agricultural productivity in Ethiopia.Integrated soil management could mitigate the multifaceted effects of land degradation.Amending the degraded soil with combination of lime, soil–water conservation, and tillage improved soil properties.The integrated use of manure, soil–water conservation, and tillage boosted the productivity of Brachiaria.Integrating multiple soil management practices can entirely restore degraded land and improve crop productivity. [ABSTRACT FROM AUTHOR]

A soil's responses to phosphorus (P) input differs based on its chemical composition. Soil acidity and the presence of metallic cations dictate a soil's chemical composition. Currently, soil P application recommendations are universal and do not account for differing soil composition. A targeted soil‐specific approach is required to optimize P efficiency and availability. A pot incubation experiment was established to explore the effects of contrasting lime and P application rates across a range of soils (25), characterized by fine particle size and high levels of soil organic matter. Three contrasting rates of P were applied (0, 50, and 150 kg P ha−1) both with and without ground lime (CaCO3) at 5 tonne ha−1 over a 140‐day incubation period. The addition of lime buffered the soil, increasing nutrient availability and reducing P fixation. The 50 kg P ha−1 treatment rate was required to achieve sufficient plant available P in both mineral soil textural classes. Current legislative recommendations however do not allow the application of such rates, which has an impact on agronomic performance. Loam soils experienced a greater increase in M3 soil P in comparison to clay and organic soils. Organic soils posed a major threat to water quality due to poor P retention. A re‐evaluation of P recommendations is required to account for soil variability as current P allowances are insufficient on these particular soils. [ABSTRACT FROM AUTHOR]

Soil acidification is caused by a number of factors including acidic precipitation and the deposition from the atmosphere of acidifying gases or particles, such as sulphur dioxide, ammonia and nitric acid. The most important causes of soil acidification on agricultural land, however, are the application of ammonium-based fertilizers and urea, elemental S fertilizer and the growth of legumes. Acidification causes the loss of base cations, an increase in aluminium saturation and a decline in crop yields; severe acidification can cause nonreversible clay mineral dissolution and a reduction in cation exchange capacity, accompanied by structural deterioration. Soil acidity is ameliorated by applying lime or other acid-neutralizing materials. 'Liming' also reduces N2O emissions, but this is more than offset by CO2 emissions from the lime as it neutralizes acidity. Because crop plants vary in their tolerance to acidity and plant nutrients have different optimal pH ranges, target soil pH values in the UK are set at 6.5 (5.8 in peaty soils) for cropped land and 6.0 (5.3 in peaty soils) for grassland. Agricultural lime products can be sold as ' EC Fertiliser Liming Materials' but, although vital for soil quality and agricultural production, liming tends to be strongly influenced by the economics of farming. Consequently, much less lime is being applied in the UK than required, and many arable and grassland soils are below optimum pH. [ABSTRACT FROM AUTHOR]

CONSERVATION AGRICULTURE PRACTICE Conservation agriculture practices include minimum mechanical soil disturbance such as no-till, permanent soil organic cover with crop residues and/or cover crops, and species diversification with crop rotation (FAO, [19]; Hobbs et al., [33]). However, the health of global soil is threatened by a variety of pressing factors, including loss of soil nutrients (Lal, [41]), diminishing soil organic carbon (Smith, [62]), pollution (Beans, [3]), salinization (Singh, [60]), erosion (Borrelli et al., [4]; Starke et al., [63]) and decline in biodiversity (Guerra et al., [28]; Hou, [35]). Keywords: adaptation; conservation agriculture; food security; soil degradation; soil nutrient management EN adaptation conservation agriculture food security soil degradation soil nutrient management 1 7 7 02/01/23 20230101 NES 230101 INTRODUCTION Food security is one of the major challenges of modern society (Prosekov & Ivanova, [56]). Based on data from Web of Science, annual research output linking soil phosphorus and crop yield increased by nearly 12-fold since 1990, and in the same period, research linking soil nitrogen and crop yield increased by nearly 9-fold. [Extracted from the article]

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]

The increasing cost of lime and the agronomic problems associated with soil acidity management has prompted the need to re‐examine management strategies to correct soil pH while maintaining forage productivity. This study evaluated the effect of different lime sources (pelletized dolomitic limestone [dolomite] and hydrated calcitic limestone [Hi‐Cal]) and application levels (0, 1.1, 2.2, and 4.4 Mg ha–1 yr–1) on soil chemical properties and bahiagrass (Paspalum notatum Flügge) responses in 2014 through 2017. Forage and soil responses were monitored during the 4‐yr period, and residual lime effect was also evaluated 3 yr after liming ceased (2020). Liming increased bahiagrass herbage accumulation by 12% relative to control; however, no effect of lime source (P =.6), application level (P =.16), or their interaction (P =.11) was observed. Both lime sources increased tissue P, Mg, Ca, and S concentrations relative to control; however, tissue B, Zn, Mn, Fe, and Cu generally decreased. A single application of Hi‐Cal or two annual applications of dolomite increased soil pH from 4.5 to the recommended level of 5.5 for bahiagrass. Soil pH (0–45 cm depth) increased with repeated lime applications particularly in Hi‐Cal treatments, but no adverse effects on bahiagrass were observed. Soil pH remained above the recommended level 3 yr after liming ceased. Despite the lack of treatment effect, soil P and K levels decreased with time likely because of nutrient removal with harvested forage. Proper P and K fertilization along with soil pH management are key components to maintain long‐term productivity of bahiagrass. Core Ideas: Calcitic limestone increased soil pH faster than dolomitic limestone.Soil pH remained above the recommended level 3 yr after lime application ceased.Liming increased bahiagrass herbage accumulation by 12%.Selection of lime sources should be based on availability and cost.Proper liming and P and K fertilization is key to maintain bahiagrass productivity. [ABSTRACT FROM AUTHOR]

Summary: Lime and phosphorus (P) applications are common agricultural management practices. Our aim was to quantify the effects of long‐term application practices on root growth and abundance of arbuscular mycorrhizal fungi (AMF) under field conditions. We assessed the effects of lime and P fertilizer applications on barley yield, root growth and AMF abundance in 2016. Treatments were no, low, medium and high liming rate corresponding to application of 0, 4, 8 and 12 Mg lime ha−1 every 5–9 years since 1942 combined with no or yearly application of 15.6 kg P ha−1 since 1944. At harvest, grain yield, root intensity (core‐break) and AMF abundance at different soil depths were estimated. Root development was monitored during early growth with minirhizotrons in treatments receiving low, medium and high liming rates and P fertilization. A quadratic model relating grain yield to liming rate estimated yields to peak at 6.4 Mg lime ha−1 with yields of 4.2 and 3.2 Mg grain ha−1 with and without P fertilization, respectively. Low and medium liming rates resulted in greater AMF abundance, especially in the no P treatments. During early growth in P‐fertilized treatments, 77% and 65% more roots developed in the soil profile when treated with medium and high liming rate, respectively, compared to low liming rate. We conclude that long‐term application of lime in soils receiving yearly P fertilization improved conditions for root growth in soil layers below 30 cm, but at the high liming rate, this did not translate into higher yield. [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]

Surface liming to correct soil acidity may have limited effectiveness in subsurface layers in no‐till systems (NTS). The possibility of downward movement may be increased when liming is combined with fertilization with urea (ammoniacal N), as NO3– formed by nitrification of NH4+ can form ion pairs with exchangeable Ca2+ and Mg2+. Liming can also increase the nitrogen use efficiency (NUE) of crops and reduce dependence on soil N. In this work, we investigated the effects of surface application of lime under NTS and N topdressing on soil chemical properties and the nutrition, productivity, and NUE of maize (Zea mays L.) and upland rice (Oryza sativa L.). The treatments comprised four lime rates applied superficially (0, 1,500, 3,000, and 6,000 kg ha–1), and absence (–N) or presence of N fertilization (+N) as urea by topdressing. The treatments were applied during two agricultural years (2011/2012 and 2012/2013), with maize in the first crop season and upland rice in the second crop season. At 18 mo after liming, the application of 6,000 kg lime ha–1 significantly improved the chemical attributes of the soil (pH, soil organic matter (SOM), K, Ca2+, Mg2+, and base saturation [BS]). The application of urea increased the mobility of Ca2+ and Mg2+ to greater depths. The combination of 3,000 kg lime ha–1 with N fertilization synergistically increased the nutrition (N, P, and S), grain yield, and N‐related efficiency indexes in the maize and upland rice crops. Core Ideas: Nitrogen fertilizer contributes to the mobility of Ca2+ and Mg2+ in depth.Surface‐applied lime in no‐till increases the N use efficiency.Maize and rice yields are higher with 3,000 kg ha‐1 of lime and N‐fertilizer application. [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]

Association of organic carbon (C) with iron (Fe) minerals is one important mechanism for long‐term terrestrial C storage. Yet, specific edaphic variables that directly contribute to Fe‐associated C across diverse soil types are still unclear. Through analyzing soils from the National Ecological Observatory Network (NEON) and other published data, here we show that soil pH primarily controls Fe‐associated C across the globe. Fe‐associated C in most soils ranged from 0 to 20 g kg−1 soil, with a strong increase from pH 4.2 to 3.5, but a small change in soils with pH > 4.2. A microcosm experiment further showed that raising soil pH by liming reduced the formation of Fe‐associated C in an acidic Oxisol. Together, these findings demonstrate the dominant role of soil pH in controlling the abundance of Fe‐associated C. Key Points: Soil pH, rather than reactive iron content, is a primary control on concentration of iron‐associated carbon at the global scaleNeither soil orders nor vegetation types have significant relationships with concentration of iron‐associated carbonIron‐associated carbon represents a relatively small fraction of total soil organic carbon globally [ABSTRACT FROM AUTHOR]

Acidity and low P availability in tropical soils constrain cassava (Manihot esculenta Crantz) yield. Liming increases soil Ca and P availability, but Ca can increase the storage root cooking time, and its effects vary with soil P availability. The effects of liming and P fertilization on cassava yield and their relationship with storage root cooking need to be better understood. A 2-yr field experiment was conducted to evaluate the effect of liming at 0, 1.5, 3.1, and 4.8 Mg ha-1 with 0 or 70 kg P ha-1 on plant nutritional status and growth, yield, and cooking of fresh storage roots of the cassava cultivar IAC 576-70. Foliar concentrations were increased for N, P, and Mg and reduced for Mn and Zn with lime application. Maximum cassava fresh storage root yield (26.4 Mg ha-1) was obtained with an optimal lime rate of 3.0 Mg ha-1 and a base saturation of 50%. Liming promoted a 6.5% increase (1.7 min) in the cooking time of storage roots. Application of P fertilizer increased shoot biomass in acidic soil and the diameter and mean weight of the storage roots in the amended soil. Phosphorus fertilization increased the yield (22% or 4.7 Mg ha-1) and P concentration of the storage roots without changing their P/Ca ratio or cooking time. Liming and P fertilization can be managed to improve cassava storage root yield without affecting storage root cooking. [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]

Soil acidification due to crop removal and the use of acidifying fertilisers reduce land productivity in many agricultural systems worldwide. The most common remedy is to apply lime to the soil surface. An alternative approach is to incorporate lime into the sub‐soil. This is a more expensive option, but it substantially reduces the time required to reduce acidity in the sub‐soil horizons. This paper presents a dynamic optimisation model to determine optimal rates, frequency and methods of lime application for a wheat monoculture system in the northern part of the Western Australian wheatbelt. Results show that optimal application rates depend on rainfall levels and soil‐acidity conditions. The net present value of profit is not sensitive to the frequency of lime application. Incorporating lime into the sub‐soil increases the net present value of profit, but only by a small amount: two to four per cent in most scenarios modelled. In the process, sub‐soil lime application reduces both the optimal lime application rate and the time required for the soil pH to increase to a target level. [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]

Land evaluation is the process of land performance predictions over time based on land uses and soil features. Traditional methods in determining soil features are proved to be time‐consuming and costly. Therefore, in order to overcome these limitations, a simpler automated method using the image segmentation was developed in this study. The method was designed by integrating dynamic region merging and genetic algorithm. An area index was calculated for each soil profile using the automated method. It was used to present the amount of soil coarse particles and thereupon to determine the rating value of text‐structure. Using the method, the mean intersection over union of above 0.7 was obtained for detecting the coarse particles which confirms its suitability. Data analysis showed that (a) compared to the Storie‐land index (R2 = 0.71), the Square root‐land index was more correlated to the harvest index (R2 = 0.73), and (b) comparing to manual methods, not only the automated text‐structure had a higher correlation with the harvest index (R2 = 0.64) but also it decreased the determination time (>3.75 times). Furthermore, among the models developed by response surface methodology for estimation of soil features, the developed model for estimation of soil lime showed the highest accuracy (R2 = 0.89). In conclusion, since the developed method is more accurate, more economic and faster than the usual manual methods, it can be widely used in land suitability evaluation. [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]

Soil acidification caused by long‐term nitrogen (N) fertilizer applications has been a growing concern for dryland crop production in both tilled and no‐till soils in the Pacific Northwest (PNW). Many no‐till soils have stratified soil pH in the 5–10 cm depth due to repeated N fertilizer applications at this depth. In the PNW, the practice of liming to correct low soil pH is complicated due to lack of affordable lime sources and because the inherent difficulty in ameliorating stratified soil acidity in no‐till systems. An intact soil‐column incubation study was conducted to investigate whether mixing lime materials with lignin‐containing black liquor—a by‐product from the pulp industry—could elevate soil pH change in both conventional and no‐till systems and expedite vertical downward movement of lime in no‐till system. Results indicate that mixing lime with black liquor has the potential to not only elevate the increase in soil pH in both conventional till and no‐till systems, but also accelerate downward movement of lime to correct soil pH below the soil surface. Mixing agricultural lime or super fine micro lime with black liquor increased soil pH to a depth of 25–30 cm within 147 days after surface application to a no‐till soil. [ABSTRACT FROM AUTHOR]

This research is aimed at addressing the complaints of local people living near chicken farms who are disturbed by odors caused by livestock activities, and specifically, by the generation of ammonia gas from chicken manure. Methods that are expected to reduce the intensity of ammonia gas odors include both scattering lime on the surface of the soil and planting soybeans around the cages. The results obtained showed a reduction in the levels of ammonia gas by 57.48%–from 1.67 parts per million (ppm) near an untreated cage to 0.71 ppm near the cage that achieved the best results. The study found that spreading lime evenly over the chicken manure was the most effective method that farmers could use to reduce ammonia odors. The sample area treated by the addition of soybean plants showed a reduction in the levels of ammonia gas from 1.67 to 0.78 ppm. [ABSTRACT FROM AUTHOR]

Cadmium accumulates in soils that receive repeated applications of Cd-rich superphosphate fertilizers. There is evidence that adding clovers to a crop solubilizes soil Cd, increasing the bioavailability of Cd. This can lead to high plant Cd concentrations. This research aimed to test whether liming-induced increases in pH in mixed crops of clovers and ryegrasses reduced forage Cd concentrations. A greenhouse pot trial applied lime at three rates (0, 1, and 2% of soil dry weight) to eight different plant treatments--four as monocultures (perennial ryegrass [Lolium perenne L.], Italian ryegrass [L. multiflorum Lam.], white clover [Trifolium repens L.], and red clover [T. pratense L.]) and four as ryegrass--clover mixtures (two plant types in each treatment)--in soil (initial soil pH = 5.1, initial soil Cd concentration = 1.31 mg kg-1) with added Cd (CdSO4 ~ 1 mg kg-1). Adding lime increased soil pH in both mono- and mixed crops and, in most treatments, increased forage yields. However, the relationship between forage Cd and soil pH differed between plant treatments. In mono- and mixed crop treatments containing perennial ryegrass, adding lime increased the forage yield but did not increase the mass of Cd in the plants compared with the no-lime treatment. However, adding lime to treatments that included Italian ryegrass increased both the forage yield and the Cd compared with the no-lime treatment. The results show that a combination of certain plant species composition and lime rates can optimize forage yields without increasing forage Cd concentrations. [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 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]

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]

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.

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.

It is generally accepted that liming ameliorates soil acidity. However, the method of lime application is thought by many to influence its effectiveness in acid soils. In this study, we wanted to assess the degree of effectiveness of surface-applied lime and lime incorporated into the soil on soil structural attributes and water retention of a Dystrudept soil in the SE region of the State of Paraná, Brazil. Lime was added at the rate of 15 t/ha to soil through: (i) surface broadcasting, (ii) incorporation via ploughing and harrowing, (iii) incorporation via subsoiling and harrowing. A control treatment with zero lime application was included in the experiment. The addition of lime by surface broadcasting resulted in significant reductions in soil bulk density ( BD) and macroporosity (Ma) and increases in total porosity ( TP) and microporosity (Mi) of the top soil layer (0-0.10 m). The reverse was the case in the 0.10- to 0.20-m soil layer; where lime was incorporated via ploughing and harrowing, increases in BD and reductions in TP and Ma were observed. Addition of lime also significantly increased soil water retention, with maximum retention recorded from soil amended with surface broadcast lime. Changes in soil chemical attributes (increases in pH, Ca2+ and Mg2+ contents; reductions in potential acidity and Al3+ content) were responsible for the changes observed in structural and physical attributes, and water retention. Bearing in mind the lower application costs, improvement in the soil chemical attributes for plant development and soil physical quality, surface broadcast lime can be considered a promising alternative for no-till farmers. [ABSTRACT FROM AUTHOR]

Liming with Ca and Mg carbonates is commonly used to reduce soil and stream acidity and to improve vegetation growth and nutrition in forests. Ten years ago, dolomite lime was experimentally applied to a forest catchment on granite in the Vosges Mountains (northeast France), which is characterized by acid soils and drained by an acid stream. The average Mg isotope composition of the dolomite lime (-1.75%) was low compared with that of tree foliage (-0.70%), granite and deep soil layers (-0.40%), and stream water (-0.80%) in the control catchment. After liming, the exchangeable Mg concentrations in surface soil layers, which were initially very low, increased, and the Mg isotope composition decreased (up to -0.60%). The decrease was smaller in deeper layers but not in proportion to the increase in exchangeable Mg content, suggesting contributions from mineralization of organic matter and/or displacement of exchangeable Mg from surface layers. Before application, Mg concentration in beech and fir leaves was low, and that of 1-yrold fir needles was lower than that in current needles. Internal Mg translocation within fir needles also resulted in a lower d26Mg of older needles. Three years after dolomite application, the Mg isotope composition of plant leaves was lower than that in the control catchment; this decrease (up to -1.00%) was attributed to direct uptake of Mg from dissolving dolomite. Liming doubled the concentration of Mg in the stream, whereas the Mg isotope composition decreased correspondingly from -0.80 to -1.20%, indicating a fast transfer of dolomite Mg to the stream. Our findings indicate that monitoring of δ26Mg may be a promising tool to study the fate of dolomitic inputs in terrestrial and aquatic ecosystems. [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]

Lime in pelletized form is potentially more convenient for farmers than ground limestone, as it can be applied using conventional fertilizer-spreading equipment. Pelletized lime is intended to maintain an optimum soil pH when applied annually at a rate of 350 kg lime/ha/yr. Interactions between lime and N fertilizer rate were examined by applying 0, 75, 150, 225 and 300 kg N/ha/yr (as calcium ammonium nitrate) in combination with 0, 175, 350 and 525 kg pelletized dolomitic lime/ha/yr over 3 yr to a permanent grassland sward used for silage production in County Down, Northern Ireland. Equal rates of ground lime, from the same source as the pelletized lime, were applied as a comparison. Effects on soil chemical properties, grass dry matter (DM) yield and herbage nutrient removal were examined. Lime maintained or slightly increased the soil pH, particularly in the top 2.5 cm of the profile, but there was no difference in the performance of pelletized lime compared to ground lime in any of the parameters measured. Lime had no significant effect on grass DM yield or grass quality; however, there was a significant ( P < 0.05) reduction in yield at the first cut, particularly in year 2, when the highest lime rate (525 kg lime/ha/yr) was applied in the absence of N fertilizer. The dolomitic nature of the lime (11% Mg) resulted in significant ( P < 0.001) increases in soil and herbage magnesium levels, and this could be beneficial for reducing the incidence of grass tetany in grazing animals. The P content of the herbage was also significantly higher in plots receiving lime, which suggests that lime may have enhanced the mineralization of P or stimulated root growth. [ABSTRACT FROM AUTHOR]