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Soil acidification is an issue for agriculture that requires effective management, typically in the form of lime (calcium carbonate, CaCO3), application. Mid infrared (MIR) spectroscopy methods offer an alternative to conventional laboratory methods, that may enable cost-effective and improved measurement of soil acidity and responses to liming, including detection of small–scale heterogeneity through the profile. Properties of an acidic soil following lime application were measured using both MIR spectroscopy with Partial Least Squares Regression (MIR-PLSR) and laboratory measurements to (a) compare the ability of each method to detect lime treatment effects on acidic soil, and (b) assess effects of the different treatments on selected soil properties. Soil properties including soil pH (in H2O and CaCl2), Aluminium (Al, exchangeable and extractable), cation exchange capacity (CEC) and organic carbon (OC) were measured at a single field trial receiving lime treatments differing in rate, source and incorporation. Model performance of MIR-PLSR prediction of the soil properties ranged from R2 = 0.582, RMSE = 2.023, RPIQ = 2.921 for Al (extractable) to R2 = 0.881, RMSE = 0.192, RPIQ = 5.729 for OC. MIR-PLSR predictions for pH (in H2O and CaCl2) were R2 = 0.739, RMSE = 0.287, RPIQ = 2.230 and R2 = 0.788, RMSE = 0.311, RPIQ = 1.897 respectively, and could detect a similar treatment effect compared to laboratory measurements. Treatment effects were not detected for MIR-PLSR-predicted values of CEC and both exchangeable and extractable Al. Findings support MIR-PLSR as a method of measuring soil pH to monitor effects of liming treatments on acidic soil to help inform precision agricultural management strategies, but suggests that some nuance and important information about treatment effects of lime on CEC and Al may be lost. Improvements to prediction model performance should be made to realise the full potential of this approach. [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]

Tillage conservation practices (CA), traditional agriculture (TA), and liming influence soil properties and crop yield. However, it is essential to demonstrate which tillage and liming practices improve soil properties and forage corn yield. This study compared soil properties and forage corn production in two tillage systems with the addition of dolomite and lime, which formed four treatments. The tillage in the first three days surpassed the TA soil CO2 emission, with 64.8% more CO2 than in the CA soil, and the TA hydraulic conductivity and bulk density were more suitable than those in the CA soil. The CA soil had 233 earthworms m−2 more than in TA. The TA green forage corn yielded 6.45 t ha−1 more than in CA, with a higher P, Ca, and Mg foliar content than in CA, but in the CA, the foliar N and K were higher than in TA. The liming increased soil cations (except K), highlighting the lime on dolomite with—52% Al and + 4.85 t ha−1 of forage corn compared to the control. Soil CO2 emission was far lower in CA than in TA, with a slightly lower forage yield, and other soil properties were improved, meaning lower land preparation costs and time savings than in TA. Lime improved acidic soil faster than dolomite, generating higher forage yields. [ABSTRACT FROM AUTHOR]

Results of eleven survey rounds of arable soils performed from 1964 to 2022 in the southwestern part of the central chernozemic region in Belgorod oblast are analyzed. Ordinary chernozems predominate in the steppe zone of the region, and typical and leached chernozems predominate in the forest-steppe zone. During the eleventh survey round (2019–2022), the average application of mineral fertilizers was 114.4 kg a.i./ha; of organic fertilizers, 9.6 t/ha; the rate of liming of acid soils was 43 800 ha per year. As a result, the average yield of winter wheat increased to 5.09 t/ha, sugar beet up to 45.6 t/ha, and corn for grain up to 7.15 t/ha. At the same time, the maximum value of the weighted average content of organic matter (5.3%) was recorded in the soils of cropland for the entire observation period. The part of acid soils decreased to 28.6%, and the part of moderately acid soils decreased to 3.0%. The hydrolytic acidity decreased to 2.7 cmol(c)/kg. The weighted average content of available phosphorus (139 mg/kg) and potassium (161 mg/kg) was the highest in the central chernozemic region. Soils with the low content of available sulfur comprised 85.7% of surveyed soils, those with the low content of zinc, 97.2%; copper, 92.5%; cobalt, 98.8%, manganese, 40.1%; and molybdenum, 21.3%. In terms of the content of available boron, 98.2% of soils were classified as very rich. [ABSTRACT FROM AUTHOR]

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

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]

Modelling the lime requirement (LR) is a fast and efficient way to determine the amount of lime required to obtain a pH that can overcome the adverse effects caused by soil acidification. This study aimed to model the LR based on the properties of soil and lime. A total of 17 acidic soils and 39 lime samples underwent soil–lime incubation in the laboratory. The predictive equations for the LR (t ha−1) were modelled using ∆pH (the difference between the target pH and initial pH), the neutralizing value (NV, mmol kg−1) of lime, soil pH, soil clay content (%), soil bulk density (BD, g cm−3), and the depth of soil (h, cm) as the factors in an exponential equation. The generic predictive equation, L R = ∆ p H × e − 3.88 − 0.069 × N V + 0.51 × p H + 0.025 × C l a y × B D × h , was validated as the most reliable model under field conditions. Simplified predictive equations for different soil textures when limed with quicklime and limestone are also provided. Furthermore, the LR proportions provided by hydrated lime, quicklime, limestone, and dolomite in commercially available lime can be expressed as 0.58:0.64:0.97:1.00. This study provides a novel and robust model for predicting the amount of lime product containing components with different neutralizing abilities that are required to neutralize soils with a wide range of properties. It is of great significance to agronomic activities and soil remediation projects. [ABSTRACT FROM AUTHOR]

Background and Aims: Suitable N source supply is critical to improve plant growth and N uptake, but the importance of nitrate (NO3−) for rice (Oryza sativa L.) and microbiota is often neglected in acidic paddy soils where ammonium (NH4+) is dominant. This study aimed to explore the differential effects of NH4+ and NO3− on rice growth, fertilizer nitrogen recovery efficiency (FNRE), and rhizosphere bacterial community in acid soil. Methods: Two rice varieties, Kasalath (Al-sensitive indica) and Koshihikari (Al-tolerant japonica), were exposed to different N sources with or without lime in an acid soil. Results: Liming and NO3− application solely improved the growth and FNRE of the Al-sensitive rice, namely, by increasing soil pH and alleviating Al toxicity. Compared with liming and rice variety, N source had a more pronounced influence on rhizobacterial community composition. Of the two sources, NO3− had a stronger effect on the rhizobacterial community than NH4+. Remarkably, rice plants fed with NH4+ specifically recruited Desulfosporosinus and Desulfitobacterium associated with ferric NH4+ oxidation in the rhizosphere, whereas those exposed to NO3− recruited Alicyclobacillus with NO3−-reducing iron oxidation ability. Three keystone taxa were identified in a rhizobacterial co-occurrence network analysis: Alicyclobacillus, which was positively associated with rice growth and FNRE, and Acidobacteriales and WPS-2, both with negative associations. Conclusion: Compared with NH4+, NO3− enhances the growth and FNRE of Al-sensitive rice and exerts dominant effects on the rhizobacterial community, which indicates the importance of NO3− for rice and has instructive implications for N management in acid soil. [ABSTRACT FROM AUTHOR]

In the course of highway construction and use in loess area, subgrade settlement disease is common and has great destructiveness. The cone penetration test (CPT), especially the pore pressure cone penetration test, can provide three continuous readings along the exploration depth cone tip resistance, lateral friction resistance and excess pore water pressure. In this paper, CPT tests are carried out in the losses areas in Shanxi, China. Some data and curves are obtained by using CPT, which are quite different from those obtained by conventional drilling, reflecting the soil layer characteristics of the subgrade section, in order to provide a reference for similar projects. The results showed that CPT has a strong advantage in the analysis of the effect of compacted pile in the treatment of pile length and the improvement and reduction of indicators of different layers along the depth direction. However, the correlation between the static penetration and the compaction coefficient commonly used in the current norms still needs to be further studied to enhance the correlation analysis with detection parameters. [ABSTRACT FROM AUTHOR]

N2O contributes to increasing the greenhouse effect and is also involved in stratospheric ozone depletion. In soil and water, N2O reductase catalyses the reduction of N2O into the inert form N2. N2O reductase activity is known to be affected by acidic conditions and the application of liming materials to acidic soils is now proposed as a solution for mitigating soil N2O emissions. During a one-year laboratory experiment, we studied the functioning of N2O reductase after the application of calcium carbonates to an acidic soil with a very low capacity to reduce N2O. The functioning of N2O reductase was characterised through anaerobic incubations using the acetylene inhibition technique combined with a logistic model to determine the main enzyme functioning characteristics (latency, maximal rate). Both changes in soil pH and soil capacity to reduce N2O were rapidly observed after the application of lime materials. The activity of N2O reductase was observed to be efficient throughout the experiment even when the soil had returned to initial acidic conditions, revealing a hysteretic response of N2O reductase to pH variations. Nevertheless, some signs of lower N2O reductase activity over time were observed mainly after 200 days of applying lime materials. Altogether, these results suggest that, in this soil condition, the beneficial impact of the application of liming materials on N2O emissions could last longer than this on soil pH. [ABSTRACT FROM AUTHOR]

Acid soils cover about 30% of the total ice-free land area. Based on this, the study aimed to evaluate soil acidity correction, focusing on identifying studies on limestone recommendations and corrective measures in agricultural systems. To do so, a systematic literature review (SLR) was carried out, composed of: 1) a systematic literature mapping (SLM), which identifies studies using topic-specific keywords and database automatic search; 2) Snowballing, technique that expands the initial selection using references of the selected studies; and 3) a SLR to synthesize the selected papers. First, 169 scientific papers were selected, of which 116 by SLM, 26 by backward Snowballing, and 27 by forward Snowballing. Most of the papers were about lime requirement (LR) methods (43%) and liming effects on soil and plants (19%). A total of 26 LR methods were found in the papers, of which most were base saturation and Shoemaker-McLean-Pratt methods. Calcium and magnesium carbonates, as well as dolomite, were the main sources of soil acidity correction. In brief, the study provided a critical and constructive analysis of the existing literature on soil acidity correction; the findings showed that liming is the most used and effective method to neutralize soil acidity. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) pollution poses a growing threat to rice production in acidic paddies. In south China, a common agricultural practice involves the combined utilization of Chinese milk vetch (M) and rice straw (R). However, it is unclear how the addition of lime to these amendments affects Cd bioavailability and accumulation in soil. Control (CK), chemical fertilizer (F), Chinese milk vetch + rice straw + chemical fertilizer (MRF), and Chinese milk vetch + rice straw + chemical fertilizer + lime (MRFL) treatments were applied to develop a kind of green, efficient, and practical amendment for acidic paddies. We conducted a microplot experiment to explore Cd immobilization in paddy soil and the Cd content in rice grains with these treatments. The results showed that compared with F, the rice Cd in the MRF and MRFL treatments were significantly decreased by 51.7% and 65.2% in early rice and 23.0% and 43.3% in late rice, respectively. Both the MRF and MRFL treatments significantly reduced soil available Cd and weak acid-extractable cadmium (Aci-Cd) concentrations and increased soil organic matter (SOM), exchangeable cation concentrations, and pH, which converted Cd into a stable form in soil. In addition, the MRF and MRFL treatments increased soil pH value by reducing soil exchangeable hydrogen ion concentration (E-H). Additionally, recombination of Cd forms was the primary factor in the reduction in available Cd concentration according to partial least squares path modeling (PLS-PM) analysis. The Cd concentration of rice grains was primarily associated with soil available Cd, soil pH value, and SOM. Overall, these results provide useful data and novel insights into reducing rice grain Cd in south China. [ABSTRACT FROM AUTHOR]

The soils of four citrus orchards in western Zhejiang were studied in this research. In order to explore the effects of lime on soil chemical properties and bacterial communities, the incubation experiment was conducted with six different dosages of lime addition, 0, 0.6, 1.2, 2.4, 4.8, 7.2 g/kg, respectively. The results showed that soil pH increased significantly (p < 0.05) and the contents of exchangeable acid decreased significantly (p < 0.05) at the early stage of lime application. As time went by, the reacidification existed in the soil of each treatment, mainly reflected in a significant (p < 0.05) decrease in soil pH. Liming increased the nitrate nitrogen content and decreased the ammonium nitrogen content in the four soils. However, the responses of other nutrient indexes to lime varied in different soils, which might be due to the different degrees of soil acidification. In general, the addition of lime increased the soil integrated fertility index (IFI) and improved the soil nutrient status. The application of lime under 2.4 g/kg significantly improved the structure of bacterial community and increased the relative abundance of soil bacterial community species, while the application of lime above 4.8 g/kg might inhibit the growth and activity of microorganisms, resulting in the reduction of soil microbial biomass and diversity. Redundancy analysis (RDA) showed that lime affected the bacterial community mainly by reducing the content of soil active acid and exchangeable acid. At the same time, network analysis showed that the bacterial community had a stronger buffer capacity against external disturbances after lime application. In conclusion, the addition of lime with appropriate amount (2.4~4.8 g/kg, corresponding to a field application rate of 5.8~11.5 t/ha) in acid orchard soil could improve soil properties, soil integrated fertility, and the diversity and stability of the bacterial community. [ABSTRACT FROM AUTHOR]

Phosphorus (P) transformations and associated changes in soil chemistry following lime application in acidic soils are very determinant to enhance P use efficiency. Thus, this study was conducted to evaluate the effects of different rates of lime on soil P fractions and chemical properties in acidic Luvisols of southern Ethiopia. The lime rates were 0 t/ha (0%), 3.75 t/ha (50%), 7.5 t/ha (100%), and 11.25 t/ha (150%), and incubated for a month with three replications. The soil P fractions analyzed includes soluble P (P-sol), P associated with iron (Fe-P), aluminum (Al-P), calcium (Ca-P), organic part (Org-P) and residual (Res-P). The result indicated that liming significantly (p < 0.05) improved the release of P-sol, Ca-P, and Res-P, and reduced Fe-P, Al-P, and Org-P. The changes in soil chemical properties were also significant. For instance, increased rate of lime enhanced soil pH from 5.3 to 6.5, reduced exchangeable acidity from 1.47 to 0.15 cmol(+)/kg, and increased available P from 2.74 to 8.72 cmol(+)/kg. Yet, the amount of P-sol was found low for plant needs even at a 150% rate of lime. Thus, working on external P requirement to equilibrate the need for plants followed by crop response validation are suggested. [ABSTRACT FROM AUTHOR]

Acid soils are a major constraint to agricultural productivity in many parts of sub-Saharan Africa, including Ethiopia. Restoring soil pH to optimal ranges for agriculture can have a significant impact on yields, particularly for acid intolerant crops like wheat and barley. The application of agricultural lime is the standard corrective, although the large application requirements, lack of farmer awareness, and weak or non-existent lime supply chains make this a complex problem to address at scale. To date, no large-scale farmer trials of lime application have been undertaken in Ethiopia. This leaves open the question to local policy makers as to the economic benefits given the enormous capital and logistics investments required. To help address this we leverage existing spatial edaphic data and longitudinal crop surveys to simulate the productivity impact of varying lime and fertilizer applications. Our estimates find the impact of moving pH from 5.5 to 6.5, modeled as a lime soil remediation strategy, increases yields by 22% and 19% for wheat and barley, respectively. In addition, at lower pH levels our models indicate that commonly used nitrogen-based fertilizers are less cost-effective. For wheat in highly acidic soils, we find that fertilizers cost over two times as much as a single application of lime over a five-year period. The cost savings of the use of lime reaches as high as 121% of average one-year agricultural household income for wheat; with barley these savings are lower but still substantial at 24%. In general, we advocate for an integrated soil fertility management strategy that applies appropriate levels of fertilizer on pH balanced soil. If successful, Ethiopia's acid soil reclamation could become a modest version of Brazil's successful "cerrado miracle" and serve as an example for Africa. [ABSTRACT FROM AUTHOR]

The human body needs calcium (Ca) to maintain strong bones and teeth and to build a strong structure, helping muscles contract and playing a crucial role in the structural and signalling process. However, low calcium consumption in the diet has related to a variety of disorders in humans, which can have long-term health repercussions. Therefore, this study aimed to evaluate the Ca biofortification capacity of cabbage (Brassica oleracea var capitata) supplied with different Ca-supplying inorganic fertilizer sources at various fixed levels based on soil liming potential grown in open field conditions where four hybrids of cabbage grown in Ca deficient acidic soil. Ca applied as Limestone (CaCO3) (150% and 175% liming potential) and Dolomitic limestone [CaMg(CO3)2]150% liming potential yield high Ca content in cabbage head and foliage (61.3 mg 100 g-1), high glucosinolates content (53.12 mg 100 g-1) and lower oxalate(0.31 mg 100 g-1) that produced firmer head as compared with Ca untreated control which also promoted high market value for Ca biofortified ones. On the other hand, Ca addition leads to lower Fe and Mg content in the cabbage tissues due to an antagonistic effect. All four hybrids of cabbage studied using the agronomic method of biofortification significantly(p=0.05) improved Ca enrichment (20% more compared to control) without showing any toxicity symptoms making possibility to obtain Ca biofortified cabbage in acidic soil of a hilly ecosystem by application of liming. [ABSTRACT FROM AUTHOR]

Soil acidity with associated low nutrient availability is one of the major constraints to soybean production in southwestern Ethiopia. Integrated use of lime and acid-tolerant crops is believed to reduce soil acidity and improve crop production. The experiment was conducted in the field condition of Mettu, southwestern Ethiopia during the 2017/18 main cropping season. The experiment comprised fifteen soybean genotypes and two soil amendment (lime and unlimed) treatments arranged in a split-plot design with three replications. For each treatment, four rows were planted per plot; data related to growth, root, nodule, and yield of the crop were collected at a necessary stage for each. Liming and genotype interaction had significantly (P = 0.01) affected all parameters considered except for hundred seed weight and root volume and were affected only by the main effects of genotypes and liming. A significant reduction for most parameters was found on lime-untreated soil than treated soil. Though some genotypes showed higher performance for root, growth parameters, and yield components under unlimed soils; however, gave higher yield and yield components, when grown on lime-untreated with an average yield reduction of 13.7%, due to soil acidity. The maximum grain yield of (1943.93 kg ha-1) was obtained under lime treated acid soil from PI567046A genotype; while the lowest (510.49 kg ha-1) were recorded from SCS-1genotype under the lime untreated acid soil. Genotype BRS268 showed higher yield (1319.83 kg ha-1) under lime untreated acid soil than lime treated acid soil (1143.47 kg ha-1) and showed less reduction percentage for a number of the nodules, root weight, and number of seeds per plant; while PI567046A showed high reduction percentage for yield, biomass, number of pod and seed per plant. A high difference was observed among the soybean genotypes for soil acidity tolerance, which might be further exploited by breeders for the genetic improvement of soybean. Genotype BRS268 had performed better than other tested genotypes under increased soil acidity. selection would be effective to improve soybean genotypes performance on acid soils and identify low Phosphorus tolerant genotype that helps smallholder farmers optimize soybean productivity on acid soils in the study area. HAWASSA-04 variety is the most tolerant among the tested materials. However, further study is required by considering additional genotypes to reach a conclusive recommendation [ABSTRACT FROM AUTHOR]

Background and aims: Liming is widely used to alleviate soil acidity worldwide. However, the vast majority of studies with liming are restricted to agricultural systems that incorporate lime into the soil, not considering its effects as surface applications. Although liming effects on soil fertility and crop yield are well understood, there are few studies that elucidate the role of soil improvements in the established crop physiology and the revenue in lime-amended soils, especially when cultivated in regions prone to agroclimatic risks. Here, we address the effects of surface liming, for three growing seasons (2017–2019) subsequent to the lime treatment (2016), on soil fertility, root growth, crop nutrition, photosynthetic pigment concentrations, gas exchange parameters and production costs of maize cultivated in a tropical region on an acidic soil with low water regime. Methods: The treatments consisted of four dolomitic lime doses applied to the soil surface as follows: i) control (untreated soil), ii) half the recommended dose (½ RD), iii) full recommended dose (1 RD) and iv) twice the recommended dose (2 RD). Results: Surface liming increased soil fertility, and higher doses provided better results. Ca2+ and Mg2+ concentrations increased at greater depths under higher lime doses, directly influencing maize root growth. Even under low water availability, also in the driest year of 2018, this liming induced improvement of growing conditions and increased growth was observed'. Maize grown under lime at 2 RD exhibited better nutrition, improved chlorophylls concentration, photosynthetic parameters and water use efficiency. As a result, both shoot growth and grain yield also increased. Net profit in the first growing season was higher in 1 RD, whereas in the two following growing seasons the application of 2 RD resulted in higher revenue. Conclusions: Increased water use efficiency, chlorophyll and photosynthesis were the main physiological traits regulating the growth and yield of maize plants in response to lime supply. Additionally, root development was favoured in the entire soil profile, mainly in deeper layers, after improvements on soil fertility by cascading effects of liming. These results were more prominent in 2RD lime-amended soil, which also resulted in greater net profit over the 3 years studied. [ABSTRACT FROM AUTHOR]

• The potential of microorganisms in olive trees in southern Brazil is still a gap. • Beneficial microorganisms can improve seedling growth and resistance to stress. • Each species of microorganism had its beneficial potential affected by pH. • The inoculant species can be adjusted according to the soil condition. The benefits of plant growth-promoting microorganisms to increase productivity have been demonstrated in various crops. Little is known about their potential in olive orchards in southern Brazil, whose naturally acidic soils are intensively limed for olive production. The present study investigated the effect of four inoculations (no inoculation, inoculation of the bacterium Azospirillum brasilense , inoculation of the fungus Trichoderma harzianum and inoculation of the fungus Trichoderma virens) at different levels of soil liming on the development of olive seedlings. The results showed that the microorganisms T. virens, T harzianum, and A. brasilense, but especially T. virens , when applied to the soil, promoted increased growth in height, diameter, and total dry mass yield of young olive trees, especially in conditions of lower soil acidity, with increases of 92, 34 and 33 % respectively, compared to the soil without inoculation. Less acidic environments, more favorable for olive tree development, enhanced the positive effect of these microorganisms. The microorganisms also mitigated the effects in potentially more stressful conditions, as observed by the higher concentration of photosynthesizing pigments, the reduction in hydrogen peroxide content, and the reduction in antioxidant enzyme activities in leaves and roots, in soil pH below that recommended for olive cultivation. [ABSTRACT FROM AUTHOR]

High nitrous oxide (N2O) emissions (2–10% of fertiliser N) were observed previously from acid soils cropped with sugarcane (Saccharum officinarum) in Australia. We assessed the impact of lime, a nitrification inhibitor (NI, as 3,4-dimethylpyrazole phosphate, DMPP), and copper (Cu) on N2O emissions from an acid sugarcane soil in a laboratory experiment using (1) urea (U), (2) U + DMPP, (3) U + CuSO4.5H2O (U + Cu), and (4) U + DMPP + Cu. The treatments were applied to both an un-limed soil (pH 5.1) and a limed soil (pH 6.9) and incubated at 25 °C and 55% water holding capacity (WHC) for 28 d, and then increased to 90% WHC for another 8 d to favour denitrification. At 55% WHC, both the addition of the NI (U + DMPP) and the liming of the acid soil significantly decreased cumulative N2O emissions, due to significantly lower net nitrifications. Liming and DMPP decreased N2O emissions by 79% and 90%, respectively. However, where lime and DMPP were applied together, N2O emissions decreased by 94% compared to those in the un-limed (acid) U-treated soil. In contrast, the addition of Cu and the increase in water content to 90% WHC had no significant effect on N2O emissions. Therefore, the combined use of lime and DMPP provides the best option to decrease N2O emissions from the acid soil. [ABSTRACT FROM AUTHOR]

Fertilization with suitable amendment in acidic soil is crucial to achieve long-term high crop yield without deteriorating soil health in intensive cropping system. We studied the chemical and biological properties of soil, soybean, and wheat yield after 47 years of long-term fertilization in an acidic Alfisol. Treatments were: unfertilized (control); recommended N dose (N); recommended N and P (NP); recommended N, P and K (NPK); NPK + hand weeding (NPK + HW); NPK + 10 Mg ha−1 farmyard manure (NPK + FYM) and NPK + 0.40 Mg ha−1 lime (NPK + lime). Long-term application of NPK + FYM significantly enhanced the soil cation exchange capacity (CEC), organic carbon, available NPK and microbial functions compared to NPK. Application of NPK + lime increased soil pH, dehydrogenase activity (DHA) and bacterial population by 15.7%, 38.8% and 145% respectively, over NPK. Continuous inorganic-P fertilizer application leads to substantial build-up of available-P in soil. Fertilization of FYM/lime with NPK recorded higher crops yield compared to NPK. Soil DHA, bacterial population and CEC were most influencing factors governing grain yield. Overall, long-term application of NPK with FYM/lime improved soil health and crop yield, but rate of inorganic-P input should be curtailed in an Alfisol. [ABSTRACT FROM AUTHOR]

Soil acidification is a natural phenomenon that human activity can accelerate or manage. Acid soils limit plant growth by reducing nutrient availability and causing aluminum toxicity, significantly reducing crop production. Liming has proven efficient for increasing crop yield on acidic soils. Knowledge is required on the effect of liming on the soil pH dynamics to find the suitable material, application rate, timing, and method. The objective of this study was to develop a prediction model of soil pH temporal variations after lime application using data from the literature. A database was built from research results extracted from 16 scientific papers that provided data on soil acidity changes over time under different liming treatments. Machine learning (ML) was used to predict soil pH dynamics from eight predictive parameters: rate of application, time since application, neutralizing value (CCE), grind fineness (D50), pH measurement depth, soil acidity (pH prior to liming), the type of solution used for pH measurement (water or CaCl 2) and the soil:solution ratio used to measure pH. Since soil pH fluctuates with seasons, all pH values were expressed as difference between the actual pH value and that of an unlimed control (ΔpH). The Random Forest (RF) algorithm was tested to predict ΔpH over time. On testing, we obtained an R2 between measured and predicted ΔpH values of 0.881 and an RMSE of 0.230. These results are excellent, considering the heterogeneity in soils, liming materials, and pedoclimatic conditions found in the 16 papers. The primary factors influencing ΔpH, ranked by their impact are application rate, time elapsed post-application, and lime characteristics including its grind fineness and neutralizing value. • Random Forest robustly predicts soil pH change over time following lime application. • The predictors are: rate, neutralizing value, particle size, depth, and initial pH. • The model predicts that, on average, lime increases soil pH for 82 weeks. • Machine learning models are promising tools in managing liming practices. [ABSTRACT FROM AUTHOR]

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

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

Introduction: Beans are most widely cultivated legume in the world. In Mexico it is second most important crop after corn and of basic importance for human consumption. Selection of varieties tolerant to water deficit constitutes a strategy to increase the genetic stability of crops and reduce losses in yield in order to define specific agroecotypes for bean crop. Method: Objective of work was to evaluate four varieties of black beans with horizontal resistance to hydric stress under rainstorm conditions in acid soils in two localities of Northeastern Sierra of state of Puebla. A randomized complete block design with 10 treatments and 5 repetitions was used; variables evaluated were a) survival during phenological cycle of crop and b) potential yield with addition of agricultural lime to soil, during 2019 agricultural cycle. Results: The emergence of the crop was recorded 10 days after sowing (dds), flowering (60 dds) and physiological maturity at 124 dds, in San Juan Acateno of the municipality of Teziutlán and in Pezmatlán of the municipality of Tlatlauquitepec. The Huejonapan and Acatlán bean varieties without lime application, obtained the highest potential yield with 757 and 562 kg ha-1 respectively in the town of San Juan Acateno under rainstorm conditions during the 2019 agricultural cycle. Conclusion: Application of agricultural lime did not have a significant effect on yield of improved varieties, as well as in Michigan regional control; However, highest production was presented in Huejonapan and Acatlán variety without application of agricultural lime during 2019 agricultural production cycle for town of San Juan Acateno in municipality of Teziutlán, Puebla. [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]

Given that cadmium (Cd) poses high persistence in the environment and toxicity to humans, strategies to either decrease or avoid Cd entry in the trophic chain are fundamental to secure food safety. Here we assessed the effects of applying rates of Si as a diatomaceous Earth-based fertilizer on the amelioration of Cd toxicity towards maize plants grown on soil with or without pH correction. Besides determining Si and Cd concentrations, we also evaluated plant accumulation of nutrients (N, P, K, Ca, Mg, Fe, Mn, Cu, and Zn) as a function of Si doses applied to the soil. Results showed that both the Si application and the liming had a positive effect on biomass and nutrient uptake, but the Si effect on plants' performance took place irrespectively to the soil pH. Silicon ameliorated Cd phytotoxicity in both limed and unlimed soils by decreasing Cd concentration in shoots and improving biomass yield and plant nutrition. Silicon alleviation of Cd-inhibitory effects on plants was more effective in the unlimed soil owing to the higher Cd availability in acidic soils. Also, taking into account the reduced transfer of Cd to shoots driven by Si, lower Cd accumulation in maize grains is likely, with implications to food safety. So, further studies on field conditions are warranted. [ABSTRACT FROM AUTHOR]

[Display omitted] • In soil, adsorption of FA is limited by the binding to external surfaces of nano-aggregates. • The overall adsorption of FA is pH independent and has a relatively low affinity. • In acid soils, FA prefers direct interaction with soil oxide particles, releasing phosphate. • NOM-oxide interaction can be reduced by soil liming, decreasing the solubility of oxyanions. • A dual-phase model is developed to describe the release of PO 4 upon FA addition. For more insight into the interaction of natural organic matter (NOM) with metal (hydr)oxides and oxyanions, the adsorption of added fulvic acid (FA) and the corresponding release of phosphate (PO 4) were studied for a series of agricultural soils (∼0 – 25 cm), strongly varying in soil properties. Interpretation of the data with surface complexation modeling using the NOM-CD model applied in a dual-phase mode shows that the adsorption of added FA, in contrast to PO 4 , is restricted to the external surfaces of nano-aggregates. The adsorption is relatively weak and pH-independent, due to its competition with the native NOM of the organo-mineral phase. At low pH, the functional groups of both added FA and native NOM shift in the interface towards the soil oxide surfaces, making both a good competitor for adsorbed phosphate, resulting in a higher amount of phosphate being released. With an increase in pH, the competition becomes weaker. As a result, more phosphate is bound and less is released when FA is added. Our surface complexation modeling points to the existence of organo-mineral nano-aggregates with sizes of >∼10 – 270 nm, which depends on the total reactive surface area of the soil. Our findings imply that organic amendments containing FA equilibrate with only a portion of the total reactive surface area. In acidic soils, the addition of such organic amendments will be more effective in solubilizing phosphate, which is beneficial from a plant nutrition perspective, but simultaneously it may also contribute more to environmental eutrophication. [ABSTRACT FROM AUTHOR]

[Display omitted] • 5 RDs neutralise 500 up to 10 000 mmol H+/kg, variation in mineralogy and target pH. • Automatic titration (pH stat) estimates pH-dependent dissolution rates and slopes. • Novel soil-RD suspension estimates fast/slow pools of acid neutralising capacity. • Low and high doses (12 Mg/ha, 340 Mg/ha) for validation in 2 year soil-RD mesocosm. • Mechanistic model using pH stat and soil-RD suspension predicts mesocosm soil pH. The ongoing acidification of soil poses a significant threat to the proper functioning of various ecosystems worldwide. Silicate rock dusts (RD) are increasingly amended to acid soils to restore their pH, but the acid neutralising capacity (ANC) and dissolution rate of these products are highly variable and lack proper assessment protocols. It is expected that pH-dependent RD ANCs and dissolution rates dictate the pH increase in soils depending on the initial pH and pH buffer power of the soil. This study addressed these questions by comparing and validating three accelerated weathering tests for their capacity to predict the gradual liming effects in a two-year outdoor mesocosm. Five commercial RDs (two basalts, phonolite, foidite, and trachy-andesite) were tested in four acidified forest soils varying in initial pH, in texture and associated pH buffer power. First, RD dissolution was measured in aqueous batch renewal systems during one year at various starting pH (3.5, 4.5, and 5.5) and constant temperatures (20 °C, 37 °C, and 65 °C). These showed that the ANCs of RDs exhibit a fast fraction (half-life < 1 day) followed by a slower fraction. Second, titration tests of RDs at fixed solution pH, i.e., pH stat , performed between pH 3.5 and 4.5 revealed surface normalised dissolution rates that decreased factors 10–100 per unit pH increase, the slope depending on the RD's mineralogy. Indeed, the rate ranking of observed surface area normalised dissolution rates confirmed that of literature-based values, weighed by the XRD-derived mineralogical fractions. Third, lime-calibrated agitated soil-RD suspension tests were conducted for two months, illustrating the dependency of RD ANC on soil context, and yielding ANCs that were factor 2–5 times larger than in the batch renewal test because of pH buffering effects of soil particulates. Finally, an outdoor soil mesocosm on the four acid soils amended with RDs at 12 Mg/ha and 340 Mg/ha was established and soil pH was monitored for 2 years. The observed pH trends corresponded well for both the low dose (R2 a = 0.67) and the high dose (R2 a = 0.93) with model predictions made using the pH- and temperature-dependent RD dissolution rates (pH stat test) and the soil pH buffer power and RD slow ANC-fraction (soil-RD suspension test). This model predicts half-lives of RD dissolution ranging between <1 month to >100 years depending on the starting pH of the soil, its pH buffer power, the RD mineralogy (XRD based) and its specific surface area. This study shows that the dissolution and ANC of RD can be most pragmatically predicted with a series of lime-calibrated soil-RD suspension tests of maximally two months. [ABSTRACT FROM AUTHOR]

The solubility of cadmium (Cd) in soil and its transfer to plants are influenced by soil pH. While increasing soil pH reduces Cd solubility and accumulation in rice plants grown in acidic soils, its effect on Cd accumulation in vegetables remains inconclusive. Here, we investigated the impact of soil pH on Cd accumulation in dicotyledonous vegetables and elucidated the underlying molecular mechanisms. Soils collected from various locations were supplemented with varying quantities of lime to achieve soil pH values of around 5.0, 6.0, 7.0, and 8.0. Raising soil pH from around 5.0 to 8.0 markedly decreased extractable Cd. However, increasing soil pH tended to promote shoot Cd accumulation in dicotyledonous vegetable species including lettuce, pakchoi, and Chinese cabbage, and the model dicotyledonous plant Arabidopsis thaliana. Conversely, soil pH increase resulted in a monotonic decrease in rice Cd accumulation. In our hydroponic experiments, we discovered that iron (Fe) deficiency substantially increased Cd uptake and accumulation in dicotyledonous plants but not in rice. Increasing soil pH reduced soil Fe availability and induced the Fe transporter gene IRT1 expression in dicotyledonous vegetables roots, which led to an increase in IRT1-mediated Cd uptake and subsequently increased Cd accumulation as soil pH increases. A comprehensive model incorporating extractable Cd and root IRT1 expression better explained Cd accumulation in vegetable shoots. The application of 50 mg/kg of Fe fertilizer in neutral or alkaline soils resulted in a significant reduction in Cd accumulation by 34–58% in dicotyledonous vegetables. These findings reveal that increasing soil pH has two opposite effects, decreasing soil Cd availability while promoting Cd uptake through IRT1 upregulation, reconciling the inconsistency in its effect on Cd accumulation in dicotyledonous plants. Our findings provide important insights for understanding the factors affecting Cd uptake in plants and offer a practical solution to mitigate Cd contamination in vegetables. [Display omitted] • Elevating soil pH increases Cd accumulation in lettuce, pakchoi, and cabbage. • Fe-deficiency increases IRT1-mediated Cd uptake by dicotyledonous vegetables. • Fe-transporter gene IRT1 is responsible for Cd uptake in dicotyledonous vegetables. • Applying Fe fertilizer can decrease Cd accumulation in dicotyledonous vegetables. [ABSTRACT FROM AUTHOR]

There is a wide application of rhizobia inoculants to legume crops in Africa, irrespective of the soil acidity, though the latter limits the effectiveness of inoculants. Two trials were conducted in a controlled environment to determine suitable soil pH and impact of liming on soybean nodulation and nitrogen fixation to inform proper application of the rhizobia-inoculant technology on acid soils. In the first trial; soil, variety and inoculation had significant influence (p < 0.05) on weighed nodule effectiveness (WNE) and N fixation. Strongly acidic soils recorded low WNE and N fixation. In the second trial, WNE and N fixation significantly increased with co-application of lime and inoculation (p < 0.05). The results showed that soybean inoculation is effective in increasing nodulation and N fixation in moderate acidic soils, contrarily to strongly acidic soils. Interestingly, co-application of lime and inoculation has potential of increasing nodulation and N fixation in strongly acidic soils. The WNE is recommended as a robust formula to report nodule effectiveness, compared to the current percentage method. [ABSTRACT FROM AUTHOR]

A field experiment was conducted during Kharif and Summer seasons for two consecutive years of 2016-17 and 2017-18 with rice (Oryza sativa L.) and cowpea (Vigna unguiculata L.), grown in a sequence at Zonal Agricultural Research Station, Mandya on an acid soil to study the effect of biochar, lime and mangala setright on yield, nutrient uptake and fertility status of an acidic soil. Application of biochar along with soil test value based fertilizer (STV) + FYM + ZnSO4 influenced the productivity of rice and cowpea of 104.82 q ha−1 and 2474.77 kg ha−1, respectively and the uptake of nitrogen, phosphorus and potassium by rice (107.72, 28.16 and 69.34 kg ha−1, respectively) and cowpea (68.06, 5.86 and 38.67 kg ha−1, respectively) significantly, which was found on par with application of biochar along with RDF + FYM + ZnSO4. The soil pH (6.01), organic carbon content (5.03 g kg−1) and available nitrogen (340.45 kg ha−1), phosphorus (39.45 kg ha−1) and potassium (166.45 kg ha−1) significantly increased through the integrated use of biochar, FYM, ZnSO4 and fertilizers. Yield and soil properties like soil pH, organic carbon content and available nitrogen, phosphorus and potassium significantly increased with application of lime and mangala setright as compared to farmer's practice. Highest net income and benefit:cost ratio (2.65) was obtained with integration of soil test value based fertilizer application, FYM and biochar. Significant reduction in the productivity of crop and soil fertility was recorded in farmer's practice. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate effects of liming on phosphorus (P) adsorption and desorption capacity of acid soils in Assosa and Bambasi Districts. The soil samples were collected from six rural Kebeles; three from each Kebele and totally 18 samples were collected. The study was conducted in accordance with batch equilibrium method and adsorption values were fitted to Langmuir, Freundlich, and Temkin models to evaluate the goodness of curve fit. Differences between the models' indices and soil property parameters were analyzed by analysis of variance (ANOVA). The study revealed that unlimed soils of Amba-7, Sonka, and Amba-1 sites had higher range of P-sorption maxima (416.7–500.0 mg/kg) than the limed ones. In addition, the limed soils had shown lower adsorption maxima than the unlimed soils based on the Langmuir model. According to Freundlich model, limed soils had a lower Kf value than the unlimed soils. Similarly, Temkin model also verified that unlimed soils had higher b value (sorption energy) than limed soils. Total P desorbed (TPD) value of limed soils had shown a significant difference (p =.022) between the soils of different sites; then soils of Amba-16, Amba-7 and Sonka had relatively higher TPD value than the soils of the left sites. On lime treated soils the total P desorbed had shown increment relative to the untreated soils. The P-sorption isotherm was fitted best to Temkin model than the Langmuir and Freundlich models. Soils of the study area require liming to improve the P-adsorption problem; especially soils of Amba-7, Sonka, and Amba-1. [ABSTRACT FROM AUTHOR]

There is currently no quick available method for assessing chemical reactivity of liming materials used to neutralize soil acidity. This study was conducted to assess the effectiveness of a method developed to determine the chemical reactivity of liming materials. The reactivity of five conventional liming materials, biochar, charcoal and wood ash was determined using the method. Liming materials were applied to surface samples of two Ultisols at rates intended to neutralize exchangeable acidity. Physico-chemical and mineralogical properties of liming materials and soils were determined. Soils treated with the liming materials were incubated for 12 weeks in plastic containers using a soil: water ratio of 1:1. The pH and exchangeable acidity of the samples were measured every fortnight. The reactivity of the conventional liming materials was found to be strongly and positively (r = 0.99) correlated with their calcite contents, and strongly and negatively (r = −0.98) correlated with their dolomite contents. Strong positive linear relationships (R2 ≥ 0.79, p <.05) were observed between the reactivity and mean pH of the two soils between the 2nd and the 12th week, while strong negative linear relationship (R2 ≥ 0.79, p <.05) was observed between the reactivity and mean exchangeable acidity of the soils. Conventional liming materials were better than biochar and charcoal in neutralizing acidity. The new method was effective in predicting the ability of liming materials to neutralize exchangeable acidity and to raise the pH of acid soils. It can be used by farmers and lime producers to assess the reactivity of liming materials. [ABSTRACT FROM AUTHOR]

Many agricultural soils are naturally acidic, and agricultural production can acidify soil through processes such as nitrogen (N) fixation by legumes and application of N fertiliser. This means that decisions about mitigation of soil acidity (e.g. through application of lime), crop rotation and N fertiliser application are interdependent. This paper presents a dynamic model to determine jointly the optimal lime application strategies and N application rates in a rainfed cropping system in Western Australia. The model accounts for two crop rotations (with and without a legume break crop), for the acid tolerance of different crop types, and for differences in the acidifying effect of different N fertilisers. Results show that liming is a profitable strategy to treat acidic soils in the study region, but that there are interactions between N and acidity management. Choice of fertiliser affects optimal lime rates substantially, with the use of a more acidifying ammonium-based fertiliser leading to higher lime rates. The optimal liming strategy is also sensitive to inclusion of a legume crop in the rotation, because its fixed N can be less acidifying than fertiliser, and it allows a reduction in fertiliser rates. Higher rainfall zones have greater N leaching, which contributes to a higher optimal rate of lime. We find that injection of lime into the subsoil increases profit. Optimal lime rates in the absence of subsoil incorporation are higher than usual current practice, although the economic gains from increasing rates are small. [ABSTRACT FROM AUTHOR]

Red acid soil is generally distributed in humid tropical areas under high rainfall. The main constraint is usually the extremely low pH of the soil due to the very intensive leaching of the bases from the soil. At the same time, however, the soluble micro elements, such as iron, are high. This can cause plant toxicity. The liming of acidic soils is normally performed to reduce the iron toxicity as the first step toward providing a balanced nutrition for cultivated plants. The objective of this study is to determine the effects of liming on the soil pH, on the decrease of iron in the soil and on the growth of the pineapple. The research was done in the Greenhouse of the Research and Development Department, PT Great Giant Pineapple, Lampung, Indonesia, from November 2015 to April 2016. The design of the experiment was arranged as a completely randomized design with seven treatments and three replications, consisting of: No dolomite (D0), dolomite 1 t ha−1 (D1), dolomite 2 t ha−1 (D2), dolomite 3 t ha−1 (D3), dolomite 4 t ha−1 (D4), dolomite 5 t ha−1 (D5) with added Fe-EDTA and for the control treatment, no dolomite and no Fe-EDTA (C0). The results showed that an increase in the dolomite dose can increase the pH, potassium (K), calcium (Ca) and magnesium (Mg) in the soil and can decrease the iron (Fe) in the soil significantly. Increasing the pH, K, Ca and Mg and decreasing the Fe in the soil were seen to influence the growth of the pineapple. In particular, the leaf area of the pineapple plant increased considerably. The other parameters also increased, but not significantly. [ABSTRACT FROM AUTHOR]

The dual role of biochar for inhibiting soil acidification induced by nitrification was determined through two-step incubation experiments in this study. Ca(OH) 2 or biochar was added respectively to adjust soil pH to the same values (pH 5.15 and 5.85), and then the amended soils were incubated in the presence of urea for 70 days. The results showed that compared with Ca(OH) 2 treatment, both rice straw biochar and peanut straw biochar inhibited the decrease in soil pH and the increase in exchangeable acidity during the incubation. The application of biochars suppressed soil nitrification during the incubation, and thus reduced 7.5 mmol kg−1 and 1.4 mmol kg−1 protons released from nitrification compared to Ca(OH) 2 treatments. Compared with Ca(OH) 2 treatment, the ammonia-oxidizing bacteria population size was decreased by 8% and 12% in rice straw biochar and peanut straw biochar treatments respectively, which was the main responsibility for the inhibited nitrification after biochar application. In addition, the application of rice straw biochar and peanut straw biochar increased soil pH buffering capacity (pHBC) respectively by 22% and 32%. The increased pHBC played the main role (75%) in inhibiting the acidification of the soil amended with peanut straw biochar, while the rice straw biochar inhibited soil acidification mainly through suppressing nitrification during the incubation. Overall, compared with lime application, biochars can inhibit soil acidification caused by urea application through suppressing the nitrification process and improving the resistance of soils to acidification. The crop residue biochars presented a longer-lasting effect on ameliorating acidic soils than mineral lime. Image 1 • Biochar played a dual role in inhibiting soil acidification from nitrification. • Biochar decreased proton release through suppressing soil nitrification. • Biochar increased soil pH buffering capacity and the resistance to acidification. • Biochar would be a better option to ameliorate acidic soils than liming. [ABSTRACT FROM AUTHOR]

• Liming has been recognized to be beneficial for soil physical properties. • The physical resilience of a soil is related to its structural stability. • It may take several years to develop a sustainable structure system. Liming is a well-established practice to ameliorate acidic soils worldwide. However, the role of liming in soil structure formation and its relation to the nitrogen cycling is only little explored. We hypothesized that improved physical and mechanical soil properties, which are directly linked to soil structure, lead to lower nitrogen losses in an agricultural system. Water holding capacity, total pore volume, bulk density, hydraulic conductivity, shear stress and pre-compression stress were quantified in the topsoil of three surveys located in Germany on different soil types: Eutric Gleyic Cambisol (Loamic) (Magdeburg, Saxony-Anhalt), Haplic Luvisol (Neubrandenburg, Mecklenburg-Western Pomerania) and Eutric Cambisol (Loamic) (Puch, Bavaria). The field experiments were arranged in a Randomized Complete Block Design and treated with two different rates of lime (calcium carbonate). Furthermore, three rates of nitrogen in form of urea or calcium ammonium nitrate were applied every year. Liming significantly increased the pH, plant available water capacity, total pore volume and decreased bulk density in the soils six months after application, but twelve months after lime application the soil structure collapsed again causes by ploughing and chiseling. We, therefore, assume a positive influence of lime application on soil physical parameters, if tillage is excluded at least initially. On the other hand, our results from the shear stress parameters and the pre-compression stress values indicate that their changes need time and we assume that it may take several years to develop a sustainable structure system. [ABSTRACT FROM AUTHOR]

Soil acidity limits crop growth and yield all over the world. Low grain yields is usually associated with poor soil fertility; however, little attention has been given to the nitrogen-based fertilizer use efficiency in soils managed with lime. Given the current scenario of uncertainties regarding the availability and prices of fertilizers, our study aimed to understand how maize intercropped with ruzigrass and soybean plants develop in long-term soils managed with lime rates, and what the fate of the 15N–labeled ammonium sulfate [(15NH 4) 2 SO 4 ] applied in the soil-plant system. The treatments consisted of four dolomitic lime rates applied to the soil surface [control, half the recommended lime rate (½ RLR), full recommended lime rate (1 RLR) and double the recommended lime rate (2 RLR)]. The higher lime rate (2 RLR) improved fertility, carbon and nitrogen stocks in the soil profile, and grain and/or stover production of maize, ruzigrass and soybean. As a consequence, maize and ruzigrass recovered a high amount of 15N-fertilizer. On the other hand, soybean recovered less 15N-fertilizer, regardless of treatment, but a greater amount was found in acidic soils. At the end of the maize and soybean growth cycles, our results showed that in 2 RLR-amended soil, the 15N unrecovered was 71% lower than control. Finally, our results suggested that the use of low lime rates (½ RLR) may increase the 15N losses potential to deep layers, whereas low amounts of 15N were found in the subsoil when higher lime rates were applied. Soil acidity management through higher lime rates leads, over time, to increased soil fertility, resulting in a favorable environment for plant growth and the use of nitrogen fertilizers. In this way, it is possible to obtain a more productive and less costly agricultural system, and with less potential to pollute the environment. • Soil fertility increases after long-term liming with higher lime rates. • The 15N-fertilizer recovery by crops is proportional to the soil fertility level. • Low lime rates increased the concentration of 15N-fertilizer in deep soil layers. • The higher 15N recovery leads to higher yields and lower N-fertilizer losses. [ABSTRACT FROM AUTHOR]

Acidification of soils is one of the most important soil degradation processes and this type of soils can be provisionally remediated towards increasing soil fertility by liming practices. However, Ca / Mg containing liming materials cannot be used in areas where perennial calcifuge plants are present. The aim of this study is to determine the ability of materials such as milled fine-grained forms of zeolite and feldspar with alkaline character to neutralize acid ions in soil environment. The ability to buffer H ions was determined by equilibrating HCl solution at varying concentrations with zeolite samples having a particle size of 1-0.5 mm, 0.5-0.25 mm and 0.1 mm and feldspar with a particle size <0.1 mm. The titration curves of the zeolite samples were found to vary significantly depending on the particle size and all zeolite sizes had better buffering ability than the feldspar. As a result, it has been concluded that zeolite and feldspar can be used as an alternative liming material for calcifuge plants both in remediating the acidity and in improving the chemical properties of soils. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Liming and organic fertilizer increased soil pH and decreased Al concentration. • Microbial communities were altered by lime and organic fertilizer. • Soil organic carbon and microbial activities were promoted by organic fertilizer. • Organic fertilizer may enhance synergistic microbial interactions. • Organic fertilizer, not heavy lime alone, effectively increased banana growth. Abstract Low soil pH and low soil organic matter content are major factors limiting banana production in acid soils. A pot experiment was conducted to determine whether liming or organic fertilizer is effective in mediating banana growth and soil health. The experiment comprised an unamended control and two treatments, lime and OF (organic fertilizer) and sampling was conducted twice, 65 and 280 days after planting. Soil nutrient concentrations, soil microbial communities and enzyme activities, and banana biomass and nutrient uptake were determined. As expected, the application of lime or organic fertilizer significantly increased soil pH and mineral nutrient concentrations and decreased Al3+ concentration. At both harvests an increase in bacterial and fungal diversity in the lime treatment and a shift in the soil bacterial and fungal communities did not translate into increased plant biomass. Organic fertilizer application significantly increased soil organic carbon content and enzyme activities, root length density down the soil profile, plant biomass and nutrient uptake compared to the lime treatment and the control. Changes in the soil microbial community in the organic fertilizer treatment compared to the control followed the same direction as in the lime treatment. However, the relative abundances of Actinobacteria and Ascomycota increased significantly 280 days after planting and potential pathogenic fungi including Fusarium decreased. Our results indicate that heavy liming alone may not be a viable approach to overcome the growth limiting factors in banana production on acid soils. In addition to the increased soil organic matter and nutrient availability, organic fertilizer may prime microbial activities and act as biologically active agent and/or enhance synergistic interactions within the soil microbiome in enhancing plant biomass. Increased soil biological activities after organic fertilizer application emphasize the importance of soil health in promoting the yield of banana crops. [ABSTRACT FROM AUTHOR]

Abstract An 18-year field experiment was conducted on a highly acidic soil in the mixed farming zone of south-eastern Australia. The experiment was a fully phased design with three major treatment contrasts: perennial systems versus annual systems; unlimed versus limed treatments; and permanent pasture versus pasture-crop rotations. The hypotheses tested in this study were that a) perennial systems would be less acidifying than annual systems, and b) surface liming would lead to amelioration of subsurface soil acidity over time. Results showed that there was no significant difference in soil pH in terms of acidification rate and amelioration rate between perennial and annual systems, thus we rejected the first hypothesis. However, both perennial and annual systems did acidify or re-acidify soil. The re-acidification rate was at least 0.09 pH units per year in the 0–0.10 m depth under the limed treatment. The acidification rate was 0.005 pH units per year in the 0.10–0.20 m depth under the unlimed treatment. The vigorous lime regime of maintaining pH ≥5.5 (measured in 0.01 M CaCl 2) in the 0–0.10 m depth increased soil pH in the 0.10–0.20 m depth at a rate of the 0.04 pH units per year, hence we accepted the second hypothesis. There was clear evidence of alkali movement vertically over time, but it was confined within the top 0.30 m depth over the 18-year period of experiment. It is recommended that soil should be limed regularly to maintain pH ≥5.5 to keep the system productive and sustainable. Highlights • Both perennial and annual systems acidify soil in depths at a similar rate. • Surface liming can alleviate subsurface (below 0.10 m) soil acidity. • Soil re-acidification rate is 0.09 pH units per year in the 0–0.10 m depth. • Soil acidity amelioration rate is 0.04 pH unit per year in the 0.10–0.20 m depth. • Soil should be limed regularly to maintain pH ≥5.5 to keep the system productive and sustainable. [ABSTRACT FROM AUTHOR]

Irrespective of treatments, available K decreased in limed over that of un-limed soil. In general, available K progressively increased in both un-limed and half limed soils up to 60 day period of incubation but thereafter showed a decreasing trend on 90th day of the experiment. However, full limed soil showed a different trend of results. Available K increased up to 30th day, thereafter decreased on 60th day then again increased on 90th day of the experiment. The results thus revealed that available K is not retained in the soil for longer period rather it is converted to other forms at the later stage of the experiment. [ABSTRACT FROM AUTHOR]

The static fertilisation experiment conducted in Skierniewice (Central Poland) since 1923 investigates the effect of mineral fertilisation with lime (CaNPK) or without lime (NPK) on the accumulation and release of phosphorus in reference to phosphorus sorption properties in the sandy soil profile. In the case of application of same doses of mineral fertilisers, the content of total phosphorus was higher in NPK than CaNPK soil. Parameters related to sorption capacity and bonding energy from Langmuir and Freundlich model of P sorption were significantly lower in CaNPK than NPK soil profile. This was particularly caused by a lower content of poorly crystallised hydro(oxide) aluminium and iron forms in CaNPK than NPK soil. Higher content of oxideextractable and bioavailable phosphorus extracted with double lactate solution, dissolved reactive phosphorus in water solution as well as degree of phosphorus saturation in the CaNPK soil profile suggests higher mobility and possibility of occurrence of losses of phosphorus from the profile of limed soil than from acidified soil. Therefore, management of phosphate fertilizers on permanently limed sandy soils requires the optimisation of phosphorus doses to a greater degree corresponding to the actual take-off of the element with crop. An additional finding of the study was evidence of the possibility of re-estimating contents of bioavailable phosphorus and, as a consequence, the degree of phosphorus saturation with Mehlich3 method in strongly acid soil receiving P mineral fertilisers, which can make it difficult to use the test for fertiliser recommendation. [ABSTRACT FROM AUTHOR]

The study aimed at investigating effects of lime and mineral P fertilizers on P uptake and growth of maize (Zea mays subsp.) in greenhouse pot experiment. Combination of four P rates and four lime rates were applied to four highly acidic soil samples and the soils were incubated for a total of 112 days after which maize (Zea mays subsp.) was planted. The maize plants were harvested for analysis after 42 days of growth. Control experiments were also included. Available P (Bray I) and pH were significantly increased after incubation. Maximum available P was obtained in the soils that received the highest P rate and optimum lime rate. Levels of exchangeable acidity were significantly decreased in the P and lime treated soils compared to the control experiments. Plant biomasses and P uptake of maize increased significantly (p ≤ 0.001) with application of P and lime compared to the control experiments. [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]

The rate and method of lime application modify soil chemical attributes, but the re-acidification process after liming remains poorly understood in the long-term. This study aimed to assess the long-term effect of surface and incorporated liming on shifting soil use from native grassland of South Brazilian Campos to no-tillage system (NTS) for grain production in a highly acidic sandy-loam Ultisol. In 1994, an experiment in a randomized block with split plot design and four replications was installed in Southern Brazil. The main plot consisted of lime application method (surface or incorporation by soil tillage), while the subplots were lime rates (0.0, 2.0, 8.5 and 17.0 Mg ha −1 ), corresponding, approximately, to 0, 1/8, 1/2, and 1 fold the recommended dose to rise soil pH to 6.0 in the 0–20 cm soil layer. The 2 Mg ha ‒1 treatment had reapplication every two years until soil accumulated 8 Mg ha ‒1 of lime. In October 2006 and 2012 (i.e., 12 and 18 years after lime application), soil samples were collected at every centimeter from 1 to 10 cm depth, every 2.5 cm from 10 to 25 cm, every 5 cm from 25 to 50 cm and 50 to 60 cm. The chemical attributes related to soil acidity were evaluated. Even after 18 years of lime application, the re-acidification process recovered only 50% of the exchangeable Al and 30% of the potential acidity compared to native soil. Lime incorporation before NTS adoption proved to be more rapid and efficient to mitigate soil acidity than surface liming, and it is suitable for correction of deep-layered soil acidity in the soil profile. Surface lime application induced a lower alkalinization front in the soil profile, and even after 18 years there was no neutralization of total exchangeable Al in the 10–20 cm layer. [ABSTRACT FROM AUTHOR]

The new EU regulations on maximum levels of cadmium (Cd) in cacao products sparked research on countermeasures to reduce Cd concentrations in cacao beans. This study was set up to test the effects of soil amendments in two established cacao orchards (soil pH 6.6 and 5.1) in Ecuador. Soil amendments included: 1) agricultural limestone at 2.0 and 4.0 Mg ha−1 y−1, 2) gypsum at 2.0 and 4.0 Mg ha−1 y−1 and 3) compost at 12.5 and 25 Mg ha−1 y−1, all amendments were applied at the surface during two subsequent years. Lime application increased the soil pH by one unit down to 20 cm depth. On the acid soil, leaf Cd concentrations decreased by lime application and the reduction factor gradually rose to 1.5 after 30 months. No effects of liming or gypsum on leaf Cd was found in the pH neutral soil. Compost application in the pH neutral soil reduced leaf Cd concentration with factor 1.2 at 22 months but that effect was absent at 30 months after application. Bean Cd concentrations were unaffected by any of the treatments at 22 months after application (acid soil) or 30 months (pH neutral soil) suggesting that any treatment effects on bean Cd might be even more delayed than in leaves. Soil columns experiments in the laboratory showed that mixing lime with compost largely enhanced the depth of lime penetration compared to lime only. Compost + lime reduced 10−3 M CaCl 2 extractable Cd in soil without lowering extractable Zn. Our results suggest that soil liming has the potential to lower Cd uptake in cacao in the long term in acid soils and that the compost + lime treatment should be tested at field scale to accelerate the effects of the mitigation. [Display omitted] • Soil amendments significantly reduced Cd in leaves but not cacao beans in long-term field experiments. • Surface lime application increased soil pH only at the first 15 cm soil layer. • The lowest leaf Cd concentrations occurred during the flowering/filling stage of cacao. • Compost and gypsum effects on elemental leaf composition were inconsistent over time. • Lime + compost applications are advocated for future research as compost increases lime penetration into the soil profile. [ABSTRACT FROM AUTHOR]

• Silicate-containing amendments increased calcium and available silicate contents. • Silicate-containing amendments moderately increased soil fertility. • Silicate and lime co-application increased the relative change in soil fertility. • Long-term application of silicate and lime reduced C stratification. • Carbon stocks reduced in lime and silicate amended soils. Most agricultural soils are unproductive due to soil acidity which limits crop growth and yield. To ameliorate soil acidity constraints and enhance the ecosystem services the soil renders to achieve optimum crop yields, lime, and silicate are mostly used. However, there are few studies reporting the impacts of the combined application of silicate and lime on soil properties, soil fertility and carbon stocks and stratification in long-term experiments. This study evaluated the impacts of the combined application of silicate and lime on soil fertility indicators (pH, soil organic matter (SOM), available phosphorus, exchangeable potassium, magnesium, and calcium, and available SiO 2), carbon stratification and stocks in comparison to sole lime and sole silicate applied to a Fluvaquentic Eutrudepts over a 67-year period. Each treatment's rate of application was calculated to raise the soil pH to 6.5. Incorporation of the treatments increased the soil pH by 1.30, 1.22, and 1.35 folds in the sole silicate, sole lime, and combined silicate and lime-treated soils, respectively, relative to the baseline soil pH (5.5). The combined application of silicate and lime resulted in significant decreases in C stratification and C stocks. The significant reduction in the C stocks in the silicate and lime-treated soils implies that its long-term application could potentially reduce carbon sequestration and increase the carbon footprint of rice cultivation. This information is crucial to develop sustainable soil management interventions to curtail the environmental footprint in rice paddy ecosystems. Comparatively, the combined silicate and lime treatment caused an increase in the relative change of soil fertility by 65.7% and the average annual growth rate in the soil fertility improvement by 0.0115, as compared to the untreated soil. Among the soil variables, soil pH, exchangeable calcium, and available silicate contributed most to the variation the soil fertility. The obtained results could serve as a guide in revising the lime and silicate fertilization programs instituted by the Korean Government and reviewing national soil fertility management systems in temperate paddy ecosystems. [ABSTRACT FROM AUTHOR]