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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]

Several studies have recommended balanced fertilization for increased and sustainable maize productivity in northern Ghana. However, the effectiveness of balanced fertilization in strongly acid soils is unknown. We conducted nutrient omission trials on strongly acid soils in four communities in northern Ghana to quantify impact of balanced fertilization and its synergism with liming on maize productivity. We evaluated the following treatments, each with and without liming: (i) balanced fertilization (BF), which contained all essential limiting nutrients, (ii) BF without sulfur (minus-S), (iii) BF without zinc (minus-Zn), (iv) BF without boron (minus-B), (v) NPK-only, and (vi) control. Without liming, maize yield was generally low (ranging from 0.4 to 2.2 t ha−1) and followed the order: minus-Zn > NPK-only > BF = Minus-S = Minus-B > Control. However, regardless of fertilization treatment, liming significantly increased maize productivity with grain yields ranging from 0.7 to 4.2 t ha−1, with BF having the greatest yield. With liming, the minus-Zn treatment resulted in a ≥ 30% yield decrease, compared to BF. The combined data suggest that in strongly acid soils, unless lime is applied, addition of micronutrients to NPK fertilizers would not have the desired effect on maize productivity. Without lime application to such soils, omission of Zn from BF in will not only reduce production cost but could have a positive impact on maize productivity. However, we recommend that BF in strongly acid soils should be accompanied by liming to ensure increased and sustainable productivity. [ABSTRACT FROM AUTHOR]

Guava is one of the most important fruits in the Brazilian export market. The objective of this work was to evaluate the effects of liming and phosphorus (P) sources on micronutrients content in guava seedlings. The experimental design was completely randomized in a factorial scheme (2 × 3 × 3) comprising two dolomite limestone rates (0 and 5 Mg ha−1), three soil types (Typical Red Oxisol, Typical Yellow Oxisol, and Typical Yellow Ultisol), and three P sources (Arad rock phosphate, thermophosphate 'Yoorin,' and triple superphosphate) at 150 mg kg−1, with three replicates. Boron [B], copper [Cu], zinc [Zn], iron [Fe], and manganese [Mn] concentrations in guava seedling leaves and stems were affected by liming, by the P source, and by the soil type. Limestone and P sources altered the B, Cu, Zn, Fe, and Mn concentrations in leaves and stems of guava seedlings in each of the three evaluated soil types. Due to its low solubility, and regardless of soil type and liming, Arad rock phosphate was less effective than triple super phosphate as a P source for guava seedlings. [ABSTRACT FROM AUTHOR]

Lime-cement stabilisation of clayey soils has been successfully used for many years. However, limited published studies have investigated the influence of varying mellowing period for two-stage lime-cement stabilisation on the secant elastic and resilient moduli of subgrade soils. The two-stage stabilisation starts with mixing the soil with lime, allow it to mellow for a specific period to improve soil's workability and reduce plasticity. Cement is mixed with the treated soil and compacted to ensure strength development. The effects of lime-cement stabilisation on compaction, bearing capacity, compressive strength, elastic modulus, and resilient modulus of a medium plasticity clayey soil were investigated. A continuous reduction in the E50 of soaked lime-cement stabilised specimens was observed with longer mellowing periods specimens with 24 h mellowing showed the highest ability to absorb energy under the applied load. Repeated load triaxial test showed that the resilient moduli were significantly improved after the two stages stabilisation, and mellowing the lime treated soil will considerably enhance the soil stiffness. The three-parameter regression model showed that the two-stages stabilised materials have a strain hardening property. Increasing the mellowing period beyond 48 h, before adding cement and compaction will reduce in compressive strength, elastic modulus, and resilient modulus. [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]

This study investigated phosphorous (P) sorption characteristics under lime rates, and validated them under field conditions. Soil samples from nitisols and luvisols were taken, mixed with lime(tha−1) at[0,0], [5.25, 3.75], [10.5, 7.5] and [15.75, 11.25], respectively, and incubated for 30 days. It was equilibrated with KH2PO4 at 0, 10, 20, 30, 40, and 50 mgPL−1. The data were tested with Freundlich and Langmuir models. External P requirement (EPR) and changes in chemical properties were evaluated. The field validation on wheat involved rates of P (0, 8.2, 16.4, 24.6, 32.9, and 41.1 kg ha−1) and lime (0, 650, and 1300 kgha−1) in a randomized complete block design with three replications. Freundlich was found the best-fitted model. Freundlich coefficient (Kf) ranged from 212 to 45 mgPkg−1 (nitisols) whereas it was 112.7 to 16.29 mgPkg−1 (luvisols). EPR (kgPha−1) without and the highest lime rate were: nitisols (142.5 and 52.32 kgPha−1) and luvisols (124.84 and 25.94 kgPha−1). Liming reduced EPR by 63.3% (nitisols) and 79.3% (luvisols). Liming increased soil pH from [4.55 to 6.60 in the nitisols, and 5.33 to 6.51 in luvisols]; exchangeable acidity (cmol(+)kg−1) 3.84 to 0.01 nitisols, and 0.72–0.05 luvisols, and available P (mg/kg) 3.2–6.32 nitisol, and 2.74–8.72 luvisols. Furthermore, applying 32.9 kgPha−1 x 1300 kgha−1 lime resulted in grain yield (4345.2 kgha−1) that was 449% more than the untreated crop (791.3 kgha−1). The validation result suggested higher P than blanket P recommendation. It also justifies that excess P or lime alone cannot be a complete solution for P management and increased yield. [ABSTRACT FROM AUTHOR]

This work evaluates the development of silty soil's split tensile strength (qt) from the Guabirotuba Formation of Curitiba/BR artificially cemented over 28 days. For this, two binders were used: lime and cement. The lime used was hydrated dolomitic type, and the cement had high initial strength, added in percentages of 3, 5, 7 and 9% about the dry mass of the soil. Specimens of 50 mm in diameter and 100 mm in height were molded with different contents of lime (L), different contents of cement (C), different porosities (η), different apparent dry weights (γd), moisture of molding (ω) between 20 and 23% and subjected to indirect traction under saturation conditions. The voids/lime (η/Liv) and voids/cement (η/Civ) ratio represented by the porosity/volumetric binder content ratio (η/Biv) was used to evaluate the development of qt in addition to variables such as L, C and η and its influence on qt. The results demonstrate an increase in strength with increasing lime and cement content and with decreasing voids (i.e., higher dry specific weight and lower η). In terms of addition, the soil-cement mixture developed greater tensile strength than the soil-lime mixture by 15%. Finally, a dosage equation for qt of the studied soil mixed with lime and cement was calculated using the η/Biv ratio adjusted to an exponent of 0.20 for cement and lime, obtaining an acceptance of 95% and a mean error of 4%. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of liming on soil fertility, growth, nutrition and production of red pitaya (Hylocereus monacanthus) plants cultivated in pot. The experiment was conducted in blocks, with five doses of limestone (0.0; 0.6; 1.2; 1.8; and 2.5 t ha−1) and four replicates. Corrective doses were established to achieve base saturation of 20 to 70%. Liming increased soil pH (4.5 to 6.7), Ca concentration (5.36 to 20.11 mmolc dm−3), Mg concentration (4.36 to 16.53 mmolc dm−3) and base saturation (23.69 to 72.61%) and reduced potential acidity (37.39 to 15.41 mmolc dm−3). Liming reduces nitrogen concentration and increased phosphorus, calcium and sulfur concentrations in the cladodes. There was an increase in phosphorus concentration and decrease in boron and iron concentrations in fruit peel according to the increase in limestone doses; in the pulp, there was an increase in boron concentration and decrease in iron and zinc concentrations, from the lowest to the highest dose of limestone. Based on the principal component analysis, the limestone dose of 1.8 t ha−1 increased base saturation to 59%, providing favorable chemical conditions for the growth and productivity of red pitaya. [ABSTRACT FROM AUTHOR]

The effect of aging on the internal mechanism of the dry shrinkage cracking of lime soil was studied from the perspective of macroscopic cracking phenomenon and microscopic composition change, and the reasonable aging time of lime soil was determined. Large numbers of cracks often occur in buildings constructed using lime soil, which impacts sustainable development and building environmental protection. This study explored the influence of aging time on the mechanical properties and shrinkage cracking of lime soil. The influence of aging time was evaluated using a triaxial compression test; using the dry–wet cycle, sieving, pH, and other tests, the influence of aging time on volume crack rate, expansion shrinkage rate, particle size distribution, and pH was analyzed. Scanning electron microscopy and X-ray diffraction experiments were used to analyze changes in the lime soil particle structure for different aging times and the formation of new substances. The results show that as aging time increases, the stress–strain curve of the soil softens significantly, shear strength deteriorates, and cohesion decreases. When the aging time is 6 h, the expansion rate and shrinkage rate at the center of the soil sample are the maximum. The volume fracture and expansion shrinkage rates decrease first, and then plateau with aging time, with the changes remaining stable after 72 h; these rate decreases are positively correlated with the change rate of pH. The formation of Ca(OH)2 affects the sample pH, and the changes in pH, Ca(OH)2, and CaO tend to be stable. With an increase in aging time, the proportion of particles of a size less than 0.1 mm decreases, and that of particles of size 0.1–0.5 mm increases. After 72 h of aging, the particle size proportion remains unchanged. Reasonable aging time can, thus, reduce the hydration reaction of lime, improve particle agglomeration effects, and reduce the crack development of the soil. [ABSTRACT FROM AUTHOR]

Less uptake of zinc (Zn) in maize is a serious issue when cultivated in lime soils. The higher concentration of lime significantly affects soil pH. It also minimized the phyto-available pool of micronutrients, i.e., Zn, iron (Fe), copper (Cu), in soil. In these micronutrients, the balance uptake of Zn and its enrichment in maize has prime importance. Application methods and sources of Zn application can overcome this problem. The current study was conducted to assess soil and foliar application's efficacious functioning toward improvement in Zn uptake and dry matter production of maize Two sources of Zn (zinc-methionine and zinc sulfate) were applied at the rate of 5 mg Zn kg−1, 0,2% Zn. Results showed that soil + foliar Zn methionine performed significantly better than all other treatments for increase in dry weight of maize in lime-rich and poor soils. A significant increase in Zn concentration of maize signified soil + foliar Zn methionine's imperative functioning over all the treatments in lime-rich and poor soils. However, results also showed that both sources of Zn application via soil and foliar caused a significant decline in Fe, Cu and Mn concentration in maize in lime-rich and poor soils. On an average, in lime-rich and poor soils, performance was better in lime-poor soils over lime-rich soils. In conclusion, soil + foliar Zn methionine is an effective amendment for improving maize dry matter and Zn enrichment in maize when cultivated in lime-rich and poor soils. [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]

Using polypropylene fiber (PPF) and nano clay modified lime treated soil (LS), the static and dynamic properties of fiber modified lime treated soil (FLS), nano clay modified lime treated soil (NLS), and fiber nano clay composite modified lime treated soil (NFLS) were studied. Through the unconfined compressive strength (UCS) test and dynamic triaxial test of FLS, NLS, and NFLS, the static and dynamic elastic modulus characteristics at 7 day curing age were explored, and the damage stress–strain model was established. The results show that: (1) Polypropylene fiber and nano clay can significantly enhance the mechanical properties of NFLS. Nano clay can promote the reaction between lime and soil to produce calcium silicate hydrate (C-S-H) and calcium aluminate hydrate (C-A-H), thus improving the strength of NFLS, and UCS can be increased by up to 103%. Polypropylene fiber can enhance the ductility of NFLS and increase the residual ductility strength, and the residual strength can be increased by 827%. (2) Nano clay can enhance the static and dynamic elastic modulus of modified lime treated soil. The static and dynamic elastic modulus of NLS, FLS, and NFLS are linear with the change of polypropylene fiber and nano clay content. The static and dynamic elastic modulus of NLS, FLS, and NFLS are linear, exponential, and logarithmic, respectively. (3) The mesoscopic random damage model can characterize the stress–strain relationship of NFLS. Polypropylene fiber and nano clay can improve the ductility and strength of modified LS, and the composite addition of polypropylene fiber and nano clay can improve the ability of modified LS to resist damage. [ABSTRACT FROM AUTHOR]

Australian design practice for granular pavements with lime-modified subgrades is very conservative and does not consider the initial and long-term strength improvement. It recommends that the assigned California bearing ratio (CBR) of a modified subgrade soil should not exceed 15% for most roads. Two types of clay soils with plasticity indices of 22% and 42.5% were treated herein with their minimum lime demand (MLD) and tested to evaluate the modification influence on their properties. These properties include pH, compaction, compressive strength, bearing capacity, resilient modulus, and permanent deformation. Three different mellowing periods, 24, 48, and 72 h, between lime treatment and compaction, were used in this study to identify their optimum mellowing periods. Analysis of testing results for long-term compressive strength and CBR showed that MLD improves both soils' compressive strength and bearing capacity. Using the actual CBR values of lime-treated soils in designing the cover over subgrade results in a 30% reduction in pavement thickness. Lime modification of these soils also improves their resilient moduli and permanent deformation. The best results are achieved with mellowing periods of 24 h for Soil A and 72 h for Soil B. These optimum mellowing periods reduced permanent deformation of Soil A to less than 0.15% and 0.11% for Soil A. Considering the study findings, it is believed that thinner pavements can be designed and built on modified subgrades with MLD, which will help road agencies save funds. [ABSTRACT FROM AUTHOR]

• Plasmodiophora brassicae is an obligate biotrophic protest and plasmodiophorid in the eukaryotic kingdom of Rhizaria. • P. brassicae can infect almost all species of Brassicaceae, resulting in yield and quality losses. • The use of beneficial endophytic fungi is a possible promising strategy for suppression/controlling club root disease. Clubroot, as a major disease and severe threat to cruciferous crops, is caused by the pathogen Plasmodiophora brassicae Woronin. The pathogen is an obligate biotrophic protist and plasmodiophorid in the eukaryotic kingdom of Rhizaria. P. brassicae can infect almost all species of family Brassicaceae, resulting in yield and quality losses of these important oil and vegetable producing crops worldwide. Resting spores of the pathogen can persist in soil for more than 18 years and can easily be transmitted through a number of agencies, including infected transplants and animals. Furthermore, resting spores can rapidly increase with continuous cropping system devastating both protected vegetables and infected fields. Cruciferous crops such as Canola and others are of enormous importance, as they are important source of vegetable oil for human and industrial lubricants, where mineral oils are inappropriate. Several strategies are in practice such as adjustment of soil pH, soil liming, controlling the soil environment and changes in hormonal levels etc. for suppression and/or controlling clubroot disease. But these are conventional techniques impractical under most circumstances and insufficient for controlling the disease. Thus, the use of fungi could be a possible promising strategy for suppression/controlling clubroot disease in economically important plants. This review summarizes the historical background of clubroot, current knowledge about its pathogen life cycle, its host range, problems in controlling the spreading of disease as well as the recent attempts for suppression/controlling the pathogen via beneficial endosymbiont fungi. [ABSTRACT FROM AUTHOR]

In this paper, a method to control the lime reaction by different slaking conditions is proposed to reduce the occurrence of cracks in newly repaired earthen city walls. The effects and mechanisms of the slaking time (0 h, 12 h, 24 h, 48 h and 72 h), lime content (10%, 15% and 20%), and moisture content (14%, 18% and 22%) on the cracking and mechanical properties of lime soil were analyzed by the test results of surface cracks, triaxial compression, particle gradation, pH value, X-ray diffraction and scanning electron microscope. The results show that proper slaking of lime soil specimens can reduce surface cracks and improve mechanical properties. After 12 h of appropriate slaking, the crack rate of the lime soil with 20% content decreased by 97.13%, the cohesion increased by 20.27%, and the internal friction angle decreased by 11.27%. However, the mechanical properties decreased when the slaking time was too long. After 72 h of slaking, the cohesion of 20% lime soil decreased by 8.21% and the internal friction angle increased by 2.82%. Further analysis shows that the appropriate slaking conditions can regulate the reaction rate and alkali environment, control the lime produced cementitious substances, improve the particle gradation and further reduce the occurrence of surface cracks. These results provide a basis for the restoration technology of newly repaired earthen city walls. [ABSTRACT FROM AUTHOR]

Urea is the most used nitrogen (N) fertilizer worldwide, but its rapid hydrolysis on the soil surface results in N loss in the form of ammonia (NH3-N). Enzyme inhibitors have been investigated for their ability to reduce NH3-N volatilization, particularly from no-till and surface-limed soils. This study assessed the efficiency of stabilized fertilizers in reducing NH3-N volatilization under different lime rates and application methods. The experiment followed a 2 × 4 × 3 factorial design, with two liming methods (surface application and incorporation), four base saturation levels (50, 60, 70, and 90%), and three urea (45% N) sources: conventional urea, urea + N-(n-butyl)-Thiophosphoric triamide (NBPT), and urea + Boron (B) + Copper (Cu). NH3-N volatilization losses varied from 9.15 to 20.43 kg ha−1, accounting for 11.4 to 25.5% of the applied N rate. Base saturation did not influence NH3-N volatilization. Liming method, however, had a significant effect. Urea + B + Cu was effective in reducing volatilization loss only in soils ameliorated by lime incorporation (23% reduction compared with conventional urea). Urea + NBPT was effective in surface-limed and incorporated soils (up to 55.5% reduction). The results showed that soil management influences the efficiency of stabilized fertilizers and that urea + NBPT provides the best results. [ABSTRACT FROM AUTHOR]

This study evaluates the use of rice husk ash (RHA)-eggshell lime (ESL) and RHA-commercial lime (CL) as alternative binders for clayey soil stabilization, as well as the performance of soil-binder mixtures under acidic attack. A central composite design was carried out to analyze the reactivity by batch tests with a sulfuric acid solution. Physical and mechanical behavior was evaluated by compaction test and unconfined compressive strength (UCS). Reactivity tests demonstrated better neutralization of contaminant acidity for mixtures with ESL. The highest compressive strength, reactivity and partial encapsulation of toxic elements are associated with application of 30% RHA and 6% ESL in the soil. A C–S–H gel is observed in poorly crystalline phases through the XRD pattern. The application of RHA-ESL in soils exposed to acidic attack has environmental feasibility. Analysis of RHA grinding processes combined with the mixture strength over time, and its application tests in impermeable barriers, in landfills, are recommended. [ABSTRACT FROM AUTHOR]

Soft soil as a pavement subgrade leads to early pavement failure or increased pavement thickness. Ground improvement techniques have been used as a solution to this. The published studies on coir waste treated soft soil depict that the adverse volume change characteristics of clayey soils are mitigated by the resistance offered by coir waste. However, on analyzing, it can be seen that the engineering properties of coir waste treated soil are on a lower side. Hence, an additional stabilizer lime was used in combination with coir waste to investigate the enhancement in strength and reduction in deformation behavior. This paper presents the experimental studies carried out to investigate how the addition of lime to soil treated with coir waste affects various aspects like compression behavior, undrained shear strength, and deformation behavior. The degree of expansion and effect of the curing period was also analyzed and an optimized design model was arrived to quantify the strength in terms of lime content added to the coir waste treated soil and its curing period. Design charts for pavement thickness over treated subgrade soil were also developed. [ABSTRACT FROM AUTHOR]

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

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]

Brandon Research and Development Centre, Agriculture and Agri-Food Canada, 2701 Grand Valley Road, Brandon, MB R7A 5Y3, Canada i Root rot, caused by several soilborne pathogens including I Fusarium i spp., I Aphanomyces euteiches, Pythium i spp., I Phytophthora i spp. and I Rhizoctonia solani i , is a major threat to field pea production in western Canada. B An update on an indexed microbial culture collection and preservation of plant pathogens derived from Alberta crops b . I Swift Current Research and Development Centre, Agriculture and Agri-Food Canada (AAFC), 1 Airport Road, P.O. Box 1030, Swift Current, SK S9H 3X2, Canada; (P.G.) Saskatoon Research and Development Centre, AAFC, 107 Science Place, Saskatoon, SK S7N 0X2, Canada; (M.E.) Department of Plant Science, 222 Agriculture Building, 66 Dafoe Road, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; (G.S.) I The Alberta Plant Health Lab, Crop Diversification Centre North, 17 507 Fort Road NW, Edmonton, AB T5Y 6H3, Canada i Preservation and maintenance of plant pathogens in pure culture with known identities in a living and stable state is vital for pathological research, and is of critical importance when diagnosing new or emerging plant pathogens, as well as for confirming specific diseases to enable the development of appropriate control strategies. [Extracted from the article]

Since September 2020, Germany has experienced the first ever outbreak of African swine fever (ASF). The first known cases occurred exclusively in wild boar in forest areas in Brandenburg and Saxony; in July 2021, infected domestic pigs were also confirmed for the first time. As wild boar are considered the main reservoir for the virus in the European region, an effective interruption of this infection chain is essential. In particular, the removal and safe disposal of infected carcasses and the direct disinfection of contaminated, unpaved ground are priorities in this regard. For the disinfection, highly potent as well as environmentally compatible disinfectants must be used, which are neither influenced in their effectiveness by the soil condition nor by increased organic contamination. Thus, in this study, slaked lime, milk of lime and quicklime (1% to 10% solutions) were selected for efficacy testing against the test virus recommended by the German Veterinary Society (DVG), Modified Vaccinia Ankara virus (MVAV), and ASF virus (ASFV) in conjunction with six different forest soils from Saxony in two different soil layers (top soil and mineral soil) each. In summary, 10% of any tested lime type is able to inactivate both MVAV and ASFV under conditions of high organic load and independent of the water content of the soil. At least a 4 log reduction of the virus titer in all tested forest soil types and layers and by all applied lime types was observed. In conclusion, the high efficacy and suitability of all tested lime products against both viruses and in the presence of high organic load in forest soil can be confirmed and will help to control ASF spread. [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]

The longevity of a single 22.4 Mg·ha−1 application of dolomitic limestone at four northern hardwood stands was evaluated over 30 years (1986–2016) to determine whether changes in soils, foliage, and tree growth were sustained on the unglaciated Allegheny Plateau in northern Pennsylvania, USA. In limed plots, soils, sampled to 45–55 cm depth, and sugar maple (Acer saccharum Marsh.) and black cherry (Prunus serotina Ehrh.) foliage had significantly (P ≤ 0.05) greater concentrations of calcium (Ca) and magnesium (Mg) through 2016 compared with samples from unlimed plots. Ca and Mg capitals (g·m−2) in the Oi through A horizons combined were greater on limed plots than unlimed plots, largely due to increases in the thickness and nutrient concentration in the A horizon. Over 30 years, sugar maple basal area increment (cm2·year−1 BAINC) was greater in limed plots (30.6 cm2·year−1 vs unlimed 13.3), American beech (Fagus grandifolia Ehrh.) BAINC was unaffected by lime application, and black cherry BAINC was reduced in limed plots compared with unlimed plots. The sustained effect of this one-time lime treatment shows the strong role of efficient nutrient cycling in forests and suggests that the benefits over a substantial portion of a stand rotation may increase the feasibility of operational liming. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to analyze the effects of different chemicals (fertilizers) on the prevention and control of ratoon chlorosis as well as the influence of growth and yield in sugarcane to provide a reference for the high-efficient and low-cost control of ratoon chlorosis in sugarcane. [Method] Using a randomized block design, setting up 6 chemical treatments(fertilizers) in a first ratoon field in 2020, treatment A was spraying iron fertilizer on the leaf surface at 3-leaf stage seedlings, treatment B was 10. 0 kg/667 m² ferrous sulfate applied to the soil before emergence, treatment C was 20. 0 kg/667 m² of hydrated lime applied to the soil before emergence, treatment D was 500. 0 g/667 m² (diluted 3000 times) of soil irrigating and repairing bacteria in the root zone before emergence, treatment E was 1. 0 t/667 m² of biochar applied in the soil before emergence, treatment F was 1. 0 t/667 m² coal ash from the sugar mill before emergence, and no treatment was using as a control (CK). Seventy days after treatments, the incidence of chlorosis in the current year and the consequent ratoon year were counted, and agronomic characteristics such as plant height, tiller rate, number of leaves, and yield components such as millable stalks and stalk diameter were compared with the control, and were used in evaluation the control effects. [Result] The tested chemicals (fertilizers) had extremely significant (P < 0. 01, the same as below) control effects on sugarcane ratoon chlorosis, the range of control effect was 5. 57% to 71. 33% in year 2020, and 1. 96% to 73. 67% in year 2021. In 2020, treatment A (foliar spraying iron fertilizer) had the best control effect, with the 71. 3 3 % control effect, next was the treatment F (sugar factory coal ash) with 30. 01 % control effect. Treatment B and D had poor effect, and the difference was not significant (P > 0. 05), but both were significantly worse than other soil modulators (fertilizer) treatments. In 2021, the control effect of each soil modulator (fertilizer) treatment was extremely significantly different, and significantly (P < 0. 05, the same as below) or extremely significantly better than in 2020, especially the best treatment effect was F, reaching 90. 06%, followed by treatment E, and the control effect was 73. 67 %. All treatments can significantly promote plant growth, increase tillers, and leaves, in addition to extremely significantly improve the yield traits. Among them, treatment F performed the best effect. The cost of each treatment was in the range of 70 - 2100 yuan/667 m², and costs from high to low was E >A > F > C > D > B. [Conclusion] Foliar spraying with Fe2+ foliar fertilizer has a significant re-greening effect on sugarcane seedlings that have ratoon chlorosis, can quickly recover the yield loss caused by ratoon chlorosis, but the control time is short, and it is difficult to fundamentally prevent ratoon chlorosis of sugarcane. Considering the control effects, as well as cost and the influence of sugarcane growth, the applying coal ash 1. 0 t/667 m² is the best way to prevent and cure sugarcane ratoon chlorosis and sugarcane early growth and yield. [ABSTRACT FROM AUTHOR]

Flocculation by chemicals can adequately reduce the clogging effect, and the bending effect of prefabricated vertical drains can be eliminated by laying a prefabricated drain in the horizontal direction. Various settling column tests with different contents of chemicals, polyacrylamide (PAM) and hydrated lime (Ca(OH)2), were initially conducted to find the optimum dose for the fastest settling. Then, the combined effect of using both PAM and lime on the dewatering behavior of dredged clay slurry is studied using a prefabricated horizontal drain (PHD) and vacuum pressure of 80 kPa. Initially, sedimentation and self-weight consolidation with the optimum dose of PAM and lime are allowed to occur, and then further vacuum preloading is carried out. The combined effect of lime and PAM is very effective in increasing the dewatering rate, taking only 207 hours in comparison to 247 hours for the soil slurry treated with only PAM and 411 hours for the soil slurry without any chemicals. After the treatment, the shear strength substantially increases to 58.5 kPa for the soil with lime and PAM in comparison to 42.8 kPa for the soil with PAM only and 16 kPa for the soil without any chemicals. [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]

Slow decline disease caused by Tylenchulus semipenetrans is a major threat to global citrus production. Identification of suitable bio-agents that can be applied through a drip irrigation system by growers becomes inevitable for successful citrus production. Hence, field experiments were conducted to evaluate the effect of different liquid bio-inoculants, such as Bacillus subtilis, Purpureocillium lilacinum, and Trichoderma viride delivered through drip irrigation system on acid lime trees naturally infected with T. semipenetrans. They were applied at 4 L/ha, and their effect was compared with that of the spot application of carbofuran 3G at 100 g per tree. All tested bio-inoculants substantially suppressed the population density of T. semipenetrans in soil and acid lime roots. Among the bio-inoculants, P. lilacinum with 54.9–74.4% and 53.4–74.3% reductions in population in soil and root, respectively, performed best, followed by B. subtilis and T. viride. The effect of P. lilacinum was comparable to that of the chemical standard check carbofuran in location I, but P. lilacinum surpassed carbofuran in location II. Survival in soil and colonization on acid lime roots by P. lilacinum was higher than by B. subtilis and T. viride. The egg mass parasitization by P. lilacinum was also 7.1–7.5 times higher than by T. viride. The suppression of T. semipenetrans by P. lilacinum led to an increase in the number of fruits (19.0–23.3%), fruit weight (20.2–22.3%), and fruit yield (35.4–40.3%) in acid lime trees. The cost–benefit ratio by P. lilacinum was also higher (1: 2.6–1: 3.0), whereas it was lower in carbofuran treatment (1: 2.3—1: 2.4). It is concluded that the delivery of liquid P. lilacinum at 4 L/ha through a drip irrigation system was highly effective and economical for the management of acid lime trees infected with T. semipenetrans under field conditions. [ABSTRACT FROM AUTHOR]

Soil acidification is a major and growing concern in many cropping regions globally. Whilst spatial variability in acidification is a common consideration in the management of soil health and fertility at sub-paddock scale, insufficient focus has been directed toward the identification of this variability. Suitability of portable visible near infrared reflectance (vis–NIR) spectroscopy was assessed in this study as a potential technique to achieve rapid, precise, inexpensive and spatially specific quantification of key soil parameters to inform lime requirements. Spectral fingerprints were taken using a 1 ha grid sampling approach, with four sampling protocols investigated as follows, scans: (i) directly on cleared soil surfaces; (ii) on 0–100 mm undisturbed cores; (iii) on dried 0–100 mm cores; and finally (iv) on dried, ground, sieved and mixed cores. Data was analysed using a partial least squares regression (PLSR) model to identify the strength of linear relationship between reference chemistry data and predictions derived from spectral readings. Lime requirement maps using vis–NIR predictions were then theoretically compared against traditional aggregated sampling patterns while considering the trade-offs between accuracy, economics and agronomy associated with the identification of spatial variability. The vis–NIR measurements demonstrated moderate predictive capabilities in field for determining pH (R2 = 0.3–0.5) and liming requirements (R2 = 0.5–0.6) rapidly at high spatial resolution. Vis–NIR in field mapping techniques, which enable the use of site specific management of soil resources, were found to positively redirect lime resources from alkaline areas toward acidic areas of the paddock, resulting in minimal difference to overall expenditure on lime purchase and potential for increased agronomic benefits over the long-term. Further spectral library development, calibration, and research on in-field sampling methods is recommended. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at Zonal Agricultural Research Station, Mandya to evaluate the effect of biochar, lime and fertilizer on soil acidity and microbiological properties in an acidic soil. The experiment was laid out in randomized complete block design with seven treatments and three replications. The results revealed that application of fertilizer based on the soil test value (STV) either in combination with biochar or lime influenced soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), dehydrogenase, urease and phosphatase activities significantly. Similarly, application of STV-based fertilizer along with biochar+FYM (Farm Yard Manure) + ZnSO4 significantly decreased exchangeable aluminum, exchangeable acidity and total acidity as compared with recommended dose of fertilizer (RDF) + FYM+ ZnSO4 treatment. The grain yield of rice was increased by 37.90% in STV + biochar + FYM + ZnSO4 and by 22.87% in STV + lime +FYM + ZnSO4 plots than RDF + FYM + ZnSO4 plot. Seed and haulm yield of cowpea increased by 33.57% and 18.53% in STV + biochar + FYM + ZnSO4 treatments as compared with RDF + FYM + ZnSO4 treatment. Exchangeable aluminum and exchangeable acidity were found to be negatively correlated with yield of rice (r = -0.179) and cowpea (r = -0.266). However, yield of rice and cowpea showed the significantly and positively correlated with microbiological properties. The exchangeable Al and exchangeable acidity were found to be negatively correlated with SMBC, SMBN, dehydrogenase activity, urease activity and phosphatase activity. [ABSTRACT FROM AUTHOR]

Nowadays, for soil stabilisation and cleaner production of geo-composites, the possibility of utilizing waste rubber is in vogue. The present paper deals with experimentally investigating the mechanical and micro-structural characteristics of weak Indian clayey soil partially substituted with lime (0–3.5%) and waste rubber tyre powder (0–15%). It was observed that, with increasing lime and rubber powder content, the plasticity index of the soil decreases. The shear strength and compaction testing results reveal that adding lime and rubber tyre powder (RTP) enhances the geotechnical performance of clayey soil up to an optimum dosage value. Also, the tri-axial shear testing was performed to obtain stress-strain curves for all considered soil mixes. For modified clayey soil containing 3% lime and 12.5% rubber powder, the cohesion values and bearing capacities improved phenomenally by 36.1% and 88.6% respectively, when compared to clayey soil. Further for this mix, SEM analysis reveals a compacted microstructure which improves dry-density and California's bearing ratio among all modified mixes. The novel co-relations upon regression analysis are found able to predict plasticity index, dry density, bearing capacity and shear strength with higher confidence levels. Overall, the cost-benefit analysis worked out to obtain the optimum cost of construction of footings and flexible pavement shows cost deductions up to 19% and 39% respectively while utilizing modified clay soil mixes containing 3% lime and 12.5% rubber powder in subgrade, ultimately making production stronger, cheaper and environment friendly. • Experimental investigations on finding synergistic performance of clayey soil, lime and waste rubber tyre powder. • Atterberg's limits, shear, compaction, CBR, & microstructural characteristics shows better performance of modified mixes. • Optimised clay-lime-RTP mix reports 44% and 88.63% improvements in shear strength and bearing capacities respectively. • Decrement in productional cost of up to 39% for modified geo-mixes in road pavement and foundation constructions. [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]

Continuous monitoring of soil quality is vital to understand the effects and to identify best management practices for sustainable agroecosystems. This study focuses on evaluating the soil quality and crop yield sustainability in a long-term maize-wheat cropping system experiment spanning 47 years. Physical, chemical, and biological soil quality indicators were assessed at two soil depths (0–0.15 m and 0.15–0.30 m) under eleven fertilizer and amendment regimes i.e., 50 % NPK, 100 % NPK, 150 % NPK, 100 % NPK + Zn, 100 % NPK+ hand weeding, 100 % NP, 100 % N, 100 % NPK + farmyard manure (FYM), 100 % NPK(S), 100 % NPK + lime and control, laid out in a completely randomized block design. Principal component analysis (PCA) was employed to select a minimum data set (MDS) of indicators for soil quality assessment, followed by weighted additive approach to calculate the soil quality index (SQI). Results showed that balanced dose of NPK fertilizers, in combination with FYM or lime, enhanced average wheat grain yield by 39.9 and 29.4 % over sole 100 % NPK fertilizers, respectively. Treatment 100 % NPK + FYM recorded a significant improvement in aggregate stability, available nutrients, microbial biomass over control and 100 % NPK. The highest value of SQI (0–0.15 m) was recorded in 100 % NPK + FYM (0.99), followed by 100 % NPK + lime (0.86) and lowest in 100 % N (0.41). Omission of NPK, PK, K and S from fertilizer regime caused a decline of respective 33, 39, 22 and 6 % in the SQI, whereas, all the treatments recorded a decline in SQI in sub-surface layer. The average contribution of MDS towards the SQI of 0–0.15 and 0.15–0.30 m depth was labile carbon (LC) (30 %) > microbial biomass N (MBN) (28 %) > mean weight diameter (MWD) (17 %) > pH (16 %) > available K (6 %) and LC (33 %) > N mineralization (24 %) > MWD (22 %) > pH (21 %), respectively. The SQI positively correlated with average grain yield and SYI, highlighting the importance of soil quality for sustainable crop production. This research underscores the significance of continuous soil quality monitoring and use of balanced fertilization, organic manure and lime in maintaining soil health and crop productivity in agroecosystems. • Balanced NPK fertilizers with FYM or lime increased the wheat yield by 39.9 and 29.4 %, respectively. • Continuous urea application rendered the soil unproductive. • Labile carbon was the major contributor towards the soil quality index. • Soil quality index correlated positively with grain yield and sustainable yield index. [ABSTRACT FROM AUTHOR]

Soil acidity is the most limiting factor for agricultural yield and sustainability in acid soils. Liming is the management practice recommended for reducing soil acidity and increasing the availability of macronutrients, but it can also lead to reduction in the availability of cationic micronutrients when applied at high rates. The aim of this study was to evaluate the effect of application of high rates of limestone, incorporated in the 0–0.40 m soil layer, on nutrient availability and their relation to cumulative grain yield in an annual crop production system. Three experiments were set up in 2017 with six liming rates (0, 3, 6, 9, 12, and 15 Mg ha−1), with incorporation in the 0–0.40 m layer. Soil and leaf samples were collected for determination of macro- and micronutrient concentration in the leaves. Regression and linear correlation analyses were used to evaluate the effect of the application rates on the availability of nutrients and on cumulative yield in soybean, maize, dry bean (common bean) wheat crops over three crop years. The micronutrient that showed the greatest reduction in level in the soil through liming was Fe, in contrast with Zn, which was not affected. The concentrations of micronutrients in soybean and common bean leaves were more sensitive to the effect of deep liming than the levels in the soil, and reductions were observed in the concentrations of B, Fe, Mn, and Zn; however, they remained at suitable levels according to regional standards. Thus, even with the reductions in the availability of the micronutrients brought about by incorporation of higher doses of limestone (≥ 9 Mg ha−1), the cumulative grain yields showed an increase in accordance with liming rates, with the optimal dosage from 8.77 to 12.6 Mg ha−1, depending on the site. The main factors that had positive correlation with yield were soil pH and the macronutrients concentration in the leaves, which generally increased along with the liming rates. • Micronutrients availability to plants reduces with increasing limestone doses incorporated at 0.40 m. • The concentrations of macronutrients in the leaves increased with increasing limestone rates incorporated at 0.40 m. • There is a positive correlation with grain yield and soil pH and macronutrient concentration in leaves. • Accumulated grain yield increases with increasing limestone rates incorporated at 0.40 m. [ABSTRACT FROM AUTHOR]

Plant functional traits can serve as indicators of plant resource-use strategies in response to environmental changes. Plants growing in acidified soil exhibit conservative traits and limit growth, but there is still little known about changes in above- and belowground functional traits and their coordination under alleviation of soil acidification. Here, we conducted a pot experiment on raising soil pH by liming in Chinese fir (Cunninghamia lanceolata) saplings in southern China. The experiment involved in two degrees of acidified soil (Mild, pH = 4.3; Severe, pH = 3.6) and three liming treatments: Control (CK, 0), low liming treatment (L, 1000 kg CaO hm−2) and high liming treatment (H, 4000 kg CaO hm−2). We measured 22 above- and belowground functional traits of Chinese fir including allocation, morphological, photosynthetic, and chemical traits to assess their response to liming. The results show that liming enhanced aboveground mass fraction and total leaf area (TLA), and reduced construction cost (lower C concentration). However, specific leaf area (SLA), nutrient concentrations of N and P, and photosynthetic rate (Pn) remained unchanged. These results suggest that aboveground components exhibited acquisitive strategies in response to liming with greater TLA and lower construction cost. Moreover, liming reduced root mass fraction (RMF), increased specific root length (SRL), specific root area (SRA), and root N and Ca nutrient concentrations. These results suggest that belowground components also exhibited acquisitive strategies through constructing longer and thinner roots with greater metabolic rates. Our findings show that liming shifts above- and belowground resource-use strategies of Chinese fir from conservative to acquisitive. These changes in functional traits support the ability of Chinese fir to grow rapidly in response to alleviation of soil acidification. Our research not only contributes to a deeper understanding of plant adaptation mechanisms in the face of environment changes but also provides valuable insights for improving carbon sequestration of plantations in subtropical China. • 22 functional traits of Chinese fir were measured to assess their response to liming. • Liming elevated total leaf area and reduced leaf construction cost. • Liming elevated specific root length, specific root area and root N concentration. • Liming shifts resource-use strategies of Chinese fir towards acquisitive. [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]

Quarry dust is a waste material which could pose as a serious environmental risk factor, which requires proper handling for safety. Also to harness locally available materials, lateritic soil and quarry dust have been an attractive proposition. This work studied 0-180 min at 30 min intervals of elapsed time between mixing operation and compaction for lateritic soil treated with lime and quarry dust. Constant dosages of lime 2, 4, 6 and 8% were mixed with variations of quarry dust of 3, 6, 9, 12, 15 and 18%; all percentages were measured by weight of the dry lateritic soil. Preliminary tests were conducted on the natural lateritic soil for characterization. The clay minerals present in the lateritic soil were identified using X-ray diffraction technique while the mineral oxide composition of quarry dust was done using X-ray fluorescent technique. The tests carried out on the treated lateritic soil were compaction test (British Standard Light), California Bearing Ratio (CBR) and unconfined compressive strength (UCS). The lateritic soil was classified to be A-6 (3) in the AASHTO rating system and Clayey Sand (SC) in the Unified Soil Classification System. The predominant non-clay mineral and clay mineral present in the soil were quartz and kaolinite, respectively, with traces of Moganite, Gismondine, Sanidine, Muscovite and Dickite. The quarry dust was found to satisfy the requirements for good pozzolanic materials. The Atterberg limits for the treated lateritic soil all reduced with increase in lime and quarry dust contents. The compaction and strength characteristics of the treated lateritic soil all reduced with increase in elapsed time between mixing and compaction. The California bearing ratio and the unconfined compressive strength at 7 days of curing period increased by 230.77% and 126.61%, respectively, at the addition of up to 8% of lime and 18% of quarry dust contents. A predictive model of good fit was developed for maximum allowable time elapsed between mixing operation and compaction for any given mix and strength characteristics. The correlation coefficient "R" and coefficient of determination "R2" are 0.902 and 0.814, respectively. Also at 95% confidence level, lime content, quarry dust content, optimum moisture content (OMC), California bearing ratio (CBR) and unconfined compressive strength (UCS) all affected the elapsed time between mixing and compaction significantly. [ABSTRACT FROM AUTHOR]

Optimizing the recommendation for the management of Liming Requirement (LR) is essential for cost reduction and increased yield of mango. Therefore, the objective of this study was to delimit management zones for the limestone recommendation in areas of irrigated mango in the Brazilian semi-arid region using precision agriculture techniques. The experiment was carried out in three commercial mango orchards located in the region of the São Francisco River Valley, Brazil. Soil samples were collected in the 0.0-0.2 m and 0.2-0.4 m layers following regular grids where the number of samples varied from 50 to 56. Soil analyses were performed. The kriging and inverse distance weighting methods were used to interpolate the maps. The LR map was created from the potential cation exchange capacity (T) and base saturation (BS) maps. It was verified that the Mandacaru area obtained 63.42% of the field requiring liming, being subdivided into four management zones. The Sempre Verde area obtained 1.20% of the area requiring liming and the Barreiro de Santa Fé area showed no need for the LR map. The use of precision farming techniques to delineate management zones was adequate to separate the areas into smaller and more homogeneous zones, for a more precise recommendation of liming. [ABSTRACT FROM AUTHOR]

Two liming fertilizers for soil deacidifi cation in Polissya were investigated: dolomite and lime fl our, which were applied at the beginning of the 8-year crop rotation with medium fertilizer N112P82K105 between 2011 and 2019. The experiments were performed in a stationary fi eld trial by the Institute of Agriculture of Western Polissya of the National Academy of Agrarian Sciences of Ukraine on crop rotation of winter wheat, corn, barley and winter rape. The object of the research was Albic Retisol (Arenic, Aric) (WRB, 2014) in a stationary trial. Before starting the research, soil pHKCl was 4.3 and hydrolytic acidity (Hh) 2.80–2.97 cmol(+)·kg–1. Liming fertilizer doses were determined on the basis of soil hydrolitic acidity (Hh) for dolomite fl our: 0.5 Hh – Dd0.5 2.230 t∙ha–1; 1 Hh – Dd1.0 4,740 t∙ha–1; 1.5 Hh – Dd1,5 6,700 t∙ha–1 and lime fl our: 1 Hh – Dl1.0 4,940 t∙ha–1. Application of dolomite fl our at a dose of Dd1.5 6,700 t∙ha–1 proved to be the most effective. It neutralised the acidity of the soil to the highest level pHKCl (6.64) and maintained in this case pHKCl 6.04 until the end of the 8-year of crop rotation. 3D modeling showed that the effectiveness of soil deacidifi cation by dolomite fl our increases with moderate simultaneous climate warming and humidifi cation. Meanwhile, the simultaneous stronger increase of temperature and humidity weaken the neutralising effect of this liming fertilizer. The usage of dolomite and lime causes a gradual increase in Ca2+ soil content from 1.68 to 2.57 cmol(+)·kg–1 of soil similar to the dynamics of Mg2+ concentration (from 0.28 to 0.84 cmol(+)·kg–1 of soil). The usage of lime causes a maximum reduction content of soil Mg2+ (0.23 cmol(+)·kg–1 of soil) against the highest Ca2+ content. Doses of dolomite and lime had a signifi cant effect on the Al3+ soil content. The concentration of Al3+ was highest in non-limed and fertilized areas in the fi nal year of the crop rotation. The usage of dolomite rapidly reduced the content of exchangeable Al3+ from 2.48 and 2.67 cmol(+)·kg–1 of soil to 1.31 cmol(+)·kg–1 a 1.5 Hh dose. The average long-term crop-rotation productivity (in grain units) depended on the mineral fertilization and the type and doses of the liming fertilizers applied. Mineral fertilizers within the normal range N112Р82К105 without liming have contributed to the collection of 3.06 t∙ha–1 grain units. The maximum crop yield was set on the option of applying 1.5 Hh dose of dolomite fl our on the background of the average annual mineral fertilizer norms of N112P82K105 – 5.33 t∙ha–1 grain units. Lime fl our proved to be less effective as it reduced the Mg2+ soil content, which is an important element for plants, and with a smaller impact on crop yield. [ABSTRACT FROM AUTHOR]

All forms of potassium in the soil are in a dynamic equilibrium with K in the soil solution, which affects K availability to the plants and it is affected by the soil pH. The objective of this study was to evaluate the effect of the soil pH and K application on the distribution of soil K forms in five Brazilian soils. The experiment was conducted in laboratory, using five soils. Treatments consisted of a factorial combination including rates of limestone (0, 0.25, 0.5, 1.0 and 1.5 times the amount of lime indicated by the SMP method to raise soil pH to 6.0) and two rates of K (0 and 1000 mg kg-1). Addition of KCl, together with limestone, promoted lower values of soil pH relatively to limestone alone. Solution K was the most sensitive K form affected by liming rates, which decreased in all soils with increases on K rate, regardless of K addition. Exchangeable K also decreased in all soils with the increase on lime applied, except on the Argisol. The non-exchangeable K levels were the least affected by liming. Addition of lime affects the distribution of K among all K forms and this may affect the availability of K to the plants. [ABSTRACT FROM AUTHOR]

The Sistan region in south-east Iran is subject to highly active wind erosion and is considered one of the most important sources of dust in south-west Asia. This research was concerned with the assessment of the efficiency of mulches in stabilising sand dunes. The mulches are mixtures of local silty loam soil and hydrated lime in different concentrations, which were sprinkled on plots on the surface of sand dunes. The amount of wind erosion was measured at two-month intervals from January to September 2015. The results showed a significant increase in the shear strength of the substrate where the soil content of mulches had been increased. The mulch containing 15% local soil and 1% hydrated lime demonstrated the best performance against wind erosion. [ABSTRACT FROM AUTHOR]

Studies involving oil-contaminated lateritic fine-grained soils are still scarce in literature, especially regarding treatments for improving soils mechanical properties. In this study, geotechnical properties and microstructure of a diesel-contaminated lateritic soil treated with lime are investigated and compared to tests conducted on lime-treated soil (2% to 8% lime) and diesel-contaminated soil (2 to16% diesel). The presence of diesel had no significant effect on soil plasticity but decreased soil strength. Lime stabilization applied to diesel-contaminated soils significantly improved soil properties after 6% of lime stabilizer. The diesel presence led to an inhibition of lime reaction due to reduction of cation exchange capacity and flocculation, which reflected in loss of its effectiveness in improving strength as compared to natural soil response. The water retention behavior and unsaturated hydraulic conductivity of soil were affected by diesel contamination, leading to curve shapes similar to clay materials. Adding 2% of lime to the contaminated soil, increase in the soil pores and changes in the shapes of water retention curve and k-functions were observed with similar behavior of a course-grained material. Overall, this study highlights how the presence of diesel and lime affects lateritic soil properties and microstructure. [ABSTRACT FROM AUTHOR]

The use of organic amendments improves the quality and increases the fertility of the soils due to their adsorption properties, stimulates nutrient cycling and can be used to reduce the availability of heavy metals. The main objective of the research was to evaluate the effect of biochar (BC) derived from pig manure on the availability of Pb in a contaminated and limed agricultural soil. A randomized experimental design was applied, the pig manure was dried at room temperature (23 °C) and pyrolyzed at 500 °C for 2 h. Doses of 5%, 10% and 20% of BC were applied to the Pb soils contaminated (165.7 mg/kg), that were arranged in 2 kg pots except for the control sample, and Lactuca sativa was subsequently grown cultivated to evaluate the Pb availability. The results indicated an improvement in soil quality at higher BC dose, increase of 0.34 pH units, decrease of Pb extracted by EDTA (27% to 62% of decrease), and non-significant Pb content in leachates (< 1 mg Pb/L) and no detection in plant roots (< 0.01 mg/kg), except for the control plant (0.7 mg Pb/kg) in the original soil. A logarithmic relational model between BC dose and Pb adsorbed in the soil was obtained (R² = 0.9938, p < 0.05) showing that the decrease of Pb availability in the soil increased for higher BC doses, which represents an eco-friendly remediation alternative. It is recommended to investigate the interaction relationships between the soil quality parameters and to establish functional models of bioaccumulation and extractable metal of the amended soil. [ABSTRACT FROM AUTHOR]

The objective of this work was to verify the effect of the application of lime in doses higher than those recommended and of agricultural gypsum on the productivity and macronutrient content of the native field in the "Campos de Cima da Serra" region (Southern Brazil). The experiment was conducted in a native pasture located in Vacaria municipality (Rio Grande do Sul state). The experiment was arranged in randomized blocks allocated in split plots, with four replications each. Conducted in a 3x2 factorial scheme: three doses of limestone (0, 3, and 5 ton ha-1, aiming to reach a base saturation of 65% and 5.0 ton ha-1, aiming to reach a base saturation 75%) and two doses of gypsum (0 and 2.0 ton ha-1), applied superficially. In addition, agricultural gypsum was randomly applied to one of the subplots. At the end of each climatic season, evaluations of forage mass production and macronutrient content were carried out in dry shoot matter in two samples collected from an area of 0.25 m2 per plot by cutting the aerial part "close to the ground”. The production of dry matter in the native field in autumn, winter and spring showed a significant increase with the application of 5 ton ha-1, with no influence in summer. Furthermore, the application of lime in the soil increased the nitrogen and potassium content in the leaf tissue of the native field in the autumn period. Interestingly, the same happens to calcium in the spring. On the other hand, the application of agricultural gypsum increased dry matter production only in spring and reduced magnesium contents in winter. Therefore, the results demonstrate the potential of using limestone in doses higher than those currently recommended and agricultural gypsum to increase natural forage production and their quality at time intervals evaluated in this work. [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]

Ferocious demands for waste tyres have posed remarkable threats to environment. The reuse of these materials can reduce the environmental concerns. This article investigates the influence of lime content, curing time, tyre cord scrap and shredded tyre contents on unconfined compressive strength (UCS), compaction properties and plasticity of clayey sand. The results indicated that the combination of both shredded tyre and tyre cord scrap with lime can be considered as an efficient method for ground improvement, since not only does it increase the UCS, but also it can reduce the plasticity of the studied soil. It was evident that both maximum dry density and optimum moisture content (OMC) values decreased with the addition of waste materials. Moreover, for lime stabilised specimens, it was found that the addition of a limited amount of shredded rubber allows the UCS to increase more than it does by treating the soil with lime only. In particular, the UCS stood at the highest level for specimens treated with 6% lime, cured for 56 days and additive with 0.5% tyre cord scrap. In this case, the increase in UCS was as high as 300% with respect to natural 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]