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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]

Cropping of acid sulfate soils requires effective treatment of their inherently low pH. We evaluated the efficacy of applications of two levels of lime (0 or 2 Mg/ha), two levels of organic fertiliser (0 or 5 Mg/ha), and three levels of biochar (0, 10 or 30 Mg/ha) in a factorial design for ameliorating acidity in an acid sulfate soil, and measured the subsequent growth and yield of baby corn (Zea mays L.). Lime increased soil pH(H2O) from 3.75 to 4.12, salinity from 1.72 to 1.95 dS/m, and cob yield by 30%. None of the amendments significantly altered total organic carbon or total nitrogen concentrations in the soil. Biochar additions increased cob yields by an average of 28% on both unlimed and limed soil. Addition of organic fertiliser increased cob yield by 45% on unlimed soil but had no significant effect on yields on limed soil. The yields obtained with liming were similar to the highest yields achieved with biochar or organic fertiliser applied either separately or in combinations. Overall, cob yields were increased by 19% with addition of organic fertiliser. The yield increseas from additions of biochar or organic fertiliser were associated with improvements in nutrient supply. However, the increases in cob yield were associated with reduced cob protein, probably resulting from poor availability of nitrogen late in the season. We conclude that biochar and organic fertiliser applied in relatively large quantities can be viable treatments for cropping acid sulfate soils. Biochar and organic fertiliser when applied in relatively large quantities can be as effective as liming for cropping acid sulfate soils. The three amendments added separately or in any combination increased growth and yield of baby corn but impaired cob protein content. [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]

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]

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]

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]

Lime is a common amendment to overcome soil acidity in agricultural production systems. However, plant root effects on lime and soil carbon (C) dynamics in acidic soils under varied temperature remain largely unknown. We monitored root effects of soybean on the fate of lime applied to an acidic soil at 20 and 30°C in growth chambers. Soil respired CO2 was continuously trapped in columns without and with plants until the final stage of vegetative growth. Lime‐derived CO2 was separated from total respired CO2 based on δ13C measurements in CO2. Leaching was induced at early and late vegetative growth stages, and the leachates were analysed for dissolved organic (DOC) and inorganic C (DIC) concentrations. Soil respiration significantly increased with lime addition at both temperatures (p < 0.001). The presence of soybean doubled the recovery of lime‐derived CO2‐C at 20°C at the early growth stage; however, by the end of the experiment, the contribution of lime‐derived CO2‐C to soil respiration was negligible in all treatments, indicating that the contribution of lime to soil respiration was shortlived. In contrast, DIC and DOC concentrations in leachates remained elevated with liming and were greater in the presence of soybean. We observed no main temperature effects and no interactive effects of temperature and soybean presence on lime‐derived CO2‐C, DIC and DOC. These results highlight the role of plant‐modulated processes in CO2 release and C leaching from lime in acidic soils, whereas an increase in temperature may be less important. Temperature and plant roots alter the rate of key processes controlling C dynamics in a limed acidic soil. Lime‐derived CO2‐C, DIC and DOC increased more in the presence of plants than with increased temperature. Root effects are more important than temperature for inorganic and organic carbon dynamics in limed acidic soils. [ABSTRACT FROM AUTHOR]

Good soil structure is important for achieving high productivity of agricultural land and also affects the ability of soil to withstand erosive forces. Given the importance of soil structure, efforts are commonly made to improve it, usually by application of amendments of different kinds (e.g. lime, biochar, compost, manure etc.). However, little is known about the effect of these amendments on the soil resistance to detachment. This study assessed the resistance to detachment of soil cores treated with different liming products, using a cohesive strength meter (CSM) which measures the rate of soil detachment under the action of water jets at different pressures. The amount of soil removed by the water jets was taken as an indirect measure of soil resistance to detachment, under the assumption that more resistant soils will lose less material than more susceptible soils at a given water jet pressure. The results showed that all soil amendments studied reduced detachment of particles under the action of water jets compared with unamended soil (control). [ABSTRACT FROM AUTHOR]

This study aimed to determine the effects of solid and liquid manures on soil microbial status and activity in organic farming model under greenhouse conditions. Two different test plants, rocket (Eruca vesicaria) and lettuce (Lactuca sativa), were grown also to determine the effects of plant species on related traits of the soil. A greenhouse experiment was conducted in randomized complete blocks with three replicates. The experiment was consisted of treatments with and without plants and manure. The combined doses of solid and liquid manure in rocket and lettuce soils resulted in an increase by 142.09 and 105.49% in urease, 130.75 and 135.24% in alkaline phosphatase, 162.40 and 195.06% in β-glucosidase, 135.29 and 329.88% in dehydrogenase activities and 306.34 and 182.42% in number of bacteria, respectively, compared to the control without manure. Significant changes for each parameter were also observed according to plant species (increase ranging from 54 to 128.06%). Even though influence of plants was positive, it was not as effective as manure on the measured parameters. It was determined that, in general, stimulating effect of the combined application of solid and liquid manures on the enzyme activities and number of bacteria in soil is significantly higher than the plant-derived effects (plant type, root secretions, etc.). [ABSTRACT FROM AUTHOR]

In addition to its role as an organic amendment, compost can play a role in plant protection. Due to the high water content and the landfill option in several Arab countries without upstream sorting, household waste generates large quantities of leachate that pose problems. The transformation of this leachate into compost using alkaline lime sludge and the green constitutes a new solution. Two barrels were filled with 100 l of leachate: the lime sludge was added to barrel 2 while barrel 1 was the control. After 24 hours, the green waste was added to the 2 barrels. After homogenization, the contents of the two barrels were dumped to form 2 windrows which were followed for 90 days. The contact time of 24 h allowed reducing the load of faecal streptococci, by 85.7% and the bad odors disappear within the first 3 days. The temperature had shown an increase from the first week: 58.5 °C for the windrow with sludge and 56.6 °C for the control; Humidity was kept around 50-60% by regular watering. The degradation of organic matter is better in the presence of lime sludge (31%). Despite the alkaline nature of the lime sludge, the pH of the final compost remains acceptable for many plants. Within particular 38% DS of organic matter, the final quality of the compost complies with NFU44-051; no toxicity was observed; the final compost could therefore be used as an organic amendment for palm grove as well as for the rehabilitation of degraded sites in Arabic countries. [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]

Aluminum toxicity is a major limitation to crop production on highly weathered and leached soils in Rwanda. Moreover, sulfur though widely deficient in Rwanda acidic soils has received little attention by soil fertility researchers. A field experiment on maize response and soil nutrients status to liming materials of travertines at 3.4 t ha−1, ash wood 1.2 t ha−1of CaO equivalent and sulfur at 10 kg ha−1combined with NPK at 80, 60, and 45 kg ha−1respectively was conducted in Rubona Ultisol and Nyamifumba Oxisol. Results revealed that travertine and wood ash increased the soil pH from 4.7 to 5.8 or higher and decreased exchangeable Al3+and H+to near 0 cmolc kg−1. Soil nutrients generally increased to high or medium ranges for crop production. Leaf dry biomass, plant height and maize grain yields were significantly higher in Rubona Ultisol than in Nyamifumba Oxisol. Plots that received wood ash, with NPKS or with NPK, generally had higher maize yields, followed by those which received travertines and NPKS or NPK which had maize growth response as compared to the control plots which received NPK only. Thereby, a combination of wood ash with NPKS or NPK, travertines with NPKS was found to neutralize soil aluminum toxicity, increase soil nutrients status to required levels for plant growth and increase maize yields significantly. [ABSTRACT FROM PUBLISHER]

Sugar maple (Acer saccharum Marsh.) decline disease, decreased growth, and regeneration failure have been related to a low supply of Ca and Mg. There is increased interest in augmenting cation availability via liming, but there is little information on the amounts of lime required and the longevity of the lime treatment. A single application of 22.4 Mg ha-1 of dolomitic limestone in 1985 at four forested sites in Potter County, PA has shown that soil, soil water, and sugar maple foliage chemistry are significantly altered by liming and the changes in soils and foliage persist as long as 21-yr post-treatment. By 2001, only 3 kg ha-1 of lime remained undissolved while increases in exchangeable Ca and Mg, and pH continued through 2006 at depths up to 35 to 45 cm. Exchangeable Mn and Al concentrations were significantly reduced by lime application, though effects were slower to develop at deeper depths. Soil solution chemistry from 1996 was highly variable but reflected the changed soil nutrients. On limed plots, sugar maple foliage had elevated concentrations of Ca and Mg in 2006 samples, indicating the persistence of the lime treatment. Comparison of Ca/Al ratios in soil solution, soils, and foliage show inconsistencies from previous published risk thresholds. Species-specific thresholds of Ca and Mg availability in soil and foliage have better potential management application and should be more rigorously tested as stress indicators. [ABSTRACT FROM AUTHOR]

• Lime addition impacts organic matter (OM) preservation in both top- and sub-soil. • Lime addition destabilizes N-poor OM associated with minerals in the topsoil. • The effect of lime on OM decomposition with depth depends on the OM availability. The development of effective strategies to maintain/increase soil C is hindered by the poor process-level understanding of the impact of management practices on C preservation, particularly at different soil depths. Based on the distinct biogeochemistry existing across a soil profile, a depth-dependent response of organic matter (OM) to soil amendments was hypothesized. To test this, we investigated the effect on OM preservation of lime addition to the topsoil and the subsoil of a volcanic soil classified as Andosol – the mineral soil with the largest organic C content worldwide. We incubated samples from each soil layer with (or without) lime addition, in the presence or absence of 13C- and 15N-labeled plant residue (simulating plant C inputs to the soil). The fate of OM in bulk soil and OM-mineral associations of microaggregates was measured using conventional chemical analyses and nano-scale secondary ion mass spectrometry, respectively. The results revealed contrasting geochemical properties existing within the soil profile, i.e. pH and amount of allophane increasing with soil depth. Functional complexity of OM also increased with depth, as revealed by an increase in spatial and molecular heterogeneity of OM, i.e. a larger proportion of microbial-derived OM with high spatial separation found in the subsoil. Lime addition caused OM destabilization as denoted by the increase in the amount of water-extractable C in both the topsoil and the subsoil (P < 0.05). In the topsoil, OM coverage of mineral surfaces decreased with liming from 49% to 30% whereas the opposite was observed in the subsoil, where it increased from 23% to 29%. Thus, liming caused the disruption of OM-mineral associations within microaggregates in the topsoil, but not in the subsoil. We infer that, at depth, the OM destabilization involved the mobilization of OM previously protected within macroaggregates. This pulse of labile C generated an advantageous environment for microbial OM mineralization in the subsoil, but this effect was diluted in the topsoil, richer in OM and where OM functional complexity is smaller. Depth-dependent soil geochemical properties and functional complexity determine differences in the effect of liming on the fate of soil OM in top vs. subsoils. [ABSTRACT FROM AUTHOR]

Carbocalk is a byproduct of sugar factory and is suitable for liming of acid soils. In the autumn of 2000 two field experiments in four replicates were conducted with increasing rates of carbocalk application (0, 15, 30, 45 and 60 t ha-1). In this study, yields of the field crops and cadmium (Cd) concentrations in the leaves and grains were shown. In both experiments maize was grown eight times (four years) and wheat four years in total. The lowest rate of applied carbocalk was adequate for both maize and wheat yield considerable increases by 16% and 28%, respectively (maize 6.92 and 8.04 t/ha; wheat 4.85 t/ha and 6.20 t ha-1). Applying higher quantities of the carbocalk, the yields were less increased. Sunflower, sugar beet, barley and soybean were grown only one growing season and by liming the yields were increased for 48%, 43%, 30% and 8%, respectively. Cd concentrations in the leaves of tobacco were considerably higher (mean 2.4 mg Cd kg-1) in comparison with those of maize (0.10 mg Cd kg-1) and soybean (0.15 mg Cd kg-1), while in grain of wheat and barley they were considerably lower (0.02 mg Cd kg-1). In general, liming considerably affected decreases of Cd uptake by plants as follows: for 45% in tobacco leaves (3.6 and 2.0 mg Cd kg-1, for the control and mean of the carbocalk treatments, respectively, but only in one of two tested years). The corresponding values for the leaves of maize were 0.16 and 0.08 mg Cd kg-1 (decrease for 52%) and for soybean 0.50 and 0.06 mg Cd kg-1 (decrease for 87%), respectively. In the third experiment, effects of liming with carbocalk were lower, but soil properties considerably improved (for example, base saturation) as well as P and Ca uptake by maize and wheat plants. [ABSTRACT FROM AUTHOR]

Highlights: [•] Biochar treatment at 20–40tha−1 reduced rice Cd by 20%–90% from metal polluted rice fields. [•] Grain Cd under biochar treatment fell in a safe level by 0.4mgkg−1 in soils with Cd in range 0.16–4.83mgkg−1. [•] Biochar amendment caused Cd immobilization primarily due to the liming effect by biochar. [Copyright &y& Elsevier]

• Low-lability S contents in soil decreased with depth. • Ca-phosphate extractable S contents increased with depth after surface application of phosphogypsum. • Sulfate adsorbed to hematite was the main oxidized inorganic S-species. Sulfur (S) is present mainly in organic forms in the most superficial layers of well-drained soils, despite sulfate (SO 4 2−) being the main S-species absorbed by plants. Coupled broadcast application of lime and phosphogypsum (PG) is widely deployed as an agricultural practice to improve soil chemical properties and increase crop yields in highly weathered tropical soil areas under no-tillage system (NTS). However, the effects of large-scale application of these soil amendments to S-species distribution in soil in NTS are largely unknown. We combined S wet-chemical analysis with Synchrotron-based X-ray Absorption Near-Edge Structure Spectroscopy (XANES) to evaluate the effects of lime and PG application to S-species distribution along the soil profile (up to 150 cm). Soil samples were collected from a field-scale experiment under NTS for over 15 years. Soil was amended with lime and PG, either individually or in combination, four times during the experiment. Soil sampling was conducted 16 months after the last amendments' application, and treatments (lime, PG and lime + PG) were compared to a control (under NTS without amendments' application) and with soil samples from a native forest (reference for an undisturbed site). Broadcast PG application increased the contents of Ca-phosphate extractable S and pseudo-total S (microwave assisted acid digestion) contents in the deeper layers. Two peaks representing reduced and oxidized S species were detected in S K -edge XANES spectra of all treatments and NF soil. The oxidized S peak gets sharper with increase in depth, as reduced S peak intensity decreases, and fingerprint analysis suggested a greater contribution of reduced organic S species in the most superficial soil layer followed by an increase in highly oxidized S species as depth increased. Linear combination fitting analysis confirmed a greater contribution of highly oxidized S species to the total S-species as depth increased, especially in soil samples that received PG application. [ABSTRACT FROM AUTHOR]

Soil acidification is a global issue that significantly reduces crop productivity. Lime application is a viable agricultural strategy to ameliorate soil acidification. However, the knowledge of the impact of lime application on the soil microbiome is still limited. Therefore, the objective of this study was to investigate the diversity, structure, and compositions of the soil bacterial community after liming on wheat fields. We established winter wheat plots in two precipitation zones, Pendleton and Moro in Oregon, facing soil acidity stress, and conducted bacterial microbiome analysis after lime application using Illumina MiSeq. Soil pH increased with increasing rates of lime amendments in the surface soil (0–7.5 cm) but did not significantly change in deeper soil (7.5–15 and 15–22.5 cm). High-throughput sequencing results revealed that liming had marginally effects on soil bacterial communities. A few bacterial families, including Cytophagaceae, Flavobacteriaceae, Intrasporangiaceae, Phyllobacteriaceae, Propionibacteriaceae, Pseudomonadaceae, and Sphingobacteriaceae, were correlated with lime application. In contrast, location and soil depth had a strong effect on soil bacterial communities. In addition, the impacts of liming on soil bacterial diversity and taxa were inconsistent and location- and soil depth-dependent. Furthermore, four nitrifiers were quantitated from all samples by qPCR assay. Ammonium oxidizing bacteria (AOB) and Nitrobacter were most abundant in the topsoil, while ammonia oxidizing archaea (AOA) and Nitrospira were more abundant in deeper soil. Only Nitrospira was significantly influenced by soil pH. Overall, these results suggest that location, soil depth, lime amendments, and their interactions have significant impacts on the soil bacterial community that may influence plant health and crop yields. [ABSTRACT FROM AUTHOR]

Denitrification plays an important role in N-cycling. However, information on the rates of denitrification from horticultural growing media is rare in literature. In this study, the effects of pH, N, C, and moisture contents on denitrification were investigated using four moderately decomposed peat types ( oligotrophic, mesotrophic, eutrophic, and transitional). Basal and potential denitrification rates (20°C, 18 h) from the unlimed peat samples varied widely from 2.0 to 21.8 and from 118.9 to 306.6 μg (NO + N)-N L dry peat h, respectively, with the highest rates from the eutrophic peat and the lowest from the transitional one. Both basal and potential denitrification rates were substantially increased by 3.6-14- and 1.4-2.3-fold, respectively, when the initial pH (4.3-4.8) was raised to 5.9-6.5 units. Emissions of (NO + N)-N from oligotrophic, mesotrophic, and transitional peats were markedly increased by the addition of 0.15 g NO-N L dry peat but further additions had no effect. Denitrification rates were increased by increasing glucose concentration suggesting that the activity of denitrifiers in all peat types was limited by the low availability of easily decomposable C source. Increasing moisture contents of all peats from 40 to 50% water-filled pore space (WFPS) did not significantly ( p > 0.05) increase (NO + N)-N emissions. However, a positive effect was observed when the moisture contents were increased from 60% to 70% WFPS in the eutrophic peat, from 70% to 80% in the transitional, from 80% to 90% in the oligotrophic and from 70% to 90% in the mesotrophic peat. It can be concluded that liming, N-fertilization, availability of easily decomposable C, and moist condition above 60% WFPS could encourage denitrification from peats although the rates are greatly influenced by the peat-forming environments (eutrophic > mesotrophic > oligotrophic > transitional types). [ABSTRACT FROM AUTHOR]

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

This paper presents the results of experiments carried out at the Vezaiciai Branch of the Lithuanian Institute of Agriculture during the period 1996-2004. The effects of long-term liming (at × 0.5 rate=3.8 t ha-1 CaCO3 every 7 years and × 2.0 rate=15.0 t ha-1 CaCO3 every 3-4 years) on soil chemical properties, aggregate composition and population distribution of micro-organisms and activity of two enzymes across different size classes of soil aggregates (<0.25, 0.25-0.5, 0.5-1.0, 1.0-2.0, 2.0-3.0 and 3.0-5.0 mm) were investigated. The soil of the experimental site is a Dystric Albeluvisol and textural class is sandy loam (sand (2.0-0.05 mm) 51%; silt (0.05-0.002 mm) 34%; clay (<0.002 mm) 15%). Moderate periodical liming at×0.5 rate every 7 years enabled us to maintain soil reaction at a low acidity level (pH in KCl 5.5), whereas when the soil was limed intensively at × 2.0 rate every 3-4 years topsoil reaction was slightly alkaline: pH in KCl 7.2. Moderate liming (×0.5 rate every 7 years) affects an increase in the amount of agronomically-valuable mesoaggregates (especially of 1.0-2.0 and 1.0-0.5 mm size class). Microbe distribution in different aggregate fractions in acid and moderately limed soil were not significantly different. In intensively limed soil, there was an observed tendency of microbe displacement from the smallest aggregate-size classes to the largest (1.0-2.0 mm). [ABSTRACT FROM AUTHOR]

Citrus cultures have a fundamental importance to the Brazilian economy; certain aspects such as plant nutrition, yield, and fruit quality are vital for the citrus industry sustainability. The present study evaluated the nutritional status of manganese in adult Pear orange trees using different lime rates topically applied to the soil. The direct evaluation of lime rates effects on leaf manganese (Mn) levels revealed a decrease of the nutrient correlated to its increased, as well as passage of time between application and measurement. Foliar sampling 30 months after surface lime application evidenced a high correlation of foliar manganese levels with soil base saturation of 10-20 cm. Leaf manganese levels which showed a great probability of high productivity were between 33 and 70 mg kg-1. [ABSTRACT FROM AUTHOR]

The aim of this study was to critically assess the accumulation and depletion in total contents of trace elements from non-point pollution areas, specifically agricultural fields. Enrichment or depletion of trace elements was assessed using Al, Fe and V (control topsoil and B horizon) as reference elements. We found that various reference elements and selecting reference horizons could give contradictory results and lead to different assessments of the effects of various agricultural practices in Lithuanian soils. Cultivation on naturally acid soils in east and west Lithuania led to enrichment in some trace elements, predominantly Ag, Mn and Sr in sandy loams or loams of west Lithuania and B, Cu and Sr in sandy loams of east Lithuania. Differential fertilization led to Sr accumulation in calcareous silt loams of central Lithuania. Many experiments revealed Sr accumulation, which means that Sr concentrations have profoundly changed during decades of soil fertilization and liming in Lithuanian soils. Subsoil reference indicated a greater number of affected elements in almost all the cases. It is probable that other regional factors (such as atmospheric pollution and precipitation chemistry) influence differences in enrichment factors (EFs) between topsoils and subsoils. Research findings accord with earlier published results on changes of mobile element forms after liming and adds knowledge on the total amounts of affected elements. We suggest that assessment protocols using a few reference elements and soil layers allow filtering of datasets and indicate reliable changes in enrichment factors (EFs). However, changes occurred in other specific elements in specific circumstances, and these reference elements merit special attention. Reference selection procedures also merit further investigation and discussion. [ABSTRACT FROM AUTHOR]

Citrus pulp is the pulp and peel waste generated by citrus fruit processing. It can be a pollutant when it is disposed of by burning or dumping, but it is rich in organic carbon (monosaccharides, polysaccharides, pectins, and organic acids), suggesting that it could also be a valuable soil amendment. For the purpose of studying the effects of citrus pulp amendant on soil fertility, a study was carried Out using lysimeters where the soil was amended with different quantities of dried citrus pulp. Soil samples were taken periodically over a period of 2 years to evaluate the evolution of the organic matter and the activity of the microbial biomass. The former was evaluated by calculating the TOC and by extracting and characterizing the humified component. while the latter was evaluated through the calculation of the basal respiration, the C microbial content and some enzymatic activities (alkaline phosphatases, ß-glucosidase, and arylsulphatase). The introduction of citrus pulp brought about an improvement in soil quality which continued for 20 months after the application of the amendant. In particular, there was an increase in the soil organic matter, despite the notable mineralization process which took place in the short-term due to the citrus fruit industry residues. In the medium term, the chemical-spectroscopic characterization of the organic compounds of the soil highlighted a great similarity to the natural humic substances. The improvement in soil quality was also demonstrated by the activity of the microbial biomass, with a large and long-lasting increase in microbial and respired C and the stimulation of enzymatic activity. [ABSTRACT FROM AUTHOR]

Accurately estimating lime requirements (LR) of acidic soils has been a concern since liming practices began. The objectives of this study were to: (i) determine if the Shoemaker-McLean-Pratt (SMP) buffer is accurately predicting the LR of Kansas soils, (ii) calibrate the SMP and Mehlich buffers to accurately estimate the LR of Kansas soils to specific target pH values, and (iii) compare the effectiveness of 60-d incubations vs. field-observed lime response in determining LR. Kansas soils were used to evaluate the current LR according to the SMP buffer and calibrate SMP and Mehlich methods. Slope values (SMP LR vs. 60-d LR) <1 andy intercepts >0 indicated that the SMP either overestimated the LR at low values or underestimated the LR at relatively high LR values compared with 60-d incubations with CaCO3. Calibration of the Mehlich buffer to a target pH of 6.8 provided a better fit than the SMP buffer but the opposite was true at target pHs of 5.5 and 6.0. Titration with 0.022 MCa(OH)2 resulted in a LR (target pH 6.8) 55% less than that measured by the 60-d incubation. Evaluation of the SMP buffer, Mehlich buffer, and Ca(OH)2 titration method on 12 soils indicated that the LR estimated by the Mehlich buffer was not significantly different than the LR from the 60-d incubation. Comparison of the LR from 60-d incubations with field-observed lime response showed that the actual LR in the field was greater than that predicted by the 60-d incubation, which warrants further investigation. [ABSTRACT FROM AUTHOR]

Fine root systems may respond to soil chemical conditions, but contrasting results have been obtained from field studies in non-manipulated forests with distinct soil chemical properties. We investigated biomass, necromass, live/dead ratios, morphology and nutrient concentrations of fine roots (<2 mm) in four mature Norway spruce ( Picea abies [L.] Karst.) stands of south-east Germany, encompassing variations in soil chemical properties and climate. All stands were established on acidic soils (pH (CaCl2) range 2.8–3.8 in the humus layer), two of the four stands had molar ratios in soil solution below 1 and one of the four stands had received a liming treatment 22 years before the study. Soil cores down to 40 cm mineral soil depth were taken in autumn and separated into four fractions: humus layer, 0–10 cm, 10–20 cm and 20–40 cm. We found no indications of negative effects of N availability on fine root properties despite large variations in inorganic N seepage fluxes (4–34 kg N ha−1 yr−1), suggesting that the variation in N deposition between 17 and 26 kg N ha−1 yr−1 does not affect the fine root system of Norway spruce. Fine root biomass was largest in the humus layer and increased with the amount of organic matter stored in the humus layer, indicating that the vertical pattern of fine roots is largely affected by the thickness of this horizon. Only two stands showed significant differences in fine root biomass of the mineral soil which can be explained by differences in soil chemical conditions. The stand with the lowest total biomass had the lowest Ca/Al ratio of 0.1 in seepage, however, Al, Ca, Mg and K concentrations of fine roots were not different among the stands. The Ca/Al ratio in seepage might be a less reliable stress parameter because another stand also had Ca/Al ratios in seepage far below the critical value of 1.0 without any signs of fine root damages. Large differences in the live/dead ratio were positively correlated with the Mn concentration of live fine roots from the mineral soil. This relationship was attributed to faster decay of dead fine roots because Mn is known as an essential element of lignin degrading enzymes. It is questionable if the live/dead ratio can be used as a vitality parameter of fine roots since both longevity of fine roots and decay of root litter may affect this parameter. Morphological properties were different in the humus layer of one stand that was limed in 1983, indicating that a single lime dose of 3–4 Mg ha−1 has a long-lasting effect on fine root architecture of Norway spruce. Almost no differences were found in morphological properties in the mineral soil among the stands, but vertical patterns were apparently different. Two stands with high base saturation in the subsoil showed a vertical decrease in specific root length and specific root tip density whereas the other two stands showed an opposite pattern or no effect. Our results suggest that proliferation of fine roots increased with decreasing base saturation in the subsoil of Norway spruce stands. [ABSTRACT FROM AUTHOR]

The potential effect of acidification of contaminated sandy soils on Cd transport in the unsaturated zone was assessed. Forty-eight soil profiles were sampled at five depths in a polluted field that was set aside in 1992. The Cd concentration in the top 30 cm of this field was, on average, 10 mg kg−1. A column experiment was carried out with one of the topsoil samples. Homogeneously packed columns were leached with 0.001m CaCl2, adjusted to pH 3 or pH 5.7, at a pore water velocity of 6 cm day−1. The Cd and proton transport was predicted with coupled transport equations. The Cd transport was modelled by assuming local equilibrium and by using sorption parameters derived from batch experiments, while acidification was modelled with a kinetic approach, on the assumption that proton buffering was due to cation exchange and mineral weathering. Organic matter was the main contributor to the cation exchange capacity of these soils. Observed and predicted pH and Cd profiles in the columns agreed well. With the same model, the proton and Cd transport at field scale was calculated for each of the 48 profiles sampled (‘grid model’). It was predicted that the field-averaged Cd concentration in the seepage water will increase from 6 μg litre−1 at present to 200 μg litre−1 over 260 years, which greatly exceeds the maximum permissible concentration (MPC) in groundwater of 5 μg litre−1. Predictions of Cd transport using field-averaged soil properties yielded a later breakthrough time and a larger peak Cd concentration than predicted with the grid model, which illustrates the impact of spatial variability on solute transport. Continuation of liming practices is a possible solution to prevent breakthrough of Cd at concentrations far in excess of the MPC. [ABSTRACT FROM AUTHOR]

Abstract: Tea is a widely consumed beverage. However, recent studies revealed that there were an increasing number of cases of tea products exceeding the former maximum permissible concentration (MPC) in China for Pb (2mgkg−1). Tea Pb contamination is an issue affecting trade and consumer confidence. Root uptake of Pb could contribute significantly to Pb accumulation in tea leaves due to the strong acidity of many tea garden soils. We conducted pot and field experiments to evaluate the effect of liming on Pb uptake by tea plants on two highly acidic soils (pH3.6). Additions of CaCO3 significantly increased soil pH by up to 1unit and decreased soil extractable Pb by up to 32%. Liming resulted in a decrease in the proportion of Pb in the exchangeable and carbonate-bound fractions, with a concurrent increase in the fractions bound to Fe/Mn oxides and residues. Liming significantly decreased Pb concentrations of fine roots, stems and new shoots of tea plants in the pot experiment. In the field experiments, the effect of liming was not significant during the first year following CaCO3 application, but became significant during the second and third years and Pb concentration in the new shoots was decreased by approximately 20–50%, indicating that liming of acidic tea garden soils is an effective way to reduce Pb contamination of tea. The study also reveals a distinct seasonal variation, with Pb concentration in the new shoots following the order of spring>autumn>summer. [Copyright &y& Elsevier]

In a base-poor northern hardwood stand in Quebec, subjected to high acid deposition, sugar maple (Acer saccharum Marsh.) nutrition, growth, and crown vigor were evaluated 10 years after application of 0–50 t·ha–1 of CaMg(CO3)2 in 1994. One decade after treatment, foliar calcium and magnesium concentrations of sugar maple were still higher for treated than for control trees. The analysis of foliar nutrient indices showed that liming improved the nutrition of nitrogen and calcium, but caused imbalance of phosphorus, potassium, and magnesium. In 2004, crown dieback was much lower for limed trees (0.5%–4.5%) as compared to unlimed trees (23.7%). When compared with crown dieback before treatment, dieback of limed trees generally had decreased by 2004, while dieback of untreated maple trees increased over the 1994–2004 period. In 2004, basal area increment for limed trees was nearly double that of unlimed trees. However, no difference was detectable among trees limed at different rates. Midterm efficacy of liming in this study was demonstrated by the improvement of sugar maple calcium nutrition, crown vigor, and stem growth 10 years following treatment. This confirms the potential of liming to limit damage caused by acid deposition in base-poor and declining northern hardwood stands. [ABSTRACT FROM AUTHOR]

Large amounts of flue gas desulfurization (FGD) and fluidized bed combustion (FBC) by‐products from burning coal, consisting primarily of gypsum, are available for potential use as a soil amendment. However, information is limited on longer‐term changes in chemical and physical properties induced over time and over small depth increments of the upper soil profile after applying these amendments. This study examined longer‐term effects in an abandoned Appalachian pasture soil amended with various liming materials and coal combustion by‐products (CCBPs). Soil chemical and physical properties were investigated over time and depths. The results indicated limited dissolution and movement of the calcium (Ca) and magnesium (Mg) applied with the chemical amendments, except for Ca and Mg associated with sulfate. However, sufficient dissolution occurred to cause significant increases in exchangeable Ca and Mg and decreases in exchangeable Al that were reflected in corresponding increases in soil pH. These beneficial effects persisted over time and were confined to the upper 0‐ to 15‐cm depth of the profile. The greatest benefits appeared to be in the upper 0‐ to 5‐cm surface layer. Both Ca and Mg applied as calcitic dolomitic limestone tended to be immobilized in the upper 0‐ to 5‐cm layer of the soil profile; Ca more so than Mg. The presence of S applied in the FGD and FBC amendments appeared to enhance the mobility of Ca and Mg. The ratio of Ca/Mg in HCI extracts from the calcitic dolomitic treatment was close to that of applied calcitic dolomite, implying that the inactive component in soil might be the original calcitic dolomite particles. Soil physical properties measured over small depth increments showed that application of the amendments improved the saturated hydraulic conductivity only in the upper 0‐ to 5‐cm depth and had little or no significant effect on the dry bulk density and plant‐available water. [ABSTRACT FROM AUTHOR]

Alfalfa pasture has not been sustainable on the coastal plain of the United States because of its intolerance to soil acidity. This study examined the responses of alfalfa metabolism to differential amendments of acid soil and to serial harvesting. The soil was spatially amended with different quantities of flue gas desulfurization sludge and gypsum after liming to pH 7. The serial harvests oscillated the RNA synthetic activity of glutamate dehydrogenase (GDH) from an oxidized to a reduced state irrespective of the soil amendments. The amplitudes of the redox cycles changed from one harvest to the next, thus demonstrating improved regrowth persistence. The chlorophyll, hexose, nucleotide, and protein contents, and the fructose‐1, 6‐bisphosphatase activity, decreased and fluctuated inconsistently in the successive cuttings. Consideration of the metabolic responses per harvest showed that the alfalfa had optimized saccharide metabolism in the first harvest, optimized RNA metabolism in the second harvest, optimized saccharide and RNA metabolism in the third harvest, and depressed saccharide metabolism in the fourth harvest, thereby optimizing the regrowth potential of the alfalfa pasture. Sustainability of the pasture was conferred by the coordinate compensatory regulation of metabolism in response to the synergistic interaction between the differential amendments and the nitrogen (N) nutrient excreted by the alfalfa into the soil. [ABSTRACT FROM AUTHOR]

Denuded landscapes adjacent to big polluters represent an extremely harsh environment for plants due to a unique combination of soil toxicity and physical stress. In a 5-year experiment we tested whether survival and performance of seedlings of Mountain birch ( Betula pubescens ssp. czerepanovii) planted in two barren sites around the nickel–copper smelter at Monchegorsk, northwestern Russia, can be enhanced by physical sheltering and how large the supposed benefits to survival and performance are in relation to liming. Seedling performance was assessed by measuring growth parameters and chlorophyll fluorescence. Physical sheltering was found to be beneficial in some conditions: when soil characteristics were not so harsh as to cause 100% mortality, sheltering increased both survival and performance of birch seedlings. Although the benefits of liming on seedling performance and survival were stronger than the benefits of sheltering, sheltering may still have its uses in restoration when large-scale liming is not applicable, for example, when the ecological side effects of liming are to be avoided. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this paper is to study changes in water-stable aggregation and void space in an upland grassland soil following a surface application of calcium carbonate intended to increase the diversity of soil fauna. Samples of the H and Ah horizons were collected at the time of the first lime application (June 1999) and 1 and 2 years thereafter. Void space in both horizons was quantified by image analysis of thin sections and the size distribution of water-stable aggregates in the Ah horizon was determined by laser granulometry. The effect of liming was largely seen in the H horizon where pH in CaCl2 increased from 3.4 to 4.1. Percentage void space and % voids >1000 μm2 increased significantly in the H horizon between 1999 and 2001, and there was a significant liming effect. In the mineral Ah horizon, only the change in void space over time was statistically significant. There were no significant differences in aggregate stability following liming or over time, despite a significant reduction in organic carbon concentration between 1999 and 2001. The change in void space with liming was consistent with reported changes in the abundance of larger enchytraeid genera such as Fridericia and with changes in earthworm abundance. Changes in void space with time may be linked to the cessation of grazing at the experimental site. [Copyright &y& Elsevier]

We combined microbial community phospholipid fatty acid (PLFA) analyses with an in situ stable isotope 13CO2 labelling approach to identify microbial groups actively involved in assimilation of root-derived C in limed grassland soils. We hypothesized that the application of lime would stimulate more rapid 13C assimilation and turnover in microbial PLFAs. Four and 8 d after label application, 18:1ω9, 18:2ω6,9 (fungal biomarkers) and 16:1ω7, 18:1ω7, 19:0cy (Gram-negative bacterial biomarkers) showed the most 13C enrichment and rapid turnover rates. This suggests that these microorganisms were assimilating recently-photosynthesized root C inputs to soils. Contrary to our hypothesis, liming did not affect assimilation or turnover rates of 13C-labelled C. 13C stable isotope pulse-labelling technique paired with analyses of PLFA microbial biomarkers shows promise for in situ investigations of microbial function in soils. [Copyright &y& Elsevier]

The effects of amending an acid Andisol with lime and gypsum on soil pH, aluminum (Al) saturation, the plant-availability of sulfur (S) and phosphorus (P), and the growth, botanical, and chemical composition of a ryegrass/white clover pasture were measured in a field trial in southern Chile. The combined amendment of limestone, dolomite and gypsum raised soil pH slightly, decreased A1 saturation from 20 to less than 1% and increased the concentration of plant available P, S, calcium (Ca), magnesium (Mg), and potassium (K) in the soil. The growth of a recently-sown rye grass-white clover pasture increased by 50% and the proportions of ryegrass, white clover and weed species changed from 12.6, 0.2, and 87% to 75, 7.7, and 17%, respectively. Plant chemical analysis suggested that, while N, P, and S concentrations in mixed pasture were less than critical values in spring, S was the most limiting nutrient in pastures from both the amended and control areas. [ABSTRACT FROM AUTHOR]

Biochar, an ecologically friendly soil amendment, is suggested for large-scale field application for its multiple potential benefits, including carbon sequestration, crop yield improvement, and the abatement of greenhouse gas emissions. However, it is unknown how effective it is in changing soil properties and its associated yield improvement when biochar is co-applied with lime in acidic soil. Here, we examined the effects of two different biochars, i.e., rice husk biochar (RHB) and oil palm empty fruit bunches biochar (EFBB), and lime on nutrient availability, the yield of maize, and soil CO2 emission of acid soil. Biochars were applied at two different rates (10 and 15 t ha−1) in combination with two rates of lime (100% and 75%), while the recommended rate of NPK fertilizers, 100% lime, and without any amendments (control) were also included. Hybrid sweet corn was grown in pots with 20 kg soils for 75 days. Plant performance and soil analyses were performed before and after crop maize cultivation while CO2 emission was recorded. Compared to the control, combined RHB biochars with lime significantly buffered soil pH and increased nutrient availability (e.g., P by 137%), while reducing Al and Fe concentration at harvest. These changes in soil properties significantly increased maize yield (by 77.59%) and nutrient uptake compared to the control. Between the two biochars, RHB was relatively more effective in making these changes than EFBB. However, this treatment contributed to a greater carbon loss as CO2 (209% and 145% higher with RHB and EFBB) from soil than the control. We believe that biochar-mediated buffering of soil pH is responsible for this change. Our results suggest that combined biochar application could bring desirable changes in soil properties and increase crop performance, although these effects can be short-lived. [ABSTRACT FROM AUTHOR]

Copper is an element necessary for the proper growth and development of plants, but when taken in excess amounts, it can be toxic. Its availability for plant can be reduced by using organic fertilizers or soil liming. The aim of the study was to investigate the effect of increasing doses of copper (100, 200, and 300 mg Cu·kg−1 of soil) application in combination with various organic amendments (cattle manure, chicken manure, and spent mushroom substrate) on the yield of cocksfoot and its content and uptake of this metal, and to determine its coefficient of bioaccumulation and tolerance indices. The toxic effect of copper manifested by significant decrease in the yield of the test plant was after the application of 300 mg·kg−1 of soil. Increasing doses of copper application increased its content and uptake by the test plant, while observing the decreasing bioaccumulation factor. All the soil amendments reduced the toxic effect of copper on cocksfoot. The most effective organic amendment in terms of yield and protective effects against high levels of copper was cattle manure, in the case of which the Org/Cu and Cu/Org tolerance indices were highest. [ABSTRACT FROM AUTHOR]

The article presents a study on the use of lime sludge waste from the paper industry. It adopts the situation at the Nagaon Paper Mill, a public sector pulp and paper mill which is a unit of the Hindustan Paper Corporation Ltd. in Assam, India wherein it generates 448 tonnes of lime sludge per day as solid waste. It notes that Assam's agricultural soil is acidic and that liming is important to maintain the potential hydrogen of the soil through lime sludge waste instead of marketed lime.

Despite ample evidence since the 1950s that the N2O product ratio of soil denitrification decreases with increasing pH, no systematic research has been carried out to investigate liming as mitigating tool. Here we report a N2O flux experiment with soils three years after applying calcareous (dolomite, calcite) and non-calcareous (norite, larvikite, olivine) limes in a field experiment in SE Norway. To create homogeneous conditions with respect to drainage, soils from field plots were excavated, homogenized and packed into freely draining pots. After sowing the pots to ryegrass, N2O fluxes were monitored after subsequent addition of NH4NO3 (160 kg N ha-1), NaNO3 (110 kg N ha-1) and simulated ploughing in late autumn, i.e. mixing the grass sward and adding additional KNO3 (5 g N m-2). Whereas the flux response to NH4NO3 was independent of liming treatment (plausibly due to dry summer conditions with no denitrification), N2O fluxes after KNO3 addition showed lowest fluxes in dolomite (90.2 g N m-2 in 22 weeks) and marble (80.8 g N m-2 in 22 weeks) treatments. The incorporation of grass in autumn was followed by diurnal freezing- and thawing, eliciting N2O fluxes of up to 6677 µg N m-2 h-1, likely originating from denitrification. Under these conditions a clear pH dependency emerged with 50% lower cumulative fluxes (over 22 weeks) in calcite treated soils (pH 6.7) as compared with acid control (pH 4.9) and soils with siliceous amendments, which did not show any pH response. Our results suggest that liming acidic soils can be used to mitigate N2O emissions during "hot moments" of vigorous denitrification. However, possibilities for precision liming should be investigated in order to reduce the byproduct of CaCO3 dissolution, CO2 which is a potent greenhouse gas. Site-specific fertilization and liming could regulate emissions derived from denitrification and lower N2O emissions overall. [ABSTRACT FROM AUTHOR]