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

Short-term potential carbon (C) and nitrogen (N) mineralization of soil organic matter and belowground plant litter was determined in the top soil layer of a sandy soil of a short-rotation coppice (SRC) and the effect of addition of lime, mineral nitrogen and poplar roots was determined. Lime addition was equivalent to 1.2 mg CaCO 3 g − 1 , mineral N and root litter were added corresponding to 6.8 μg N g − 1 and 13.8 mg roots g − 1 soil respectively. Partitioning of carbon dioxide (CO 2 ) derived from lime and soil organic matter (SOM) was calculated by using stable isotope analysis of the CO 2 . In addition, particulate organic matter (POM) as well as microbial biomass carbon and nitrogen were analyzed after 51 days of incubation. Addition of lime decreased CO 2 derived from organic matter in all treatments, but the level of decrease varied with N and root litter addition. Microbial biomass C and N increased with N addition in soil without root litter but decreased with root litter, nevertheless an immobilization of mineral N was especially high in soil amended with root litter. Particulate organic matter (POM) decreased by 41% of its dry weight in root litter amended soil. Liming decreased decomposition of POM in these soils, whereas no effect was observed after addition of mineral nitrogen or mineral nitrogen and lime. These results show that liming has the potential to decrease C mineralization of humified organic matter as well as plant residues and that decreased mineralization of organic matter occurred after liming, even if mineral N was added. [ABSTRACT FROM AUTHOR]

Productivity of resources on acid soils occupying one fourth of the total area in India is abysmally low. Lime is applied to such soils with the primary objective of increasing the productivity of crops by enhancing the availability of native and applied plant nutrients. Greenhouse pot experiments and laboratory experiments were conducted to evaluate the effects of lime and boron (B) on the availability of nutrients in soils and their uptake by plants. The application of lime enhanced the available nitrogen (N,), phosphorus (P), calcium (Ca), magnesium (Mg), sulfur (S), and zinc (Zn) content in soils, which was reflected in their uptake by sunflower (Helianthus annus). On the contrary, availability of copper (Cu), iron (Fe), and manganese (Mn) in soil was reduced due to liming. Sunflower responded very well in terms of dry matter yield to B application to the extent of 175% and 188% under 1 and 2 mg kg−1applied levels of B, respectively. Dry matter yield of sunflower was reduced to the tune of 29.2 and 42.7% under 2/3 and 1 lime requirement (LR), respectively, over control. Lime application at 1/3 LR with 2 mg kg−1of applied B emerged as an optimum combination in acid soils. [ABSTRACT FROM PUBLISHER]

Examines the interactions of lime, nitrogen, phosphorus and organic mater with respect to plant growth and arsenic and mercury uptake. Relationship between arsenic plant uptake, root length density and soluble arsenic; Mercury concentrations of soil; Use of multiple regression analysis.

Liming (at 2.5 or 10t ha−⊃1) of peat taken from under a Picea sitchensis stand reduced mortality and weight-toss of five earthworm species, measured over 8 weeks in the laboratory. In the limed treatments, least population biomass was lost by Aporrectodea caliginosa, A. longa and Lurnbricus terrestris. A. caliginoxa was the only species to gain any weight in any treatment. All earthworm species increased the amount of N released in leachates from limed and unlimed peat. Nitrate-N release was substantially greater (by up to 50fold) in treatments with lime and earthworms than with earthworms alone. Aporrectodea caliginosa was the most suitable species of those tested for inoculation into limed deep peat soils under P. sitchensis to improve rates of N mineralization. Aporrectodea caliginosa was successfully introduced into limed peat profiles in field lysimeters under a stand of N-deficient P. sitchensis. Total earthworm biomass was sustained over the 12 months of the experiment in the limed treatments, whereas only 4% remained in the treatment without lime. Earthworm cocoons were produced in the limed treatments only. Aporrectodea caliginosa in limed soil significantly increased leachate N release (to 60 kg ha−⊃1 year−⊃1) compared with untreated ( 19 kgha−⊃1 year−⊃1). and limed soils (36 kg ha−⊃1 year−⊃1). Nitrogen release was mainly as NO3−-N. Ammonium-N and NO3−-N mobilized by addition of earthworms plus lime appeared to be taken tip by living roots of P, sitchensis. This increased mineralization can be expected to lead to enhanced tree growth. [ABSTRACT FROM AUTHOR]

Plots in a beech-forest in southern Sweden were artificially limed with 2, 5 and 10 tonnes of dolomite lime ha-&sup-1;. Snail populations were sampled. The population increases correlated with lime dosages. In plots treated with 10t ha-¹, mean densities increased 4–40 times, depending on the species (5 years after liming). There were highly significant correlations between snail density and pH, Ca concentration, base cation concentration and base saturation; however, the correlations between nitrogen, phosphorus and potassium were very low. The results indicate that liming positively effects land snail population densities in relatively nutrient-poor deciduous forests. [ABSTRACT FROM AUTHOR]

Nitrogen (N) fertilization is a worldwide indispensable agricultural practice serving the survival of half of global population. Nitrogen transformation in soil as well as plant N uptake leads to release of protons and enhances soil acidification. Neutralization of this acidity in carbonate-containing soils (7.94 109 ha; ca. 54% of global land surface area) results in CO2 release corresponding to 0.21 kg C per kg applied N. Based on the global N fertilization map and the distribution of soils containing CaCO3, we calculated the annual amount of CO2 released from carbonates as 7.48 1012 g C y-1. These baseline levels of continuous CO2 release will remain until N fertilization occurs. In the second half of the study, we estimated that about 273 1012 g C are released annually in the same process of CaCO3 neutralization by liming of acidic soils, a common agricultural practice to revitalize over-fertilized fields. These two CO2 sources correspond to 3% of global CO2 emissions by fossil fuel combustion or 30% of CO2 by land use changes. However, the duration of CO2 release after land use changes usually takes only 1-3 decades before a new C equilibrium is reached in soil. In contrast, the CO2 released by CaCO3 acidification cannot reach equilibrium until it is completely neutralized, which will take centuries or even millennia. This promotes limiting soil acidification as an effective strategy for inhibiting millennial CO2 efflux to the atmosphere. Hence, N fertilization should be plant demand-specific to prevent over fertilization, not only because of its role in local eutrophication, but also this newfound role of continuous CO2 release by global acidification.Key words: CO2 efflux, global acidification assessment, global warming, mitigation policy, nitrogen fertilization, soil acidification mechanisms, soil inorganic carbon [ABSTRACT FROM AUTHOR]

Liming to increase soil pH is a common agricultural practice to mitigate acidification ofcultivated soils and optimize crop yields. However, changes in soil pH have pervasiveeffects on various soil processes including microbial activity. Notably, soil pH hasbeen identified as a strong regulator of gaseous emissions from denitrification withincreasing ratios of nitrous oxide (N2O) to dinitrogen (N2) emissions (N2O/N2 ratio) atlower soil pH. Therefore, liming as such could also be a potential option to mitigateN2O soil emissions. Within the EU ERA-NET project MAGGE-pH, studies of soilmicrobiology in response to long-term pH changes in a coarse sandy soil was initiatedin 2018 in Jyndevad, Denmark. The study site was a long-term liming field trialestablished in 1942 with four levels (and three replicates) of lime (0, 4, 8 and 12 Mg/ha)applied recurrently at intervals of few years to keep the soil pH at around certaintarget levels. The current levels of soil pH was around 3.8, 5.0, 6.4 and 6.8 (soil pHmeasured in solution of 0.01 M CaCl2). The soil was cropped to spring barley and inthe season of 2018, N2O emissions were measured during three field campaignperiods using the closed chamber technique. The results substantiated that liming toincrease soil pH mitigated N2O emissions as compared to the un-limed references.Further, laboratory assays with soil samples from the replicated field plots, showedthat N2O/N2 ratios from denitrification enzyme activity was strongly controlledby soil pH, i.e., with gradually decreasing ratios at increasing soil pH. A strongregulatory effect of soil pH was also seen for soil nitrification potential, however inthis case the process rates were gradually increasing at increasing soil pH. Furtherassays of soil microbial processes such as beta-glucosidase activity also showedgradually increasing rates at increasing soil pH. Profiles of microbial carbon substrateutilization will be studied to further identify the link between liming-induced pHchanges and soil microbiology with the overall aim of mitigating N2O emissions. [ABSTRACT FROM AUTHOR]