石灰处理对红壤中镉形态及其毒性的影响

The effect of liming 4 red soils developed from Quaternary red clay and red sandstone on the cadmium forms and its toxicity were investigated. Liming the acid red soils could greatly reduce Cd toxicity to plants because the soluble Cd and organic Cd in the soils decreased significantly while Cd bound to minerals/oxides and residual Cd increased markedly with increasing lime rates (pH).     

Long‐term effects of liming on the fine‐root standing crop of Picea abies and Pinus sylvestris in relation to chemical changes in the soil

The long‐term effects of lime application on fine roots of Norway spruce, Picea abies (L.) Karst, and Scots pine, Pinus sylvestris (L.), have been studied in five experimental forest stands subjected to different lime applications 5 to 18 years before the present study was undertaken. The effects of liming does not seem to significantly influence fine‐root development in forest stands in the long term. The only response to liming in measured root variables was a tendency to increased specific root length (SRL = fine‐root length/fine‐root dry weight, m/g). A correlation between increased SRL, decreased root biomass and increased stem volume growth was indicated. Changes in water extractable amounts of mineral elements—P, K, Ca, Mg, Mn, S, Al and Fe‐in bulk soil and rhizosphere soil from the mineral soil layers were studied in a control area and an area treated with 3830 kg CaCO₃ ha^‐1. Few significant differences were found between treatments, and then mainly in the case of Ca.     

Effects of lime and ash treatments on ectomycorrhizal infection of Pinus sylvestris L. seedlings planted in a pine forest

A pine forest in the south of Sweden was treated with lime and wood ash. In early June, 12 months after the ash treatment and 18 months after the lime treatment, one year old Pinus syhestris L. seedlings were planted. Four months later six différent ectomycorrhizal types had infected the seedlings in all the treatments. A mycorrhizal type designated “pink”; was more than twice as common in the lime treatments as in the control and ash treatments. Piloderma croceum Erikss. & Hjorts. was significantly more abundant in limed soil than in ash treated soil. The results were compared to those from a bioassy performed in the laboratory, where P. syhestris seedlings had been grown in soil from the same forest. Similar soil pH values in the two studies resulted in different relative infection rates of the mycorrhizal types found. One additional mycorrhizal type, designated “white”; was found in the field experiment. This suggests that mycelial connections to the mature host plants may significantly alter the ability of different fungi to colonize host plant roots in competition with each other compared to when the fungi infect from propagules in the soil.     

The Contribution of Various Components to pH Buffering Capacity of Acrisols in Southeastern Vietnam

This paper examined the contribution of various soil components to pH buffering capacity (pH_BC) of haplic Acrisols in an upland area of Southeastern Vietnam. Sampling was conducted in 2016 in Tan Bien district, Tay Ninh province at seven sites from the surface to 60-cm depth. Soils were very acidic (pH_H2O 4.53 ± 0.05). The pH_BC were very low, 0.46 ± 0.04 and 0.44 ± 0.05 cmol H⁺ kg^?1 pH^?1, respectively, for original samples and those from which soil organic carbon (SOC, 0.52 ± 0.09%) were removed. The contribution of Al³⁺ to pH_BC was remarkable while that of SOC was of little significance. The contribution of clay minerals to pH_BC was unclear due to the low (9.37 ± 0.76%) and kaolinite-dominated clay content. The current soil conditions indicated a potential for further soil acidification. Liming would be one of the measures to remediate soil acidity in the research area.     

Impact of pond management on tambaqui, Colossoma macropomum (Cuvier), production during growth-out phase

This study evaluated the impact of pond management on tambaqui, Colossoma macropomum (Cuvier), rearing during the growout phase. Juvenile tambaqui were stocked in ponds with three different management regimes: (1) natural ponds (Nat); (2) limed ponds (Lim); and (3) limed and bimonthly fertilized ponds (LimFer). The experiment lasted 210 days and the growth parameters were evaluated monthly. Water quality and effluent measurements were performed every 15 days and at the end of the experiment yield parameters were obtained. There was no difference in weight and length among treatments. Stomach contents and zooplankton availability were not influenced by pond management, but the rearing period had an influence on them. Food conversion rate (FCR) was better in fish from the Lim treatment than in fish from the Nat treatment. The pH, hardness and alkalinity values were significantly higher in the Lim and LimFer ponds, where the liming procedure was performed. The effluent analysis showed a more potentially impacting effluent in the LimFer treatment, where phosphorus and orthophosphate concentrations showed values significantly higher than those in Lim and Nat ponds. The results show that the Lim treatment is the best approach, as in this treatment fish achieve market size, better FCR, yield and have a reduced environmental impact.     

Effect of organic matter concentration on agricultural limestone dissolution in laboratory soil–water systems

Laboratory soil – water systems in which soil organic matter was increased by 0.0%, 0.5%, 1.0%, 2.0% and 4.0% by adding dry, chopped ryegrass (Lolium perenne) shoots to sandy soil containing 0.06% organic matter. Agricultural limestone was added to the systems, and pH, alkalinity and hardness of the water were monitored for 65 days. The pH, alkalinity and hardness increased with greater soil organic matter concentration. Amounts of carbon dioxide released by microbial respiration increased at the higher soil organic matter concentrations, and this resulted in more rapid and greater solubility of agricultural limestone. The results suggest that greater soil organic matter concentrations in ponds favour the rate and extent of agricultural limestone dissolution.     

Potential use of wood ash in South African forestry: a review

The use of landfills as a disposal method for wood ash is costly, environmentally detrimental and is pitted against increasingly stern environmental regulations. Literature has shown that wood ash has the potential to be used as a forest fertiliser and the effects tend to be highly site-specific. Wood ash contains a combination of carbonates, hydroxides and other calcium-containing minerals that are responsible for the liming effect observed following application to soils. In addition, it contains significant magnesium and potassium concentrations, but little nitrogen and sulphur. The phosphorus availability of wood ash varies considerably and in effect can limit soil phosphorus uptake and may affect subsequent nutrient balance in plants. Short-rotation forestry practices and whole-tree harvest systems can induce periodic or persisting nutrient deficiencies and acidify the soil. This may affect the ability of a site to sustain adequate nutrient levels over successive rotations. Utilising wood ash as a soil amendment can offset or correct some nutrient deficiencies and imbalances induced by intensively managed plantation forests. This review covers the international literature on ash applications to forest land, including the effect of ash-beds remaining after slash burning (as a useful analogy for the effects of wood ash on soil properties and tree growth). The results show that ash applications to forest land can be done safely and can potentially stimulate microbial activity and improve pine and eucalypt growth. Safe ash application rates should be determined after consideration of (1) soil buffer capacity and ash alkalinity (expressed as calcium carbonate equivalence) and (2) an evaluation of the concentrations of heavy metals existing in soils and present in the available ash, particularly from cadmium, chromium, lead and arsenic.     

Extractants for available boron in limed acid soils and its correlation in crops with high carbon storage capacity (Tectona grandis)

The objective of this work was to evaluate the efficiency of six extractants for available boron in acid soils undergoing to liming, and to correlate the results of soil analysis with foliar response seen in the teak plants in greenhouse conditions. Acid soil samples were collected and their chemical characterization was performed using standard analysis protocols. Later, agricultural lime was added to the experimental units in greenhouse conditions in order to control the soil acidity and these were incubated for 30 days. Six extracts for available boron were evaluated and correlated with response in the plant by foliar analysis. It is concluded that a high dissolution power of boron extractant solution produces a high sensitive in the determination of the changes of boron concentration in the limed acid soil. These methods are seen to be not adequate for the determination of available boron contents at high concentrations.     

The long-term effects of catchment liming and reduced sulphur deposition on forest soils and runoff chemistry in southwest Sweden

Whole catchment liming or forest liming has been proposed and implemented as a countermeasure to the effects of elevated sulphur deposition. Since the end of the 1980s the Swedish Forest Agency has undertaken experimental forest liming experiments in selected catchments in southern Sweden. These studies were with low doses (3 tonnes ha⁻¹) of lime (CaCO₃) and dolomite (CaMg(CO₃)₂). Data from both soil samples and stream water samples have been collected for the 16 years following treatment. The stream data has been complemented with data from untreated catchments, from the Swedish monitoring stream network. Significant differences due to treatment were seen for Ca, cation exchange capacity (CEC) and base saturation (BS) in the humus layer, none of these variables showed a statistically significant change in the mineral soil due to treatment alone. Soil samples from both the treated and untreated sites showed temporal changes in both the humus layer and the mineral soils with increases in pH, Ca and CEC and decreases in BS and Al which were independent of treatment. A combination of treatment and time, gave significant changes in BS and TA down to 10 cm in the mineral soil. In the stream water samples no statistically significant differences were observed between treated and untreated sites. Regardless of treatment, the streams exhibited a general pattern of declining concentrations of SO₄, Ca, sum of base cations (BC) and increasing acid neutralizing capacity (ANC). In summary, the application of a low dose of lime (3 tonnes ha⁻¹) did not result in significant changes in surface water chemistry in the study catchments and changes in soil chemistry were mainly restricted to the humus layer during the 16 years following treatment. The natural recovery, as a result of reductions in sulphur deposition, dominated the effects and was clearly seen in both the treated and untreated study sites. MAGIC simulations indicate that this recovery will continue in the coming decades.     

Relative Neutralizing Value as an Indicator of Actual Liming Ability of Limestone and Byproduct Materials

Methods used to compare the effectiveness of liming materials (e.g., relative neutralizing value, RNV; effective calcium carbonate equivalent, ECCE) were developed for ground limestone. This method is relatively untested on industrial byproducts that could be used when limestone is expensive or unavailable. The objective was to determine if RNV applies to both ground limestones and industrial byproducts. A 42-d incubation study was performed on three acid soils with 11 ground limestones and 9 different byproducts at four rates based on titration and the modified Adams-Evans buffer method. Overall effectiveness, assessed as RNV compared to Ca(OH)₂, averaged 101.5 ± 0.9% for all the evaluated liming materials, except the paper sludge and dolomitic marble. Thus, RNV was a good estimate of neutralizing ability when particle size was accurate. Addition of RNV to packaging would facilitate the commercial use of byproducts as liming materials allowing consumers to compare products by price and properties.