Effects on Motile Factors and Cell Growth of Euglena gracilis After Exposure to Wood Ash Solution; Assessment of Toxicity, Nutrient Availability and pH-Dependency

Wood ash application (WAA) to the forest has been suggested as a resource of nutrients for trees and for restoration of acidified soils and surface waters. However, studies of the effects of WAA on aquatic systems are few. This study investigated the effects of wood ash (1–25 g L^?1) on the unicellular flagellate Euglena gracilis, which has been proved to be a sensitive test organism for assessing environmental change. Long-term (7 days) growth studies and short-term (direct, 24 and 48 h) studies of different motile factors, using the automatic biological test system Ecotox, were conducted. The results show no indication of biotoxic effects due to wood ash (adjusted to neutral) treatments. However, when no adjustments of pH in wood ash solutions were made, inhibitory effects on motile factors and cell growth were observed at higher concentrations of wood ash (10–25 g L^?1) due to high pH (> 8). In tests with pH adjusted to neutral, enhanced motility was observed. These results indicate that high concentration of WAA could affect freshwater environments.     

Effects of Wood Ash Dose and Formulation on Soil Chemistry at Two Coniferous Forest Sites

Harvesting stem biomass from the forest inevitably involves exporting nutrients from the ecosystem. The amount exported is increased when the logging residues are also removed for use as fuel. Recycling of the resulting wood ash has been advocated as a measure to compensate for the nutrient losses and to sustain future forest production. The physical formulation of the wood ash may have an important influence on its effects on soil properties. In this paper, we report effects of two different types of wood ash (one self-hardened and crushed, the other pelleted), with differences in solubility, on soil chemistry in the humus layer and upper 15 cm of the mineral soil, at two coniferous sites in south-central Sweden, 5 yr after their application. The crushed ash was applied at three doses (3, 6 and 9 ton ha^–1), while the pelleted ash was applied at only one dose (3 ton ha^–1). At both sites the soil was podzolized. The two sites differed with respect to soil conditions, despite being situated only a few kilometers apart. The application of wood ash increased both soil pH and base-cation content in the humus layer at both sites. In the mineral soil, the effects were less pronounced. Treatment effects on soil chemistry did not differ between the two ash formulations. The retention (i.e. the extractable amount of nutrients found in the soil that could be attributed to the ash application) of nutrients varied strongly between the two sites, and K retention (ca. 10%) was generally lower than that of Ca and Mg.     

Application of lime and wood ash to decrease acidification of forest soils

Liming and wood ash application are measures to decrease acidification of forests soils. The assessment of lime requirement can be based on that base saturation, which indicates a low risk of acid toxicity. Because of a wide spread Mg deficiency in Central European forests, Mg containing lime is normally applied. Ash from untreated wood is applied to decrease soil acidity as well as to improve K and P nutrition. In wood ash, K is the most soluble nutrient, follwed by Ca and Mg. The overall dissolution rate of lime applied to the forest floor is about 1t ha^?1 a^?1. After liming, soil solution alkalinity and Mg concentrations increase markedly, while changes of Ca, H ions and Al concentrations are less pronounced. After the application of wood ash, K concentrations increase due to the high K content and the high solubility of K in wood ash. After the application of a sufficiently high dosage of lime to the forest floor, the decrease of acidity in deeper soil layers may need decades because of the low solubility of lime. Nitrification and nitrate leaching induced by lime or wood ash may reduce their acid buffering efficiency.     

Effect of wood ash on soil chemistry of a pine stand in Northern Germany

Addition of wood ash to acid soils will affect the soil chemistry of forests in a number of ways which were assessed for a pine stand in northern Germany. A field experiment was carried out in a fifty‐year old pine stand on a sandy Podzol at Fuhrberg (Lüneburger Heide, Lower Saxony/Germany) which involved depositing wood ash (2.4 t ha^—1) on the surface. Soil solution chemistry was investigated monthly at different depths for 24 months. Prior to and 19 months after the ash addition, exchangeable cations and amounts of heavy metals were determined at different depths. Two to four months after addition of wood ash, maximum mean concentrations in the soil solution of Ca were 240 μmol l^—1 at 0 cm (surface of mineral soil) and 100 μmol l^—1 at 100 cm and of K 980 μmol l^—1 and 140 μmol l^—1, respectively. The pH values in soil solutions dropped temporarily by 0.3 units at 0 and 10 cm depth. Nitrate concentrations increased at all depths and maximum mean concentration was 230 μmol l^—1 at 100 cm. Concentrations of Pb and Cr in soil solution did not change significantly (p < 0.05) after ash addition. Concentrations of Cd and Zn increased significantly at some depths but stayed well below the legal limit for drinking water and below the limits given by the German recommendation for soil conservation. Nineteen months after ash addition, the cation exchange capacity (corrected for the release of cations from the ash) of the upper 6 cm of the organic layer was almost doubled and amounts of exchangeable Ca and Mg increased significantly in the upper 8 cm of the organic layer. Amounts of Zn were increased in the entire organic layer, but changes were significant only in the upper 4 cm. The results of this study suggest that ash from untreated wood (using modest additions) may be recommended for amelioration of forest soils.     

Water chemistry in forested catchments after topsoil treatment with liming agents in South Sweden

Critical loads of sulphur and nitrogen are exceeded in South Sweden, and nutritional imbalances are expected to appear with time in forests. During 1984 paired catchments were established in a northwestern-southeastern gradient in South Sweden. The aim was to study long-term liming effects on throughfall, soil water, groundwater and runoff. Dolomitic limestone and wood ash were tested at one locality, Hagfors (59° N). Three adjacent catchments were used; one reference area, one treated with dolomitic lime (0.5 kg/m²) in 1985, and one with wood fly ash (0.22 kg/m²) in 1988. The lime and the fly ash was granulated and applied by a helicopter in the end of May. Measurements concerning chemistry of the precipitation, throughfall, soil water and runoff has been conducted since spring 1984. The results showed that top-soil spreading of liming agents, besides the desired effects on soil chemistry, after some years also affected the quality of the recipient water. In the dolomitic lime treated catchment the positive effects were most obvious, with raised pH-, Ca-, and Mg-values and lowered Al-, Fe- and Mn-values. A positive trend regarding lower nitrogen (NO₃ ^?) leaching could also be calculated. Wood ash in the used amount affected only slowly, but after six years the runoff water indicated increased pH-values as well as increased Ca- and K-values and Ca/Al-ratios. Dolomitic lime in the amounts of 0.5 kg/m² was concluded to be sufficient to achieve positive effects in catchments of the present type. Wood ash in the amount of 0.22 kg/m² although enough for recycling purposes, was not sufficient enough in increasing pH in runoff to prevent acid leaching from the forest soils.     

Evaluation of wood ash disposal on agricultural land. II. Potential toxic effects on plant growth

Abstract

Land application of wood ash is a rapidly growing disposal option for industries combusting wood for steam or electricity. Recent research has demonstrated that wood ash is a valuable soil amendment and liming agent. The objective of this study was to examine the potential phytotoxic components of wood ash and their interactive effects in order to determine appropriate land application rates.

Bush beans (cv. ‘Blue Lake 274') were grown under greenhouse conditions in an acidic Palouse silt loam soil treated with a background concentration of wood ash equivalent to 10 mt/ha (0.09 kg/ha of B, 462 kg/ha of K, and pH 6.5). The ash‐soil mixture was then amended with different concentrations of B, K, and CaO (for pH change) in a completely randomized factorial experiment.

Soil pH and K concentration appeared to be the major rate limiting components in land application of wood ash. Bean yield was adversely impacted when application rates resulted in a soil pH >6.5 and 2,662 kg K/ha. Since pH was the most important rate limiting component, ash application rates should be based on the calcium carbonate equivalent of the ash and the pH requirements of the crops.     

Annual losses of iron from moorland soils and their relation to free iron contents

The temporal pattern of iron loss from a moorland catchment was investigated by intensive stream water sampling. The total loss in 1 year was 2.11 kg ha^?1 of Fe, with a pronounced autumn maximum. Iron concentrations in stream water were strongly correlated with dissolved organic matter content, but again with seasonal variation. Free iron content measured on a number of soils in the catchment ranged from 3.1 to 8.7 kg m^?2. Assuming soil development over 10 000 years, predicted loss of iron from the catchment is comparable in quantity to the amounts of free iron in the soils.     

Soil nitrate sources and nitrate leaching losses, Slapton, South Devon

Abstract. Concentrations of soil nitrate were measured in areas of different land use within a small drainage basin. From previous work on nitrate losses from subcatchments, soil nitrate levels were expected in the order arable > grassland > woodland. Although differences were detected, they were not consistent and seasonal variations in soil nitrate for the same land use were greater than those between land uses. Seasonal fluctuations in stream nitrate loads were not strongly related to the seasonal differences in soil nitrate levels but were more closely related to stream discharge and antecedent climatic conditions. Losses of nitrate from the catchment seemed to be transport limited and independent of variations in soil nitrate supply; the implication is that water quality control by land use manipulation will only be successful in supply limited situations when leaching losses are sensitive to variations in soil nitrate supply.     

Short-Term Influence of Clinker Dust and Wood Ash on Macronutrients and Growth in Norway Spruce (Picea abies) and Scots Pine (Pinus sylvestris) Seedlings

The effects of clinker dust and wood ash on Norway spruce and Scots pine seedlings were compared in buried pots. Clinker dust (0.5 kg m^?2) and wood ash (0.5 kg m^?2) were applied to the surface of a nutrient-poor mineral soil. In the second year, the increase in soil pH by the dust and ash were larger than in the first year. Both alkaline treatments caused a large increase in the needle potassium (K) concentration. An excess of soil K relative to magnesium (Mg) was observed by decreased Mg concentration in needles shortly after treatment. However, Mg concentration in needles stayed in the sufficiency range. Current results confirmed earlier findings that despite a positive effect on base cation nutrition, wood ash has a low potential for increasing the biomass of forest stands on mineral soils due to the N limitation in these soils.     

Batch‐Determined Elements Release from Wood Ash Mixed with an Acidic Forest Soil Sample

Abstract

A serial batch leaching experiment was carried out to evaluate the release of elements from wood ash mixed with a strongly acidic forest soil sample. Wood ash application resulted in increased leachate pH, dissolved organic carbon (DOC), and electrical conductivity (EC). Increasing application of wood ash increased cumulative release of inorganic carbon (IC), chloride (Cl), nitrate (NO₃), sulfate (SO₄), potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), manganese (Mn), phosphorus (P), and copper (Cu). Release of NO₃, P, iron (Fe), aluminum (Al), Cu, and lead (Pb) continued. Large amounts of DOC, K, Ca, and SO₄ were mobilized. Inorganic C, Fe, and Mg were released in moderate quantities. Manganese, Na, Al, Cl, and NO₃ were released in limited amounts. Amounts of leached P, Pb, and Cu were lower. The mixed order equation adequately described the release of elements in the soil‐ash mixture. Accumulation of elevated amounts of trace elements does not appear to be a problem when higher wood ash rates are avoided. Wood ash should be applied in split application to avoid short‐term concentrated alkaline and salty conditions that could interfere with plant growth.     

Characterization of hydrophobic acid fractions in water-soluble organic matter in Dystric Cambisol and in a stream in a small forested watershed: Seasonal and vertical variations in chemical properties

Abstract

Chemical properties of hydrophobic acid (HoA) fractions in water-soluble organic matter in soil and water are concerned with its interactions with mineral soil surfaces and organic pollutants. In 2004 we examined the seasonal and vertical changes in chemical properties of the HoA fraction in a Cambisol profile and compared these properties with those in the HoA fraction of an adjacent stream (aquatic humic substances) in a temperate forested watershed using high performance size exclusion chromatography (HPSEC) and ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy. The HoA fractions from Oi, Oe/Oa, A and B horizon soils in summer had lower O-alkyl C proportions than those recorded in samples in other seasons. The proportions of aromatic C in HoA fractions from A and B horizons were highest in summer. These seasonal variations were less significant than variations with soil depth. O-alkyl C proportions in HoA fractions decreased with increasing soil depth from the Oi to the A horizon. The HoA fractions from the B horizon showed a higher alkyl C proportion than samples from other horizons in winter and spring. These changes with soil depth from the Oi to A horizons might result from selective utilization of carbohydrate carbon by microorganisms, whereas those in the B horizon may result from sorption to mineral surfaces. The HoA fractions in the stream were similar in relative molecular weight, distribution of each type of proton and carbon species in HoA fractions from the B horizon, whereas stream HoA fractions collected in summer would be derived from organic horizons. This indicated that vertical changes in the chemical properties of HoA fractions in soil and pathways of water to the stream would largely affect the chemical properties of HoA fractions in the stream.     

General Chemical Properties of Brown Forest Soils Developed from Different Parent Materials in the Submontane Zone of the Kanto and Chubu Districts, Japan

It is essential to analyze chemical properties including the amount of various materials and the soil colloid characteristics in forest soils to forecast wood production and the distribution of and variations in the environmental functions of forest soils, such as conservation of stream water and carbon sequestration. Approximately 70% of the forest soils in Japan consists of Brown Forest Soils (BFS), which are considered to be typical zonal soils under the humid-temperate and warm-temperate regime of Japan. BFS were subclassifled into several groups according to the soil moisture environment along the slope and morphological properties. However, even the same type of soil may display different properties depending on the climatic conditions, parent materials and vegetation types. In the present study, the variations in the carbon content, nitrogen content, cation exchange capacity and some properties depending on the parent materials, were clarified by using 34 sola of BFS, and 3 sola of black soils (BLS) for comparison, which were distributed in the submontane zone of the Kanto and Chubu districts in central Japan under the same climatic conditions. We observed differences in the pH, cation exchange capacity, base saturation and clay content among BFS samples derived from various parent materials. The BFS derived from volcanic ash contained obviously larger amounts of carbon and nitrogen than the BFS derived from other parent materials. However, the BFS derived from volcanic ash differed from the BLS derived from volcanic ash in the vertical distribution pattern of carbon and nitrogen. Thus, even in the submontane zone of the Kanto and Chubu districts, the chemical properties of BFS varied considerably with the parent materials. It was concluded that the classification of BFS by the parent materials was useful for evaluating the ability of the BFS, that cover 70% of the forests in Japan, to store various materials.     

Effect of fire on solute release from organic horizons under larch forest in Central Siberian permafrost terrain

To evaluate the effects of forest fire and post-fire stand recovery on the organic layer chemistry and solute release within mound and trough microrelief elements (termed earth hummock microtopography) that mainly distribute permafrost affected area, we chose five fire plots (larch forests burned in 1951, 1981, 1990, 1994 and 2005) paired with adjacent control plots in mature larch forests in Central Siberian permafrost terrain. We determined total carbon, nitrogen and ash content in solid organic soils, and analyzed total carbon, nitrogen, bases and major anions in water extracts. There was a significant correlation between water-extracted organic carbon (WEOC) and total carbon (kg m⁻²) in area basis, implying that the quantity of total carbon was a major factor in WEOC production. WEOC correlated negatively with pH, indicating strong control by organic horizons (organic solute leaching) on soil acidity and base cation dynamics. The sum of water extractable base cations was also correlated significantly to total carbon, indicating that cations can be released through organic matter decomposition. Organic horizons in troughs in burned plots released greater amounts of Ca, Mg and K than those in mounds, probably due to greater content of organic matter as a cation source. Anions including nitrate and phosphate and WEOC also accumulated in trough depressions, due probably to organic matter degradation. The contrasting distribution of solutes between mounds and troughs in burned plots seems to be controlled by organic horizon development via changes in microtopography after forest fires.     

Application of wood ash compared with fertigation for improving the nutritional status and fruit production of kiwi vines

Application of wood ash can potentially improve the fertility of acid soils and the nutritional status of crops. However, there is limited information about the effectiveness of this practice with fruit trees. The application of wood ash as a fertilizer in a kiwifruit plantation—both with and without fertigation/irrigation—was compared with that of a conventional fertigation program in a completely randomized field experiment on an acid soil in northwest (NW) Spain. The effects on plant nutritional status and on fruit yield, as well as environmental effects, were evaluated over a period of 2 y. The application of wood ash led to modest increases in soil pH and extractable nutrients (phosphorus, P; calcium, Ca; magnesium, Mg; potassium, K; boron, B). However, no consistent effects in foliar nutrient concentrations were found. Ash application led to an increase of up to 45% in the number of fruits produced, which was mainly attributed to the inputs of Ca and Mg. Although moderate increases in soil available manganese (Mn) and nickel (Ni) after ash application were recorded, there were no changes in heavy‐metal concentrations in leaves or fruits. From the results of the study it can be concluded that wood ash can be used to improve the growth conditions of kiwi vines on acidic soils. Wood ash should be applied at rates adapted to the liming needs of the soil, while also taking into account the chemical composition of the ash.     

Cadmium in upland forests after vitality fertilization with wood ash—a summary of soil microbiological studies into the potential risk of cadmium release

The use of wood ash in forestry has been questioned because of the potential risk associated with its cadmium (Cd) content (1–30 mg kg^–1). In agriculture, wood ash is only allowed for use as a fertilizer when its Cd content is below 3 mg kg^–1. This restriction has not been applied to forest soils and there is a lack of knowledge about the potentially harmful effects of the Cd in wood ash on forest ecosystems. This paper summarizes our recent studies on the microbial communities of boreal coniferous forest humus exposed to Cd-containing wood ash treatment. The main objectives of our studies were to test if the Cd in wood ash has the potential to affect the humus layer microflora of coniferous upland forests and if it has the potential to enter the human food chain. These objectives were tested both in laboratory and field experiments with ash and ash spiked with Cd (in laboratory 400 or 1,000 mg Cd kg^–1 as CdO or CdCl₂; in field 400 mg Cd kg^–1 as CdO). In one study the dissolution of ash was accelerated by irrigating it with simulated acid rain (SAR). Wood ash increased humus layer pH and microbial activities (respiration or thymidine incorporation rates) and changed its microfloral community structure (Biolog, PLFA, 16S or 18S rDNA PCR-DGGE) in both laboratory and field experiments. Spiking ash with Cd induced no further changes in the above-mentioned variables compared to ash alone. The Cd added with wood ash did not become bioavailable as detected with a bacterial biosensor Bacillus subtilis BR151(pTOO24). The form and level of Cd added in the ash had no further effect on the microbiological variables studied. Irrigation of ash with SAR did not increase the amount of bioavailable Cd, although the dissolution rate of the ash was increased. The concentration of Cd in soil water and in the berries of Vaccinium uliginosum and V. vitis-idaea, and the amount of humus bioavailable Cd did not increase with applied ash or ash spiked with Cd although the ash spiked with Cd increased the amount of humus total and extractable Cd in the 4-year field study. Only the ash spiked with Cd and not the unspiked normal wood ash resulted in significantly higher Cd concentrations in the mushroom Lactarius rufus and a slight increase in the berries of Empetrum nigrum (first year only). In conclusion, the Cd in wood ash did not become bioavailable and harmful to forest soil microbes, or leach into the humus layer even when treated with simulated acid rain. It is thus safe to use wood ash as a fertilizer in forests. However, since wood ash adds Cd to the environment, it is recommended that the same sites should not be fertilized with wood ash more than once. The effects of wood ash (3 t ha^–1) on forest soil humus layer microbes are long-term, lasting at least 20 years, and probably longer if higher application dose and/or hardened ash is used.     

不同类型水源保护林水资源保护功能的分析和评价

针对北京市密云县密云水库上游清水河流域现有水源保护林类型现状,对油松林、刺槐林、板栗林及混交林4个林分类型的截留降雨、枯枝落叶容纳雨量、林地土壤蓄水、减少地表径流及净化水质能力进行了分析、比较和评价。结果表明,在最小消耗水资源和有利于水资源积累的前提下,水源保护林中的油松水资源消耗较少,混交林次之,刺槐林、板栗林最多。因此建议水源保护林营造应加大耗水能力小和净化水质的树种比例。     

雨强和土地利用方式对豫西南山区有机质流失的影响

[目的]研究丹江口水库水源区不同降雨强度和土地利用方式对土壤中有机质流失的影响,为该区域的面源污染和水土流失防治提供依据。[方法]通过人工模拟降雨试验,以豫西南山区5种常见土地类型的表层土壤为研究对象,应用双因素方差分析,研究雨强和土地利用方式对土壤中有机质的影响。[结果]雨强对径流中有机质的流失影响显著,雨强越大流失量也越大,而土地类型对其影响不大;泥沙中的有机质流失量受雨强和土地类型的影响均显著,随雨强增加而增大;农用地(梯田和坡耕地)中随泥沙流失的有机质含量较高,林草地则低;分别对径流和流失泥沙中的有机质含量与雨强作回归分析,均显示出多项式拟合效果最好(除灌草地的泥沙拟合外)。[结论]梯田作为一种水保措施,能够保持养分和水土流失,因此其土壤中富集的养分也最多;林草地土壤结构较好,能够减缓土壤侵蚀,因而流失的养分也较少。     

Transport of metal cations through a nutrient-poor forest ecosystem

Metal cations were analyzed in bulk precipitation, soil water, and stream flow in a southeastern U.S. lower Coastal Plain pine flatwoods for 6 yr. Extractable ions in mineral soil and total amounts in herbaceous vegetation were also determined. Concentrations for all ions were higher in soil water than in bulk precipitation, but especially Na⁺ and Mg⁺⁺. There were smaller concentration differences between soil water and stream flow, except for three-fold higher Ca⁺⁺ in stream flow. Base saturation in the mineral soil was less than 10%, with Al dominating cation exchange sites. Of all cations, only K showed a significant relationship between exchangeable amounts in the soil and total amounts in herb layer vegetation. Soils in the watershed-ecosystem are experiencing minimal mineral weathering, although this can be spatially quite variable. We conclude that the chemistry of such soils is susceptible to change over several forest harvest rotations and continued acid deposition.

     

Wood ash effects on chemical and microbiological properties of digestate- and manure-amended soils

A field study was carried out to evaluate the potential of wood ash as a fertilizer in grassland systems in combination with enriched N organic wastes. Six treatments including manure or digestate, each combined with wood ash at 0, 1, and 3 t?ha^?1 were spread onto the soil to an amount equivalent to 120 kg?N ha^?1. Three soil samplings and one cutting was carried out within one growing season (3 months). A higher pH value was found in manure-treated plots, the pH rise being proportional to the amount of wood ash added. Those plots amended with digestate were characterized by a larger content of total C, NH₄ ⁺, and total P (TP) regardless of the amount of ashes. Microbial activity, assessed by basal respiration and microbial biomass carbon of the differently treated soils, was not affected neither by the nature of the organic waste nor by the amount of wood ash added. However, amending soil with digestate resulted in a more efficient soil microbial community, as shown by the lower values of the metabolic quotient. Such effects were accompanied by a higher percentage of plant cover, particularly of leguminous plants in digestate-treated plots. The time of sampling (seasonal effects) was found to influence the soil pH and electrical conductivity (EC), as well as the nutrient content (total N, NH₄ ⁺, and NO₃ ^?). Overall, the combined use of wood ash and biogas digestate can constitute an efficient way for the disposal and recycling of both products and additionally, it may constitute an environmentally friendly alternative to mineral fertilizers for acid soils.     

Alterations in forest detritus inputs influence soil carbon concentration and soil respiration in a Central-European deciduous forest

In a Quercetum petraeae–cerris forest in northeastern Hungary, we examined effects of litter input alterations on the quantity and quality soil carbon stocks and soil CO₂ emissions. Treatments at the Síkfőkút DIRT (Detritus Input and Removal Treatments) experimental site include adding (by doubling) of either leaf litter (DL) or wood (DW) (including branches, twigs, bark), and removing all aboveground litter (NL), all root inputs by trenching (NR), or removing all litter inputs (NI). Within 4 years we saw a significant decrease in soil carbon (C) concentrations in the upper 15 cm for root exclusion plots. Decreases in C for the litter exclusion treatments appeared later, and were smaller than declines in root exclusion plots, highlighting the role of root detritus in the formation of soil organic matter in this forest. By year 8 of the experiment, surface soil C concentrations were lower than Control plots by 32% in NI, 23% in NR and 19% in NL. Increases in soil C in litter addition treatments were less than C losses from litter exclusion treatments, with surface C increasing by 12% in DL and 6% in DW. Detritus additions and removals had significant effects on soil microclimate, with decreases in seasonal variations in soil temperature (between summer and winter) in Double Litter plots but enhanced seasonal variation in detritus exclusion plots. Carbon dioxide (CO₂) emissions were most influenced by detritus input quantity and soil organic matter concentration when soils were warm and moist. Clearly changes in detritus inputs from altered forest productivity, as well as altered litter impacts on soil microclimate, must be included in models of soil carbon fluxes and pools with expected future changes in climate.