Exchangeable Base Cations Research Articles

Four years of simulated N and S depositions did not cause N saturation in a mixedwood boreal forest ecosystem in the oil sands region in northern Alberta, Canada

We conducted a simulated nitrogen (N) and sulfur (S) deposition experiment in the Athabasca oil sands region (AOSR) where NOx and SO2 have been emitted from oil sands mining/extracting and upgrading activities and then deposited to the surrounding ecosystems for decades. To evaluate changes in tree growth rates, N pool sizes, and nutrient losses by S and N deposition, the following four treatments were applied: control (CK), N addition (+N, 30kgNha−1yr−1), S addition (+S, 30kgSha−1yr−1), and +NS additions (+NS, 30kgN and 30kgSha−1), from 2006 through 2009. Nitrogen addition increased (p<0.05) tree growth in the +N and +NS treatments, indicating N-limitation in the studied forest, while none of the treatments affected understory growth or soil microbial biomass. The treatments affected inorganic N concentrations in the soil only immediately following N addition. Minimal amounts of NO3- were leached below 45cm (considered to be below the main rooting zone) of the soil profile in any of the treatments. Decreases in exchangeable Ca2+ and Mg2+ by N and S additions were likely due to increased tree uptake following increased tree growth in the former and increased leaching with sulfate in the latter. Although the lack of significant N leaching indicates that the risk of N saturation was low after 4yr of elevated N deposition, reduction of exchangeable base cations implies that nutrient imbalance remains a concern in AOSR in the long term.

Soil Depletion of Ca, Mg and K Due to Vicinal Intensive Hog Farming Operation Located in East Mediterranean

One of the main environmental impacts of concentrated animal feeding operations is soil degradation in the vicinity of the livestock breeding facilities due to substances such as ammonia emitted from the various stages of the process. In this research, the soil degradation effects of an intensive hog farming operation (IHFO) located at a Mediterranean limestone soil coastal area have been investigated. Soil samples of the upper mineral soil were taken in various distances and directions from the IHFO boundaries. Thirteen experimental cycles were carried out in the duration of 1.5 years starting in March 2009 until October 2010. The soil samples were analysed on total, exchangeable and water-soluble Ca, Mg and K as well as water-soluble ammonium concentrations. Significantly lower concentrations of the exchangeable and water-soluble base cations were observed on soil samples at increasing proximity downwind from the farm (south). Southern soil average concentrations of exchangeable base cations ranged between 78.6 and 128.52 mmol Ca2+ kg−1 soil, 8.42–21.39 mmol Mg2+ kg−1 soil and 4.25–8.1 mmol K+ kg−1 soil, respectively. Southern soil average concentrations of water-soluble base cations ranged between 0.57 and 2.17 mmol Ca2+ kg−1 soil, 0.16–0.89 mmol Mg2+ kg−1 soil and 0.48–0.95 mmol K+ kg−1 soil, respectively.

Effect of European Black Alder Monocultures on The Characteristics of Reclaimed Mine Soil

The effect of European black alder (Alnus glutinosa L.) on the contents of carbon and nitrogen,exchangeable base cations, and plant available forms of phosphorus in the reclaimed mine soils formed bywaste deposition from opencast lignite mines was researched in central Serbia. It was concluded that thegreatest part of dead organic residues reaching the soil under European black alder monocultures was liable torapid decomposition into end products. This was the consequence of a narrow C/N ratio in the European blackalder litterfall which amounted on average to 12.77 in the study monocultures. Only a small part of organicresidues was transformed into humus. On that account, European black alder monocultures did not have amajor impact on the accumulation of organic carbon and total nitrogen in the soil. The content of carbon in thesurface layers accounted for 1.55-1.57%, and the content of nitrogen to 0.085-0.132%. Fast mineralisation oforganic matter, and thus also of the organic forms of nitrogen, resulted in the surplus of soil nitrates, whichwere liable to washing through the soil. Nitrate movement resulted in the soil leaching and the movement ofbase cations, primarily calcium, to the deeper layers of the solum. The total soil phosphorus content was low,and also the level of plant available forms. A significant portion of total phosphorus in the surface layers of thereclaimed mine soils was composed of its organic forms.

Use of crop residues with alkaline slag to ameliorate soil acidity in an Ultisol

AbstractInformation regarding the interaction between liming agents and crop residues on soil acidity amelioration is limited. A laboratory incubation study was undertaken to investigate the combined application of alkaline slag (AS, the major component is CaO) and crop residues with different C/N ratios and ash alkalinity content. Incorporation of amendments was effective in reducing soil exchangeable acidity and Al saturation and increasing exchangeable base cations (P &lt; 0.05), but the effect of AS on soil pH adjustment was reduced when added with a high amount of residue with a low C/N ratio. Initial increases in soil pH were attributed to the release of alkalinity from the combined amendments and the mineralization of organic nitrogen (N). During subsequent incubation, the soil pH decreased because of nitrification. Crop residues with a high C/N ratio increased N immobilization and reduced net nitrification, resulting in a slight pH decrease. Crop residues with a low C/N ratio resulted in a sharp decrease in soil pH when applied with low levels of AS because of stimulated soil nitrification, whereas high AS had no consistent effect on net nitrification. Hence, compared to the control (pH = 4.21), a large increase in soil pH occurred, especially when peanut straw was applied at 10 g/kg (pH = 5.16). It is suggested that crop residues with high C/N ratio and also combined with a liming agent such as AS are preferred to ameliorate soil acidity. The liming effect of AS is likely to be negated if added in combination with residues with high N contents.

Effects of biochars generated from crop residues on chemical properties of acid soils from tropical and subtropical China

The chemical compositions of biochars from ten crop residues generated at 350°C and their effects on chemical properties of acid soils from tropical and subtropical China were investigated. There was greater alkalinity and contents of base cations in the biochars from legume residues than from non-legume residues. Carbonates and organic anions of carboxyl and phenolic groups were the main forms of alkalis in the biochars, and their relative contributions to biochar alkalinity varied with crop residues. Incubation experiments indicated that biochar incorporation increased soil pH and soil exchangeable base cations and decreased soil exchangeable acidity. There were greater increases in soil pH and soil exchangeable base cations, and a greater decrease in soil exchangeable acidity, for biochars from legume than from non-legume residues. The biochars did not increase the cation exchange capacity (CEC) of soils with relatively high initial CEC but did increase the CEC of soils with relatively low initial CEC at an addition level of 1%. The incorporation of biochars from crop residues not only corrected soil acidity but also increased contents of potassium, magnesium, and calcium in these acid soils from tropical and subtropical regions and thus improved soil fertility.

Nitrate role in basic cation leaching under no-till

Especially under no-tillage, subsuface soil acidity has been a problem, because it depends on base leaching, which has been associated with the presence of low molecular weigth organic acids and companion anions. The objective of this study was to evaluate exchangeable base cation leaching as affected by surface liming along with annual urea side-dressing of maize and upland rice. Treatments consisted of four lime rates (0, 1500, 3000, and 6000 kg ha-1) combined with four nitrogen rates (0, 50, 100, and 150 kg ha-1) applied to maize (Zea mays) and upland rice (Oryza sativa), in two consecutive years. Maize was planted in December, three months after liming. In September of the following year, pearl millet (Pennisetum glaucum) was planted without fertilization and desiccated 86 days after plant emergence. Afterwards, upland rice was grown. Immediately after upland rice harvest, 18 months after surface liming, pH and N-NO3-, N-NH4+, K, Ca, and Mg levels were evaluated in soil samples taken from the layers 0-5, 5-10, 10-20 and 20-40 cm. Higher maize yields were obtained at higher N rates and 3000 kg ha-1 lime. Better results for upland rice and pearl millet yields were also obtained with this lime rate, irrespective of N levels. The vertical mobility of K, Ca and Mg was higher in the soil profiles with N fertilization. Surface liming increased pH in the upper soil layers causing intense nitrate production, which was leached along with the base cations.

Effects of logging residue harvest in thinnings on amounts of soil carbon and nutrients in Scots pine and Norway spruce stands

The effects of whole-tree thinning on soil were investigated in 9 Scots pine and 4 Norway spruce experiments in Finland. Three pine experiments had been thinned once, the other experiments twice. Time between thinning and soil sampling varied from 3 to 30 years. Amounts of exchangeable base cations, Ca, K and Mg, seemed to have decreased after whole-tree thinning. The larger the amount of removed logging residues, the greater these decreases tended to be. Changes in base cations in soil due to whole-tree harvest were more expected than were changes in the amounts of nitrogen, because, e.g. potassium and magnesium in logging residues of one thinning corresponded, on average, to 60–70% and to 30–40%, respectively, of the total amounts of nutrients in the organic layer, but nitrogen only to 10%. Overall, in the experiments studied, whole-tree harvest induced only slight changes in soil nutrients. The changes would be even smaller if the present motorised whole-tree harvest, in which logging residues are not totally removed, were compared to the present motorised stem-only harvest, in which logging residues are not distributed evenly over the cutting area.

Exchangeable basic cations and nitrogen distribution in soil as affected by crop residues and nitrogen

In this work, a greenhouse experiment was conducted to study the effects of N fertilization and residues of pearl millet, black oats and oilseed radish on pH and Ca, Mg, K, NO3-, and NH4+ distribution within the profile of a Distroferric Red Latosol. The equivalent of 8 t ha-1 of plant residues were placed on soil surface. Lime was applied on the soil surface and nitrogen was applied over the straw at 0, 50, 100, and 150 mg kg-1, as ammonium nitrate. Corn was grown for 57 days. Calcium contents and pH in the soil profile were decreased by Pearl millet residue, while black oat and oilseed radish increased Ca contents and these effects are not related with Ca contents in residue tissue. However, the presence of plant residues increased nitrate, ammonium, and potassium contents in the deeper layers of the pots.

Soil fertility and fine root dynamics in response to 4 years of nutrient (N, P, K) fertilization in a lowland tropical moist forest, Panama

AbstractThe question of how tropical trees cope with infertile soils has been challenging to address, in part, because fine root dynamics must be studiedin situ. We used annual fertilization with nitrogen (N as urea, 12.5 g N m−2 year−1), phosphorus (P as superphosphate, 5 g P m−2 year−1) and potassium (K as KCl, 5 g K m−2 year−1) within 38 ha of old‐growth lowland tropical moist forest in Panama and examined fine root dynamics with minirhizotron images. We expected that added P, above all, would (i) decrease fine root biomass but, (ii) have no impact on fine root turnover. Soil in the study area was moderately acidic (pH = 5.28), had moderate concentrations of exchangeable base cations (13.4 cmol kg−1), low concentrations of Bray‐extractable phosphate (PO4 = 2.2 mg kg−1), and modest concentrations of KCl‐extractable nitrate (NO3 = 5.0 mg kg−1) and KCl‐extractable ammonium (NH4 = 15.5 mg kg−1). Added N increased concentrations of KCl‐extractable NO3and acidified the soil by one pH unit. Added P increased concentrations of Bray‐extractable PO4and P in the labile fraction. Concentrations of exchangeable K were elevated in K addition plots but reduced by N additions. Fine root dynamics responded to added K rather than added P. After 2 years, added K decreased fine root biomass from 330 to 275 g m−2. The turnover coefficient of fine roots &lt;1 mm diameter ranged from 2.6 to 4.4 per year, and the largest values occurred in plots with added K. This study supported the view that biomass and dynamics of fine roots respond to soil nutrient availability in species‐rich, lowland tropical moist forest. However, K rather than P elicited root responses. Fine roots smaller than 1 mm have a short lifetime (&lt;140 days), and control of fine root production by nutrient availability in tropical forests deserves more study.

Soil Acidification from Long-Term Use of Nitrogen Fertilizers on Winter Wheat

Although N fertilizers are not acidic, their inputs to soil are acid forming. As a result of the long-term use of N fertilizers, soils in the Great Plains are becoming more acidic and this acidity may become a yield-limiting factor. In 1970, long-term plots were initiated to compare sources (anhydrous NH 3 , NH 4 NO 3 , urea, and S-coated urea), application rates (34, 68, 136, and 272 kg N ha ―1 ), and an untreated check (0 N) on wheat (Triticum aestivum L.) grain yield, soil pH, exchangeable base cations, and Al saturation. For the soil properties evaluated, significant differences among the different N sources did not exist after 30 annual applications of N fertilizer. The long-term N fertilization significantly reduced soil pH in the surface soil layer (0-15 cm), especially at the higher application levels. Soil pH decreased with time and was significantly related to the amount of total N applied for each N source. Nitrogen fertilization with each N source significantly increased exchangeable Al and Al saturation (Al sat ) but decreased exchangeable base cations (Ca 2+ and Mg 2+ ). Both exchangeable Al and Al sat increased with increasing N rate and were inversely related to soil pH. Despite decreased soil pH levels to <5.0 as early as 1980 in the experiment, significant reductions of wheat yield did not occur until 1995. Reductions in yield occurring between 1995 and 2002 coincided with the greatest change in soil pH occurring during the same time period.

Amendment of Acid Soils with Crop Residues and Biochars

The liming potential of some crop residues and their biochars on an acid Ultisol was investigated using incubation experiments. Rice hulls showed greater liming potential than rice hull biochar, while soybean and pea straws had less liming potential than their biochars. Due to their higher alkalinity, biochars from legume materials increased soil pH much compared to biochars from non-legume materials. The alkalinity of biochars was a key factor affecting their liming potential, and the greater alkalinity of biochars led to greater reductions in soil acidity. The incorporation of biochars decreased soil exchangeable acidity and increased soil exchangeable base cations and base saturation, thus improving soil fertility.

Comparison of the ameliorating effects on an acidic ultisol between four crop straws and their biochars

The amelioration effects of crop straws and their biochars on an acidic ultisol were compared in incubation experiments to determine suitable organic amendments for acid soils. Four crop straws, including non-legumes (canola straw and rice straw) and legumes (soybean straw and pea straw) were used to prepare biochars using a low temperature (350°C) oxygen-limited pyrolysis method. Two application rates of 1% and 2% were used for both crop straws and their biochars in incubation experiments lasting 90 days. Soil pH (1:2.5 soil to water), soil exchangeable acidity, soil exchangeable base cations, and soil cation exchange capacity (CEC) were determined to evaluate the amelioration effects of these crop straws and their biochars on an acidic ultisol. The incorporation of crop straws increased or decreased the soil pH depending on the relative contribution of alkalinity of the straws, mineralization of organic N and nitrification of NH4 +. The incorporation of biochars produced from crop straws increased the soil pH, and their ameliorating effects increased with the application rates of biochars. The biochars from legume straws induced more increase in soil pH than non-legume biochars. The addition of both crop straws and their biochars decreased soil exchangeable acidity and exchangeable Al3+, and increased soil exchangeable base cations and base saturation degree. The biochars (especially legumes) induced a greater decrease in soil exchangeable acidity and a greater increase in soil exchangeable base cations compared to their feedstock due to their much higher contents of base cations. The CEC of biochars were 10–20 times that of soil CEC and thus biochar incorporation increased the soil CEC significantly, as well as the retention of Ca2+, Mg2+, K+, and NH4 + by acid soils. The biochars produced from legume crop straws were better choices as amendments for acid soils than their feedstock. Organic anions and carbonates were the main forms of alkali in the biochar; both contributed to neutralizing soil acidity and increasing soil pH. The incorporation of biochar cannot only neutralize soil acidity, but can also improve soil fertility.

Landscape Determinants of Exchangeable Calcium and Magnesium in Ozark Highland Forest Soils

Exchangeable base cations, particularly Ca and Mg, largely govern soil acidity and, consequently, plant species composition in temperate forests. Although studies have identified soil and terrain characteristics affecting exchangeable Ca and Mg, few studies have identified the relative importance of factors affecting Ca and Mg distribution across landscapes. Objectives of this study were to: (i) identify the relative importance of geomorphic and soil properties for exchangeable Ca and Mg concentrations and quantities, and (ii) examine relationships between these properties and tree species abundance. A classification and regression tree (CART) analysis was applied to 74 pedons sampled across a 3800‐ha forested research area in the Ozark Highlands in southeastern Missouri. This analysis identified depth to bedrock and the bedrock lithology as important factors associated with exchangeable Ca and Mg concentrations, which ranged from 0.30 to 2.88 and 0.24 to 1.35 g kg−1, respectively. The CART analysis also indicated that the underlying bedrock was associated with exchangeable base cation quantity, and values ranged from 4263 to 20,144 kg ha−1 for Ca and 1650 to 9977 kg ha−1 for Mg. Analysis of variance indicated that the most common oak (Quercus L.) and hickory (Carya Nutt.) species were significantly more abundant on soils with lower Ca concentrations. The analysis framework applied in this study provides a basis for distinguishing among soils and ecological land types by pools of exchangeable Ca and Mg, thereby aiding in the identification of locales where base cation depletion may be of concern.

Assessing Decadal Change in Mineral Soil Cation Chemistry at the Turkey Lakes Watershed

Mass balance studies and direct measurement of changes in soil chemistry have provided evidence of depletion of base cations in soils across decadal time scales. Losses of base cations have been attributed to leaching as a consequence of elevated levels of S and N deposition. Chemical properties of mineral soil horizons were determined at seven plots in a tolerant hardwood forest at the Turkey Lakes Watershed in 1986 and in 2003 and 2005. Archived soils from the original sampling were used to assess the impact of storage and changing methodology on results. Exchangeable cation concentrations were compared between the two sampling times, as were concentrations normalized for organic C. The effects of air‐dry storage were significant for some cations, but in absolute terms the changes were small when contrasted with the spatial variation in exchangeable cation concentrations for the samples collected in 2003 and 2005. There were no statistically significant declines in pH, exchangeable Ca, Mg, or K concentrations, or Ca, Mg or K concentrations normalized for organic C concentration during the 17‐ to 19‐yr sampling period across the watershed. Exchangeable Na and normalized Na concentrations decreased in deeper horizons of the soil profile. There were various patterns of cation change at the plot level, but these changes were unable to be attributed to the range of soil profile base status at the site. Mineral weathering inputs appeared to provide stability to the exchangeable base cation pool in spite of large leaching losses at the Turkey Lakes site.

The amelioration effects of low temperature biochar generated from nine crop residues on an acidic Ultisol

AbstractBiochar was prepared using a low temperature pyrolysis method from nine plant materials including non‐leguminous straw from canola, wheat, corn, rice and rice hull and leguminous straw from soybean, peanut, faba bean and mung bean. Soil pH increased during incubation of the soil with all nine biochar samples added at 10 g/kg. The biochar from legume materials resulted in greater increases in soil pH than from non‐legume materials. The addition of biochar also increased exchangeable base cations, effective cation exchange capacity, and base saturation, whereas soil exchangeable Al and exchangeable acidity decreased as expected. The liming effects of the biochar samples on soil acidity correlated with alkalinity with a close linear correlation between soil pH and biochar alkalinity (R2 = 0.95). Therefore, biochar alkalinity is a key factor in controlling the liming effect on acid soils. The incorporation of biochar from crop residues, especially from leguminous plants, can both correct soil acidity and improve soil fertility.

Soil Acidification of Alfisols as Influenced by Tea Cultivation in Eastern China

Soil acidification is an important process in land degradation around the world as well as in China. Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern China. Cultivation of tea plants caused soil acidification and soil acidity increased with the increase of tea cultivation period. Soil pH of composite samples from cultivated layers decreased by 1.37, 1.62 and 1.85, respectively, after 13, 34 and 54 years of tea plantation, as compared to the surface soil obtained from the unused land. Soil acidification rates at early stages of tea cultivation were found to be higher than those at the later stages. The acidification rate for the period of 0–13 years was as high as 4.40 kmol H + ha −1 year −1 for the cultivated layer samples. Soil acidification induced the decrease of soil exchangeable base cations and base cation saturation and thus increased the soil exchangeable acidity. Soil acidification also caused the decrease of soil cation exchange capacity, especially for the 54-year-old tea garden. Soil acidification induced by tea plantation also led to the increase of soil exchangeable Al and soluble Al, which was responsible for the Al toxicity to plants.

Identification of Nutrient Deficiencies at Calcareous Soils for Maize

Most of rubber plants in Indonesia are cultivated in highly-weathered soils; therefore, their annual productions are relatively low with the low quality of latex. The aim of this reseach was to increase the latex quality from a rubber plantation grown on low fertility soils by applying a locally-produced organic fertilizer (LOF) to the soils. This research consisted of two steps, i.e. LOF production and a field fertilization experiment. The LOF was made mainly from waste of a latex processing industry. The field fertilization experiment was conducted to assess the effects of LOF additions to the soils on the latex quality. The field experiment was performed using a randomized complete block design with 6 LOF levels, 4 levels of land slopes, and 5 rubber trees in each block, resulting in 120 rubber trees. The LOF levels were 0, 10, 20, 30, 40, and 50 kg tree-1. The LOF contained 17.35% organic-C, 1.14% total-N, 0.53 ppm available-P, and 1.21 cmol (+)kg-1 exchangeable-K, with slightly alkaline pH (pH 8.0). The soil has low fertility status as indicated by the low amounts of total-N and exchangeable base cations (K, Na, and Mg), and very acid pH (pH 4.5). Indicators of latex quality comprising of blockage index, ash-, impurity- and dry rubber-content, and N, P, K contents in the rubber leaves were measured. Although there were no significant differences in most observed latex properties due to LOF addition, their values tended to be higher when the rubber trees were fertilized with LOF. Apparently N and K contents in the rubber leaves are better correlated to the latex properties compared to the P content.

Soil chemical and physical properties at the Bear Brook Watershed in Maine, USA

Acidic deposition leads to the acidification of waters and accelerated leaching and depletion of soil base cations. The Bear Brook Watershed in Maine has used whole-watershed chemical manipulations to study the effects of elevated N and S on forest ecosystem function on a decadal time scale. The objectives of this study were to define the chemical and physical characteristics of soils in both the reference and treated watersheds after 17 years of treatment and assess evidence of change in soil chemistry by comparing soil studies in 1998 and 2006. Results from 1998 confirmed depletion of soil base cation pools and decreased pH due to elevated N and S within the treated watershed. However, between 1998 and 2006, during a period of declining SO4(2-) deposition and continued whole-watershed experimental acidification on the treated watershed, there was little evidence of continued soil exchangeable base cation concentration depletion or recovery. The addition of a pulse of litterfall and accelerating mineralization from a severe ice storm in 1998 may have had significant effects on forest floor nutrient pools and cycling between 1998 and 2006. Our findings suggest that mineralization of additional litter inputs from the ice storm may have obscured temporal trends in soil chemistry. The physical data presented also demonstrate the importance of coarse fragments in the architecture of these soils. This study underscores the importance of long-term, quantitative soil monitoring in determining the trajectories of change in forest soils and ecosystem processes over time.

Soil cover structure and main soil properties of the Vorob’evy Gory nature park

Anthropogenic and semianthropogenic soils prevail in the soil cover structure of the Vorob’evy Gory nature park (Moscow), adding up to ∼90%. Their chemical properties are typical of technosols and characterized by a relatively high content of organic carbon, neutral or alkalescent pH, and high saturation of SEC by exchangeable basic cations. Thus, the features of urban forest-park soils more closely resemble technosols than natural soddy-podzolic soils.

Patterns of snow, deposition, and soil nutrients at multiple spatial scales at a Rocky Mountain tree line ecotone

The forest‐alpine tundra ecotone in the Front Range of Colorado typically occurs as a gradual transition from the treeless tundra to the closed canopy coniferous subalpine forest. We evaluated the patterns of snow, deposition inputs, and soil properties at three spatial scales: across the entire ecotone, with distance from tree limit in the transitional krummholz zone, and around individual trees. Snow depth was deepest in the krummholz zone and lowest in the alpine tundra and upwind of trees near tree limit, but was not predictive of most soil properties except for surface litter decomposition. Inorganic deposition ranged from 0.7 to 7.7 g m−2 yr−1 across the ecotone and tended to be higher downwind than upwind of trees. The exchangeable acid cation concentrations were significantly higher in the forest and increased gradually toward the tundra. The exchangeable base cations (Ca, Mg, and K) were only predictable at the scale of individual trees with greater concentrations downwind of trees. Resin bag available N was rarely predictable at any spatial scale, but was correlated among seasons. While the ecotone is in many ways a gradual transition from alpine tundra to subalpine forest, patterns observed across this vegetation gradient were often replicated on the scale of individual trees: downwind of trees was more similar to the forest, and upwind of trees was more similar to the tundra. No single spatial scale or gradient can provide uniform generalities about the amounts or fluxes of materials that determine the soil properties of this ecotone.