Exchangeable Base Cations Research Articles

Changes in basic soil properties and enzyme activities along an afforestation series on the dry Aral Sea Bed, Kazakhstan

Afforestation of the desiccated Aral Sea Bed is needed for the rapid introduction of vegetation and rehabilitation of the soil environment. The present study aimed to detect the soil amelioration effect by afforestation of the Aral Sea Bed with respect of changes in topsoil properties and enzyme activities. In August and November 2018, soils were sampled from the barren areas and from areas afforested in 1991, 2005, 2009, 2010, and 2013. The exchangeable base cation concentrations (Ca2+, K+, Mg2+, and Na+), cation exchange capacity (CEC), plant-available P concentration, electrical conductivity, pH, and enzyme activities (acid phosphatase, β-glucosidase, and N-acetyl-glucosaminidase) were analyzed in the surface soil (0–10 cm). Base cation concentrations, CEC, and electrical conductivity decreased following afforestation possibly because of root absorption. The observed increase in soil pH could be affected by both root absorption and decomposition of plant residues. Enzyme activities, which are early indicators of soil recovery, might have been increased by afforestation through the release of nutrients from litter and root exudates. Our findings indicate that the establishment of vegetation through afforestation can provide supportive microenvironments for plants and microorganisms by decreasing soil salinity and activating soil microbial enzymes; these effects of afforestation are amplified over time.

Amelioration of Ultisols in West Java Indonesia with microparticle of steel slag

Researchs used steel slag as ameliorant had proven that it can improve some soil chemical characteristics. The objective of this reasearch was to investigate the influence of microparticle of steel slag in improving some soil chemical characteristics of Ultisols. The treatments were arrange in Completely Randomized Designed (CRD) with ten treatments: control (without steel slag), steel slag in coarse particle (mesh), and 1-9% (in weight percentage) of microparticle of steel slag. The soil and the treatments were repeated three times and incubated for four months and then be analyzed the change of soil characteristics due to the amelioration after 1, 2, 3 and 4 months of incubation period. The result showed that amelioration of Ultisols with microparticle of steel slag improved several soil characteristics like increased pH, CEC, available P, and exchangeable basic cations like Ca, Mg, K and Na. The treatments did not decrease the P-fixation, however they increased available P.

Changes in abundance and composition of nitrifying communities in barley (Hordeum vulgare L.) rhizosphere and bulk soils over the growth period following combined biochar and urea amendment

To understand the effects of biochar and urea on soil N availability and plant growth, we conducted a pot experiment growing barley (Hordeum vulgare L.) under six treatments: control (N0), soil with 30 g kg−1 biochar (N0B), soil with 0.23 g kg−1 urea (N1), soil with 0.23 g kg−1 urea and 30 g kg−1 biochar (N1B), soil with 0.46 g kg−1 urea (N2), and soil with 0.46 g kg−1 urea and 30 g kg−1 biochar (N2B). The nitrifying community abundance and compositions in rhizosphere and bulk soils were analyzed using quantitative polymerase chain reaction (qPCR) and amplicon-based Illumina Hiseq sequencing. Adding urea with biochar (N1B) produced the greatest increase in above- and belowground plant biomass, followed by doubling the amount of urea with biochar (N2B); both treatments raised pH (p < 0.001) and lowered extractable N in the rhizosphere (p < 0.05). N1B treatment produced the greatest increase in ammonia-oxidizing bacteria (AOB) amoA gene copies, presumably because the combined amendment raised soil pH, which favored AOB access to NH4+. Nitrifier sequences were selected after blasting with reported nitrifiers in NCBI (similarity ≥ 97%). Nitrosospira dominated AOB communities during the plant seedling stage; however, during the mature stage, Nitrosomonas dominated over Nitrosospira and the nitrite-oxidizing bacteria (NOB) community became diverse. Redundancy analysis indicated that nitrifying community composition was affected by multiple soil properties, including N availability (i.e., exchangeable NH4+ and NO3−) and soil chemistry (i.e., pH, dissolved organic C, and exchangeable base cations). Our research suggests a positive application of combining biochar with urea in improving N bioavailability and promoting plant growth in the acidic soil.

Changes in Soil Chemical and Physical Properties of Andisols under Oil Palm Small holder in the West Pasaman District of West Sumatra

Monitoring the productivity and sustainability of oil palm plantations is very important to anticipate the possibly land degradation occurs. The objective of this research was to comprehend the influence of oil palm plant age on the change on soil chemical and physical properties in small oil palm plantation in West Pasaman district of West Sumatra. Field research was conducted from May to July 2016 by using survey method under 3 different plant ages (5-10, 10-15, and >15 years old) in 3 areas (Kinali, Pasaman, and Koto Balingka sub-district). The variables of this study consisted of soil chemical properties: SOM, CEC, pH, total N, available-P, exchangeable base cations (K, Ca, Mg and Na-exch.); physical properties: bulk density, plant available water and water content at pF 2.54 and pF 4.2. Soil quality value calculations obtained with least squares linear regression for three different ages of oil palm plants, did not show significant effect on soil quality of Andisols under small oil palm plantation in West Pasaman district. Our findings suggested that there was no effect of oil palm ages on soil quality of Andisols, however other researches in soil biology and biochemical properties are still needed to obtain a comprehensive result.

Soil Acidity and Its Management Options in Western Ethiopia: Review

Soil acidity has become a serious threat to crop production in most highlands of Ethiopia in general and in the western part of the country in particular. An earlier study estimated that about 41% of arable lands of Ethiopia are affected by soil acidity/Al 3+ toxicity. But recently the status of most soil in western Ethiopia were became acidic though the degree varied from location to location; severely limiting crop production. In western Ethiopia acidification occurs simultaneously with other conditions including eroded topsoil and depleted organic matter, depleted nutrients, and alternating drought stress and high rainfall which is high enough to leach appreciable amounts of exchangeable basic cations. In moisture-stressed areas, acidification can also be caused by continuous application of acid-forming chemical fertilizers. As low pH affects the availability of nutrients particularly that of phosphorus and other macronutrients, correction of the low pH through liming, and/or application of organic materials is critical for sustainable management of these soils. Agricultural liming is proved a good way of correcting soil pH along with supplying calcium to the soil. Another potential organic amendment sources in coffee producing areas of western Ethiopia were coffee pulp and husk, by products from wet and dry coffee processing respectively. These coffee by-products are utilized in other coffee producing countries as soil amendments especially in highly weathered soils. While in Western Ethiopia enormous quantities are either dumped into streams or burnt in big piles, with contributions to environmental hazards. Therefore, farmers should be encouraged to increase productivity of the acidic soils by using lime and organic amendments which is easily available such as composted coffee wastes (coffee husk and pulp). Keywords: Soil acidity, lime, organic amendment, coffee husk and pulp DOI : 10.7176/JEES/9-10-04 Publication date :October 31 st 2019

Characterization of Biochar Produced from Different Feed Stocks for Waste Management

The objective of this study was to characterize the biochar produced from different agricultural wastes to explore its potential use as organic soil amendments. The feedstock of Eucalyptus globules (EG), Acacia decarance (AD), farmyard manure (FYM) and rice straw (RS) were collected and biochar was produced by slow pyrolysis at 300oC in the furnace. The biochar chemical composition was determined using standard laboratory procedure. Characterization of biochar mainly focused on chemical properties (pH, carbon, phosphorus, cation exchange capacity, electrical conductivity, exchangeable basic cations).

Effects of termite sheetings on soil properties under two contrasting soil management practices

Soil organic matter (SOM) dynamics and termite activity have now been widely accepted as key players for improving soil properties in tropical agro-ecosystems. Numerous studies have described environmental impacts of aboveground termite mounds, while few data are available on temporary structures built for food foraging, called termite sheetings. The effects of termite activity on soil properties resulting from organic matter (OM) amendment under two contrasting management practices were studied in similar pedological and climatic conditions in Southern India (Auroville). Our results showed an increase in bio-available nutrients (K, Mg and P), organic carbon (OC) content, cationic exchange capacity (CEC), exchangeable base cations and water pH in the termite sheetings compared to the underlying and reference soils, in the organic tilled field. On the other hand, only bio-available K increased in the permanent raised beds. Aggregation processes were improved in termite sheetings for the organic tilled field, as the amounts of macroaggregates (250 μm – 2 mm) and protected microaggregates increased, whereas the amount of free microaggregates (50–250 μm) decreased. Moreover, termite activity favoured SOM storage in termite sheetings by increasing OC content in each aggregate fraction, while no differences were observed in the permanent raised beds. Our study demonstrates that termite activity can improve nutrient availability, carbon storage and pH conditions in agro-ecosystems but that the magnitude of the effect likely depends on the agronomic practices in use.

Atmospheric deposition control of soil acidification in central Italy

Acidification is a major soil-forming process, and concerns about acidifying anthropogenic atmospheric deposition make it a significant environmental issue. In the long term, the depletion of exchangeable base cations (BCEs) is the main process underpinning soil acidification. In south-central Italy, acidic soils are not rare and are often located in areas with no excess rainfall over potential evapotranspiration. Many such soils are understood to have been derived from long-term weathering, although whether acidification is an active process remains an open question.Data from the International Co-operative Programme (ICP-Forests) monitoring system revealed that BCE atmospheric deposition was high and stable in south-central Italy and allowed us to estimate the BCE budget of some acidic forest soils. We estimated the overall BCE budget of four sites in this network. Tracer approaches using conservative ions, Na+ and Cl−, were calibrated to estimate dry BCE deposition and soil water fluxes. The contribution of atmospheric deposition to the BCE budget was such that potassium was found to be regularly accumulating at all sites at the rate of 0.08 to 0.42 g⋅m−2⋅y−1, while calcium was accumulating at a rate of 1.11 g⋅m−2⋅y−1 at a central Italy site. For Ca2+ at the other sites and for magnesium at all sites, the effect of deposition was such that the rate of BCE depletion was significantly reduced. Soil acidification appeared to be a non-active process in the central, lowland and hilly areas of Italy.

Nutrient effect of various composting methods with and without biochar on soil fertility and maize growth

ABSTRACTThis work showed for the first time that organic nutrient transformation techniques based on locally available materials (manure, green waste and advanced biochar) can increase fertilizing efficiency of the resulting substrate by a factor of three compared with other organic amendments without biochar. We used three different composting methods to investigate the techniques of organic nutrient transformations; i) conventional composting (composting process completed without turning the piles) ii) aerobic composting (composting process with manual turning of piles) and iii) bokashi composting (anaerobic lacto-fermentation). Composting was carried out in the absence (compost alone) and the presence of biochar (co-composted). Biochar was produced locally from an invasive forest shrub ‘Eupatorium adenophorum’. A pot trial with maize grown in silty loam soil was carried out to investigate the agronomic effect produced using three above-mentioned composting methods that were compared with conventional mineral fertilizers (NPK). Significant effects of co-composted bokashi-biochar (60 t ha−1) were observed on maize growth, which increased biomass by 243% compared to mineral NPK, also showing better growth effects than conventional and aerobic composting amendments. Improved soil available nutrients (available P and other exchangeable base cations (K+, Ca2+ and Mg2+)) were probably the cause of the superior growth effect of co-composted bokashi-biochar.

Nutrients in litterfall, forest floor and mineral soils in two adjacent forest ecosystems in Greece

The fluxes of masses and the nutrients Ca, Mg, K, N, P and S were determined in the litterfall of two adjacent forest ecosystems of Hungarian oak (Quercus frainetto L.) and European beech (Fagus sylvatica L.) in a mountainous area of northeastern Greece in 2010–2015. The foliar litterfall for both species reached about 70% of the total litterfall, and was significantly higher from the other two fractions (woody and rest litterfall). The fluxes of masses and nutrients were compared between ecosystems for each fraction separately. Only one significant statistical difference was found, that of K in the woody litterfall. In addition, the stocks of masses and nutrients were calculated in the forest floors and mineral soils of the two ecosystems. Likewise, the stocks of nutrients in the forest floors and mineral soils were compared between ecosystems. In the L horizon of the forest floors, statistical differences, as a result of species effect, were found for the stocks of Ca and N. In the FH horizons, the masses and all the nutrient stocks differed significantly, as the beech plot had much higher quantities of organic matter and nutrients. These higher quantities were probably due to low soil temperatures (microclimate) and high acidity in the beech plot (species effect) that slowed down decomposition. In the mineral soils, the propagation of random error derived from random errors of the individual soil layers was an important factor in the statistical comparisons. Because of the soil acidity in the beech plot, the stocks of exchangeable base cations were significantly higher in the oak plot, whereas the other nutrient stocks did not differ.

Impacts of earthworm species on soil acidification, Al fractions, and base cation release in a subtropical soil from China.

Soil-exchangeable aluminum (Al) has toxic effects on living organisms in acidic soils. Earthworm presence and activity can alter soil pH, which has a significant influence on Al toxicity. However, the effects of earthworms on soil Al toxicity and fractions are still largely unknown. This laboratory study focused on the effects of three earthworm species (endogeics Pontoscolex corethrurus and Amynthas robustus, anecis Amynthas aspergillum) on soil acidification, Al fraction distribution, and base cation release. Three native earthworm species and a soil (latosolic red soil) collected from a botanical garden in South China were incubated under laboratory conditions. After 40days of incubation, six Al fractions in soil, namely exchangeable (AlEx), weakly organically bound (AlOrw), organically bound (AlOr), amorphous (AlAmo), Al occluded in crystalline iron oxides (AlOxi), and amorphous aluminosilicate and gibbsite (AlAag) fractions, were extracted using a sequential procedure. Soil pH; organic carbon; total nitrogen; total Al (AlTotal); exchangeable K, Na, Ca, Mg contents; and CEC were determined as well. Compared to control soil, pH values increased by 0.79, 0.41, and 0.57units in casts in the presence of P. corethrurus, A. robustus, and A. aspergillum, and 0.70, 0.32, and 0.50units in non-ingested soil, respectively. Compared to control soil, the 61.7%, 30.7%, and 36.1% of AlEx contents in casts and 68.5%, 25.9%, and 39.0% of AlEx in non-ingested soil significantly decreased with the addition of P. corethrurus, A. robustus, and A. aspergillum, respectively. Moreover, compared to control soil, the 78.7%, 37.7%, and 40.1% of exchangeable Ca2+ and 12.3%, 24.7%, and 26.8% of exchangeable Mg2+ contents in casts significantly increased with the presence of P. corethrurus, A. robustus, and A. aspergillum, respectively. Soil treated with P. corethrurus had higher soil pH values, exchangeable Ca2+ contents, and lower AlEx than those with A. robustus and A. aspergillum. Results of principal component analyses showed that P. corethrurus, A. robustus, and A. aspergillum casts and non-ingested soil differ for soil pH, Al fractions, and exchangeable base cations release. These results indicate that earthworms, especially P. corethrurus, can reduce soil Al toxicity, increase soil pH, and affect the release of exchangeable base cations.

Making the most of scarce data: Mapping soil gradients in data‐poor areas using species occurrence records

AbstractMaps of environmental characteristics are needed to improve our understanding of species distributions and ecosystem dynamics. Despite the growing demand for digital environmental maps, scarcity of environmental field samples to be used as input data often constrains the accuracy of such maps, especially for soils.We developed and tested a method that combines information on species–environment associations and the spatial distribution of indicator species (as retrieved from repositories such asGBIF) to improve mapping accuracy of environmental variables.Our approach includes: (a) Compile field data on the environmental variable of interest (direct environmental data) and documented occurrences of the species to be used as indicators; (b) define species optima for the environmental variable; (c) use georeferenced records of the indicator species to calculate species‐based environmental values (indirect environmental data); (d) generate maps using direct and indirect environmental data as input data for interpolation; (e) validate the maps. We applied the method to map the concentration of exchangeable base cations in Amazonian soils using fern and lycophyte species as indicators.Including soil values that had been indirectly estimated using indicator species represented a 12‐fold increase in the number of input data points used for mapping. At the same time, map accuracy improved considerably: the correlation between mapped soil cation concentration estimates and field‐measured values from an independent validation dataset increased fromr = 0.48 tor = 0.71.Knowledge on species–environment relationships can be useful for modelling ecologically relevant environmental variables in areas where species occurrence data are more readily available than direct environmental measurements. The method works even with haphazard species occurrence points obtained from public repositories such asGBIFand can be applied to other environmental variables and other indicator groups, provided that the environmental variable of interest is relevant as a determinant of species occurrences in the indicator group. The Amazonian soil cation concentration maps produced (available athttps://doi.pangaea.de/10.1594/PANGAEA.879542) can be used as digital layers in species distribution and habitat modelling, and to guide conservation actions in Amazonia.

Effects of land use types on selected soil physical and chemical properties: The case of Kuyu District, Ethiopia

Information about effects of land use types on selected soil physical and chemical properties is essential in sustainable utilization of soil resources. Therefore, this study was conducted to evaluate effects of land use types on selected soil physical and chemical properties on Kuyu district, Ethiopia. Totally, 24 composite soil samples were collected from grass, cultivated, forest and grazing lands by two soil depths ( 0-20 cm and 20-40 cm) with three replications. The two way analysis of variance was used to test the mean differences of the soil physical and chemical properties. The highest mean values of sand and clay were recorded in cultivated and grasslands, respectively. The mean bulk density of the soils ranged from 1.10 and 1.37 g cm -3 and the mean total porosity ranged from 48.2 to 58.7%, which indicated the less soil compaction. The pH ranged from 7.68 to 8.00 while the mean values of OM ranged from 3.15 to 5.02%. However, the mean values of total N ranged from 0.18 to 0.26%. The mean value of available P ranged from 1.26 to 5.37 mg kg -1 , which implies that high deficiency of available P in the study area. The exchangeable basic cations and CEC values were within high to very high ranges in all land use types. Conversion of land use types from one to another has adverse effects on soil properties, especially overgrazing and cultivation of deforested land. Therefore, the proper soil and water conservation practice are important in the study area to enhance soil fertility and crop productivity.

Effects of N addition on soil exchangeable cations in a young Keteleeria fortunei var. cyclolepis forest

ABSTRACTThe effects of simulated nitrogen (N) addition on soil exchangeable cations were assessed in a young Keteleeria fortunei var. cyclolepis forest in subtropical China. Three N addition schemes with three replications were designed for the forest control (without N addition, CK), low N (5 g N m−2 a−1, L-N) and high N (50 g N m−2 a−1, H-N). Results showed that continuous N addition resulted in increased, although not statistically significant, plant biomass of K. fortunei var. cyclolepis, while it significantly decreased cation exchange capacity (CEC), base saturation (BS) and exchangeable base cations (BCs) (especially Ca2+ and Mg2+ under high N addition). General soil properties (except total P) were significantly affected by high N addition compared with the control. High N addition significantly increased the concentration of foliar N, and decreased the concentrations of foliar P, Ca2+ and Mg2+. Soil pH was also significantly altered by increased N addition, indicating that N addition significantly accelerated soil acidification. This study found that N addition was negatively correlated with soil pH, CEC and Ca2+, and that loss of BCs might be related to increased NO3–.

Effects of fertilizer of calcium silicon magnesium potassium on the dynamics of soil acidity and exchangeable base cation in paddy field of southern China

Soil acidification of large areas of paddy fields in southern China has become an important problem in rice production. Therefore, how to ameliorate or remedy the acidifying paddy soil and to exposit its mechanism has important theoretical and practical significance for rebuilding healthy soils and guaranteeing national food security. Although lime has already been extensively used to remedy acidified soils, long-term application of a large amount of lime would not only cause the soil to harden, but also disturb the balance between calcium, potassium and magnesium in the soil. Given the advantages of lower solubility and comprehensive nutrient supply, fertilizer of calcium silicon magnesium potassium (CSMP) may be used as an alternative. The aim of this study was to clarify the functions of CSMP and its effects on soil acidification in paddy fields. A four-year field experiment was conducted to investigate the dynamics of soil pH, exchangeable acidi-ty, exchangeable base cation and available silicon, as well as 0~30 cm pH buffer capacity (pHBC), net base production under CSMP fertilization in the paddy soil. There were five treatments, i.e. CK (traditional fertilization practice of the local farmers), treatment I (CK plus 750 kg·hm-2 CSMP); treatment II (CK plus 1125 kg·hm-2 CSMP), treatment III (CK plus 1500 kg·hm-2 CSMP), and treatment IV (CK plus 1875 kg·hm-2 CSMP). The results showed that the traditional fertilization practice of the local farmers resulted in a decline of soil pH, soil exchangeable base cation and base saturation year by year, but soil exchangeable acid was increased with year. Conversely, CSPM fertlization significantly raised soil pH, with the magnitude of increases positively depending on the number of application times or application rate. Continuous and repeated application of CSMP effectively promoted the accumulation of exchangeable base cation and the consumption of soil exchangeable acid in paddy soil, especially for the accumulation of soil exchangeable Ca2+, Mg2+ and the consumption of soil exchangeable Al3+. Furthermore, the more amount of CSPM application resulted in the more accumulation or consumption, but with relatively slower rate. The exchangeable base cation and alkali released by CSMP contributed 108.8% to the total reduction of soil exchangeable acid, suggesting that it was the main path to reduce soil exchangeable acid. Meanwhile, CSMP application improved soil acidity in paddy field, with the content of available silicon increased year by year and the increase amplitude became larger with the more amount of CSMP application. The traditional fertilization of local farmers resulted in soil acidification, with a acidification rate was 2.86 kmol H+·hm-2·a-1. CSMP application could effectively control soil acidification, producing a lot of alkalinity with net alkalinity production of 9.93-13.82 kmol OH-·hm-2·a-1. CSPM could release Ca2+, Mg2+ and alkali, which would mitigate soil acidification in paddy fields.

Mutual relationships of biochar and soil pH, CEC, and exchangeable base cations in a model laboratory experiment

The majority of biochar studies use soils with only a narrow range of properties making generalizations about the effects of biochar on soils difficult. In this study, we aimed to identify soil properties that determine the performance of biochar produced at high temperature (700 °C) on soil pH, cation exchange capacity (CEC), and exchangeable base cation (Ca2+, K+, and Mg2+) content across a wide range of soil physicochemical properties. Ten distinct soils with varying physicochemical properties were incubated for 12 weeks with four rates of biochar application (0.5, 2, 4, and 8% w/w). Soil pH, CEC, and exchangeable base cations (Ca2+, K+, and Mg2+) were determined on the 7th and 84th day of incubation. Our results indicate that the highest biochar application rate (8%) was more effective at altering soil properties than lower biochar rates. Application of 8% biochar increased pH significantly in all incubated soils, with the increment ranging up to 1.17 pH unit. Biochar induced both an increment and a decline in soil CEC ranging up to 35.4 and 7.9%, respectively, at a biochar application rate of 8%. Similarly, biochar induced increments in exchangeable Ca2+ up to 38.6% and declines up to 11.4%, at an 8% biochar application rate. The increment in CEC and exchangeable Ca2+ content was found in soils with lower starting exchangeable Ca2+ contents than the biochar added, while decreases were observed in soils with higher exchangeable Ca2+ contents than the biochar. The original pH, CEC, exchangeable Ca2+, and texture of the soils represented the most crucial factors for determining the amount of change in soil pH, CEC, and exchangeable Ca2+ content. Our findings clearly demonstrate that application of a uniform biochar to a range of soils under equivalent environmental conditions induced two contradicting effects on soil properties including soil CEC and exchangeable Ca2+ content. Therefore, knowledge of both biochar and soil properties will substantially improve prediction of biochar application efficiency to improve soil properties. Among important soil properties, soil exchangeable Ca2+ content is the primary factor controlling the direction of biochar-induced change in soil CEC and exchangeable Ca2+ content. Generally, biochar can induce changes in soil pH, CEC, and exchangeable Ca2+, K+, and Mg2+ with the effectiveness and magnitude of change closely related to the soil’s original properties.

Distribution of nutrients and trace elements in forest soils of Singapore

Information on chemical fertility status and on trace element concentrations for Singapore soils is sparse. In this study, concentration and distribution of nutrients and trace elements in forest soils of Singapore, and the effect of geology on the current conditions of soils, were evaluated. Litter and mineral soil samples (0–10 cm, 10–20 cm, 20–50 cm) were divided into three groups according to geology (sedimentary rocks, Neogene-Quaternary sediments and igneous rocks). Basic soil properties, exchangeable cations including cation exchange capacity (CEC), and pseudototal concentrations of 17 elements including nutrients and potentially toxic elements (PTE; As, Cd, Cu, Cr, Ni, Pb, Zn) were determined. Results showed that the soils of Singapore were acidic (pH 3.7–6.2) and characterised by a low CEC (maximum mean value: 100 mmolc kg−1) and low P concentrations (mean values of 0.28 g kg−1 or less) irrespective of geology. Pseudototal concentrations of PTE were also low, except for As. However, significantly (p < 0.05) higher concentrations of soil organic carbon, total P, base forming elements, exchangeable base cations and PTE (except As and Cd) were found in soils developed on sedimentary rocks and Neogene-Quaternary sediments compared to those developed on igneous rocks. Although total N and S concentrations did not differ significantly between the three geological groups, the differences in nutrient status were more pronounced than in trace element levels across geology. The properties of forest soils, which are mainly unaffected by anthropogenic activities, vary depending on the parent material, i.e. igneous or sedimentary rocks and Neogene-Quaternary sediments.

Alleviation of aluminum phytotoxicity by canola straw biochars varied with their cultivating soils through an investigation of wheat seedling root elongation

The types and amounts of cations and their uptake by plants vary with cultivating soils, which correlates with the carbonates and subsequent alkalis contents in the derived biochars. However, regional differences in the alkaline properties of crop straw biochars are unclear. In the present study, biochars pyrolyzed from canola straws collected from four different regions were used to assess the differences in the alkaline properties among them. The biochars were referred to as YTBC, XCBC, NJBC, and HYBC, respectively, and their feedstocks were collected from four different regions from south to north of China. The NH4OAC exchangeable base cations (K+, Na+, Ca2+, Mg2+) in the biochars were 270.74, 1427.05, 2089.23, and 1516.48 mmol kg−1 for YTBC, XCBC, NJBC, and HYBC, respectively, which were roughly consistent with the exchangeable base cations in the corresponding planting soils (17.57, 28.20, 151.26 and 444.65 mmol kg−1, respectively). The pH, carbonates content, and alkalinity of biochars considerably increased as follows: YTBC < XCBC < NJBC < HYBC. Wheat seedling root elongation experiment indicated that the Al(III) phytotoxicity alleviation effect of the biochars was as follows: HYBC > NJBC > XCBC > YTBC, which was corroborated by the subsequent findings of Evans blue staining, the remnant aluminum (Al(III)) in the reaction solution and Al(III) distribution in the wheat seedling roots. Thus, planting soil had a dominant influence in alleviating Al(III) phytotoxicity, and studies on crop straw biochar properties concerning alkalinities or liming potentials should not only consider crop genera and pyrolysis conditions, but also cultivating conditions.

Litter quality, land-use history, and nitrogen deposition effects on topsoil conditions across European temperate deciduous forests

Topsoil conditions in temperate forests are influenced by several soil-forming factors, such as canopy composition (e.g. through litter quality), land-use history, atmospheric deposition, and the parent material. Many studies have evaluated the effects of single factors on physicochemical topsoil conditions, but few have assessed the simultaneous effects of multiple drivers. Here, we evaluate the combined effects of litter quality, land-use history (past land cover as well as past forest management), and atmospheric deposition on several physicochemical topsoil conditions of European temperate deciduous forest soils: bulk density, proportion of exchangeable base cations, carbon/nitrogen-ratio (C/N), litter mass, bio-available and total phosphorus, pHKCl and soil organic matter. We collected mineral soil and litter layer samples, and measured site characteristics for 190 20 × 20 m European mixed forest plots across gradients of litter quality (derived from the canopy species composition) and atmospheric deposition, and for different categories of past land cover and past forest management. We accounted for the effects of parent material on topsoil conditions by clustering our plots into three soil type groups based on texture and carbonate concentration. We found that litter quality was a stronger driver of topsoil conditions compared to land-use history or atmospheric deposition, while the soil type also affected several topsoil conditions here. Plots with higher litter quality had soils with a higher proportion of exchangeable base cations, and total phosphorus, and lower C/N-ratios and litter mass. Furthermore, the observed litter quality effects on the topsoil were independent from the regional nitrogen deposition or the soil type, although the soil type likely (co)-determined canopy composition and thus litter quality to some extent in the investigated plots. Litter quality effects on topsoil phosphorus concentrations did interact with past land cover, highlighting the need to consider land-use history when evaluating canopy effects on soil conditions. We conclude that forest managers can use the canopy composition as an important tool for influencing topsoil conditions, although soil type remains an important factor to consider.

Effects of amendments on base cation and micronutrient availabilities in soils planted with tomato in a solar greenhouse

ABSTRACTIn order to obtain high tomato production, chemical fertilizers have been intensively applied in solar greenhouse in Northern China. This unreasonable use of chemical fertilizers always leads to soil degradation. One of the most serious problems is the loss of exchangeable base cations: calcium (Ca), magnesium (Mg), and potassium (K), and available micronutrients: iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn). We collected soils with different tomato cultivation durations: 0, 5, and 20 years, to investigate the effects of different fertilizers on the dynamics of soil base cations and micronutrients which extracted by 1 M ammonium acetate and 0.005 M diethylenetriaminepentaacetic acid, respectively. Five treatments were included: no fertilizer application as control (Con), chemical nitrogen, phosphorus and potassium fertilizers (CF), rice straw (FS), chicken manure (CM), and vermicompost (VM). Our results show that soil exchangeable Ca significantly decreased with the increase of cultivation duration, whereas soil exchangeable K increased due to the fertilization of K. Soil exchangeable Ca and K exhibited decreasing trends during the growth season of tomato, but not exchangeable Mg. Long-term tomato cultivation significantly increased soil available micronutrients. Soil available Fe and Mn fluctuated sharply during the growing season of tomato plant. Except Zn, fertilizers exhibited no constant significant effect on base cations and micronutrients. After long term planting of tomato, the loss of exchangeable Ca, but not Mg and micronutrients, might potentially constrain the productivity of crop under intensive chemical fertilization.