Soil Water pH Research Articles

Calibration and Application of Aquaflex TDT Soil Water Probes to Measure the Soil Water Dynamics of Agricultural Topsoil in Southwest Germany

Soil water plays a key role in crop growth and yield formation. A sustainable irrigation management depends on a reliable soil water monitoring. The present study was conducted to derive site-specific and pedotransfer calibrations for Aquaflex time domain transmission (TDT) soil water sensors and to test their performance under field conditions. In spring 2009, two soil moisture networks were installed in the Kraichgau region and in the Swabian Alb, southwest Germany. Each network consists of 21 stations, each equipped among others with an Aquaflex TDT sensor installed 15-cm-deep in the soil. At each station, soil samples were taken and analyzed for the gravimetric soil water content, bulk density, soil texture, electrical conductivity, pH, and organic nitrogen and carbon content. The factory calibration delivered highly biased soil water contents [∼−8.0 Volume (Vol.) %]. The root mean square errors (RMSEs) were high, reaching on average 8.3 and 12.6 Vol.% in Kraichgau and Swabian Alb, respectively. The RMSEs of pedotransfer calibrations declined to 3.7 Vol.% in Kraichgau and to 3.4 Vol.% in Swabian Alb. In both regions, the slope of the calibration curve was affected by soil bulk density. High-leverage independent variables affecting the intercept were electrical conductivity in Kraichgau and silt fraction in Swabian Alb. Site-specific calibrations performed best. On average, the RMSE in Kraichgau was 3.0 Vol.%, in Swabian Alb 1.9 Vol.%. The pedotransfer-based approach proposed in the present study is a good compromise between labour effort and accuracy for soil landscapes with similar texture and properties.

A 5-year study of the impact of peatland revegetation upon DOC concentrations

Summary Peatlands are among the largest long-term soil carbon stores on the globe, but their degradation can lead to significant carbon losses. Therefore, restoration of peatlands has received considerable attention but the impact of revegetation upon critical water quality parameters has not been assessed. In this paper we consider a 5-year study of three restored sites in comparison to both an unrestored, bare peat control and to a vegetated control that did not require restoration. The soil porewater dissolved organic carbon concentration (DOC) was measured (6 replicates) for each restoration treatment and each control. The soil water measurements were made in the context of measuring the depth to water table; soil water pH and conductivity; and DOC concentration in surface runoff for the same restored and control treatment. The study showed that the average soil porewater DOC concentration on the restored sites rose significantly over the 5 year study representing a 34% increase relative to the vegetated control and an 11% increase relative to the unrestored, bare control. Soil pore water concentrations were not significantly different from surface runoff DOC concentrations, and therefore restoration as conducted by this study would have contributed to water quality deterioration in the catchment. However, had water table restoration been conducted alongside revegetation then a significant decline in DOC concentrations could have been realised.

Effect of Cultivation in Different Age’s Oil Palm Plantation on Selected Chemical Properties of Peat Swamp Soils

Large-scale land conversion of peat for agricultural purposes requires clearance, drainage, fertilizer application, and liming to increase the pH and boost microbial activity. The objective of this present study was to compare the soil chemical properties of oil palm plantation one-three years oil palm planted and mature oil palm that were previously a secondary tropical peat swamp forest. Soil samples were collected randomly at difference age’s oil palm plantation from a Young Oil Palm Plantation (YOPP) in one year period of time at same place and Mature Oil Palm Plantation (MOPP) another place from oil palm plantation in Batang Igan, Sibu Sarawak, Malaysia. Approach: Forty eight soil samples were taken using a peat soil auger at 0-15 cm depths in every area. The samples were air dried and then sieved to pass 2 mm sieve. Soil pH in water and KCl, soil CEC, Organic Matter (OM), Organic Carbon (OC), Total Nitrogen (TN), Total Phosphorous (TP), Total Potassium (TK), carbon to nitrogen ratio and carbon to phosphorous ratio were determined using standard procedures. Statistical analysis showed that CEC, TC and OM content were statistically similar. Results: The soil pHwater, TN and C/N ration shows highly significant for all difference age's oil palm plantation. Difference with pHKCl and TK content shows no significantly difference between YOPP 2 years and 3 years but both areas significantly higher with MOPP. For TP and C/P ratio content has no significant difference for YOPP (2 years) and MOPP but significantly difference with YOPP (3 years). Conclusion: Regardless of difference age's oil palm plantation, total carbon, organic matter and CEC was statistically similar to different ages of oil palm plantation, but soil acidity, nitrogen, phosphorus, potassium, C/N and C/P ratio was significantly higher between three areas weather YOPP (2 years), YOPP (3 years) and MOPP.

Geology and groundwater regions to quantify primary salinity, sodicity and alkalinity in South African soils

Although anthropogenic salinisation and sodification has been researched extensively, little is known about the primary salinity in South Africa. This paper therefore aimed to determine the primary salinity, sodicity and alkalinity conditions for South African soils, based on geological units and groundwater regions, and analysed soil pHwater, electrical conductivity (EC) and exchangeable sodium percentage (ESP). Soils in the Whitehill Formation (Ecca Group) geological unit were the most saline (median EC = 2720 mS m-1) and the most sodic (median ESP = 79.8). Based on the groundwater regions, soils in the Tanqua Karoo were the most saline (median EC > 400 mS m-1), whereas those in the Richtersveld were the most sodic (median ESP > 20). Soils in the Richtersveld Subprovince and in the Eendoorn granite geological units, as well as soils in the Richtersveld, Ghaap Plateau and Western Kalahari groundwater regions were the most alkaline (median pH > 8.5). The highest EC values were found in soils occurring in the geological units of the arid western part of the Northern and Western Cape. For the groundwater regions, soils in closed basins, pan environments and in intermontane areas had the highest EC values. The arid areas of the Northern Cape and Western Cape were also the most sodic. The most alkaline geological units occurred in the Namaqua Sector of the Namaqua-Natal Province, and in the Richtersveld, Ghaap Plateau and Western Kalahari groundwater regions.

Influence of Soil Properties on Amounts of Bicarbonate-Extractable P in Soils Incubated With Three Thai Phosphate Rocks of Contrasting Mineralogies

Top- and sub-soil (0–15; 15–100 cm) samples were collected from nine acid soil series of Ultisols and Oxisols from high rainfall areas, Southeast Coastal region of Thailand. Most of them had low soil pH in water (pH Rat-PR > Kan-PR > Roi-PR. Increases in bicarbonate-extractable P (ΔPBC) in soil incubated with PR and MCP were highest at 14 days. Stepwise regression indicated that there was no single soil property that adequately predicted the increases in extractable P (ΔPBC) because of addition of PR and MCP. Soil properties that were most closely and positively related to ΔPBC were the ability of soils to provide hydrogen ions for PR dissolution and the initial amount of available P in the soils.

Fluoride sorption and desorption on soils located in the surroundings of an aluminium smelter in Galicia (NW Spain)

Aluminium smelters are major sources of F emission to the environment. We studied, in laboratory experiments, the sorption and desorption of fluoride on organic and mineral horizons of soils located within 2 km from one of these factories, situated in the northern coast of Galicia (NW Spain). The soils, developed from granite, are acid (pH H2O 3.9–5.5), rich in organic matter (4–16 % C in the A horizon) and most A horizons have high Al saturation in the exchange complex. All samples showed a notable F sorption, between 1,066 and 1,589 mg kg−1, after adding 200 mg F L−1, which accounts for 53–80 % of F added. The sorption was slightly higher in the A horizons than in the respective organic horizons (differences of up to 194 mg kg−1). The fluoride sorption upon addition of 200 mg F L−1 correlated significantly (p < 0.05) with soil pH in water (r = −0.77), iron extracted by acid ammonium oxalate (r = 0.68), aluminium plus iron extracted by acid ammonium oxalate (r = 0.63), exchange aluminium (r = 0.52) and clay percentage in soil (r = 0.76). The F sorption fitted to both Langmuir and Freundlich models. Desorbed F accounted for only 12–22 % of sorbed fluoride and correlated (p < 0.05) negatively with non-crystalline (extracted by acid ammonium oxalate) Fe (r = −0.51) and clay content (r = −0.74) and positively with organic matter (r = 0.69) and with the effective cation exchange capacity of the soil (r = 0.50).

Environmental conditions that promote the occurrence of truffles (Tuber spp.) on historical sites in Poland

Abstract This article highlights historical data regarding truffles’ occurrence in Poland. Along with the soil parameters the plant communities at the sites were studied. The results of the chemical soil analyses showed that the soil pH in water on 5 sites was acidic (from 4.3 to 6.1), and only in one, Wiązowna, was the pH (7.2) conductive to truffles development. Similarly, the content of calcium carbonate (CaCO3) in soil samples was low (from 0 to 0.03%), except for Wiązowna, where CaCO3 was 0.12%. Among the 24 reported species of trees and shrubs, 7 species were host-plants of summer truffle (Tuber aestivum Vitt.). Out of the 7 species, oak and hornbeam were present at four localisations. Across the sites, 31 species of ground-layer plants were identified. Among these, Epipactis helleborine was only one host-species of summer truffle. Our findings indicate that formation of truffles fruiting-bodies depends on specific habitat characteristics. The key factors determining this process are soil parameters, such as: texture, pH and calcium content. Our inventory showed that the sites we studied still persist as natural stands, although only one of them seems to be favorable for truffles development: this site is located in Wiązowna, where soil is of pH 7.2 and E. helleborine, (host species for truffles from Orchidaceae) is found, fulfills the environmental requirements of truffles

Aplicação de resíduo de reciclagem de papel em Cambissolo Háplico e seu efeito no solo e no cultivo de plantas

O processo de reciclagem de papel gera grande quantidade de resíduo e a sua aplicação no solo pode ser uma das estratégias de disposição desse produto, sendo necessário estudar os seus efeitos no solo e nas culturas agrícolas. O objetivo deste trabalho foi avaliar o efeito da aplicação de resíduo de reciclagem de papel sobre atributos químicos de um Cambissolo Háplico muito ácido e na produtividade de grãos de soja e feijão. Utilizou-se o delineamento experimental de blocos completos casualizados, com três repetições. Os tratamentos foram: testemunha, sem calcário ou resíduo; resíduo da reciclagem de papel nas doses de 50, 100, 150, 250, 400 e 600 Mg ha-1, em base úmida; e calcário dolomítico para elevar o pH do solo em água para 6,0. O resíduo corrigiu a acidez do solo, bem como aumentou os teores de cálcio e fósforo. As doses de resíduo não interferiram nos teores de metais pesados no solo e nos grãos. As máximas produtividades de soja e feijão são obtidas nas doses de 323 e 372 Mg ha-1 de resíduo úmido, respectivamente.

English

Acid sulfate soil in Malaysia is known to be very acidic with pH < 3.5 and have high amount of aluminum. A study was conducted to investigate the efficacy of various lime sources for alleviating the infertility of the soil and to determine its lime requirement. The treatments were ground magnesium limestone, hydrated lime, liquid lime and fused magnesium phosphate under submerged and moist condition for 3 months. Soil and water were sampled throughout the incubation period for the determination of pH, Al and Fe. The initial soil pH and exchangeable Al were 3.43 and 7.71 cmolc kg-1, respectively. After 3 months of incubation under submerged condition, the soil pH and water pH increased from 3.43 to 5.01 and from 2.38 to 5.17, respectively. Under moist condition, the pH increased from 3.43 to 4.02 due to application of 6 t ground magnesium limestone (GML) ha-1. The efficacy of hydrated lime as soil ameliorant was comparable to that of GML. It was recommended that 6 t ha-1 of GML be applied prior to the growing season for maximum benefit. This study showed that GML can be effectively applied to ameliorate the infertility of acid sulfate soils for rice cultivation. Key words: Glasshouse incubation study, ground magnesium limestone, liquid lime, fused magnesium phosphate, hydrated lime, acid sulfate soil.

古尔班通古特沙漠土壤水分与化学性质的空间分布

PDF HTML阅读 XML下载 导出引用 引用提醒 古尔班通古特沙漠土壤水分与化学性质的空间分布 DOI: 10.5846/stxb201212101775 作者: 作者单位: 中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,新疆信息工程学校,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划973项目（2009CB825102）；中国科学院西部博士专项（XBBS201205）；新疆维吾尔自治区重大科技专项（201130106-3）；国家自然科学基金（31300449，41030530）联合资助 Spatial pattern for soil water and chemical properties in Gurbantunggut Desert Author: Affiliation: Xinjiang Institute of Ecology and Geography,National Engineering Technology Research Center for Desert-Oasis Ecological Construction,Xinjiang Institute of Ecology and Geography,National Engineering Technology Research Center for Desert-Oasis Ecological Construction,Xinjiang Institute of Ecology and Geography,National Engineering Technology Research Center for Desert-Oasis Ecological Construction,Xinjiang Institute of Ecology and Geography,National Engineering Technology Research Center for Desert-Oasis Ecological Construction,Xinjiang Information Engineering School,Xinjiang Institute of Ecology and Geography,National Engineering Technology Research Center for Desert-Oasis Ecological Construction,Xinjiang Institute of Ecology and Geography,National Engineering Technology Research Center for Desert-Oasis Ecological Construction Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:区域尺度上，气象和水文状况是影响植被分布格局和土壤性状的主要因子，当然，局部的地貌特征及植被分布对土壤性质的影响也是不能忽视的。以古尔班通古特沙漠为研究对象，对其南缘至腹地约25 km的土壤水分与化学性质的空间分布及其相互关系进行研究，结果显示：水平方向上，从沙漠南缘至腹地，土壤水分在丘底呈减小趋势，尤其是距边缘10 km以外，且在距边缘6-7 km出现1个峰值。同时土壤pH值和电导率的大小以及有机碳，全氮，有效氮，全磷和有效磷含量与土壤水分的变化状况相似，在丘底呈减小趋势，而在丘坡和丘顶上均呈波动分布。这说明丘底土壤性质的空间格局受到气象和水文状况的显著影响，而丘坡和丘顶土壤性质并没有受到气象和水文状况的显著影响，这种波动分布主要由采样点的设置及植物的分布状况所引起。丘底土壤水分及化学性质均显著高于丘坡和丘顶，这说明地貌特征对土壤性质的空间分布有显著影响。垂直方向上，不同深度土层土壤性质也存在显著差异，土壤水分，pH值和电导率随着土层深度增加而增加，而土壤养分随土层深度增加而减小。相关分析结果表明：仅4、5月份的土壤含水量及年平均土壤含水量与丘底土壤化学性质显著正相关，这可能由于冬季积雪的融化导致了土壤水分在4、5月份的聚集比较明显，使土壤水分对土壤化学性质发挥作用。总之，土壤空间异质性是由气象和水文以及地貌特征共同影响的，而土壤空间异质性的变异进而影响到植被的分布，植被的分布反过来又影响土壤的空间分布，因此土壤的空间分布和植被的空间分布是相互影响，共同作用的。 Abstract:Spatial heterogeneity is considered as a ubiquitous feature in natural ecosystems. It is also well known that soil heterogeneity is a basic element for competitive and/or facilitative for resources competitive and interactions between plants, especially in the stressed environments of arid shrub-desert and steppe ecosystems. Consequently, soil spatial heterogeneity may determine the occurrence of plants, structure of vegetation and pattern of landscapes, and greatly affect biogeochemical cycles. At the regional or landscape scale, climatic and geomorphologic factors often exert strong influences on the soil spatial heterogeneity, however, local-scaled topography and vegetation should not be ignored because they are important factors in the formation of small-scaled landscape patterns. This study was designed to investigate the spatial pattern of soil water and chemical properties and their relationship in Gurbantunggut Desert ranged from the south fringe to the hinterland of about 25 km. The results showed that soil water and soil chemical properties presented a decreasing trend from the south fringe to the hinterland at the interdune, especially at about 10 km away from the south fringe, e.g., a significant peak value was appeared at the distance of 6-7 km away from the fringe. However, it was a fluctuated pattern at the slope and top dune; it indicated that climatic and geomorphologic factors exerted strong influences on the spatial heterogeneity of soil at the interdune, but not on the slope and top dune. This phenomenon can be explained as the significant decreasing of groundwater level and precipitation from the south fringe to the hinterland. In addition, soil water and chemical properties were significantly higher at the interdune than they were at the slope and the top dune, since the local topographic conditions resulted in water and soil accumulating significantly at the interdune compared to the slop and the top dune. Furthermore, soil water and chemical properties at different soil depth were significantly different, soil water content, pH and electrical conductivity increased with the soil depth, while soil nutrients content decreased with the soil depth. It indicated soil salinity and soil nutrient status behaved differently in spatial heterogeneity, with an inverse distribution between soil nutrients and soil salinity/alkalinity at different soil depth. Correlation analysis also confirmed that soil water and chemical properties were significantly correlated at the interdune in April, May and annual averaged period. It further documented that climatic and geomorphologic factors exert strong influences on the spatial heterogeneity of soil, especially since topography is the most important factor for the spatial pattern in soil properties at Gurbantunggut Desert, which lead to soil water and soil recourses accumulated significantly at the interdune in April and May. In summary, our results showed that within a population or community and over tens of kilometers, soil spatial heterogeneity was caused by climatic, geomorphologic (abiotic) and dominant plant types (biotic) together. However, these biotic and abiotic factors were not absolutely separated, but inter-linked each other, i.e., plant-soil interactions. The spatial heterogeneity of abiotic factors determined the spatial patterning of biotic factor, conversely, spatial patterns of plant distribution influenced rates of soil physical and biogeochemical processes. 参考文献 相似文献 引证文献

Air-pollution emission control in China: Impacts on soil acidification recovery and constraints due to drought

The Chinese government has established compulsory targets to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions by 8% and 10%, respectively, during 2010–2015. In this study, the effect of the policy was evaluated by predicting the recovery of acidified forest soil in Chongqing, an area severely impacted by acid rain in southwest China. Since precipitation has decreased significantly in this area in recent years, the impact of drought on soil acidification was also considered. A dynamic acidification model, MAGIC, was used to predict future trends in soil chemistry under different scenarios for deposition reduction as well as drought. We found that the current regulation of SO2 emission abatement did not significantly increase soil water pH values, the Ca2+ to Al3+ molar ratio (Ca/Al), or soil base saturation to the level of 2000 before 2050. NOx emission control would have less of an effect on acidification recovery, while emission reduction of particulate matter could offset the benefits of SO2 reduction by greatly decreasing the deposition of base cations, particularly Ca2+. Continuous droughts in the future might also delay acidification recovery. Therefore, more stringent SO2 emission control should be implemented to facilitate the recovery of seriously acidified areas in China.

Effect of urea-N on growth and indoleacetic acid production of Stenotrophomonas maltophilia (Sb16) isolated from rice growing soils in Malaysia

Growth and activity of N2-fixing bacteria can be affected by N fertilizer application. A study was conducted at Universiti Putra Malaysia, Malaysia, to determine the effect of urea-N on the growth and indoleacetic acid (IAA) production of diazotrophic Stenotrophomonas maltophilia strain Sb16 (accession number, JQ820255), previously isolated from rice (Oryza sativa L.) growing soils of Malaysia. Five rates of N from urea fertilizer were applied (0, 50, 100, 150, and 200 kg ha-1) to the flooded rice soil and incubated in the control environment for 6 wk. Results showed that the population growth increased with increased N rates and highest population (8.2 log10 cfu mL-1) recorded in soil-standing water at the second week of incubation. The population decreased with the reduction of total N. Soil and soil water pH increased from 7.1 to 8.4 at the first week of incubation. Production of indoleacetic acid was significantly reduced with N fertilizer application. The highest indoleacetic acid (2.6 mg mL-1) was produced in the control treatment. Application of high rates of N fertilizer increased the population of diazotrophic strain Sb16 but significantly reduced indoleacetic acid production.

Holocene denudation rates from the superhumid southernmost Chilean Patagonian Andes (53°S) deduced from lake sediment budgets

Holocene denudation rates and their regional variations in the superhumid and temperate climate of the southernmost Patagonian Andes are poorly surveyed. Therefore we have investigated denudation in five small lake catchments (0.11–1.62km2) across a precipitation gradient from 600 to >9000mmyr−1 in southernmost Chile at 53°S. Variations in denudation rates can be defined most precisely by using small catchments and short time spans (Holocene) thus can be related to variable bedrock types, vegetation cover, elevation, and climate. Minimum physical denudation rates were determined from sediment budgets based on sediment echosounder data and physical properties of sediment cores. The Holocene denudation rates vary from 0.08mmkyr−1 in the highly elevated, bare granitic rock catchments to 9.01mmkyr−1 in the low and vegetated catchments with a basement of sedimentary rocks. These values are comparable with those from similar areas in Norway, Sweden, and NW Iceland. The high annual precipitation in the study area has only a minor effect on denudation. Enhanced geomorphic activity during paraglacial conditions caused a faster denudation after the glacier retreat until either the clastic, glacial detritus was removed or the catchment was covered with vegetation. Chemical comparisons between basement rocks and lake sediments indicate a pronounced chemical denudation in catchments with peaty soils and low soil water pH values of 3 to 5. The Holocene surface lowering rates are on average 200 fold lower than Cenozoic surface lowering rates calculated from fission-track data for the southern Andes. This discrepancy can be explained by significantly higher erosion rates during glacial periods.

Changes in Organic Carbon and Selected Soil Fertility Parameters in Agricultural Soils in Tasmania, Australia

Twenty-four sites in northern Tasmania on Ferrosols formed on Tertiary basalt were sampled in 1997, 2005, and 2010. The farming systems at the sites during this period were either (a) continuous pasture, (b) continuous cropping of vegetable, cereal, and other cash crops in rotation, or (c) a mix of pasture and cropping (intermittent cropping). Average organic carbon (OC) concentrations across all sites and both sample depths (0–150 mm and 150–300 mm) decreased from 4.0% in 1997 to 3.5% in 2005 and 3.3% in 2010 (P < 0.001). Average OC was greater at 0–150 mm (4.1%) than at 150–300 mm (3.1%) (P < 0.001). Average total soil nitrogen (N) in 2010 (0.42%) at 0–150 mm was not significantly different (P = 0.07) from the average in 1997 (0.38%). Soil pH in water (pHw) showed the opposite trend to OC, increasing with time from 6.0 in 1997 to 6.2 in 2010. This reflects the consistent use of calcite and dolomite in Tasmanian farming because the natural pHw of these soils is less than 5.5. Exchangeable calcium and magnesium were also greater in 2010 compared with 1997. Bicarbonate-extractable phosphorus (P) averaged across both depths increased (P < 0.001) steadily from 77 mg kg−1 in 1997 to 95 mg kg−1 in 2005 to 126 mg kg−1 in 2010. At the five sites that remained under continuous cropping throughout the study, average 2010 OC in the topsoil was 3.2%, a decrease of 0.5% since 1997; pHw was unchanged at 6.4; and bicarbonate-extractable P increased by an average of 73 mg kg−1 to 211 mg kg−1. For the three sites that remained in pasture the corresponding topsoil changes were 0.3% less OC to an average of 4.8%; pHw 0.4 units greater at 6.0; and 41 mg kg−1 more bicarbonate-extractable P to an average of 99 mg kg−1. At the six sites converted from continuous pasture to intermittent cropping the average 2010 topsoil OC was 4.5%, a loss of 1.3%; pHw increased by 0.5 units to 6.1; and bicarbonate-extractable P increased by 35 mg kg−1 to 97 mg kg−1. There was a highly significant (R2 = 0.82) exponential relationship between topsoil OC in 2010 and the number of years each site had been cropped during the 38 years 1972–2010, for which reliable records were available (OC = 4.933e−0.018years), which suggested an equilibrium topsoil OC concentration of about 2.5% under continuous cropping on these soils. These results indicate that Tasmanian farmers on Ferrosols continue to increase the pHw and P fertility of their soils and that increasing cropping intensity on these soils comes at the expense of soil carbon.

Microbes on the Cliff: Alpine Cushion Plants Structure Bacterial and Fungal Communities

Plants affect the spatial distribution of soil microorganisms, but the influence of the local abiotic context is poorly documented. We investigated the effect of a single plant species, the cushion plant Silene acaulis, on habitat conditions, and microbial community. We collected soil from inside (In) and outside (Out) of the cushions on calcareous and siliceous cliffs in the French Alps along an elevation gradient (2,000–3,000 masl). The composition of the microbial communities was assessed by Capillary-Electrophoresis Single Strand Conformation Polymorphism (CE-SSCP). Univariate and multivariate analyses were conducted to characterize the response of the microbial beta-diversity to soil parameters (total C, total N, soil water content, , and pH). Cushions affected the microbial communities, modifying soil properties. The fungal and bacterial communities did not respond to the same abiotic factors. Outside the cushions, the bacterial communities were strongly influenced by bedrock. Inside the cushions, the bacterial communities from both types of bedrock were highly similar, due to the smaller pH differences than in open areas. By contrast, the fungal communities were equally variable inside and outside of the cushions. Outside the cushions, the fungal communities responded weakly to soil pH. Inside the cushions, the fungal communities varied strongly with bedrock and elevation as well as increases in soil nutrients and water content. Furthermore, the dissimilarities in the microbial communities between the In and Out habitats increased with increasing habitat modification and environmental stress. Our results indicate that cushions act as a selective force that counteracts the influence of the bedrock and the resource limitations on the bacterial and fungal communities by buffering soil pH and enhancing soil nutrients. Cushion plants structure microbial communities, and this effect increases in stressful, acidic and nutrient-limited environments.

Microbial Activity in Soils of Vegetation-Growing Concrete Slopes

Natural restoration slope and vegetation-growing concrete slope were selected as plots. Soil water content (SWC), pH, and soil organic matter, total nitrogen content (TN), total organic carbon (TOC), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), basal respiration, microbial quotient and metabolic quotient (qCO2) were analyzed. The main results show that: Soil organic matter, TN and MBC of 0-10 cm soil in the natural restoration slope are significantly lower than that in the vegetation-growing concrete slopes at 0.05 level. Both MBC and MBN show a highly significant positive correlation with soil organic matter and TN. Microbial quotient shows a highly significant negative correlation with TOC and MBN, and shows a significant negative correlation with MBC. The qCO2 shows a highly significant negative correlation with pH, and a significant negative correlation with MBC. The vegetation-growing concrete technology can improve the soil ecosystem in the impaired slope.

Changes in soil acidity and organic carbon in a sandy typic hapludalf after medium-term pig-slurry and deep-litter application

Successive applications of liquid swine waste to the soil can increase the contents of total organic carbon and nutrients and change acidity-related soil chemical properties. However, little information is available on the effects of swine waste application in solid form, as of swine deep-litter. The objective of this study was to evaluate alterations of organic carbon and acidity-related properties of a soil after eight years of pig slurry and deep-litter application. In the eighth year of a field experiment established in Braço do Norte, Santa Catarina (SC) on a sandy Typic Hapludalf samples were taken (layers 0-2.5; 2.5-5; 5-10; 10-15; 15-20 and 20-30 cm) from unfertilized plots and plots with pig slurry or deep-litter applications, providing the simple or double rate of N requirement of Zea mays and Avena strigosa in rotation. Soil total organic carbon, water pH, exchangeable Al, Ca and Mg, and cation exchange capacity (CECeffective and CECpH7.0), H+Al, base saturation, and aluminum saturation were measured. The application of pig slurry and deep-litter for eight years increased total organic carbon and CEC in all soil layers. The pig slurry and deep-litter applications reduced active acidity and aluminum saturation and increased base saturation down to a depth of 30 cm. Eight years of pig slurry application did not affect soil acidity.

Different types of sub‐alpine grassland respond similarly to elevated nitrogen deposition in terms of productivity and sedge abundance

AbstractQuestionIncreasing emissions of reactive nitrogen (N) compounds threaten the composition of species‐rich communities even in remote alpine areas. In the few studies available from (sub‐)alpine grassland, N deposition altered species composition in favour of sedges, which are assumed to be less limited by phosphorus (P) compared to other species. Is the magnitude of the sedges' relative increase modified by availability of other nutrients, which is in turn influenced by site‐specific edaphic and climatic conditions?LocationSwiss Central Alps.MethodsWe selected ten sub‐alpine sites that covered a broad range of communities and soil conditions, including both calcareous Seslerietum as well as acidic Nardetum pastures. As a model species, Carex sempervirens Vill. was present at each site. For two consecutive years, in addition to a control, two treatments were applied to the vegetation: (1) 50 kg·N·ha−1·yr−1 as NH4NO3 and (2) compound NPK fertilizer comprising the same amount of N. Total above‐ground biomass, fraction of all sedges, leaf length and leaf N, P and potassium (K) content of C. sempervirens were recorded and analysed for their responses to treatments and interaction with variables linked to productivity and nutrient availability (including soil water potential, pH and soil P).ResultsBiomass production was stimulated across all sites on average by 30% with elevated N deposition, and by 60% with NPK fertilizer application, revealing the sites to be similarly co‐limited by N and by P and K. Also across all sites, the fraction of sedges was increased on average 33% by N addition, but remained constant with NPK application, suggesting stronger P and/or K co‐limitation in non‐sedge species. N treatment effects were consistent in their direction but varied between sites; nevertheless this variation could not be explained by the measured edaphic or climatic factors. However, by trend, sedges benefited more from N fertilization on sites with higher pH, but benefited less on very dry sites.ConclusionOur findings reveal that the observed increase of sedges is a general response of sub‐alpine grassland to elevated N deposition and thus can be regarded as universal both for Seslerietum as well as Nardetum pastures.

Effects of deforestation on soil major macro-nutrient and other selected chemical properties of secondary tropical peat swamp forest

Development of agriculture and economic sector has become a subject to the current deforestation of tropical wetland region. The aim of the present study was to investigate the effect of deforestation on secondary tropical peat swamp forest (TPSF) by comparing macro-nutrients and others selected peat soil chemical properties of secondary TPSF and deforested secondary TPSF site. Peat soil samples were collected from two different plots at Batang Igan, Sibu, Sarawak, Malaysia. The plots were secondary TPSF where this area has been logged, but has not been cleared, while the other plot was clearing area where the forest has been cleared for agriculture. Sixteen soil samples were taken in each plot at a depth of 0 to 15 cm. All samples were taken randomly using peat auger. The samples were air dried and ground to pass through a 2 mm sieve. Soil pH was determined in water and potassium chloride (KCl) at ratio 1:2.5 using a pH meter. The loss on ignition method was used to determine soil organic matter and total carbon. Soil cation-exchange capacity(CEC) was determined by the leaching method. Total nitrogen was determined by the Kjeldahl method. The total phosphorus (TP) and total potassium (TK) were extracted by the aqua regia method followed by the blue method to determine TP, and TK was measured using atomic absorption spectrophotometer. pHwater, soil CEC, soil organic matter, total C, total P, total K and C/N ratio were significantly higher in secondary TPSF when compared with deforested secondary TPSF, while the pHKCl and C/P ratio content was statistically higher for deforested secondary TPSF. Deforestation of secondary TPSF significantly decreased soil pHwater, CEC, SOM, total C, total N, total P, total K and C/N ratio, but significantly increased soil pHKCl and C/P ratio. Key words: Peat swamp forest, soil acidity, soil organic matter, total carbon, total nitrogen, total phosphorus, total potassium, C/N and C/P ratio.

Characterization of Andosols in Yakushima Island

We examined soils derived from volcanic ash of Kikai-Akahoya tephra on Yakushima Island, Japan, and classified them according to the Unified Soil Classification System of Japan, 2nd Approximation (USCSJ 2nd) and the World Reference Base for Soil Resources (WRB). Five pedons with horizons showing high (>20%) volcanic glass content were investigated. Soils developed under evergreen broad-leaved forests had high acid oxalate-extractable aluminum (Alo) and acid oxalate-extractable silicon (Sio) concentrations, and low acid oxalate-extractable iron (Fe)/dithionite-citrate-extractable Fe ratio. This indicates a warmer climate and less severe leaching conditions compared with soils developed under coniferous forests dominated by Cryptomeria japonica and grasslands dominated by Pseudosasa owatarii. All soils contained considerable amount of hydroxyl-Al-interlayered 2:1 clay minerals. The surface horizons of the pedons developed under the cool-temperate C. japonica forests contained smectite as a result of podzolization. However, the surface horizon of the pedon developed under cool-temperate P. owatarii grasslands did not contain smectite. All pedons belonged to the Kuroboku soils great group (USCSJ 2nd) and Andosols (WRB). Pedons in mountainous areas did not contain horizons with more than 6 g kg−1 of Sio and hence were classified as non-allophanic Andosols. In mountainous areas, it was observed that allophane formation was inhibited by Al leaching due to intense rainfall (>10,000 mm year−1); Al consumption due to the formation of the Al-humus complex; and Al incorporation into the interlayers of vermiculite. The low soil water pH [pH(H2O)] and leaching of silicon (Si) in mountainous areas would support these anti-allophanic effects.