Potassium forms in aerated and anoxic soils of different management and potassium fertilizer history

The potassium forms and dominant clay mineralogy were studied in naturally well-drained (Hapludalfs, Eutropept) and poorly-drained soils (Fragiudalfs, Fragiaquept), both composed of the same parent materials (silty-clay or silt loam or clayey-loam). The well-drained soils (i.e. aerated) were cultivated and received larger amounts of K fertilizer; the poorly-drained types (i.e. anoxic) were grasslands and received low amount of K fertilizer. The different aspects investigated-exchangeable and nonexchangeable K, potassium fixation capacity and clay X-ray diffraction diagrams-indicated that the potassium status and the behavior of K-containing clays significantly differed between naturally well-drained aerated soils and anoxic poorly-drained soils. The aerated soils were high in both exchangeable and nonexchangeable K; the K saturation rate was high whereas fixation capacity was moderate. However, the anoxic soils showed a large K depletion and high fixation capacity. The silty-clayey soils studied were more affected by moisture regimes than the silt loam or clayey-loam.The differing K status between aerated and anoxic soils can be explained by several processes and factors, including soil weathering and management and K fertilizer history.     

Mycorrhizal Interactions in Sustainable Agriculture

Abstract

Vesicular-arbuscular mycorrhizal (VAM) fungi are an intimate link between the roots of most crop plants and soils, thereby affecting the development of host plants and host soils. The role of VAM fungi in improving plant nutrition and their interactions with other soil biota have been investigated with reference to host plant growth, but little is known about how these interactions affect soil structure. The impact of cultural practices and the particular role that VAM fungi play in improving soil structure are discussed in the context of sustainable farming.     

Comparative efficiency of wheat straw and sugarcane bagasse biochar reduces the cadmium bioavailability to spinach and enhances the microbial activity in contaminated soil

Abstract

Biochar is considered a novel soil amendment for cadmium (Cd) stabilization in contaminated soils. A pot experiment was conducted to examine the efficiency of wheat straw and sugarcane bagasse induced biochar on Cd mobility in soil and its bioavailability to spinach in contaminated soil. Soil pH, Cd contents in plant tissues and microbial biomass were examined. Results showed that Cd was significantly decreased by 30.95% and 20.83% with wheat straw and sugarcane bagasse biochar at 2% application rate respectively, relative to the control. Similarly, Cd contents were decreased in plants shoots by 15.41 and 14.33%, while in roots by 48.3 and 35.54%, when wheat straw and sugarcane biochar were added at 2% application rate respectively. Moreover, soil microbial biomass was significantly increased with the application of all biochar types and their applications rates. Finally, wheat straw biochar at 2% application rate can be considered as an effective approach for Cd stabilization in contaminated soils.     

Wedding of the Waters Cave, 48 HO 301, A Stratified Site in the Big Horn Basin of Northern Wyoming

Abstract

During the summer of 1959, the writer investigated several rock shelters at the mouth of the Wind River Canyon, about 3 miles south of Thermopolis, Wyoming. One of the rock shelters proved to be of archaeological value. A test trench revealed nearly 3 feet of stratified cultural deposits. The cultural materials fits well in the sequence for the Northwestern Plains, (Mulloy 1958: 204-223) and should be important in an area little known archaeologically.     

Two ecologically distinct subspecies ofHypochaeris radicatal L.

Summary The present paper is part of a series of papers comparing two ecologically distinct subspecies ofHypochaeris radicata L.Hypochaeris radicata ssp.radicata grows in more fertile soils thanH. radicata ssp.ericetorum.The dry-weight yield of plants grown from seeds was measured after a 25 days culture period on varying levels of nitrate. Roots and shoots were analyzed for total organic nitrogen and free nitrate. Dry-weight yield showed an almost identical response over the whole range of nitrate concentrations used. The chemical analysis did not reveal differences between the subspecies that could explain the distribution in the field. In a second experiment the growth rate of the two subspecies was measured under optimal nitrate supply during a two month period. Both subspecies exhibited initially the same relative growth rate but one month after sowing the growth rate of both subspecies declined, with a sharper decline in ssp.ericetorum resulting in an 82 per cent difference in dry-weight between both subspecies two months after sowing. Some pronounced formative differences became evident. Shoot to root ratio of ssp.ericetorum showed little response to increasing nitrate concentrations whereas ssp.radicata was clearly responsive in this respect.The contribution of the tap root in total plant dry-weight was relatively higher in ssp.Ericetorum. The decline in growth rate and the formative differences can explain the absence of ssp.ericetorum from nutrient rich soils. when grown on ammonium ssp.radicata had a slightly but not significantly higher yield than ssp.ericetorum. The difference was even greater at low pH. It is concluded that both subspecies are adapted to ammonium nutrition at pH 4.5 as well as at pH 6 and that the absence of ssp.radicata from acidic soils cannot be explained by the low pH. The possibility that both subspecies have different abilities to reduce their growth when nitrate resources become limiting, and yet remain capable for further growth and reproduction is discussed.Grassland species research group, publ. no.16.     

高磷土壤中丛枝菌根真菌的分离鉴定

【背景】丛枝菌根(arbuscular mycorrhiza,AM)真菌具有广泛的寄主范围、环境适应性和优良的植物促生能力。然而,土壤的高磷水平严重抑制了AM真菌生长及AM形成。【目的】分离鉴定出耐较高有效磷含量的华南土著AM真菌菌株,为菌根学研究工作提供新颖材料。【方法】采用经典形态学和分子系统学方法鉴定高磷土壤中AM真菌。【结果】从有效磷含量为53-131 (平均值±标准差为88.2±17.6) mg/kg的根区土壤中鉴定出7属25种AM真菌,包括无梗囊霉属(Acaulospora) 12种、球囊霉属(Glomus) 7种、隔球囊霉属(Septoglomus) 2种、近明球囊霉属(Claroideoglomus) 1种、根孢囊霉属(Rhizophagus) 1种、硬囊霉属(Sclerocystis) 1种和类球囊霉属(Paraglomus) 1种,其中幼套近明球囊霉(Claroideoglomus etunicatum)和蜜色无梗囊霉(Acaulospora mellea)是优势种。在(87.7±8.0) mg/kg的高磷水平下,AM真菌仍能形成丛枝和泡囊。但当有效磷含量达到(99.7±1.2) mg/kg时,菌根侵染率和丛枝丰度显著下降,但仍能够形成泡囊。【结论】从广州市南沙区有效磷含量为(88.2±17.6) mg/kg的耕地植物根区土壤中,鉴定出具有耐高磷潜力的7属25种AM真菌,幼套近明球囊霉和蜜色无梗囊霉等分离株可作为后续高磷抑制机制解析及耐高磷AM真菌菌剂研发工作的试验菌株。     

Chemical Analysis of Deposits at Rodgers Shelter,Missouri

Abstract

While chemical analyses of deposits from archaeological sites have often used phosphorus as an indicator of past human activity, there is little agreement on which type of phosphorus test is most useful for particular problem orientations. This paper evaluates the utility of tests for total phorphorus, available phosphorus, and organic matter in stratified cultural deposits at Rodgers Shelter, Missouri. Total phosphorus correlates highly with faunal debris density and seems to be most useful for internal site structure investigation. Available phosphorus appears to be associated with natural soil development as well as intensity of past human activity, and should be a good indicator of potential and actual subsurface cultural horizons. Organic matter is found to have lower correlation with cultural debris densities than does phosphorus. In addition, debris density and phosphorus distributions allow the formulation of hypotheses concerning natural mixing of cultural materials at the site andthe development of subsurface soil horizons     

Methodology for a comparative evaluation of sensitivity to fouling and cleanability of floor materials used in the food industry

Samples of floor materials used at present in different types of food plants were studied for their sensitivity to fouling and for their cleaning properties. A cleaning procedure close to that used in industry was carried out on seven different floor samples fouled with six industrial soils (e.g. green salad soil, reconstituted milk, and meat) and inoculated with spores of Bacillus stearothermophilus var. calidolactis as tracer. Sensitivity to fouling and the cleanability of the different floor materials were measured, and the results showed a significant difference between them. These differences were dependent upon the type of soil. Sensitivity to fouling and cleanability were not correlated with their slipping resistance characteristics.     

Soils selenium level and esophageal cancer: An ecological study in a high risk area for esophageal cancer

ProjectGolestan province, located in northeast of Iran, has been known as a high risk area for esophageal cancer (EC). This study was conducted to assess the relationship between soils selenium (Se) level and development of EC in this region.ProceduresIn this ecological study, 135 blocks were identified in Golestan province based on geographical altitude and longitude on the map. One soil sample was collected from the center of each block. Then we investigated Se concentration in soil samples by flame atomic absorption spectrometry. Statistical analysis was performed by the Pearson correlation test and Student t-tests. P-values of less than 0.05 were considered as significant.ResultsThe mean±SD of soils Se level in Golestan province was 3.7±1.61 mg/kg. There was a positive correlation between soils Se level and EC rates in this area (P=0.03) (Pearson correlation coefficient=0.19). Soils Se concentration was significantly higher in high (4.13 mg/kg) than in the low (3.39 mg/kg) EC rate areas (P=0.01).ConclusionsWe found high soils Se concentration and a significant positive relationship between soils Se level and EC rate in Golestan province of Iran. So, high soils Se level may play a possible role in developing EC in this area, specifically in Turkmensahra (very high EC rates).     

Rapid Quantification of Phototrophic Microorganisms and their Physiological State through their Colour

Quantification of phototrophic organisms on solid substrata together with their metabolic activity can be assessed easily, reliably and quickly through measurement of the organisms' colour. For that purpose only a chroma meter for solid substrata able to quantify the three components of colour is needed. A correlation between these three components and the number of organisms and their physiological state was demonstrated. The methodology developed here makes it possible to save time and materials in comparison with traditional microbiological methods. Moreover, it is a non-destructive method which can be used directly on site and in site. This characteristic is important when microbial environmental monitoring of cultural heritage is involved.     

Effect of moisture and oxidation status of alkaline rice soils on the adsorption of soil phosphorus by an anion resin

Summary Considerable effort was devoted to experimentally explaining the greater amount of anion resin-adsorbable P (ARAP) in water-saturated alkaline soils relative to moist soils with the purpose of explaining the phenomenon of increased P availability in flooded rice soils. ARAP increased when waterlogged conditions were imposed on soils, but the increase in ARAP occurred before reducing conditions were obtained. Reducing conditions did not increase ARAP. The increase in ARAP in the water-saturated alkaline soils was attributed to the enhanced P diffusion resulting from a decrease in tortuosity, thus indicating that increased P availability upon flooding could be due to increased P diffusion.Paper number 4533 of the Journal Series of the North Carolina Agricultural Experiment Station.Paper number 4533 of the Journal Series of the North Carolina Agricultural Experiment Station.     

Involvement of Streptomyces in the Deterioration of Cultural Heritage Materials Through Biomineralization and Bio-Pigment Production Pathways: A Review

Abstract

Streptomyces are involved in the deterioration of cultural heritage materials through several pathways, the most important of these are biomineralization and bio-pigment production. The biomineralization pathway can occur through the precipitation of calcite, silica, barytes, hydromagnesite and iron compounds on colonized paintings and on stone surfaces with paintings in relief. Streptomyces biomineralize boron although it was confirmed in biodeterioration of cultural heritage materials. The other pathway occurs via bio pigment production and the most common of these biopigments are melanin with colors ranging from black through brown to olive, carotenoids with colors ranging from red, yellow, and pink through to violet and thirdly, actinorhodin-related blue pigments.     

Influence of various organic materials on the recovery of molybdenum and copper added to a sandy clay loam soil

Summary In most cases, the lowest percentage recoveries of added Mo and Cu were obtained after 0 weeks. The highest recoveries of Mo were found after 12 weeks except in the case of peat, where it was after 8 weeks; and of Cu after 4 to 12 weeks of incubation. The exch. Mo content of soil was lower when organic materials and Mo were added than from soil where only Mo was added. However, in the absence of added Mo, the exch. Mo content was higher in soils where O.M. was added. Addition of peat resulted in lowest quantities of exch. Mo. Exch. Cu was higher in the presence of added organic materials, with or without the addition of Cu, when compared with soils without added O.M. The largest quantities of exch. Cu were obtained where F.Y.M. was used as a source of O.M., with or without added Cu. Contribution No.201, Research Branch, Research Station, P.O. Box 1210, Charlottetown, P.E.I., Canada.     

Using self‐portrait photographs to understand self‐concepts of Chinese and American university students

This study examines differences between self‐concepts of Chinese and American university students. Both groups used 35mm cameras to show who they are. They wrote statements about the intended meaning of their best photo. The signs of other people, materials, and objects, and cultural ideas in each photograph were analyzed. Contrary to expectations, a higher percentage of Chinese students portrayed themselves as independent, and a higher percentage of Americans were oriented to other people. Consistent with expectations, Americans were more likely to be oriented towards materials and objects. Both groups were equally likely to be oriented towards cultural ideas.     

Autotoxic Ginsenosides in the Rhizosphere Contribute to the Replant Failure of Panax notoginseng

MethodsThe autotoxicities were measured using seedling emergence bioassays and root cell vigor staining. The ginsenosides in the roots, soils, and root exudates were identified with HPLC-MS.ResultsThe seedling emergence and survival rate decreased significantly with the continuous number of planting years from one to three years. The root exudates, root extracts, and extracts from consecutively cultivated soils also showed significant autotoxicity against seedling emergence and growth. Ginsenosides, including R₁, Rg₁, Re, Rb₁, Rb₃, Rg₂, and Rd, were identified in the roots and consecutively cultivated soil. The ginsenosides, Rg₁, Re, Rg₂, and Rd, were identified in the root exudates. Furthermore, the ginsenosides, R₁, Rg₁, Re, Rg₂, and Rd, caused autotoxicity against seedling emergence and growth and root cell vigor at a concentration of 1.0 µg/mL.ConclusionOur results demonstrated that autotoxicity results in replant failure of Sanqi ginseng. While Sanqi ginseng consecutively cultivated, some ginsenosides can accumulate in rhizosphere soils through root exudates or root decomposition, which impedes seedling emergence and growth.     

Mycological Characterization of the Occupation Deposits in Excavated Medieval Russian Settlements

Microbiological analysis showed that the cultural layers of soils in excavated medieval Russian settlements differ from the surrounding soils in that the cultural layers have more fungal spores, their morphology is more diverse, the species diversity of microscopic fungi is higher, and the Penicilliumspecies that are able to grow at an elevated temperature (37°C) are more frequent.     

THE INFLUENCE OF P-RETENTION BY SOILS AND SEDIMENTS ON THE WATER QUALITY OF THE LIONS RIVER

SUMMARY

The soils of Midmar dam catchment and the sediments of the Lions river are shown to have high P-retention properties. Present conditions result in little leaching of PO₄ ^?4 from the soils and favour a net transport of P from overlying water to the sediments. P levels in the water are likely to remain low even if the loading rate of P were increased substantially. It is postulated however that other factors may induce a release of P from the sediments and adversely affect the load carried by the water.     

The effect of fallow and continuous cultivation on the chemical and physical properties of an alfisol in western Nigeria

Summary Soil properties under continuous cropping were compared with those under planted fallows and natural bush regrowth for three years after forest clearing. The cropping treatments consisted of continuous maize with and without stover returned as surface mulch, continuous soybean, and maize and cassava intercropped. The fallow treatments included pigeon pea, leucaena, Guinea grass and natural bush regrowth.In the continuous soybean and unmulched maize plots, soil organic matter and pH declined rapidly; whereas the mulched maize plots maintained a soil organic matter level comparable to the fallow treatments. To maintain soil organic matter in the surface soil at a level comparable to soil under secondary forest, two to three applications of a total amount of 16 MT/ha/annum of dry plant materials (maize stover or grass) are required when the material is applied as surface mulch.In the cropped plots, favorable physical characteristics in the surface soil were also maintained when sufficient plant residue was returned; whereas the deterioration of subsoil structure of the forest soil occurred in all cropping treatments.Guinea grass fallow has a distinct advantage in recycling mineral nutrients and maintaining soil physical properties and organic matter. It is suggested that soils may be planted with a combination of Guinea grass and pigeon pea fallow for one or two years after three or four years of arable cultivation.IITA Journal Paper No. 65 IITA Journal Paper No. 65     

Ecohydrology of the Venezuelan páramo: water balance of a high Andean watershed

ABSTRACT

Background: The páramo provides key ecosystem services, including regulation and provision of water. To understand the underlying functions, an ecosystem approach is necessary.

Aims: We quantified the combined effect of vegetation and soils (integrated topographic and vegetation units – TVU) on the hydrological balance of a Venezuelan páramo micro-watershed and analyse its hydrological response to intra- and interannual rainfall variability.

Methods: Data (2008–2016) from meteorological stations of TVUs and of a streamflow station was used to calculate watershed level hydrologic balances. We quantified the impact of the TVUs outputs by calculating evapotranspiration under non-standard conditions (ETc adj).

Result: Evapotranspiration of wetlands and tarns was high, exceeding annual precipitation. Shrubland had low evapotranspiration. Recharge of páramo reservoirs (soils, wetlands, tarns) occurred when monthly rainfall exceeded 90 mm. In dry years there were lower water yields with less effective hydrological regulation. In average years the differences between input and output in watershed balances were very small.

Conclusions: The high and constant evapotranspiration of the wetlands and tarns (due to permanent water availability) suggests they could maintain streamflow during dry periods. Their high evapotranspiration rates are compensated by low rates in shrublands units, reducing the mean total evapotranspiration of the watershed. The watershed balances suggest a limited regulatory capacity in these relatively dry páramos with no volcanic soils.     

Radioprotection of eye lens using protective material in neuro cone-beam computed tomography: Estimation of dose reduction rate and image quality

PurposeIn cerebral angiography, for diagnosis and interventional neuroradiology, cone-beam computed tomography (CBCT) scan is frequently performed for evaluating brain parenchyma, cerebral hemorrhage, and cerebral infarction. However, the patient’s eye lens is more frequently exposed to excessive doses in these scans than in the previous angiography and interventional neuroradiology (INR) procedures. Hence, radioprotection for the lenses is needed. This study selects the most suitable eye lens protection material for CBCT from among nine materials by evaluating the dose reduction rate and image quality.MethodsTo determine the dose reduction rate, the lens doses were measured using an anthropomorphic head phantom and a real-time dosimeter. For image quality assessment, the artifact index was calculated based on the pixel value and image noise within various regions of interest in a water phantom.ResultsThe protective materials exhibited dose reduction; however, streak artifacts were observed near the materials. The dose reduction rate and the degree of the artifact varied significantly depending on the protective material. The dose reduction rates were 14.6%, 14.2%, and 26.0% when bismuth shield: normal (bismuth shield in the shape of an eye mask), bismuth shield: separate (two separate bismuth shields), and lead goggles were used, respectively. The “separate” bismuth shield was found to be effective in dose reduction without lowering the image quality.ConclusionWe found that bismuth shields and lead goggles are suitable protective devices for the optimal reduction of lens doses.