Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Red soil”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2005

[Effects of Cd contamination on paddy soil microbial biomass and enzyme activities and rice physiological indices].

A pot experiment with rice under submerged condition showed that with the increase of Cd concentration, soil microbial biomass carbon (Cmic) and nitrogen (Nmic) increased initially but decreased at a certain concentration, and the turning points varied with different soil types. Soil enzyme activities had the similar variation trend with soil Cmic and Nmic, and the turning points varied with different soil types and soil enzymes. The variation coefficients were in order of dehydrogenase activity > acid phophatase activity > urease activity. Soil respiration rate and metabolic quotient increased tardily with increasing cadmium concentration. The chlorophyll content of rice increased initially but decreased then with the increase of Cd contamination, and the turning points differed with different soil types. Rice proline content and peroxidase activity were enhanced gradually with increasing cadmium concentration. The variation coefficients of rice physiological indices on paddy soils derived from silty loam and clayed red earth were in order of peroxidase activity > chlorophyll content > proline content, and peroxidase activity > proline content > chlorophyll content, respectively. Correlation analysis indicated that there was a close correlation between the variations of soil microbial biomass and enzymatic activities and rice physiological indices under Cd contamination.

Cadmium↗
PubMed2001

Initial fermentation of sea sludge using aerobic and thermophilic microorganisms in a mangrove soil.

As sea sludge has the potential to cause eutrophication and red tide resulting in the death of shellfish and offensive odors, an effective method to treat it is needed. It was found that adding soil taken from a mangrove swamp to sea sludge promoted an initial fermentation of the sludge constituents. The result suggested that certain microorganisms that were thought to inhabit the sub-tropical mangrove soil had the potential to play a significant role in the fermentation and that the use of the microorganisms in the mangrove soil might be useful for composting sea sludge.

Bacteria, Aerobic↗
PubMed1998

Distribution of a Population of Rhizobium leguminosarum bv. trifolii among Different Size Classes of Soil Aggregates.

A combination of the plant infection-soil dilution technique (most-probable-number [MPN] technique) and immunofluorescence direct count (IFDC) microscopy was used to examine the effects of three winter cover crop treatments on the distribution of a soil population of Rhizobium leguminosarum bv. trifolii across different size classes of soil aggregates (<0.25, 0.25 to 0.5, 0.5 to 1.0, 1.0 to 2.0, and 2.0 to 5.0 mm). The aggregates were prepared from a Willamette silt loam soil immediately after harvest of broccoli (September 1995) and before planting and after harvest of sweet corn (June and September 1996, respectively). The summer crops were grown in soil that had been either fallowed or planted with a cover crop of red clover (legume) or triticale (cereal) from September to April. The Rhizobium soil population was heterogeneously distributed across the different size classes of soil aggregates, and the distribution was influenced by cover crop treatment and sampling time. On both September samplings, the smallest size class of aggregates (<0.25 mm) recovered from the red clover plots carried between 30 and 70% of the total nodulating R. leguminosarum population, as estimated by the MPN procedure, while the same aggregate size class from the June sampling carried only approximately 6% of the population. In June, IDFC microscopy revealed that the 1.0- to 2.0-mm size class of aggregates from the red clover treatment carried a significantly greater population density of the successful nodule-occupying serotype, AR18, than did the aggregate size classes of <0.5 mm, and 2 to 5 mm. In September, however, the population profile of AR18 had shifted such that the density was significantly greater in the 0.25- to 0.5-mm size class than in aggregates of <0.25 mm and >1.0 mm. The populations of two other Rhizobium serotypes (AR6 and AS36) followed the same trends of distribution in the June and September samplings. These data indicate the existence of structural microsites that vary in their suitabilities to support growth and protection of bacteria and that are influenced by the presence and type of plant grown in the soil.

Journal Article↗
PubMedDate not supplied

Using the scanning electron microprobe and secondary ion mass spectrometry to locate 14C and 13C labelled plant residues within soil aggregates.

Increasing concentrations of CO2 in the atmosphere are placing emphasis on the necessity for sequestering carbon (C) into soil organic matter (SOM). By studying the interior parts of soil aggregates, a better understanding of the incorporation and sequestration of plant residue materials within these aggregates could be obtained. The location of newly added plant residues within soil aggregates may also assist in the investigation of the impact of these newly added plant materials on soil aggregation. This study investigated two different techniques for determining the location of newly added plant residues within soil aggregates by using plant materials labelled with 14C and 13C isotopes incorporated into two different soil types, Black Earth (Pellic Vertisol) and Red Clay (Chromic Vertisol). Both autoradiography combined with scanning electron microprobe analysis (14C) and secondary ion mass spectrometry (SIMS) (13C) were successfully used for detecting the presence and location of the newly added plant residues fragments within soil aggregates of both soil types. The use of labelled plant materials is essential for the study of the location of newly added plant materials within soil aggregates, and this has proven to be a useful tool for studying the impact of residue additions on soil aggregate formation. Furthermore, these methods have been shown to be useful for determining the incorporation and sequestration of C materials within soil aggregates. The development of the 13C SIMS technique could alleviate the necessity for the use of the radioactive isotope 14C in soil studies.

Carbon Isotopes↗
PubMedDate not supplied

Using the scanning electron microprobe and secondary ion mass spectrometry to locate 14C- and 13C-labelled plant residues within soil aggregates.

Increasing concentrations of CO2 in the atmosphere are placing emphasis on the necessity for sequestering carbon (C) into soil organic matter (SOM). By studying the interior parts of soil aggregates, a better understanding of the incorporation and sequestration of plant residue materials within these aggregates could be obtained. The location of newly added plant residues within soil aggregates may also assist in the investigation of the impact of these newly added plant materials on soil aggregation. This study investigated two different techniques for determining the location of newly added plant residues within soil aggregates by using plant materials labelled with 14C and 13C isotopes incorporated into two different soil types, Black Earth (Pellic Vertisol) and Red Clay (Chromic Vertisol). Both autoradiography combined with scanning electron microprobe analysis (14C) and secondary ion mass spectrometry (SIMS) (13C) were successfully used for detecting the presence and location of the newly added plant residues fragments within soil aggregates of both soil types. The use of labelled plant materials is essential for the study of the location of newly added plant materials within soil aggregates, and this has proven to be a useful tool for studying the impact of residue additions on soil aggregate formation. Furthermore, these methods have been shown to be useful for determining the incorporation and sequestration of C materials within soil aggregates. The development of the 13C SIMS technique could alleviate the necessity for the use of the radioactive isotope 14C in soil studies.

Carbon Radioisotopes↗
PubMed2001

Effects of predator chemical cues and behavioral biorhythms on foraging activity of terrestrial salamanders.

Red-backed salamanders, Plethodon cinereus, show a variety of alarm responses to chemical cues from eastern garter snakes, Thamnophis sirtalis. We measured the foraging activity of red-backed salamanders exposed to water soiled by a garter snake (fed P. cinereus) or to unsoiled water. Salamanders exposed to snake-soiled water showed less foraging activity than salamanders exposed to unsoiled water; therefore, predators could have nonlethal effects on salamander populations. Our results also show additional factors influenced salamander foraging activity. Salamander foraging activity and responsiveness to chemical cues do not appear to have been affected by sex or food deprivation. Salamander foraging activity does appear to have been influenced by activity biorhythms. Foraging activity of animals in both treatments showed a bimodal periodicity that is consistent with natural activity patterns controlled by internal biorhythms. Exposure to snake-soiled water significantly reduced foraging activity during periods of peak foraging activity, but had a subtler effect on foraging activity during natural lulls in activity. We suggest that both activity biorhythms and exposure to chemical cues are important factors affecting salamander foraging behavior.

Animals↗
PubMed1990

Solution aluminum and transpiration in Picea rubens and Gleditsia triacanthos seedlings.

Soil solution Al may contribute to red spruce (Picea rubens Sarg.) decline by inhibiting transpiration (Klein 1985). This study examines how Al affects transpiration in red spruce and honeylocust (Gleditsia triacanthos L.) seedlings and explores mechanisms for the observed responses. Red spruce seedlings were grown in dilute nutrient solutions containing 0 to 925 microM Al at pH 4.5 or 3.8. Solution Al had no effect on the transpiration, root hydraulic conductivity (K(r)) or shoot water potential (Psi) of red spruce. Transpiration of honeylocust was higher in the presence of 100 to 350 microM Al than 0, 500, or 600 microM Al. The Al-induced increases in transpiration of honeylocust were unrelated to shoot Psi or root K(r), but were closely correlated with the greater root lengths produced by intermediate levels of Al. In neither species was transpiration correlated with tissue concentrations of Al, P, K, Ca or Mg.

Journal Article↗
PubMed2004

Toxicologic and histopathologic response of the terrestrial salamander Plethodon cinereus to soil exposures of 1,3,5-trinitrohexahydro-1,3,5-triazine.

Red-backed salamanders (Plethodon cinereus) were exposed to four different concentrations of 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) in soil under controlled laboratory conditions for 28 days. Wild-caught P. cinereus (N = 20/treatment) were exposed to target concentrations of 5,000, 1000, 100, 10, and 0 mg RDX/kg soil (dry wt) using a microcosm design. Animals were fed 5 to 10 uncontaminated mutant Drosophila flies every 3 days and monitored daily. Animals were weighed 1 day before being placed in treatment and weekly thereafter. RDX concentrations in soil were analytically determined after the compound was added and mixed at the beginning, the midpoint, and the end of exposure. RDX soil concentrations were relatively stable throughout the exposure period. Signs of overt toxicity were observed primarily in the highest exposure group. Salamanders exposed to 5,000 mg RDX/kg soil exhibited signs of neuromuscular effects (lethargy, gaping, hypersensitivity, tremors) and exhibited significant weight loss. A single moribund animal from this group lost >20% of its original body weight and was killed. Animals in this exposure group also lost weight relative to animals in other treatments. Histopathologic evaluations, including an evaluation of melanomacrophage parameters, indicated no strong treatment-related findings. This study provided information regarding the effects from subchronic dermal exposure of a terrestrial amphibian species to RDX in soil and provides a microcosm approach to the evaluation of toxicity of contaminants in soil to a terrestrial vertebrate.

Administration, Cutaneous↗
PubMed1991

Biodegradation of pentachlorophenol in soil: the response to physical, chemical, and biological treatments.

The effects of physical, chemical, and biological treatments on biodegradation of pentachlorophenol (PCP) were studied in a silt-loam soil contaminated with 175 mg PCP/kg and uniformly 14C-labelled PCP. Biodegradation of 14C-labelled PCP and technical-grade PCP were monitored over 210 days incubation. Mineralization of labelled PCP was significantly (p=0.05) influenced by soil treatments. Negligible biodegradation occurred in either the sterile control soil or the uninoculated control soil, with less than 1% of added 14C recovered as 14 CO2. Inoculation of unamended soil with a strain of Flavobacterium (ATCC 39723) known to degrade PCP increased biodegradation of PCP; approximately 60% of the [14C]PCP was recovered as 14CO2. Increased soil water content (60% versus 30% w/w) enhanced biodegradation (67% recovery of 14C as CO2), while increased chloride ion concentration and anoxic conditions were inhibitory (20 and 1% recoveries, respectively). Residual soil PCP concentrations were also influenced by various treatments. In the sterile control soil and noninoculated control, after 210 days incubation, concentrations of PCP were 143 and 1223 mg/kg, respectively, while the PCP concentration in the inoculated soil was 21 mg/kg. When soil organic matter was increased by adding finely ground red clover leaf and stem material, the residual PCP concentration was reduced to 6 mg/kg after 210 days. Increased soil water content resulted in a residual PCP concentration of 5 mg/kg. High-pressure liquid chromatography of soil extracts revealed no accumulation of partial PCP degradation products. The results indicated that biodegradation of PCP in soil was significantly influenced by various soil amendments.

Biodegradation, Environmental↗
PubMed2003

[Structure and function of several intercropping ecosystems in newly built orchard].

Sloping wildland is the important potential land resource in China. Structures and functions of five optimized models selected from more than 10 intercropping patterns in the newly built orchards in the uncultivated sloping field were analyzed in this paper. The results showed that organic matter was increased by 5-20%, total N by 7-40%, total P by 8-70%, and total K by 15-80% yearly. Considering its benefit in soil and water conservation, the intercropping model of peanut and autumn soybean was the best, and followed by spring soybean and autumn soybean, tomato and Chinese cabbage, cayenne and tomato, and drought rice and red turnip. Compared with the control, the average soil erosion module and runoff amount of the 5 models were decreased by 44.19%, 38.24%, 39.52%, 37.56%, 37.30%, and 22.40%, 9.28%, 24.11%, 21.60%, 15.93%, respectively. The intercropping model of cayenne and tomato had the highest biomass, and its annual biomass averaged 1,00,267 kg.hm-2. The biomass of intercropping model of peanut and autumn soybean was the second, and the annual value averaged 77,026 kg.hm-2. Intercropping model of peanut and autumn had the highest annual productivity, which averaged 15,619 kg.hm-2, and that of intercropping model of tomato and Chinese cabbage was the second, averaged 15,394 kg.hm-2. The efficiency of energy introjection was in order of cayenne and tomato, tomato and Chinese cabbage, peanut and autumn soybean, spring soybean and autumn soybean, and dry rice and red turnip, and their values were 3.06, 2.16, 2.15, 2.06, and 0.71, respectively.

Crops, Agricultural↗
PubMed2001

Input-output budget of nitrogen and the effect of experimentally changed deposition in the forest ecosystems in central Japan.

To evaluate the current nitrogen (N) status in Japanese forests, field measurements of rainfall, throughfall, litter layer percolation, and soil solution percolation were conducted in a red pine stand (Kannondai) and a deciduous stand (Yasato) located in central Japan. N input via throughfall was 31 and 14 kg ha(-1) year(-1) and output below rooting zone was 9.6 and 5.5 kg ha1 year(-1) in Kannondai and in Yasato, respectively. Two thirds of input N were retained in plant-soil systems. Manipulation of N input was carried out. Ionic constituents were removed from throughfall with ion exchange resin at removal sites and ammonium nitrate containing twice the N of the throughfall was applied at N addition sites periodically. SO4(2-) output below 20-cm soil layer changed depending on the input, while NO3- output was regulated mainly by the internal cycle and effect of manipulation was undetected. These Japanese stands were generally considered to have a larger capacity to assimilate N than NITREX sites in Europe. However, N output fluxes had large spatial variability and some sites in Kannondai showed high N leaching below rooting zone almost balanced with the input via throughfall.

Ammonia↗
PubMed2006

[Lysosome of Eisenia fetida as biomarker of soil pollution].

The lysosome of Eisenia fetida can accumulate neutral red dye rapidly. When exposed to environment pollution, the membrane of the lysosome is easily to be cracked, and the dye shall leak to the cytoplasm gradually, making the cell red. Therefore, neutral red retention time (NRRT) can reflect the damaged degree of lysosome. In this paper, the NRRT of the lysosome in coelomocytes of E. fetida was determined after exposed to different concentrations of acetochlor and selenium. The results showed that with increasing exposure time and increasing concentration of acetochlor and Se, the NRRT was decreased significantly, and had significant correlations with the concentrations of acetochlor in soil and of accumulated Se in E. fetida's body. NRRT could be served as a biomarker of soil pollution, and a promising tool for the early warning of potential danger.

Animals↗
PubMed1977

Induction of Frost Hardiness in Stem Cortical Tissues of Cornus stolonifera Michx. by Water Stress: I. Unfrozen Water in Cortical Tissues and Water Status in Plants and Soil.

Water supply and day length were varied in cold hardiness studies of red osier dogwood plants (Cornus stolonifera Michx.). The frost killing temperature, the content and freezing of stem cortical tissue water along with soil moisture content and tension were evaluated. Seven days of water stress in long and short day photoperiod regimes caused a rapid decrease in soil moisture content and plant water potential. During the same period, the frost hardiness increased from -3 to -11 C. Further water stress treatment had little effect. Control plants in short days showed only a gradual decrease in plant water potential and only gradually increased in frost hardiness while control plants in long days were unchanged. Freezing studies using nuclear magnetic resonance showed that increased hardiness in water-stressed plants resulted from both an increased tolerance of freezing and an increased avoidance of freezing, the latter resulting from higher solute concentration in the tissue solutions. The short day controls also showed similar changes; however, the changes were smaller over the 21 days of the study.

Journal Article↗
PubMedDate not supplied

[Number and structure of actinomycetes complexes in the rhizosphere winter rye, oat and red clover].

The actinomycetes complexes in the rhizosphere of three agricultural plants by using the methods of luminescense microscopy and cup sowing were investigated. It was established, that concentration of prokaryotic biomass and biomass of actinomycetes mycelium in rhizosphere of plants is higher than in free from the radicals to soil. Rhizosphera of the oat (Avena sativa L.) and red clover (Trifolium pratense L.) is colonized by Streptomyces, Micromonospora and olygospore species. Dominante actinomycetes of winter rye (Secale cereale L.) are classified into the genera Micromonospora. It was shown that numbers and biomass of actinomycetes mycelium were fond to decreased, diversity of actinomycetes in contrast is increased in the series: "winter rye--oat--red clover". In connection with ecological safety the capability of increase with prokaryotes naturally disease suppressive soil and stability of plants to pathogen is discussed.

Actinobacteria↗
PubMed1999

Production of canthaxanthin by extremely halophilic bacteria.

Soil samples from a salt farm were used as a source for the isolation of carotenoid-producing bacteria. The conditions for optimum growth and carotenoid production were established for the isolated bacteria. Carotenoids were analysed by spectrophotometry and High Performance Liquid Chromatography (HPLC). Thirty-one red extremely halophilic bacteria were isolated from saline soil samples collected from a salt farm in Alexandria, Egypt. Among the isolated strains, strain TM exhibited the highest carotenoid-producing ability. Maximum growth of strain TM occurred in the presence of high concentrations of sodium chloride and magnesium sulfate. Growth did not occur when NaCl concentration was lower than 10% and the cells lysed at this concentration. Optimum growth of and carotenoid production by strain TM were realized at 37 degrees C in the presence of 1% yeast extract, 0.75% casamino acids, 25% NaCl, 4% MgSO4, 0.2% KCl and at pH 7.2 with shaking for 6 d. Strain TM produced 2.06 mg total carotenoids g(-1) dry cells, including 0.06 mg of beta-carotene and 0.70 mg of canthaxanthin. This is the first report of an extremely halophilic bacterium that produces canthaxanthin.

Journal Article↗
PubMed2002

Belowground carbon pools and processes in different age stands of Douglas-fir.

Forest floor material and soil organic matter may act as both a source and a sink in global CO2 cycles. Thus, the ecosystem processes controlling these pools are central to understanding the transfers of carbon (C) between the atmosphere and terrestrial systems. To examine these ecosystem processes, the effect of stand age on temporal carbon source-sink relationships was examined in 20-year-old, 40-year-old and old-growth stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Cascade Mountains of south-central Washington State. Belowground C and nitrogen (N) storage and soil respiration were measured. In addition, nylon mesh bags containing homogenized soils from each site were buried at the respective sites to quantify root ingrowth and potential C sequestration and loss. The sites supporting the 20- and 40-year-old stands had soil C stores reflecting the C contributions from logging residue, coarse woody debris and stumps left after harvest. Because the N-fixer red alder (Alnus rubra Bong.) comprised 33% of the 40-year-old stand, this site had significantly greater concentrations and pools of N in the forest floor than sites without red alder. This N-rich site had consistently lower soil CO2 efflux rates during the growing season than the sites supporting the 20-year-old and old-growth stands. Estimated annual soil C efflux was 1367, 883 and 1194 g m-2 for the sites supporting the 20-, 40- and old-growth stands, respectively. These values are higher than previously reported values. Root ingrowth was significantly less in the 40-year-old stand than in the 20-year-old stand, and both young stands showed markedly less fine root growth than the old-growth stand. At the sites supporting the young stands, C and N were lost from the soil bags, whereas there was an increase in C and N in the soil bags at the site supporting the old-growth stand. The fine root growth and soil respiration data support the hypothesis that belowground C allocation decreases with increasing fertility. Quantification of the source-sink relationship of soil C at the three stands based on litterfall, relative root ingrowth and soil respiration measurements was compromised because of significant CO2 flux from decaying organic matter in the young stands.

Alnus↗
PubMed2006

Sorption and desorption behaviors of diuron in soils amended with charcoal.

Charcoal derived from the partial combustion of vegetation is ubiquitous in soils and sediments and can potentially sequester organic contaminants. To examine the role of charcoal in the sorption and desorption behaviors of diuron pesticide in soil, synthetic charcoals were produced through carbonization of red gum (Eucalyptus spp.) wood chips at 450 and 850 degrees C (referred to as charcoals BC450 and BC850, respectively, in this paper). Pore size distribution analyses revealed that BC850 contained mainly micropores (pores approximately 0.49 nm mean width), whereas BC450 was essentially not a microporous material. Short-term equilibration (< 24 h) tests were conducted to measure sorption and desorption of diuron in a soil amended with various amounts of charcoals of both types. The sorption coefficients, isotherm nonlinearity, and apparent sorption-desorption hysteresis markedly increased with increasing content of charcoal in the soil, more prominently in the case of BC850, presumably due to the presence of micropores and its relatively higher specific surface area. The degree of apparent sorption-desorption hystersis (hysteresis index) showed a good correlation with the micropore volume of the charcoal-amended soils. This study indicates that the presence of small amounts of charcoal produced at high temperatures (e.g., interior of wood logs during a fire) in soil can have a marked effect on the release behavior of organic compounds. Mechanisms of this apparent hysteretic behavior need to be further investigated.

Adsorption↗