Aggregate associated carbon, nitrogen and sulfur and their ratios in long-term fertilized soils   总被引：3，自引：0，他引：3  

Zhihui Yang  Bal Ram Singh  Sissel Hansen 《Soil & Tillage Research》2007,95(1-2):161-171

Farmyard manure (FYM) and fertilizer applications are important management practices used to improve nutrient status and organic matter in soils and thus to increase crop productivity and carbon (C) sequestration. However, the long-term effects of fertilization on C, nitrogen (N) and sulfur (S) associated with aggregates, especially on S are not fully understood. We investigated the effects of more than 80 years of FYM (medium level of 40 Mg ka⁻¹ and high level of 60 Mg ka⁻¹) and mineral fertilizer (NPKS and NK) on the concentrations and pools of C, N, and S and on their ratios in bulk soil, dry aggregates and water stable aggregates on an Aquic Eutrocryepts soil in South-eastern Norway. A high level of FYM and NPKS application increased the proportion of small dry aggregates (<0.6 mm) by 8%, compared with the control (without fertilizer). However, both medium and high level of FYM application increased the proportion of large water stable aggregates (>2 mm) compared with mineral fertilizer (NPKS and NK). The total C and N pools in bulk soils were also increased in FYM treatments but no such increase was seen with mineral fertilizer treatments. The increased total S pool was only found under high level of FYM application. Water stable macroaggregates (>2 and 1–2 mm) and microaggregates (<0.106 mm) contained higher concentrations of C, N and S than the other aggregate sizes, but due to their abundance, medium size water stable aggregates (0.5–1 mm) contained higher total pools of all three elements. High level of FYM application increased the C concentration in water stable aggregates >2, 0.5–1 and <0.106 mm, and increased the S concentration in most aggregates as compared with unfertilized soils. Higher C/N, C/S and N/S ratios were found both in large dry aggregates (>20 and 6–20 mm) and in the smallest aggregates (<0.6 mm) than in other aggregate sizes. In water stable aggregates, the C/N ratio generally increased with decreasing aggregate size. However, macroaggregates (>2 mm) showed higher N/S ratios than microaggregates (<0.106 mm). We can thus conclude, that long-term application of high amounts of FYM resulted in C, N and S accumulation in bulk soil, and C and S accumulation in most aggregates, but that the accumulation pattern was dependent on aggregate size and the element (C, N and S) considered.  相似文献   

Ultrasensitive detection of genetically modified maize DNA by capillary gel electrophoresis with laser-induced fluorescence using different fluorescent intercalating dyes     

García-Cañas V  González R  Cifuentes A 《Journal of agricultural and food chemistry》2002,50(16):4497-4502

In this work, four different fluorescent intercalating dyes are compared for the ultrasensitive CGE-LIF detection of DNA from transgenic maize in flours. The fluorescent intercalating dyes compared are YOPRO-1, SYBR-Green-I, Ethidium bromide (EthBr), and EnhanCE. For all the four dyes optimum concentrations are established, and efficient separations of DNA fragments ranging in size from 80 to 1000 bp are obtained. The comparative study demonstrates that SYBR-Green-I and YOPRO-1 provide better limits of detection (LODs) than EnhanCE or EthBr (i.e., LODs are, respectively, 700, 1000, 11300, and 97400 zmol, calculated for a 200-bp DNA fragment). Separations using YOPRO-1 are faster than those using SYBR-Green-I (30 min vs 47 min for the analysis of the 80-1000 bp DNA fragments). Also, separations using YOPRO-1 are more efficient than those using SYBR-Green-I (e.g., 2.4 x 10(6) plates/m vs 1.6 x 10(6) plates/m, respectively, calculated for the 200-bp fragment). Also, buffer depletion and cost per analysis are worse with SYBR-Green-I than with YOPRO-1. Therefore, YOPRO-1 was selected as the preferred intercalating dye. Using this fluorescent compound, analysis time reproducibility for the CGE-LIF separation of the DNA fragments is determined to be better than 1.7% (% RSD, n = 10) within the same day, and better than 1.9% (% RSD, n = 30) for three different days. Moreover, the fluorescence signal obtained using this dye is shown to vary linearly with the DNA concentration in the range studied, i.e., 1-500 ng/microL. It is demonstrated that by using this method 0.01% of transgenic maize can be detected in flour by direct injection of the PCR-amplified sample.  相似文献   

Quantitative Measurement of Organic Carbon in Mine Wastes: Methods Comparison for Inorganic Carbon Removal and Organic Carbon Recovery     

Fang You  Ram Dalal  David Mulligan 《Communications in Soil Science and Plant Analysis》2015,46(4):375-389

The present study aims to evaluate carbon recovery and analytical precision of two methods based on dry combustion for organic carbon (OC) quantification in base metal mine tailings: (1) IC subtraction method (inorganic C(IC) measured and subtracted from total C) and (2) direct OC quantification after acid pretreatment. Results showed IC subtraction method effectively hydrolyzed a range of IC minerals [calcium carbonate (CaCO₃), magnesium carbonate (MgCO₃), dolomite, magnesite, calcite] with satisfactory IC (as CO₂ released) recovery (87–103 percent). In the direct OC quantification method, 5 M hydrochloric acid (HCl) pretreatment resulted in a satisfactory recovery (76–92 percent) of most organic compounds [ethylenediaminetetraacetic acid (EDTA), cellulose, plant litter, and charcoal], except for water-soluble OC (sucrose, 40 percent recovery). The precision of both methods declined when C levels were <5 g kg^?1 with RSD (Relative Standard Deviation) > 10 percent. The OC values in test samples of base metal mine tailings were comparable between the two methods. However, IC subtraction method is not applicable for tailings with low OC levels (<5 g kg^?1) until the precision is substantially improved. Moreover, compared to the IC subtraction method, OC values are significantly lower in direct OC quantification method for tailings with high OC levels.  相似文献   

Effect of transpiration on iron uptake and translocation in lowland rice   总被引：1，自引：0，他引：1       下载免费PDF全文

Ram K. Shrestha  Katrin Engel  Mathias Becker 《植物养料与土壤学杂志》2015,178(3):365-369

We evaluated six lowland rice (Oryza sativa L.) genotypes with contrasting responses to increasing Fe²⁺ concentrations under conditions of both low (0.3 kPa) and high (2.4 kPa) vapor pressure deficit. Dry atmospheric conditions generally enhanced transpiration with concomitant increases in Fe uptake and leaf bronzing. Some resistant genotypes were able to limit the water loss by transpiration under higher Fe concentrations thus attenuating negative effects associated with increased Fe²⁺ translocation at high vapor pressure deficit.  相似文献   

Integrating geospatial and multi‐depth laboratory spectral data for mapping soil classes in a geologically complex area in southeastern Brazil          下载免费PDF全文

G. M. Vasques  J. A. M. Demattê  R. A. Viscarra Rossel  L. Ramírez López  F. S. Terra  R. Rizzo  C. R. De Souza Filho 《European Journal of Soil Science》2015,66(4):767-779

Soil mapping across large areas can be enhanced by integrating different methods and data sources. This study merges laboratory, field and remote sensing data to create digital maps of soil suborders based on the Brazilian Soil Classification System, with and without additional textural classification, in an area of 13 000 ha in the state of São Paulo, southeastern Brazil. Data from 289 visited soil profiles were used in multinomial logistic regression to predict soil suborders from geospatial data (geology, topography, emissivity and vegetation index) and visible–near infrared (400–2500 nm) reflectance of soil samples collected at three depths (0–20, 40–60 and 80–100 cm). The derived maps were validated with 47 external observations, and compared with two conventional soil maps at scales of 1:100 000 and 1:20 000. Soil suborders with and without textural classification were predicted correctly for 44 and 52% of the soil profiles, respectively. The derived suborder maps agreed with the 1:100 000 and 1:20 000 conventional maps in 20 and 23% (with textural classification) and 41 and 46% (without textural classification) of the area, respectively. Soils that were well defined along relief gradients (Latosols and Argisols) were predicted with up to 91% agreement, whereas soils in complex areas (Cambisols and Neosols) were poorly predicted. Adding textural classification to suborders considerably degraded classification accuracy; thus modelling at the suborder level alone is recommended. Stream density and laboratory soil reflectance improved all classification models, showing their potential to aid digital soil mapping in complex tropical environments.  相似文献   

Productivity of Rainfed Sorghum — A Physiological Analysis     

D. Durga  Devi  K. M. Sundaram  N. Natarajaratnam 《Journal of Agronomy and Crop Science》1987,159(5):360-364

A field experiment was conducted to study the varietal variability of productivity in sorghum under rainfed conditions. Six varieties viz., TNS 24, TNS 27, CO 20, CO 19, CO 24 and K3 were utilized in this study. Among these varieties TNS 24, CO 19 and TNS 27 were found to be tolerant to drought situations while K 3, CO 20 and CO 24 were susceptible. The classification was mainly based on the yield data. Highest leaf area was observed in tolerant varieties, The reduction in leaf area at the harvest stage was also minimal (6.8%) in the tolerant varieties. LAD and CGR also showed higher values in the tolerant varieties. The dry matter accumulation was higher in the tolerant varieties. The yield improvement in the tolerant genotypes is mainly due to the increased dry matter accumulation while harvest index is not related to yield in the varieties studied.  相似文献   

Busulphan and thiourea as chemosterilants for the snail lymnaea acuminata     

Ravindra Singh  Ram A. Agarwal 《Pest management science》1983,14(2):123-129

Treatment of the snail Lymnaea acuminata with an alkylating agent (busulphan) or a thiocarbamide (thiourea), for 3 days, significantly reduced the number of eggs and prevented embryonic development. Both the drugs caused a dose dependent reduction in the levels of protein, DNA, RNA and the activity of the alkaline phosphatase of the ovotestis, and a dose-dependent enhancement in the levels of amino-acids and the activity of the acid phosphatase. Discontinuation of the drug treatment for 7 days resulted in a near complete recovery in DNA and RNA levels, while there was no change in the levels of protein, amino-acids and the activities of the acid and alkaline phosphatases.  相似文献   

Solution of the kinematic-wave equations for border irrigation     

Vijay P. Singh  Rama S. Ram 《Agricultural Water Management》1984,9(2):127-138

A method is developed to obtain solutions to the kinematic-wave equations for border irrigation. The accuracy of this method is assessed by comparing the results with the kinematic-wave train (KWT) method previously reported to be accurate. Experimental data on freely draining borders were utilized for comparison and evaluation of these methods. The prediction error for advance time resulting from the two methods was comparable: it was below 25% for three sets of data but as high as 50% for one set of data. The prediction error for recession time was also comparable: below 6% for the same three sets of data but 14.0% for one set.  相似文献   

Growth strategy of trees related to successional status II. Leaf dynamics     

Ram Boojh  P.S. Ramakrishnan 《Forest Ecology and Management》1982,4(4):375-386

The leaf dynamics of two early (Alnus nepalensis and Schima khasiana) and three late (Machilus kingii, Quercus dealbata and Q. griffithii) successional tree species of a subtropical humid, evergreen, montane forest at Upper Shillong (1900 m) in north-eastern India has been studied using demographic techniques. The open-grown early successional species show greater leaf production and higher turnover rate than the open-grown late successional species. The latter, under forest situations, have still slower turnover rates but with leaves of several age groups. It is suggested that the early successional species are attuned to environments of temporary resource availability while the late successional species are adapted to the relatively predictable but highly competitive environments of closed forests.  相似文献   

Multiple primary digital apocrine sweat gland carcinosarcoma in a cat     

Herráez P  Rodríguez F  Ramírez G  Aguirre-Sanceledonio M  Castro A  Espinosa de Los Monteros A 《The Veterinary record》2005,157(12):356-358

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