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At least 19 recordsLinked to original sources
PubMed2003

Effects of selenium supplementation on four agricultural crops.

Agricultural crops can be used either to remediate selenium-contaminated soils or to increase the daily selenium intake of consumers after soil supplementation using inorganic or organic selenium sources. In this study, four agricultural crops were examined for potential selenium enhancement. Soils containing tomato, strawberry, radish, and lettuce plants were supplemented with either an inorganic or an organic form of selenium. Two different soils, i.e., low Se and high Se containing, were also used. Statistically significant differences in appearance, fruit production, and fresh weights of the fruit produced were studied. Next, the amount of selenium retained in the edible fruits, nonedible plant, and soil for each was analyzed by acid digestion followed by hydride generation atomic absorption analysis. Finally, inhibition effects on the seeds of the agricultural plants were studied. The results show that supplementation with an inorganic form of selenium led to higher retention in the plants, with a maximum of 97.5% retained in the edible portion of lettuce plants.

Agriculture↗
PubMed2005

Effect of dislodging techniques on foliar residue determination for agricultural crops.

The Agricultural Reentry Task Force (ARTF) conducted a study to determine whether different dislodgeable foliar residue (DFR) techniques had any effect on the amount of residues dislodged from the leaves of vegetable crops. Four previously employed techniques were evaluated with two chemicals (carbaryl and methomyl) on two crops (cabbage and lettuce). Carbaryl, a moderately water-soluble chemical, was applied at a rate of 2.0 lbs active ingredient/acre (lb ai/A) while methomyl, a highly water soluble chemical, was applied at a rate of 0.9 lb ai/A. One day after application, leaf punches were collected and the residues were dislodged following one of four techniques that differed in the number of dislodgings per sample, the duration of dislodging, the solution volume, and/or the type of solution used. The results indicated that three of the techniques gave similar results, whereas a fourth gave marginally lower results.

Carbaryl↗
PubMed2003

Genetic consequences of radioactive contamination by the Chernobyl fallout to agricultural crops.

The genetic consequences of radioactive contamination by the fallout to agricultural crops after the accident at the Chernobyl NPP in 1986 have been studied. In the first, acute, period of this accident, when the absorbed dose was primarily due to external beta- and gamma-irradiation, the radiation injury of agricultural crops, according to the basic cytogenetic tests, resembled the effect produced by acute gamma-irradiation at comparable doses. The yield of cytogenetic damage in leaf meristem of plants grown in the 10-km zone of the ChNPP in 1987-1989 (the period of chronic, lower level radiation exposure) was shown to be enhanced and dependent on the level of radioactive contamination. The rate of decline with time in cytogenetic damage induced by chronic exposure lagged considerably behind that of the radiation exposure. Analysis of genetic variability in three sequential generations of rye and wheat revealed increased cytogenetic damage in plants exposed to chronic irradiation during the 2nd and 3rd years.

Avena↗
PubMed2005

Isolation and characterization of diazotrophic growth promoting bacteria from rhizosphere of agricultural crops of Korea.

Free-living nitrogen fixing bacteria were isolated from rhizosphere of seven different plant namely sesame, maize, wheat, soybean, lettuce, pepper and rice grown in Chungbuk Province, Korea. Five isolates with nitrogenase activity above 150nmol(-1) mg(-1) protein were identified based on, phenotypic and 16S rDNA sequences analysis. The strains were identified as Stenotrophomonas maltophilia (PM-1, PM-26), Bacillus fusiformis (PM-5, PM-24) and Pseudomonas fluorescens (PM-13), respectively. All the isolates produced indole-3-acetic acid (IAA), in the presence of tryptophan, ranging from 100.4 microg ml(-1) (PM-13) to 255 microg ml(-1) (PM-24). The isolate PM-24 (Bacillus fusiformis) exhibiting highest nitrogenase activity (3677.81 nmol h(-1) mg(-1) protein) and IAA production (255microg ml(-1)) has a promising potential for developing as a plant growth promoting rhizobacteria.

Acetylene↗
PubMed1999

Concentrations of 50 major and trace elements in Danish agricultural crops measured by inductively coupled plasma mass spectrometry. 3. Potato (Solanum tuberosum folva).

The multi-element (Ag, Al, Au, Ba, Bi, Ca, Cd, Co, Cr, Cs, Cu, Dy, Er, Fe, Ga, Gd, Ho, In, Ir, La, Lu, Mn, Mo, Nb, Nd, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, Sb, Sc, Sm, Sn, Sr, Ta, Tb, Th, Ti, Tl, Tm, U, V, Y, Yb, and Zn) concentrations (microg/kg, fresh weight) in potatoes (Solanum tuberosum, Folva) were investigated in this study. The potatoes were grown in two fertilization practices; one with pig slurry and one with calcium ammonium nitrate at three levels of N fertilization (0, 60, and 120 kg of N/ha). The experiment field was located at the Riso National Laboratory Agronomy Farms in Roskilde, Denmark. High-resolution-inductively coupled plasma mass spectrometry (HR-ICPMS) was used for analyses of the samples. The effect of three levels of N fertilization on elemental concentrations of the crop are evaluated by use of discriminant partial least-squares regression (PLS). The results provide useful biological and nutritional information on potatoes.

Crops, Agricultural↗
PubMedDate not supplied

Poultry litter ash as a potential phosphorus source for agricultural crops.

Maryland will impose restrictions on poultry litter application to soils with excessive P by the year 2005. Alternative uses for poultry litter are being considered, including burning as a fuel to generate electricity. The resulting ash contains high levels of total P, but the availability for crop uptake has not been reported. Our objective was to compare the effectiveness of poultry litter ash (PLA) and potassium phosphate (KP) as a P source for wheat (Triticum aestivum L.) in acidic soils, without and with limestone application. Two acidic soils (pH 4.25 and 4.48) were studied, unlimed or limed to pH 6.5 before cropping. The PLA and KP were applied at 0, 39, and 78 kg P ha(-1), after which wheat was grown. Limestone significantly increased wheat yield, but the P sources without limestone did not. The two P sources were not significantly different as P fertilizer. At the 78 kg P ha(-1) rate, wheat shoot-P concentrations were 1.10 and 1.12 g kg(-1) for the PLA treatment compared with 0.90 and 0.89 g kg(-1) for KP in the nonlimed and limed soils, respectively. Trace element concentrations in wheat shoots from the PLA treatment were less than or equal to KP and the control. The low levels of water-soluble P and metals in the soils and the low metal concentrations in wheat suggest that PLA is an effective P fertilizer. Further studies are needed to determine the optimum application rate of PLA as a P fertilizer.

Animals↗
PubMedDate not supplied

[Mathematical modeling of the effects of chemical pollutants on the quality of agricultural crops].

Detergents, lead, and nitrogen fertilizers were tested for their effects on the level of sugar in the beets and that of starch in the potatoes. Models were developed for estimating the quality of potatoes and beets grown under irrigation and soil nitrogen fertilization. Lead made the greatest contribution to the lowering sugar in the beets and starch in the potatoes.

Carbohydrates↗
PubMedDate not supplied

[An analysis of the cytogenetic sequelae of chronic low-dose irradiation in plantings of agricultural crops].

There is a tendency for a decrease in the yield of cytogenetic disturbances with time elapsed from the Chernobyl accident. But an increased rate of cytogenetical damages significantly dependent on the level of radioactive contamination was observed even in several years after the incident. The rate of decline with time in cytogenetic disturbances induced by chronic exposure considerably lagged behind that of radiation exposure. Analysis of genetic changeability in three sequential generations of winter rye and wheat revealed increased cytogenetic damage in crops grown on contaminated sites during 2 and 3 years.

Chromosome Aberrations↗
PubMedDate not supplied

Permethrin and its two metabolite residues in seven agricultural crops.

Metabolite residues of permethrin are not reported in the literature for most agricultural crops. This paper reports residues of permethrin and its 2 metabolites (dichlorovinyl acid and metaphenoxybenzyl alcohol) in 7 different agricultural crops (Chinese cabbage, spinach, asparagus, raspberries, green peas, turnip roots, and turnip greens). Permethrin residues declined approximately 85% within 7 days after treatment in all crops. In most cases, the acid metabolite residues peaked at 3 days, and declined after that. Translocation of residues into turnip roots was very slight; the average was less than 0.05 ppm for permethrin and alcohol metabolite residues and none was detected for the acid metabolite residue. Permethrin residues in the turnip greens averaged approximately 2 ppm for the 0.112 kg ai/ha treatment, and 6 ppm for the 0.224 kg ai/ha treatment.

Food Contamination↗
PubMedDate not supplied

[The growth-promoting effect of Beijerinckia and Clostridium sp. cultures on some agricultural crops].

New strains of Beijerinckia mobilis and Clostridium sp. isolated from the pea rhizosphere were studied with respect to their promoting effect on the growth and development of some agricultural crops. Seed soaking in bacterial suspensions followed by the soil application of the suspensions or their application by means of foliar spraying was found to be the most efficient method of bacterization. The application of B. mobilis and Clostridium sp. cultures in combination with mineral fertilizers increased the crop production by 1.5-2.5 times. The study of the population dynamics of B. mobilis by the method of genetic marking showed that this bacterium quickly colonized the rhizoplane of plants and, therefore, had characteristics of an r-strategist. At the same time, Clostridium sp. was closer to K-strategists, since this bacterium slowly colonized the econiches studied. The introduction of the bacteria into soil did not affect the indigenous soil bacterial complex. The presence of Clostridium sp. slowed down the colonization of roots by the fungal mycelium. The possible mechanisms of the plant growth-promoting activity of B. mobilis and Clostridium sp. are discussed.

Azotobacter↗
PubMed2005

Phytoremediation of soil polluted by nickel using agricultural crops.

Soil pollution due to heavy metals is widespread; on the world scale, it involves about 235 million hectares. The objectives of this research were to establish the uptake efficiency of nickel by some agricultural crops. In addition, we wanted to establish also in which part of plants the metal is stored for an eventual use of biomass or for recycling the metal. The experiments included seven herbaceous crops such as: barley (Hordeum vulgaris), cabbage (Brassica juncea), spinach (Spinacea oleracea), sorghum (Sorgum vulgare), bean (Phaseolus vulgaris), tomato (Solanum lycopersicum), and ricinus (Ricinus communis). We used three levels of treatment (150, 300, and 600 ppm) and one control. At the end of the biological cycle of the crops, the different parts of plants, i.e., roots, stems, leaves, fruits, or seeds, were separately collected, oven dried, weighed, milled, and separately analysed. The leaves and stems of spinach showed a very good nickel storage capacity. The ricinus too proved to be a very good nickel storer. The ability of spinach and ricinus to store nickel was observed also in the leaves of cabbage, even if with a lower storage capacity. The bean, barley, and tomato, in decreasing order of uptake and storage capacity, showed a high concentration of nickel in leaves and stems, whereas the sorghum evidenced a lesser capacity to uptake and store nickel in leaves and stems. The bean was the most efficient in storing nickel in fruits or grains. Tomato, sorghum, and barley have shown a storage capacity notably less than bean. The bean appeared to be the most efficient in accumulating nickel in the roots, followed in decreasing order by sorghum, ricinus, and tomato. With regard to the removal of nickel, spinach was the most efficient as it contains the highest level of this metal per gram of dry matter. The ricinus, cabbage, bean, sorghum, barley, and tomato evidenced a progressively decreasing efficiency in the removal of nickel.

Biodegradation, Environmental↗
PubMed2002

[Responses of agricultural crops of free-air CO2 enrichment].

Over the past decade, free-air CO2 enrichment (FACE) experiments have been conducted on several agricultural crops: wheat(Triticum aestivum L.), perennial ryegrass (Lolium perenne), and rice(Oryza sativa L.) which are C3 grasses; sorghum (Sorghum bicolor (L.) Möench), a C4 grass; white clover (Trifolium repens), a C3 legume; potato (Solanum tuberosum L.), a C3 forb with tuber storage; and cotton (Gossypium hirsutum L.) and grape (Vitis vinifera L.) which are C3 woody perennials. Using reports from these experiments, the relative responses of these crops was discussed with regard to photosynthesis, stomatal conductance, canopy temperature, water use, water potential, leaf area index, shoot and root biomass accumulation, agricultural yield, radiation use efficiency, specific leaf area, tissue nitrogen concentration, nitrogen yield, carbohydrate concentration, phenology, soil microbiology, soil respiration, trace gas emissions, and soil carbon sequestration. Generally, the magnitude of these responses varied with the functional type of plant and with the soil nitrogen and water status. As expected, the elevated CO2 increased photosynthesis and biomass production and yield substantially in C3 species, but little in C4, and it decreased stomatal conductance and transpiration in both C3 and C4 species and greatly improved water-use efficiency in all the crops. Growth stimulations were as large or larger under water-stress compared to well-watered conditions. Growth stimulations of non-legumes were reduced at low soil nitrogen, whereas elevated CO2 strongly stimulated the growth of the clover legume both at ample and under low N conditions. Roots were generally stimulated more than shoots. Woody perennials had larger growth responses to elevated CO2, while at the same time, their reductions in stomatal conductance were smaller. Tissue nitrogen concentrations went down while carbohydrate and some other carbon-based compounds went up due to elevated CO2, with leaves and foliage affected more than other organs. Phenology was accelerated slightly in most but not all species. Elevated CO2 affected some soil microbes greatly but not others, yet overall activity appears to be stimulated. Detection of statistically significant changes in soil organic carbon in any one study was impossible, yet combining results from several sites and years, it appears that elevated CO2 did increase sequestration of soil carbon. Whenever possible, comparisons were made between the FACE results and those from prior chamber-based experiments reviewed in the literature. Over all the data and parameters considered in this review, there are only two parameters for which the FACE- and chamber-based data appear to be inconsistent. One is that elevated CO2 from FACE appears to reduce stomatal conductance about one and a half times more than observed in prior chamber experiments. Similarly, elevated CO2 appears to have stimulated root growth relatively more than shoot growth under FACE conditions compared to chamber conditions. Nevertheless, for the most part, the FACE- and chamber-based results have been consistent, which gives confidence that conclusions drawn from both types of data are accurate. However, the more realistic FACE environment and the larger plot size have enabled more extensive robust multidisciplinary data sets to be obtained under conditions representative of open fields in the future high-CO2 world.

Air↗
PubMed1976

Gas-liquid chromatographic determination of chloramphenicol in agricultural crops.

A method is presented for the gas-liquid chromatographic determination of chloramphenicol in agricultural crops. Chloramphenicol is extracted with ethyl acetate, cleaned up by silicic acid column chromatography, acetylated with acetic anhydride and pyridine, and then measured by gas-liquid chromatography with electron capture detection. Two stationary phases, DEGS + phosphoric acid and Reoplex 400, were used. The sensitivity was ca 8 ng (40% full scale deflection). The efficicency of the analytical method was evaluated by analyzing crops fortified with chloramphenicol. The average recovery ranged from 72% in unpolished rice to 86% in Chinese radishes.

Acetylation↗
PubMed1990

Micro-organisms as fertilizers and pest control agents in agricultural crops.

Micro-organisms can potentially supplement or replace the use of chemical fertilizers and pesticides in many agricultural cropping systems. Their increased use may reduce the need for nitrogen and phosphorus fertilizers, particularly in legume and cereal crops, and provide a more ecologically sound method of controlling pests and phytopathogens. Recombinant DNA technology offers the potential to extend and improve these applications. However, genetically modified micro-organisms may occasionally themselves pose environmental risks. Model ecosystems such as intact soil-core microcosms may be useful for both testing efficacy and evaluating environmental risk prior to proceeding with field trials.

Bacteria↗
PubMed1982

Determination of background levels of lead and cadmium in raw agricultural crops by using differential pulse anodic stripping voltammetry.

A method is described for the simultaneous determination of ultratrace levels of lead and cadmium in selected agricultural crop samples by differential pulse anodic stripping voltammetry. Samples are dry ashed at high temperature with H2SO4 as an ashing aid. Techniques are described to control the lead and cadmium blank levels of 2 ng and 0.4 ng, respectively. Typical relative standard deviations for the crop analyses are 13% at 100 ng/g and 25% at 10 ng/g for lead, and 5% at 100 ng/g and 10% at 10 ng/g for cadmium. The lowest quantifiable level, based on 3 g dry sample, is 2 ng/g for lead and 1 ng/g for cadmium. Recovery studies, precision studies, and analyses of NBS Standard Reference Materials demonstrate the accuracy and reproducibility of this technique. A summary of results for over 1700 crop samples is reported.

Cadmium↗