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1.
《Soil Science and Plant Nutrition》2013,59(3):236-245
Abstract To clarify the degrading mechanisms of a newly synthesized herbicide, Beflubutamid ([RS]-N-benzyl-2-[4-fluoro-3-trifluoromethylphenoxy]butanamide; BFB), in soil, we started a series of studies. The results on the characteristics of degradation in soil, and on the isolation and identification of BFB-degrading microbes are summarized as follows. BFB was immediately degraded in non-sterilized soil, but degraded little in sterilized soil, indicating that soil microbes are involved in BFB degradation in soil. Results suggested that the application of sawdust and cattle manure (CM) increased the population and activities of microbes because the degrading activity was greater in CM-applied soil than in soil supplied with chemical fertilizer. According to the morphological characteristics and 18S rDNA sequences, the isolated strain MF1 was categorized as the class Ascomycota, belonging to the order Hypocleales, and closely related to Gibberella fujikuroi, Fusarium oxysporum f. sp. Vasinfeatum and Gibberella puricaris. The results suggested that BFB degrades fastest under acidic conditions because the growth of strain MF1 was at an optimum at pH 6.5 and was depressed at neutral and alkaline pHs. 相似文献
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Macías FA Galindo JC Castellano D Velasco RF 《Journal of agricultural and food chemistry》2000,48(11):5288-5296
A structure-activity study to evaluate the effect of 17 guaianolide sesquiterpene lactones (in a range of 100-0.001 microM) on the growth and germination of several mono- and dicotyledon target species is accomplished. Results are compared with those obtained in the same bioassay with an internal standard, the commercial herbicide Logran, to validate the results with a known active formulation and to compare the results with a commercial product to test their potential use as natural herbicide models. Specific conditions for the selective mono- or polyhydroxylation of guaianolides using the SeO(2)/tert-butyl hydroperoxide system are presented and discussed. The high regio- and stereoselectivities of the reaction are explained through the specific structural requirements of the bulky first adduct formed during the ene reaction. These compounds appear to have deeper effects on the growth of either monocots or dicots than the previously tested germacranolides. Otherwise, the lactone group seems to be necessary for the activity, though it does not necessarily need to be unsaturated. However, the presence of a second and easily accessible unsaturated carbonyl system greatly enhances the inhibitory activity. Lipophilicity and the stereochemistry of the possible anchoring sites are also crucial factors for the activity. Finally, the levels of growth inhibition obtained with some compounds on dicots or monocots are totally comparable to those of Logran and allow proposing them as lead compounds. 相似文献
4.
Macías FA Simonet AM Pacheco PC Barrero AF Cabrera E Jiménez-González D 《Journal of agricultural and food chemistry》2000,48(7):3003-3007
A collection of 11 natural and synthetic podolactones have been tested as allelochemicals in a range between 10(-4) and 10(-9) M, and their potential use as natural herbicide models is discussed. Their effects on the germination and growth of the dicots Lactuca sativa (cv. Nigra and cv. Roman), Lepidium sativum, and Lycopersicon esculentum and the monocots Allium cepa, Hordeum vulgare, and Triticum aestivum as standard target species have been studied. An important inhibitory effect on the germination and growth of all tested species (average = 90%) was produced by compounds 9-11 at 10(-4) M. The specific structural requirements related to their activities are studied. On the basis of these results, their use as potential natural herbicide models is proposed. 相似文献
5.
F. R. Zaidel’man 《Eurasian Soil Science》2009,42(1):82-92
The adverse human-induced changes in the water regime of soils leading to their degradation are considered. Factors of the
human activity related to the water industry, agriculture, and silviculture are shown to play the most active role in the
soil degradation. Among them are the large-scale hydraulic works on rivers, drainage and irrigation of soils, ameliorative
and agricultural impacts, road construction, and uncontrolled impacts of industry and silviculture on the environment. The
reasons for each case of soil degradation related to changes in the soil water regime are considered, and preventive measures
are proposed. The role of secondary soil degradation processes is shown. 相似文献
6.
Flumorph is an oomycete fungicide that is now used extensively in China. A residue analysis method for the determination of flumorph in environmental samples was developed with solid-phase extraction (SPE) for sample preparation and high-performance liquid chromatographic (HPLC) for separation. An environmental fate study was performed concerning the degradation of flumorph in soils, aqueous buffer solutions, and natural waters under laboratory-controlled conditions. The degradation of flumorph in three Chinese soil samples followed a first-order kinetics, with half-lives all longer than 100 days. No degradation of flumorph occurred in aqueous buffer solutions having different pH values or in natural waters with different physical and chemical properties. The data generated from this study could be helpful for risk assessment studies of the pesticide in the environment. 相似文献
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Camila O. Martinez Célia Maria M.S. Silva Elisabeth Francisconi Fay Aline de H. Nunes Maia Rosangela Blotta Abakerli Lucia R. Durrant 《Soil biology & biochemistry》2008,40(4):879-886
The herbicide sulfentrazone is classified as highly mobile and persistent and this study aimed to examine degradation of this compound on a Typic Hapludox soil that is representative of regions where sulfentrazone is used in Brazil. Soil samples were supplemented with sulfentrazone (0.7 μg active ingredient (a.i.) g?1 soil), and maintained at 27 °C. Soil moisture was corrected to 30%, 70%, or 100% water-holding capacity (WHC) and maintained constant until the end of the experimental period. Soils without added herbicide were used as controls. Aliquots were taken after 14, 30, 60, 120, 180, and 255 days of incubation for quantitative analysis of sulfentrazone residues by gas chromatography. Another experiment was conducted in soil samples, with and without the herbicide, at different temperatures (15, 30, and 40 °C), with moisture kept constant at 70% of WHC. The sulfentrazone residues were quantified by gas chromatography after 14, 30, 60, and 120 days of incubation. Sulfentrazone degradation was not affected by soil moisture. A significant effect was observed for the temperature factor after 120 days on herbicide degradation, which was higher at 30 °C. A half-life of 146.5 days was recorded. It was observed that the herbicide stimulated growth of actinomycetes, whereas bacterial and fungal growth was not affected. The microorganisms selected as potential sulfentrazone degraders were Rhizobium radiobacter, Ralstonia pickettii, Methylobacterium radiotolerans, Cladosporium sp., Eupenicillium sp., and Paecilomyces sp. 相似文献
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F A Macías J C Galindo D Castellano R F Velasco 《Journal of agricultural and food chemistry》1999,47(10):4407-4414
A structure-activity study to evaluate the effect of the trans, trans-germacranolide sesquiterpene lactones costunolide, parthenolide, and their 1,10-epoxy and 11,13-dihydro derivatives (in a range of 100-0.001 microM) on the growth and germination of several mono and dicotyledon target species is accomplished. Results are compared with those obtained in the same bioassay with an internal standard, the commercial herbicide Logran, to validate the results with a known active formulation and to compare the results with a commercial product to test their potential use as natural herbicide models. These compounds appear to have a more selective effects on the radicle growth of monocotyledons. Certain factors such as the presence of nucleophile-acceptor groups and their accessibility enhance the inhibitory activity. The levels of radicle inhibition obtained with some compounds on wheat are totally comparable to those of Logran and allow to propose them as lead compounds. 相似文献
10.
In laboratory experiments, the degradation of PCP in soil with regard to the relationship to soil properties was studied under upland and flooded conditions using gas-chromatographic techniques. The degradation products and their behavior were elucidated by using 10 diCferent soils collected from rice fields and adjacent upland fields and one sample of a subsoil from the forest. The results are as follows: 1) The degradation of PCP in soils was faster under flooded conditions than upland conditions. 2) The degradation under flooded conditiont was more rapid in soils collected from rice fields than in those from adjacent upland fields, Tbe reverse was true under upland conditions. 3) The degradation rate was highly correlated with the organic matter content of the soil. Almost 100% of the PCP remained in the subsoil sample even after 50 days of incubation. The rate was slightly correlated with the clay mineral composition, free iron content, phosphate absorption coefficient and C.E.C., but hardly at all with texture, clay content, degree of base saturation, soil pH and available phosphorus content. 4) As the degradation products of PCP, 3 tetrachlorophenols, 4 or 5 trichlorophenols and PCP methyl ether were detected, PCP methyl elher and 2, 3, 4, 5-tetrachlorophenol were the major products, but the amount of the latter varied greatly during the course of incubation. 相似文献
11.
Yanfang Hao Yang Yang Baoyuan Liu Yingna Liu Xiaofei Gao Qiankun Guo 《Journal of Soils and Sediments》2016,16(8):2153-2165
Purpose
The particle-size distribution of runoff sediment is important in understanding, characterizing and modeling the transport behavior of sediment and sediment-associated chemicals. The objective of this study was to investigate the particle-size distribution of sediments eroded from three soils in China under natural rainfall.Materials and methods
Each of the three soils was packed to a depth of 30 cm in a 20?×?2.1 m runoff plot. Sediments yielded in nine natural rainfall events were analyzed for their particle-size distribution prior to and following dispersion.Results and discussion
The sediment size measured in the undispersed condition was always larger than the one determined after chemical dispersion, indicating that part of the sediment was eroded in aggregated form. The degree of sediment aggregation depended on the clay content and the organic matter content of the sources. The mean sediment size quantified by mean weight diameter linearly increased with sediment yield for the two soils with relatively high clay content. The rate of increase was greater in the undispersed condition than that in the dispersed condition for these two soils. Comparing sediments to the corresponding source soil, the results of mean weight diameter and enrichment ratio both revealed that aggregate-size distribution was more sensitive to soil erosion than the primary particle-size distribution. Small aggregates, rather than the primary particles, were selectively eroded in the rainfall events.Conclusions
These findings support the use of both dispersed and undispersed sediment-size distributions for the characterization of sediment transport and the associated sediment-bound nutrients and contaminants.12.
Experiments in nutrient solution and in sterilized soil show that the sequential transformation of N-(3,4-dichlorophenyl)-propionamide (propanil) to 3,3',4,4'-tetrachloroazobenzene and other complex residues is brought about by the synergistic interaction of two common soil fungi, Penicillium piscarium and Geotrichum candidum. The interaction benefits both organisms as the end products of the transformation sequence allow higher growth yields than either the parent herbicide or its primary cleavage product. The synergism of the two fungi prevails only in the herbicide-induced stress situation. 相似文献
13.
Thomas B. Moorman Jennifer K. Cowan Ellen L. Arthur Joel R. Coats 《Biology and Fertility of Soils》2001,33(6):541-545
Pesticide contamination of soil and groundwater at agricultural chemical distribution sites is a widespread problem in the USA. Alternatives to land-farming or solid waste disposal include biostimulation and phytoremediation. This research investigated the ability of compost, corn stalks, corn fermentation byproduct, peat, manure, and sawdust at rates of 0.5% and 5% (w/w) to stimulate biodegradation of atrazine [6-chloro-N-ethyl-N'-(1-methyethyl)-1,3,5-triazine-2,4-diamine], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], and trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] added as a mixture to soil. Initial concentrations were 175ᆾ mg atrazine kg-1 soil, 182ᆭ mg metolachlor kg-1 soil, and 165ᆫ mg trifluralin kg-1 soil. After amendment addition, 30% of the atrazine, 33% of the metolachlor, and 44% of the trifluralin was degraded over 245 days, which included 63 days' aging prior to amendment additions. Atrazine degradation was enhanced by 0.5% manure, 5% peat, and 5% cornstalk amendments compared to nonamended soils. Metolachlor degradation was enhanced by all amendments at the 5% level, except for compost and peat. Amendments had no effect on trifluralin degradation. The 5% addition of compost, manure, and cornstalks resulted in significant increases in bacterial populations and dehydrogenase activity. A second experiment compared the persistence of atrazine, metolachlor, and trifluralin applied in a mixture to their persistence in soil individually. A combined average of 123 mg atrazine kg-1 remained in soil treated with the three-herbicide mixture compared to 31 mg atrazine kg-1 remaining in soil treated with atrazine only. Atrazine mineralization and atrazine-degrading microorganisms were suppressed by high concentrations of metolachlor, but not by trifluralin. 相似文献
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The gas chromatographic determination of CNP (2,4,6-trichlorophenyl 4-nitrophenyl ether), nitrofen (2,4-dichlorophenyl 4′-nitrophenyI ether), chlomethoxynil (2,4-dieblorophenyl 3′-methoxy-4′-nitrophenyl ether), CFNP (2,4-dichloro-6-fluorophenyl 4-nitrophenyl ether) and their amino derivatives in soils were carried out. Good recoveries from soils were obtained for the diphenyl ethers. On the other hand, satisfactory recoveries from soils were also obtained for the amino derivatives at high concentrations, but the recoveries at lower concentrations averaged about 66% for the least recovered compound. The degradation of several diphenyl ether herbicides in two paddy soils were compared under flooded and upland conditions. The degradation was much slower under upland than under flooded conditions. Considerable amounts of their amino derivatives were produced in soils under flooded conditions, but not under upland conditions. It was suggested that the diphenyl ethers to the amino derivatives involved both chemical and microbial processes. CNP and chlomethoxynil degraded faster at lower concentrations than at higher ones. 相似文献
16.
Degradation of parathion in flooded acid soils 总被引:8,自引:0,他引:8
N Sethunathan 《Journal of agricultural and food chemistry》1973,21(4):602-604
17.
Allan E. Smith 《Soil biology & biochemistry》1974,6(3):201-202
The persistence of 14C-trichloroacetic acid in three Saskatchewan soils was investigated at different moisture regimes under laboratory conditions at 25 ± 1°C. Following soil extraction with 0.1 m calcium chloride soln, radiochemical analytical procedures were used to monitor the breakdown. At rates equivalent to 4.4 kg/ha, degradation was most rapid in a high organic soil, with complete breakdown occurring within 3 weeks at moisture levels in excess of the wilting point. On a sandy loam and on a heavy clay breakdown was somewhat slower. 相似文献
18.
Mobility, extractability, and disappearance of the herbicides diuron, terbuthylazine, metolachlor, and pendimethalin were examined in incubation experiments with two topsoil samples of different natural microbial activity and after sterilization. Soil moisture was held constant at 10, 40, and 60 % WHC. In other variants, the soil water content was changed during the incubation. The four herbicides reveal a fairly different extent of microbial and chemical degradation and immobilization. The herbicide mobility – expressed by coefficients of partition between adsorbed and dissolved herbicide amounts – decreases at a lower rate and extent, when the microbial activity is low or the soil is sterile. With increasing initial soil moisture, also herbicide mobility and extractability increase; but in the course of time, abiotic immobilization occurs to a higher extent. When soil moisture changes during the incubation, formerly non‐extractable herbicide fractions (up to 40 % of the applied amounts) become extractable. Kinetics of herbicide immobilization follow an empirical sigmoidal function, which describes three periods of immobilization. The three‐period shape of the curve and its possible reasons are discussed for the data of the incubation experiments as well as for the results of a long‐term field trial with diuron. 相似文献
19.
Accumulation of excess sodium (Na+) in a soil causes numerous adverse phenomena, such as changes in exchangeable and soil solution ions and soil pH, destabilization of soil structure, deterioration of soil hydraulic properties, and increased susceptibility to crusting, runoff, erosion and aeration, and osmotic and specific ion effects on plants. In addition, serious imbalances in plant nutrition usually occur in sodic soils, which may range from deficiencies of several nutrients to high levels of Na+. The structural changes and nutrient constraints in such soils ultimately affect crop growth and yield. The principal factor that determines the extent of adverse effects of Na+ on soil properties is the accompanying electrolyte concentration in the soil solution, with low concentration promoting the deleterious effects of exchangeable Na+ even at exchangeable sodium percentage (ESP) levels less than 5. Consequent to an increase in the use of poor quality waters and soils for crop production, the problems of sodic soils can be expected to increase in future. The mechanisms that explain sodic behaviour can provide a framework in which slaking, swelling and dispersion of clay together with nutrient constraints in sodic soils may be assessed so that the practices to manage such soils can be refined for long‐term sustainable agriculture. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献