Imazaquin Persistence and Mobility in Three Arkansas Soils

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 576-582 ◽  
Author(s):  
Gary Basham ◽  
Terry L. Lavy ◽  
Lawrence R. Oliver ◽  
H. Don Scott
Keyword(s):  
Soil Profile ◽  
Growing Season ◽  
Furrow Irrigation ◽  
Field Conditions ◽  
Silty Clay ◽  
Silt Loam ◽  
Soil Adsorption ◽  
Quinolinecarboxylic Acid

Field persistence of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} applied preemergence as high as 16 times the 0.14 kg ai/ha recommended rate was studied at two locations in Arkansas in 1984 and 1985. Rapid dissipation of these high rates occurred on the Taloka silt loam under hot, dry field conditions in 1984 when no rainfall occurred for 2 weeks after application. In 1985, when furrow irrigation was applied 7 days after application, imazaquin phytotoxicity was greater and dissipation was delayed. Imazaquin persistence and soil adsorption were greater on Sharkey silty clay than on Taloka silt loam. Following 3- and 8-cm irrigation, 84 and 78%, respectively, of the14C-labeled imazaquin remained in the surface 5 cm, but in plots covered between rainfalls and receiving 8 cm rain, 74% leached out of this top layer. Since nonincorporated imazaquin dissipated rapidly under hot, dry field conditions, carryover into the next growing season or leaching below the plow layer would not be expected. However, in cool, wet conditions immediately after application, the weakly adsorbed imazaquin molecule was readily bioavailable and mobile in the soil profile.

Norflurazon adsorption and dissipation in three southern soils

Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 301-306 ◽  
Author(s):  
William T. Willian ◽  
Thomas C. Mueller ◽  
Robert M. Hayes ◽  
David C. Bridges ◽  
Charles E. Snipes
Keyword(s):  
Organic Matter ◽  
Soil Profile ◽  
Surface Soil ◽  
Field Conditions ◽  
Loamy Sand ◽  
Soil Horizon ◽  
Silt Loam ◽  
Laboratory Conditions ◽  
Soil Zone ◽  
Field And Laboratory Conditions

Norflurazon adsorption and dissipation under field and laboratory conditions, and distribution within the soil profile were determined in three soils representative of cotton-growing regions of the southeastern U.S. Norflurazon adsorption was greater in soil from 0 to 8 cm in a Lexington silt loam (Tennessee) and a Beulah silt loam (Mississippi) than in a Dothan loamy sand (Georgia). Adsorption was directly related to organic matter. Norflurazon degradation under controlled conditions in soil from 0 to 8 cm from each state was not different among locations, with half-lives ranging from 63 to 167 d. Degradation at 30 C in soil from the 30- to 45- and 60- to 90-cm depths was not different among locations, and was slower at the 60- to 90-cm depth than in surface soil. Norflurazon dissipation was more rapid under field conditions than under laboratory conditions, with half-lives ranging from 7 to 79 d in the 0- to 8-cm soil horizon. Dry field conditions slowed norflurazon dissipation. Norflurazon was not detected below 15 cm in the profile in any soil, and concentrations in the 8- to 15-cm soil zone were < 36 ppbw 112 d after treatment.

Influence of Rate, Method of Application, and Tillage on Imazaquin Persistence in Soil

Weed Science ◽  
1988 ◽  
Vol 36 (1) ◽  
pp. 90-95 ◽  
Author(s):  
K. A. Renner ◽  
W. F. Meggitt ◽  
R. A. Leavitt
Keyword(s):  
Zea Mays ◽  
Soil Profile ◽  
Dissipation Rate ◽  
Statistical Difference ◽  
Growing Season ◽  
Growth Reduction ◽  
Subsequent Decrease ◽  
Rate Method ◽  
Significant Injury ◽  
Quinolinecarboxylic Acid

Preplant-incorporated (PPI) applications of 280 g ai/ha of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} had significantly greater persistence than preemergence surface (PES) applications throughout the growing season in 1985. In 1984 there was no statistical difference in imazaquin remaining between PPI and PES treatments. Very little imazaquin was detected below 10 cm in the soil profile for all sampling dates each year. Imazaquin dissipated rapidly both years during the first 30 days following PPI and PES applications. A subsequent decrease in the dissipation rate occurred in the next 120 days of the growing season. Spring tillage had no significant effect on injury to corn (Zea maysL.) planted into the field the year following imazaquin application. Corn planted in 1986 into imazaquin-treated plots of 1985 had no growth reduction when compared to corn grown in plots where zero imazaquin had been applied. However, corn planted in 1985 into imazaquin applications of 1984 had significant injury. Greatest injury occurred where imazaquin had been incorporated, and injury increased as imazaquin rate was increased.

Effect of Soil and Climate on Herbicide Dissipation

Weed Science ◽  
1969 ◽  
Vol 17 (2) ◽  
pp. 241-245 ◽  
Author(s):  
O. C. Burnside ◽  
C. R. Fenster ◽  
G. A. Wicks ◽  
J. V. Drew
Keyword(s):  
Soil Texture ◽  
Soil Profile ◽  
Sandy Loam ◽  
Silty Clay ◽  
Silt Loam ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Fine Sandy Loam ◽  
Herbicide Residues ◽  
Herbicide Residue

The persistence of five herbicides in six soils across Nebraska can be ranked from greatest to least as follows: 5-bromo-3-isopropyl-6-methyluracil (isocil) at 5 and 25 1b/A, 2-chloro-4,6-bis-(isopropylamino)-s-triazine (propazine) at 3 and 9 1b/A, 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) at 3 and 9 1b/A, trichlorobenzyl chloride (hereinafter referred to as TCBC) at 7 and 49 1b/A, and 3-(3,4-dichlorophenyl)-1-methoxyl-1-methylurea (linuron) at 3 and 9 1b/A. Soil texture differences (sandy loam, very fine sandy loam, silt loam, and silty clay loam) had a greater influence on herbicide residue carryover than did climatic differences across Nebraska during 1962 to 1968. Soil carryover of herbicide residues was greater in coarse rather than fine-textured soils and in the drier regions of western than in eastern Nebraska. Leaching of herbicides into the soil profile was an avenue of herbicide dissipation.

Microbial and Photolytic Dissipation of Imazaquin in Soil

Weed Science ◽  
1987 ◽  
Vol 35 (6) ◽  
pp. 865-870 ◽  
Author(s):  
G. W. Basham ◽  
T. L. Lavy
Keyword(s):  
Organic Matter ◽  
Microbial Growth ◽  
Organic Matter Content ◽  
Soil Surface ◽  
Matter Content ◽  
Silty Clay ◽  
Silt Loam ◽  
Rapid Loss ◽  
Major Mode ◽  
Quinolinecarboxylic Acid

Microbial degradation of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} was monitored by measuring14CO2evolution for 7 months under controlled laboratory conditions. Up to 10% of the14C chain-labeled imazaquin that was applied to a Crowley silt loam was evolved as14CO2in 7 months. Less evolution of14CO2occurred on a Sharkey silty clay, a soil with higher clay and organic matter content, than on silt loam soils. The loss of 66 to 100% of the imazaquin applied to a Crowley silt loam incubated for 8 months at 18 C or 35 C, respectively, suggested that metabolic changes in addition to CO2evolution were occurring. Rapid loss of imazaquin phytotoxicity occurred when soils were held at warm-moist (35 C and −33 kPa) conditions conducive to microbial growth. Imazaquin was more persistent in soils stored under cool, dry (18 C and −100 kPa) conditions. Imazaquin on a soil surface dissipated rapidly when exposed to ultraviolet light or sunlight. Photodecomposition could be a major mode of imazaquin dissipation if this herbicide is allowed to remain on the soil surface.

scholarly journals Escherichia coli Contamination of Vegetables Grown in Soils Fertilized with Noncomposted Bovine Manure: Garden-Scale Studies

2004 ◽  
Vol 70 (11) ◽  
pp. 6420-6427 ◽  
Author(s):  
Steven C. Ingham ◽  
Jill A. Losinski ◽  
Matthew P. Andrews ◽  
Jane E. Breuer ◽  
Jeffry R. Breuer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tap Water ◽  
Silty Clay ◽  
Silt Loam ◽  
Silty Clay Loam ◽  
Manure Application ◽  
E Coli ◽  
Fertilized Soil ◽  
Low Levels ◽  
National Organic Program

ABSTRACT In this study we tested the validity of the National Organic Program (NOP) requirement for a ≥120-day interval between application of noncomposted manure and harvesting of vegetables grown in manure-fertilized soil. Noncomposted bovine manure was applied to 9.3-m2 plots at three Wisconsin sites (loamy sand, silt loam, and silty clay loam) prior to spring and summer planting of carrots, radishes, and lettuce. Soil and washed (30 s under running tap water) vegetables were analyzed for indigenous Escherichia coli. Within 90 days, the level of E. coli in manure-fertilized soil generally decreased by about 3 log CFU/g from initial levels of 4.2 to 4.4 log CFU/g. Low levels of E. coli generally persisted in manure-fertilized soil for more than 100 days and were detected in enriched soil from all three sites 132 to 168 days after manure application. For carrots and lettuce, at least one enrichment-negative sample was obtained ≤100 days after manure application for 63 and 88% of the treatments, respectively. The current ≥120-day limit provided an even greater likelihood of not detecting E. coli on carrots (≥1 enrichment-negative result for 100% of the treatments). The rapid maturation of radishes prevented conclusive evaluation of a 100- or 120-day application-to-harvest interval. The absolute absence of E. coli from vegetables harvested from manure-fertilized Wisconsin soils may not be ensured solely by adherence to the NOP ≥120-day limit. Unless pathogens are far better at colonizing vegetables than indigenous E. coli strains are, it appears that the risk of contamination for vegetables grown in Wisconsin soils would be elevated only slightly by reducing the NOP requirement to ≥100 days.

Runoff losses of cyanazine and metolachlor: effects of soil type and precipitation timing

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 800-806 ◽  
Author(s):  
David R. Shaw ◽  
Stephen M. Schraer ◽  
Joby M. Prince ◽  
Michele Boyette ◽  
William L. Kingery
Keyword(s):  
Soil Type ◽  
Water Runoff ◽  
Soil Drying ◽  
Silty Clay ◽  
Silt Loam ◽  
Regression Analyses ◽  
Precipitation Timing ◽  
Runoff Losses

The effects of time of precipitation and soil type on runoff losses of cyanazine and metolachlor were studied using a tilted-bed, microplot system. Two silt loam soils, Bosket and Dubbs, and a Sharkey silty clay were evaluated. Rainfall (22 mm h−1) was simulated at 0, 2, and 14 days after treatment (DAT). Time of precipitation did not impact herbicide losses or any of the runoff parameters evaluated in this study. Water runoff occurred sooner and in greater quantities from the surfaces of Bosket and Dubbs silt loam soils than from the surface of Sharkey silty clay. Runoff losses of cyanazine did not vary by soil type. Soil drying produced large cracks in Sharkey silty clay, which greatly reduced runoff in this soil. Combined runoff and leachate losses were highest from Dubbs silt loam. Runoff losses of metolachlor were not affected by soil type. However, regression analyses indicated that time of precipitation and soil type interacted to affect initial metolachlor concentration. At 14 DAT, initial metolachlor concentration was highest in runoff from Sharkey soil. Time of precipitation ranked with respect to initial metolachlor concentration in runoff from Bosket and Dubbs silt loam soils were 0 > 2 > 14 DAT and 0 = 2 > 14 DAT, respectively.

Resistance to water uptake by Douglas-fir seedlings in soils of different texture

1980 ◽  
Vol 10 (4) ◽  
pp. 530-534 ◽  
Author(s):  
M.G. Dosskey ◽  
T. M. Ballard
Keyword(s):  
Water Uptake ◽  
Soil Water Potential ◽  
Large Contribution ◽  
Silty Clay ◽  
Silt Loam ◽  
Unsaturated Hydraulic Conductivity ◽  
Root Shrinkage ◽  
Upper Limits ◽  
Mycorrhizal Development ◽  
Relationship Of

Seedlings of Pseudotsugamenziesii (Mirb.) Franco were grown in fertilized silty clay, silt loam, and loamy sand in a growth chamber. Needle water potentials hardly changed as soil water potential, ψs, dropped to about −2.5 MPa. At ψs = −0.6 MPa, the effect of soil texture on water uptake rate was statistically significant (p = 0.01). Calculated water uptake resistance (from soil to foliage), R, was hardly affected by ψs between −0.5 and −1.0 MPa, but nearly doubled as ψs fell from −1.0 to −2.2 MPa. Plant water resistance is inferred to change relatively little over this range. Upper limits of soil resistance at ψs > −2.5 MPa, estimated (by Gardner's equation) for silt loam and silty clay, are too low to make a large contribution to R, or to the change in R with ψs, or to the large differences in average R among different textures at ψs values from −0.5 to −2.2 MPa. It is inferred that contact resistance, Rc, is large, varies significantly with ψs, and may vary with texture. Unsaturated hydraulic conductivity differences theoretically account for a relationship of Rc, with texture, and, together with possible root shrinkage, could account for a relationship of Rc, with ψs. Mycorrhizal development in these fertilized seedlings was too slight to justify consideration of hyphal resistance.

The Degradation and Bioactivity of Metolachlor in the Soil

Weed Science ◽  
1986 ◽  
Vol 34 (3) ◽  
pp. 479-484 ◽  
Author(s):  
Michael P. Braverman ◽  
Terry L. Lavy ◽  
Clyde J. Barnes
Keyword(s):  
Oryza Sativa ◽  
Organic Carbon ◽  
Incubation Time ◽  
Soil Profile ◽  
Degradation Rate ◽  
Organic Carbon Content ◽  
Silt Loam ◽  
Treated Soil ◽  
Flooded Rice ◽  
Loam Soil

In bioassays, rice (Oryza sativaL.) recovery from metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] injury tended to be slower in flooded rice, but was not significantly different from the recovery rate in a nonflooded rice. In soils treated with 1 ppm (w/w) metolachlor and incubated in constant-temperature chambers, the half-life of metolachlor was shorter at 40 C than at 30 C. The degradation rate of metolachlor was not significantly correlated with declining moisture potentials in the range of −30 to −80 kPa. The CO2evolution from metolachlor-treated soil was negatively correlated with incubation time and positively correlated to declining moisture levels. In a field study, metolachlor, as determined by bioassay, was mobile in a Taloka silt loam soil profile. After being incorporated to 7.5 cm, it became evenly distributed in the top 15 cm of the soil profile within 18 days. Metolachlor adsorption was positively correlated with clay and organic carbon content.

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