RESIDUES OF PARAQUAT AND LINURON IN AN ORGANIC SOIL AND THEIR UPTAKE BY ONIONS, LETTUCE AND CARROTS

1976 ◽  
Vol 56 (4) ◽  
pp. 407-412 ◽  
Author(s):  
S. U. KHAN ◽  
A. BELANGER ◽  
E. J. HOGUE ◽  
H. A. HAMILTON ◽  
S. P. MATHUR
Keyword(s):  
Organic Soil ◽  
Application Rate ◽  
Field Conditions ◽  
Vegetable Crops ◽  
Harvest Time ◽  
Treated Soil ◽  
Residue Levels

Paraquat (1,1′-dimethyl-4,4′-bipyridinium dichloride) and linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] were applied to an organic soil, as spray treatments, at rates of 1.12 and 2.24 kg/ha, and 2.24 and 4.48 kg/ha, respectively. The persistence of the herbicides and their residues in lettuce (foliage), onions (root), and carrots (foliage and root) at harvest time were studied under field conditions. Proportionately more residues persisted in the soil from the higher rates of application of paraquat (2.24 kg/ha) and linuron (4.48 kg/ha). About 83–86% of the initial amounts of paraquat and 59–74% of the linuron remained in the soil 4 mo after application. Furthermore, about 50% of the paraquat was recovered from the treated soil 15 mo after application, whereas only about 20% of the linuron was recovered at the end of the same period. Carrots grown in this soil did not absorb detectable (>0.005 ppm) amounts of linuron, while onions and lettuce grown 12 mo after application absorbed the herbicide in various amounts. At the lower rate of application (2.24 kg/ha) linuron residue in onions was 0.014 ppm and that from the higher application rate (4.48 kg/ha) was 0.046 ppm. Lettuce had about 0.009 ppm residue, irrespective of the rate of application. Onions and lettuce grown on paraquat-treated soil had low residue levels (0.001–0.011 ppm). The study demonstrates the potential of paraquat and linuron residues to persist in organic soil, and their uptake by vegetable crops.

Evaluation of Imazethapyr for Weed Control in Leafy Vegetable Crops

1996 ◽  
Vol 10 (2) ◽  
pp. 253-257 ◽  
Author(s):  
Joan A. Dusky ◽  
William M. Stall
Keyword(s):  
Regression Analysis ◽  
Weed Control ◽  
Crop Yield ◽  
Relative Sensitivity ◽  
Leafy Vegetable ◽  
Field Conditions ◽  
Vegetable Crops ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Common Purslane

Imazethapyr was evaluated PRE and POST in five lettuce types and chicory under Florida field conditions. The relative sensitivity of leafy crop vigor (most sensitive to most tolerant) to imazethapyr PRE, based on 20% inhibition determined using regression analysis, was as follows: Boston > bibb > crisphead > romaine > leaf > escarole > endive. Leafy crop injury increased as the rate of imazethapyr applied POST increased, with all leafy crops responding in a similar manner. Surfactant addition increased imazethapyr phytotoxicity. Imazethapyr PRE treatments at 0.067 kg ai/ha provided greater than 80% control of livid amaranth, common purslane, flatsedge, and common lambsquarters. Imazethapyr POST at 0.067 kg/ha, with surfactant provided control greater than 85% of all weed species. Greater than 85% spiny amaranth control was provided by imazethapyr POST at 0.017 kg/ha. Use of surfactant with imazethapyr did not improve spiny amaranth control over imazethapyr with no surfactant. POST treatments did not decrease leafy crop yield compared with the hand-weeded check. Imazethapyr applied PRE reduced crop yield compared to the POST treatments and the hand-weeded control.

Effect of Native Bioinoculants on Vegetable Crops Grown on Alkaline Soil Under Field Conditions

2005 ◽  
Vol 7 (3) ◽  
pp. 75-90 ◽  
Author(s):  
Suman Kashyap ◽  
Satyawati Sharma ◽  
Padma Vasudevan
Keyword(s):  
Field Conditions ◽  
Alkaline Soil ◽  
Vegetable Crops

Breakdown and Movement of 2,4-D in the Soil Under Field Conditions

Weed Science ◽  
1976 ◽  
Vol 24 (5) ◽  
pp. 461-466 ◽  
Author(s):  
R. G. Wilson ◽  
H. H. Cheng
Keyword(s):  
Triticum Aestivum ◽  
Acetic Acid ◽  
Soil Profile ◽  
Soil Surface ◽  
Application Rate ◽  
Soil Samples ◽  
Field Conditions ◽  
Herbicide Application ◽  
Eastern Washington ◽  
Dichlorophenoxy Acetic Acid

The fate of 2,4-D [(2,4-dichlorophenoxy)acetic acid] in the soil under winter wheat (Triticum aestivumL. ‘Nugaines’) and fallow cropping schemes was studied under the field conditions of eastern Washington in 1973 and 1974 using formulated dimethylamine salt and isooctyl ester of 2,4-D. Soil samples taken 1 hour after herbicide application showed that amine-treated plots retained considerably more applied 2,4-D than ester-treated plots. The rapidity of 2,4-D breakdown decreased gradually with time, and at the end of 6 months, an average of 0.04 ppm of 2,4-D remained in the sampled soil profile regardless of formulation, application rate, or cropping scheme. Loss of 2,4-D from the soil surface in runoff occurred when the plots were irrigated heavily one day after the herbicide application. The herbicide was also leached into the soil profile by both irrigation and natural precipitation. Herbicide concentrations in the sampled portion of the upper soil profile decreased during the summer and then increased slightly in the fall.

Leaching of Seven s-Triazines

Weed Science ◽  
1968 ◽  
Vol 16 (2) ◽  
pp. 117-120 ◽  
Author(s):  
E. G. Rodgers
Keyword(s):  
Sandy Soil ◽  
Avena Sativa ◽  
Soil Samples ◽  
Field Conditions ◽  
Soil Concentration ◽  
Treated Soil ◽  
Growing Period ◽  
Leaf Chlorosis

Leaching of seven s-triazines in Lakeland fine sandy soil under greenhouse and field conditions was demonstrated by use of oats (Avena sativa L., var Seminole) and cucumber (Cucumis sativis L., var. Palomar) for bioassay. Depth of leaching was determined by abnormalities of these species grown in soil samples from the surface of treated soil to a depth of 22 in in the field and to 36 in in columns. Symptoms of injury by the different materials were similar and included primarily leaf chlorosis of both species and bending and breaking of cucumber stems within 7 to 10 days after planting; plants that failed to survive usually died 12 to 14 days after planting. Leaching of 2-methoxy-4-ethylamino-6-isopropylamino-s-triazine (atratone) was greatest, followed in decreasing order by 2-chloro-4,6-bis(isopropylamino)-s-triazine (propazine), 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine), 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), 2-chloro-4-diethylamino-6-isopropylamino-s-triazine (ipazine), 2-ethylamino-4-isopropylamino-6-methylmercapto-s-triazine (ametryne), and 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne). Oats did not significantly reduce the soil concentration of ametryne and prometryne during a growing period of 56 days.

Comparison of static and dynamic closed chambers for measurement of soil respiration under field conditions

1992 ◽  
Vol 72 (4) ◽  
pp. 605-609 ◽  
Author(s):  
P. Rochette ◽  
E. G. Gregorich ◽  
R. L. Desjardins
Keyword(s):  
Soil Respiration ◽  
Sandy Loam ◽  
Flux Measurement ◽  
Organic Soil ◽  
Exponential Model ◽  
Field Conditions ◽  
Parameter Estimates ◽  
Static Chamber ◽  
The Difference ◽  
Negative Exponential

The objective of this study was to compare the dynamic closed and static chamber techniques for the measurement of soil respiration under field conditions. The static chamber method consistently produced lower soil respiration values than did the dynamic closed system and the difference was larger at higher CO2 fluxes. A negative exponential model describes the relation between CO2 fluxes measured by both techniques. A good fit was obtained for measurements on a sandy loam soil (R2 = 0.61) and an organic soil (R2 = 0.74) but parameter estimates were different for each soil. Key words: Carbon dioxide, enclosure, gas flux measurement

THE EFFECT OF WATER TABLE DEPTH IN ORGANIC SOIL ON SUBSIDENCE AND SWELLING

1984 ◽  
Vol 64 (2) ◽  
pp. 273-282 ◽  
Author(s):  
J. A. MILLETTE ◽  
R. S. BROUGHTON
Keyword(s):  
Key Words ◽  
Water Table ◽  
Soil Surface ◽  
Organic Soil ◽  
Harvest Time ◽  
Growing Period ◽  
Subsidence Rate ◽  
Soil Subsidence ◽  
Before And After ◽  
Made In

The effects of two water table depths (WTD), 0.6 and 0.9 m below the soil surface on subsidence, subsidence rate and swelling of an organic soil were observed in large undisturbed cores under greenhouse conditions. Measurements were made in two tiers, 0–0.3 m (top tier) and 0.3 m to WTD (bottom tier) during the growth of a carrot crop with WTD as above, and continued following a rise in the water table. The WTD of 0.9 m caused the top tier to subside twice as much as the same tier in the 0.6 m WTD. Top tier subsidence seemed irreversible in both WTD because minor swelling was observed following a rise in the water table. Most of the reversible subsidence occurred in the bottom tier. Raising the water table reduced the total profile subsidence by 36 and 24% for the 0.6 and 0.9 m WTD, respectively. After correction for oxidation, subsidence accounted for 3.2 and 5.9% of the 0.6- and 0.9-m profiles, respectively. The bulk density increase in the 0.6-m profile before and after the end of the experiment was not significant but a significant increase of 11% was measured in the 0.9-m profile. Subsidence rates decreased in both tiers during the growing period reaching a minimum in both WTD at harvest time. The subsidence rate in 0.9-m profile at 100 days after seeding was 2.5 times the rate in the 0.6-m profile. Key words: Organic soil, subsidence, swelling, water table

scholarly journals Field Distance Effects of Fipronil and Chlorfenapyr as Soil Termiticides Against the Desert Subterranean Termite, Heterotermes aureus (Blattodea: Rhinotermitidae)

Sociobiology ◽  
2020 ◽  
Vol 67 (1) ◽  
pp. 94
Author(s):  
Paul B Baker ◽  
Javier G Miguelena
Keyword(s):  
Spatial Pattern ◽  
Soil Treatment ◽  
Field Conditions ◽  
Subterranean Termite ◽  
Treated Soil ◽  
Full Control ◽  
Distance Effects ◽  
Delayed Toxicity ◽  
The Impact ◽  
Desirable Trait

A desirable trait of termiticides is that they suppress termite activity at a distance from the site of application. Fipronil and chlorfenapyr are two non-repellent termiticides that display delayed toxicity and are therefore good candidates for yielding distance effects. We assessed their effects as soil-applied termiticides for the management of the desert subterranean termite, Heterotermes aureus (Snyder), under field conditions in southern Arizona. Our approach involved recording termite activity within field experimental grids consisting of termite monitoring stations at selected distances from a termiticide application perimeter. Fipronil-treated plots experienced large and significant reductions in termite presence and abundance relative to controls in stations immediately adjacent to treated soil. However, there was no evidence of reductions in termite activity in stations further away from the soil treatment. In contrast, termite abundance and presence in stations decreased relatively to controls after chlorfenapyr application in whole experimental grids and in several grid sections spatially separated from treated soil. These reductions were especially evident in the five central stations surrounded by the treatment perimeter and in the furthest set of stations. The spatial pattern of changes in chlorfenapyr plots was consistent with termiticide transfer as a mechanism behind distance effects. The impact of fipronil and chlorfenapyr on termite populations in our study suggests that they can both be useful for the management of H. aureus, although each might be suited for differentmanagement goals. Our results also suggest that perimeter treatments alone are not sufficient to accomplish full control of large H. aureus infestations.

scholarly journals Carrot Yield, Quality, and Storability in Relation to Preplant and Residual Nitrogen on Mineral and Organic Soils

2006 ◽  
Vol 16 (2) ◽  
pp. 286-293 ◽  
Author(s):  
Sean M. Westerveld ◽  
Mary Ruth McDonald ◽  
Alan W. McKeown
Keyword(s):  
Mineral Soil ◽  
Organic Soil ◽  
Application Rate ◽  
Yield Response ◽  
Organic Soils ◽  
Residual Soil ◽  
N Application ◽  
Application Rates ◽  
Yield Quality ◽  
N Management

The Nutrient Management Act (NMA) established in the province of Ontario in 2002 has prompted a re-evaluation of nitrogen (N) management practices. However, N management research in Ontario is currently outdated. The experiment in this 3-year study was designed to establish the yield response of carrot (Daucus carota) to N fertilization on mineral and organic soils and identify the relative yield effects of preplant and residual soil N. In 2002, N was applied at 0%, 50%, 100%, 150%, and 200% of recommended N application rates in Ontario as ammonium nitrate (organic soil: 60 kg·ha-1 preplant; mineral soil: 110 kg·ha-1 split 66% preplant/33% sidedress). Experimental units were split in half in 2003 and 2004, and N was applied to one half in 2003 and both halves in 2004 to identify the effects of residual N from the previous season on yield. Crop stand, yield, and quality were assessed at harvest, and storability was assessed by placing carrots into cold storage for 6 months. Nitrogen application rate had no effect on the yield, quality, or storability of carrots grown on organic soil. On mineral soil there were no effects of applied N in the first year of the 3-year study. In the second and third year on mineral soil, yield increased in response to increasing N, up to 200% and 91% of the recommended application rate, respectively, based on the regression equations. Yield declined above 91% of the recommended application rate in the third year due to a decrease in stand at higher N application rates. There were no effects of N on carrot quality or storability on mineral soil. On mineral soil, residual N from the 2002 season had more effect on yield at harvest in 2003 than N applied in 2003. This major effect of residual soil N on yield provides an explanation for the lack of yield response to preplant N application in previous studies conducted in temperate regions. These results indicate that there is no single N recommendation that is appropriate for all years on mineral soil. Assessing the availability of N from the soil at different depths at seeding is recommended to determine the need for N application.

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