Dissipation of Alachlor in Four Soils as Influenced by Degradation and Sorption Processes

Weed Science ◽  
1994 ◽  
Vol 42 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Pau Y. Yen ◽  
William C. Koskinen ◽  
Edward E. Schweizer
Keyword(s):  
Surface Soil ◽  
Sandy Loam ◽  
Soil Depth ◽  
Order Rate Constant ◽  
Silty Clay ◽  
Clay Loam ◽  
Corn Production ◽  
First Order ◽  
Degradation Data ◽  
First Order Kinetics

Laboratory studies were conducted to determine the influence of degradation and sorption processes on the dissipation of alachlor in one Colorado soil (Kim clay loam) and three Minnesota soils (Port Byron silt loam, Webster silty clay loam, and Estherville sandy loam) as a function of soil depth. Persistence and movement of alachlor in an irrigated corn production system also were determined on the Kim soil. Laboratory degradation data fit first-order kinetics, and rate constants ranged from 0.0094 to 0.0251 d-1and varied with soil type and depth. For instance, in 60- to 75-cm-depth Kim soil, alachlor degraded at a slower rate (k = 0.011 d-1) than in surface soil samples (k = 0.022 d-1). Alachlor sorption to the four soils was moderate (Kf= 0.7 to 7.4; Kf,oc= 71 to 470) and concentration dependent (1/n < 1.0). Significant hysteretic desorption of alachlor from soils also was observed (1/n desorption < 1/n sorption). The combined effect of degradation and sorption processes has been used to classify a chemical's potential to leach to groundwater. Based on Kf,ocand dissipation half-life, alachlor would be classified as a “leacher” in Kim, Port Byron, and Estherville soils and classified as transitional between “leacher” and “nonleacher” in the Webster soil. The dissipation first-order rate constant (k) of alachlor in Kim soil in the field was 0.036 α 0.012 d-1. Dissipation was apparently not due to leaching since bromide applied at the same time remained in the top 15 cm during the first 28 d. It appears that laboratory-derived leaching indices may overestimate actual leaching and should be used with caution for predictive or regulatory purposes.

Effect of Intermittent Water Application from Trickle Source on The Water Movement and Moisture Distribution in Layered Soil

2020 ◽  
Vol 27 (4) ◽  
pp. 87-97
Author(s):  
haqqi Yasin ◽  
abdul alsattar Al-Dabagh
Keyword(s):  
Sandy Loam ◽  
Soil Depth ◽  
Layered Soil ◽  
Moisture Distribution ◽  
Silty Clay ◽  
Horizontal Distance ◽  
Clay Loam ◽  
Water Application ◽  
Wetting Front ◽  
Silty Clay Loam

The aim of this research is to study the effect of intermittent water application on the wetting pattern and soil moisture distribution for homogeneous and layered soils under trickle source. Thirty experiments were conducted to monitor the advance of the wetting front in the soil profiles. Measurements of soil moisture content were also made at selected locations to evaluate the moisture distribution in soil. Four types of soil profiles were built; the first was sandy loam soil, the second was silty clay loam soil, the third was (silty clay loam/ sandy loam) layered soil, and the fourth was (sandy loam/ silty clay loam) layered soil. Three water application rates were used for each soil profile. Three continuous or intermittent applications were used; continuous applications, equally intermittent applications, and different intermittent applications. In addition, several cylindrical infiltration tests were conducted to describe some characteristics of each soil. Empirical relations to predict each of vertical (under trickle source) and horizontal (at soil surface) wetting front advance were found in this study. Empirical relations to predict the percentage of applied water volume in horizontal strips as a function of soil depth and in vertical strips as a function of horizontal distance from the trickle emitter were also found. The study showed that the wetted soil volume increases as either the water application rate increases, or the intermittent application ratio increases. Also, it showed that the ratio of horizontal advance to vertical advance of wetting front increases as either the water application rate increases, or the intermittent application ratio decreases. The study demonstrated that the accumulated ratio of water application volume at a certain soil depth from trickle source increases as the intermittent application ratio decreases. Also, it demonstrated that the accumulated ratio of water application volume at a certain horizontal distance from trickle source decreases as the intermittent application ratio decreases.

Soil Persistence of Dinitramine

Weed Science ◽  
1980 ◽  
Vol 28 (6) ◽  
pp. 650-654 ◽  
Author(s):  
J. A. Poku ◽  
R. L. Zimdahl
Keyword(s):  
Mathematical Model ◽  
Soil Moisture ◽  
Field Data ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Clay Loam ◽  
First Order ◽  
Soil Persistence ◽  
Herbicide Concentration ◽  
Increasing Temperature

The effects of soil temperature, moisture, and herbicide concentration on the rate of degradation of dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine) were measured in clay loam and sandy loam in the laboratory. In sandy loam, the rate of degradation increased with increasing temperature. In clay loam, the rate of degradation increased from 10 to 30 C and decreased at 40 C. Soil moisture content influenced the rate of degradation in the following order: 22>11>>2.2% (air-dry) for clay loam and 12.0 = 6.0>>0.5% (air-dry) for sandy loam. First-order half-lives ranged from 3.2 at 30 C to 47 weeks at 10 C in clay loam, and 2.3 at 40 C to 31 weeks at 10 C in sandy loam. Applications in 2 yr did not cause buildup of dinitramine in the field. A mathematical model was used in an attempt to correlate laboratory and field data.

Fluometuron in Soil Solution as an Indicator of Its Efficacy in Three Soils

Weed Science ◽  
1982 ◽  
Vol 30 (6) ◽  
pp. 688-691 ◽  
Author(s):  
Michael G. Patterson ◽  
Gale A. Buchanan ◽  
Robert H. Walker ◽  
Richard M. Patterson
Keyword(s):  
Organic Matter ◽  
Field Experiment ◽  
Soil Solution ◽  
Sandy Loam ◽  
Silty Clay ◽  
Clay Loam ◽  
Weed Species ◽  
Silty Clay Loam ◽  
Fine Sandy Loam

Analysis of fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] in soil solution after application of 0.5 or 1.0 ppmw revealed up to five-fold differences among three Alabama soils (Lucedale fine sandy loam, Decatur silty clay loam, and Sacul loam). Differences in fluometuron in soil solution were attributed to variable organic matter present and clay fractions. Fluometuron concentration in soil solution for each soil correlated well with control of four broadleaf weed species in a field experiment.

Influence of Various Soil Properties on the Adsorption and Desorption of ICIA-0051 in Five Soils

1992 ◽  
Vol 6 (3) ◽  
pp. 583-586 ◽  
Author(s):  
John S. Wilson ◽  
Chester L. Foy
Keyword(s):  
Sandy Loam ◽  
Clay Content ◽  
Silty Clay ◽  
Silt Loam ◽  
Clay Loam ◽  
Soil Factors ◽  
Silty Clay Loam ◽  
Freundlich Equation ◽  
General Order ◽  
Highly Correlated

The soil organic matter and/or humic matter fraction was highly correlated with the adsorption of ICIA-0051 herbicide onto five soils; clay content and other soil factors were less correlated. The Freundlich equation was used to describe the adsorption of ICIA-0051 by the various soils. Based on the K constants, the general order for adsorption for each soil was Hyde silty clay loam > Frederick silt loam > Davidson clay = Bojac sandy loam > Appling loamy sand. Across all soils, 25 to 50% of the amount adsorbed was removed by two desorptions. Appling, Bojac, and Davidson soils retained less herbicide after two desorptions than did Frederick and Hyde.

scholarly journals Study on abundance of benthic macroinvertebrates in relation to soil texture types of sediment in three ponds

2018 ◽  
Vol 7 (2) ◽  
pp. 27-35
Author(s):  
BR Irin ◽  
MA Mansur ◽  
MS Rahman
Keyword(s):  
Soil Texture ◽  
Sandy Loam ◽  
Quality Parameters ◽  
Soil Conditions ◽  
Silty Clay ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Bottom Soil ◽  
Positive Correlations ◽  
Macro Benthos

The present research was conducted to evaluate the monthly variations of macrozoobenthos of three ponds (pond 1, bottom soil is loam; pond 2, bottom soil is sandy loam; pond 3, bottom soil is silty clay loam) in relation to soil texture types of sediment. The major groups of macro-zoobenthos recorded were Chironomidae, Oligochaeta, Mollusca and Ceratopogonidae. The values of all water quality parameters such as temperature, water depth, rainfall, transparency, dissolved oxygen, pH, free CO2, NO3-N and PO4-P were found to have positive correlations in most cases, in some cases negative correlations and in few cases significant correlations. The abundance of Chironomidae was to be dominant in the pond no. 3 during the whole study period. The highest number of Oligochaeta (400 per m2) was found in pond no. 3 at depth of 150 cm and the lowest number of Oligochaeta (0 per m2) was found in pond nos. 1, 2 and 3 at both depths. The highest number of Chironomidae (1332 per m2) was found in pond no. 3 at depth of 150 cm and the lowest number of Chironomidae (444 per m2) was found in pond no. 2 at depth of 100 cm. The highest number of Ceratopogonidae (977 per m2) was found in pond no. 3 at the depth of 150 cm and the lowest number of Ceratopogonidae (178 per m2) was found in pond no. 2 at both depths. The highest number of Mollusca (1288 per m2) was found in pond no. 3 at the depth of 150 cm and the lowest number of Mollusca (222 per m2) was found in pond no. 2 at the depth of 100 cm. Satisfactory quantity of macrobenthos in the pond no. 3 at the depth of 150 cm than those of other two ponds. Between 2 depths (100 and 150 cm), the depth of 150 cm was to have highest quantity of macro-zoobenthos in all the three ponds because this depth was most favourable for macro-zoobenthos production. In pond no. 1, 2 and 3 relation of macro-benthos (no. per m2) with chemical parameters of pond bottom-soil conditions vary pond to pond which influence primary production and also influence macro-zoobenthos production (secondary production). The highest macro-zoobenthos population density was found in pond no. 3 followed by pond no. 1 and the lowest production in pond no. 2 but macro-zoobenthos production in pond no. 2 and pond no. 1 are more or less similar and macro-zoobenthos production in pond no. 3 is different and higher than those of pond nos. 1 and 2 which indicates that silty clay loam of bottom-soil is more suitable for macrozoobenthos than other soil textural classes of bottom-soil loam and sandy loam.Int. J. Agril. Res. Innov. & Tech. 7 (2): 27-35, December, 2017

EFFECT OF pH ON PLANT UPTAKE AND SOIL ADSORPTION OF 14C-FLURIDONE

1990 ◽  
Vol 70 (3) ◽  
pp. 435-444 ◽  
Author(s):  
N. MALIK ◽  
D. S. H. DRENNAN
Keyword(s):  
Soil Solution ◽  
Plant Uptake ◽  
Sandy Loam ◽  
Organic Soil ◽  
Solution Concentration ◽  
Silty Clay ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Solution Ph ◽  
Soil Adsorption

Experiments were conducted to obtain a better understanding of the role of pH on the availability of fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl) phenyl]-4(1 H)-pyridinone) in soil solution when used as a selective herbicide and the partitioning into aqueous and sediment phases when employed for aquatic plant control. Phytotoxicity of fluridone to seedling sorghum (Sorghum bicolor L.) plants increased with increasing pH of the sand-nutrient solution medium. Since stability and plant uptake of fluridone by bioassay plants were not affected by solution pH, the increasing phytotoxicity at basic pH was attributed to less adsorption and hence higher availability of the herbicide in solution. Soil adsorption studies with 14C-fluridone confirmed this trend, as the soil solution concentration at equilibrium increased from 0.091 to 0.258 μg mL−1 and from 0.216 to 0.354 μg mL−1, respectively, as pH of a sandy loam and silty clay loam increased from 3 to 9. In contrast, adsorption on the sandy loam and silty clay loam for the same pH range decreased from 4.108 to 2.435 μg g−1 and from 2.850 to 1.484 μg g−1, respectively. Smaller but significant changes in adsorption were also observed for an organic soil over this range. Key words: Herbicide, fluridone, pH, uptake, soil adsorption

scholarly journals Mechanism-based inactivation of gastric peroxidase by mercaptomethylimidazole

1993 ◽  
Vol 296 (1) ◽  
pp. 79-84 ◽  
Author(s):  
U Bandyopadhyay ◽  
D K Bhattacharyya ◽  
R K Banerjee
Keyword(s):  
Ph Dependence ◽  
Order Rate Constant ◽  
Order Kinetic ◽  
First Order ◽  
First Order Kinetics ◽  
Mechanism Of Inhibition ◽  
Catalytically Active ◽  
Pseudo First Order ◽  
Inactivation Process ◽  
Gastric Peroxidase

The mechanism of inhibition of gastric peroxidase (GPO) activity by mercaptomethylimidazole (MMI), an inducer of gastric acid secretion, has been investigated. Incubation of purified GPO with MMI in the presence of H2O2 results in irreversible inactivation of the enzyme. No significant inactivation occurs in the absence of H2O2 or MMI, suggesting the involvement of peroxidase-catalysed oxidized MMI (MMIOX.) in the inactivation process. The inactivation follows pseudo-first-order kinetics consistent with a mechanism-based (suicide) mode. The pseudo-first-order kinetic constants at pH 8 are ki = 111 microM, k(inact.) = 0.55 min-1 and t1/2 = 1.25 min, and the second-order rate constant is 0.53 x 10(4) M-1 x min-1. Propylthiouracil also inactivates GPO activity in the same manner but its efficiency (k(inact./ki = 0.46 mM-1 x min-1) is about 10 times lower than that of MMI (k(inact./ki = 5 mM-1 x min-1). The rate of inactivation with MMI shows pH-dependence with an inflection point at 7.3, indicating the involvement in the inactivation process of an ionizable group on the enzyme with a pKa of 7.3. The enzyme is remarkably protected against inactivation by micromolar concentrations of electron donors such as iodide and bromide but not by chloride. Although GPO oxidizes MMI slowly, iodide stimulates it through enzymic generation of I+ which is reduced back to I- by MMI. Although MMIOX. is formed at a much higher rate in the presence of I-, a constant concentration of I- maintained via the reduction of I+ by MMI, protects the active site of the enzyme against inactivation. We suggest that MMI inactivates catalytically active GPO by acting as a suicidal substrate.

Rice Response to Clomazone as Influenced by Application Rate, Soil Type, and Planting Date

2007 ◽  
Vol 21 (1) ◽  
pp. 199-205 ◽  
Author(s):  
John H. O'Barr ◽  
Garry N. McCauley ◽  
Rodney W. Bovey ◽  
Scott A. Senseman ◽  
James M. Chandler
Keyword(s):  
Field Experiments ◽  
Rice Yield ◽  
Sandy Loam ◽  
Application Rate ◽  
Planting Date ◽  
Silty Clay ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Planting Dates ◽  
Fine Sandy Loam

Clomazone is an effective herbicide widely used for PRE grass control in rice. However, use of clomazone on sandy textured soils of the western Texas rice belt can cause serious rice injury. Two field experiments at three locations were conducted in 2002 and 2003 to determine the optimum rate range that maximizes barnyardgrass and broadleaf signalgrass control and minimizes rice injury across a wide variety of soil textures and planting dates. At Beaumont (silty clay loam), Eagle Lake (fine sandy loam), and Ganado (fine sandy loam), TX, PRE application of 0.34 kg ai/ha clomazone applied to rice planted in March, April, or May optimized barnyardgrass and broadleaf signalgrass control and rice yield while minimizing rice injury. Data suggest that, although injury might occur, clomazone is safe to use in rice on sandy textured soils.

Simulating the vertical transition of soil textural layers in north-western China with a Markov chain model

Soil Research ◽  
2013 ◽  
Vol 51 (3) ◽  
pp. 182 ◽  
Author(s):  
Danfeng Li ◽  
Ming'an Shao
Keyword(s):  
Layer Thickness ◽  
Sandy Loam ◽  
Loamy Sand ◽  
Silty Clay ◽  
Silt Loam ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Textural Type ◽  
Log Normal ◽  
Log Normal Distribution

The heterogeneity of textures in soil profiles is important for quantifying the movement of water and solutes through soil. Soil-profile textures to a depth of 300 cm were investigated at 100 sites in a 100-km2 area in the central region of the Heihe River system, where oases coexist with widespread deserts and wetland. The probability distribution of textural-layer thickness was quantified. The vertical transition of the soil textural layers was characterised by a Markov chain–log-normal distribution (MC-LN) model based on the probability of one textural type transitioning to another. Nine types of textural layers were observed: sand, loamy sand, sandy loam, silt loam, loam, clay loam, silty clay loam, silty clay, and clay. Sand was the most frequent in the profiles, whereas silt loam and clay were rare. The layers of sand and silty clay were relatively thick, and the layers of loam and clay were relatively thin. The coefficients of variation ranged from 36–87%, indicating moderate variation in the layer thickness of each textural type. The soil profile was characterised as a log-normal distribution. A χ2 test verified the Markov characteristic and the stability of the vertical change of soil textural layers. Realisations of the soil textural profiles were generated by the MC-LN model. A Monte Carlo simulation indicated that the simulated mean layer thickness of each textural type agreed well with the corresponding field observations. Element values of the transition probability matrix of the textural layers simulated by the MC-LN model deviated <12.6% from the measured values, excluding the data from the layers of clay and silt loam. The main combinations of upper to lower textural layers in the study area were loamy sand and sand (or sandy loam), sandy loam and sand (or loamy sand and loam), loam and clay loam, clay loam (or silty clay) and silty clay loam, and silty clay loam and silty clay. The MC-LN model was able to accurately quantify the vertical changes of textures in the soil profiles. This study will aid in quantification of water and solute transport in soils with vertical heterogeneity of soil textural layers.

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