Soil persistence of triasulfuron herbicide as affected by biotic and abiotic factors

Persistence of triasulfuron [3-(6-methoxy-4methyl-1,3,5-triazin-2-yl)-1-{2-(2-chloroethoxy)-phenylsulfonyl}-urea] in soil was studied under wheat crop and laboratory conditions. Field experiment was conducted in the farms of Agronomy Division, Indian Agricultural Research Institute (IARI), New Delhi. Randomized block design (RBD) was followed with four replicates and two rates of treatments along with control and weedy check. Triasulfuron was applied as post-emergent application to wheat crop at two rates of application viz., 15 g and 20 g a.i. ha-1. Soil samples at 0 (3 h), 1, 3, 5, 7, 10, 15, 20, and 30-day intervals after application were drawn, extracted, cleaned up, and analyzed for herbicide residues by high performance liquid chromatography (HPLC) using C18 column and methanol: water (8:2) as mobile phase at 242 nm wave length. Effect of microbial activity and soil pH was studied under laboratory conditions. Dissipation of triasulfuron followed a first-order-rate kinetics. Residues dissipated from field soil with half-life of 5.8 and 5.9 days at two rates of application. The study indicated biphasic degradation with faster rate initially (t1/2 = 3.7 days), followed by a slower dissipation rate at the end (t1/2 = 9.4 days). Similar trend was observed with non-sterile soil in laboratory with a longer half-life. Acidic pH and microbial activity contributed toward the degradation of triasulfuron in soil.     

Evaluation of ozonation technique for pesticide residue removal and its effect on ascorbic acid,cyanidin-3-glucoside,and polyphenols in apple (<Emphasis Type="Italic">Malus domesticus</Emphasis>) fruits

Ozonated water dip technique was evaluated for the detoxification of six pesticides, i.e., chlorpyrifos, cypermethrin, azoxystrobin, hexaconazole, methyl parathion, and chlorothalonil from apple fruits. Results revealed that ozonation was better than washing alone. Ozonation for 15 min decreased residues of the test pesticides in the range of from 26.91 to 73.58%, while ozonation for 30 min could remove the pesticide residues by 39.39–95.14 % compared to 19.05–72.80 % by washing. Cypermethrin was the least removed pesticide by washing as well as by ozonation. Chlorothalonil, chlorpyrifos, and azoxystrobin were removed up to 71.45–95.14 % in a 30-min ozonation period. In case of methyl parathion removal, no extra advantage could be obtained by ozonation. The HPLC analysis indicated that ozonation also affected adversely the ascorbic acid and cyanidin-3-glucoside content of apples. However, 11 polyphenols studied showed a mixed trend. Gallic acid, 3,4-dihydroxybenzoic acid, catechin, epicatechin, p-coumaric acid, quercetin-3-O-glucoside, quercetin, and kaempferol were found to decrease while syringic acid, rutin, and resveratrol were found to increase in 30-min ozonation.     

Effect of light on DIMBOA synthesis in maize leaves as revealed by modified cost-effective extraction method

2,4-Dihydroxy-7-methoxy-1,4-benzoxazine-3-one (DIMBOA) known for its antibiotic properties against many pests and diseases in maize plant was extracted from different varieties. In one of the extraction methods of DIMBOA from maize leaves, Amberlite XAD7, an adsorbent, was used for extracting this and it gave a pure fraction containing DIMBOA. The adsorbent Amberlite XAD, being an expensive material, was uneconomical for processing a large number of samples. Therefore, one of the reported solvent extraction method was modified to make the extraction procedure cost effective without losing the target compounds. Using the modified method, DIMBOA was extracted for different varieties under dark and light condition. Results showed that high concentrations of DIMBOA were extracted from plants grown in dark condition as compared to plants grown in light indicating that light played significant role in inhibition of DIMBOA.     

Quantitative determination of gibberellins by high performance liquid chromatography from various gibberellins producing Fusarium strains

High performance liquid chromatographic (HPLC) method was developed for analysis of seven gibberellins, i.e., GA₃, GA₄, GA₇, GA₃ methyl ester, GA₇ methyl ester 3,13 diacetate, GA₇ methyl ester, and fusaric acid, using an isocratic system. Method was used for estimation of gibberellins from different Fusarium strains. Gibberellins were extracted from 28 strains of Fusarium, out of which six strains of Fusarium were isolated from soil of different parts of India and 22 strains were procured from the Indian Type Culture Collection, Indian Agricultural Research Institute, New Delhi. Extracts were analyzed for qualitative and quantitative estimation of gibberellins by thin layer chromatography and HPLC, respectively. On the basis of quantitative analysis of produced gibberellins by HPLC, they were categorized as low, moderate, and high gibberellin producing strain. For the first time, Fusarium solani was also reported as high GA₃ producing strain.     

Sorption-desorption behavior of metsulfuron-methyl and sulfosulfuron in soils

Sorption of metsulfuron-methyl and sulfosulfuron were studied in five Indian soils using batch sorption method. Freundlich adsorption equation described the sorption of herbicides with K_f (adsorption coefficient) values ranging between 0.21 and 1.88 (metsulfuron-methyl) and 0.37 and 1.17 (sulfosulfuron). Adsorption isotherms were L-type suggesting that the herbicides sorption decreased with increase in the initial concentration of the herbicide in the solution. The K_f for metsulfuron-methyl showed good positive correlation with silt content (significant at p = 0.01) and strong negative correlation with the soil pH (significant at p = 0.05) while sorption of sulfosulfuron did not correlate with any of the soil parameter. Desorption of herbicides was concentration dependent and, in general, sulfosulfuron showed higher desorption than the metsulfuron-methyl. The study indicates that these herbicides are poorly sorbed in the Indian soil types and there may be a possibility of their leaching to lower soil profiles.     

Biodegradation of mono-chlorobenzene by using a trickle bed air biofilter (TBAB)

In the present study, performance of the trickle bed airbiofilter (TBAB) for treating mono-chlorobenzene (MCB) was evaluated for various influent volatile organic compound (VOC) loadings using coal and mixed consortium of activated sludge as the packing material. Microbial acclimation to MCB was achieved by exposing the system continuously for 31 d to an average inlet MCB concentration of 0.688 g m(-3) at an empty bed residence time (EBRT) of 188 s. The TBAB achieved maximum removal efficiency of 87% at an EBRT of 188 s for an inlet concentration of 0.681 g m(-3), which is quite significance than the values reported in the literature. Elimination capacities of MCB increased with an increase of the influent VOC loading, but an opposite trend was observed for the removal efficiency The maximum elimination capacity of the biofilter was 110.75 g m(-3) hr(-1) at an inlet MCB concentration of 1.47 g m(-3). The effect of starvation on the TBAB was also studied. After starvation, the TBAB lost its ability to degrade MCB initially However the biofilter recovered very quickly Evaluation of the concentration profile along the bed height indicated that the bottom section of TBAB has the best performance for all concentrations. By using Wani's method of macrokinetic determination based on simple Monod kinetics, the maximum removal rate of MCB, r(max) and saturation constant K(m) was to be found as 1.304 g m(-3)s(-1) and 113.446 g m(-3), respectively.     

Effect of moisture and compost on fate of azoxystrobin in soils

The effect of compost-amendment and moisture status on the persistence of azoxystrobin [methyl (E)-2-{2-(6-(2-cyanophenoxy) pyrimidin-4-yloxy) phenyl}-3-methoxyacrylate], a strobilurin fungicide, in two rice-growing soils was studied. Azoxystrobin is more sorbed in the silt loam (K _f – 4.66) soil than the sandy loam (K _f – 2.98) soil. Compost-amendment at 5 % levels further enhanced the azoxystrobin sorption and the respective K _f values in silt loam and sandy loam soils were 8.48 and 7.6. Azoxystrobin was more persistent in the sandy loam soil than the silt loam soil. The half–life values of azoxystrobin in nonflooded and flooded silt loam soil were 54.7 and 46.3 days, respectively. The corresponding half–life values in the sandy loam soils were 64 and 62.7 days, respectively. Compost application enhanced persistence of azoxystrobin in the silt loam soil under both moisture regimes and half-life values in non–flooded and flooded soils were 115.7 and 52.8 days, respectively. However, compost enhanced azoxystrobin degradation in the sandy loam soil and half-life values were 59 (nonflooded) and 54.7 days (flooded). The study indicates that compost amendment enhanced azoxystrobin sorption in the soils. Azoxystrobin is more persistent in non-flooded soils than the flooded soils. Compost applications to soils had mixed effect on the azoxystrobin degradation.     

Age and gender differences in conviction and crash occurrence subsequent to being directed to Iowa's driver improvement program

Introduction

This paper investigates potential gender and age differences in conviction and crash occurrence subsequent to being directed to attend Iowa's Driver Improvement Program (DIP).

Methods

Binary logit models were developed to investigate the factors that influence conviction occurrence after DIP by gender and age. Because of the low crash occurrence subsequent to DIP, association rules were applied to investigate the factors that influence crash occurrence subsequent to DIP, in lieu of econometric models.

Results

There were statistical significant differences by driver gender, age, and conviction history in the likelihood of subsequent convictions. However, this paper found no association between DIP outcome, crash history, and crash occurrence.

Impact on industry

Evaluating the differences in conviction and crash occurrence subsequent to DIP between female and male drivers, and among different age groups can lead to improvements of the effectiveness of DIPs and help to identify low-cost intervention measures, customized based on drivers’ gender and age, for improving driving behaviors.     

Choices of ecosystem capital without discounting and prices

In the last decade, neo-classical economists have used the Consumption-Growth Based Utility (CGBU) framework to suggestan appropriate discount rate for eco-system capital. The CGBU framework, being based on the simplicity and single-valued nature of man-made capital, is subject to many limitations. Three general limitations of the framework, irrespective of its use for man-made capital or ecosystem capital, paradox of consumption growth, expectations' insensitive utility specification, and insensitivity to the nature of returns, arediscussed. With respect to its use for ecosystem capital, the framework has two limitations: ecosystems cannot be commoditizedand ecosystem capital satisfies differentiated needs, and, hence, gross substitution between different components of ecosystem capital or between ecosystem capital and man-made capital is not possible. Therefore, the rate of discount for ecosystem capital suggested on the basis of the framework is arbitrary. In the context of international security, choices ofecosystem capital are similar to the choices of military decisions. Similar to military decisions, ecosystem choices should be made without discounting and prices. The neo-classicalframework does not have appropriate tools for such decision analyses, and other streams of economics, specifically post-Keynesian economics, may assist decision- makers in analysing ecosystem choices without prices and discounting.