A Compile of Climatic UV-B Mesh Map in Japan

Kon, Hisashi; Yamamoto, Yusuke; Matsuoka, Norimasa; Okano, Michiaki

doi:10.2480/agrmet.59.35

Cited by 2 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At specified intervals, an aliquot of the reaction mixture (3 ml) was sampled, and the concentrations of I and II were quantified. Daily UV-B was estimated from daily solar irradiation observed at Shizuoka Local Meteorological Observatory 17) using the ratio of daily UV-B to daily solar irradiation reported by Kon et al 18) Photoisomerization rates of I and II were calculated by the nonlinear least-squares method with Microsoft Excel Solver Add-In software. 19) 3.…”

Section: 8ϫ10mentioning

confidence: 99%

See 1 more Smart Citation

Improved PADDY model including photoisomerization and metabolic pathways for predicting pesticide behavior in paddy fields: Application to the herbicide pyriminobac-methyl

et al. 2009

View full text Add to dashboard Cite

Rice production is one of the major non-point sources of pesticide pollution in Japan because more than half of all arable land is paddy fields, from which pesticides can easily be transported to rivers. Public concerns regarding the adverse effects of pesticides in runoff on aquatic ecosystems and drinking water are increasing. In 2003, the Ministry of the Environment of Japan imposed a new pesticide registration scheme concerning ecological risk in an aquatic environment based on concepts adopted in the EU and the USA. In this scheme, the acute effect concentration in the assessment species (i.e., fish, Daphnia, or algae) is compared with the predicted environmental concentration calculated using environmental models based on the standard scenario of the pesticide use. 1)Recently, mathematical models (e.g., PADDY 2,3) and PCPF-1 4-6) ) have been developed to simulate the transport and fate of paddy rice pesticides in Japan; however, these models do not consider metabolites derived from the parent compound by hydrolysis, photolysis, or microbial degradation. The RICEWQ model, developed in the EU and the USA, is the only one that considers metabolites under paddy conditions. 7)The metabolites of some pesticides, such as organophosphorus insecticides, may be more toxic to aquatic organisms than the parent compound. Therefore, for ecological risk assessment it is necessary to evaluate the exposure of aquatic organisms not only to the parent compound but also to its metabolites. PADDY 2,3) is used to predict pesticide behavior in paddies. The objective of this study was to develop and evaluate an improved PADDY-based model that includes photoisomerization and metabolic pathways for the herbicide pyriminobacmethyl [methyl 2-(4,6-dimethoxy-2-pyrimidinyloxy)-6-(E,Z)-(1-methoxyiminoethyl)benzoate], which is used for selective control of early water grass. To validate the model, values calculated by the improved model were compared with measured values from paddy lysimeter and field experiments. Theory, Materials, and Methods ChemicalsPyriminobac-methyl herbicide consists of a mixture of its (E)-isomer (I) and (Z)-isomer (II) as active ingredients, with an (E)/(Z) ratio of ca. 5/1 in a technical grade of the active ingredient. The photo-transformation of this compound is the Improved PADDY model including photoisomerization and metabolic pathways for predicting pesticide behavior in paddy fields:Application to the herbicide pyriminobac-methyl Kumiai Chemical Ind. Co., Ltd., Tamari, Kakegawa, Shizuoka 436-0011, Japan (Received May 16, 2009; Accepted September 17, 2009) An improved simulation model for predicting pesticide behavior in paddy fields based on PADDY was developed to include photoisomerization and metabolic pathways and applied to the herbicide pyriminobac-methyl. Isomerization of pyriminobac-methyl in paddy water by sunlight was modeled as a reversible first-order reaction between the (E)-and (Z)-isomers in response to UV-B irradiation. The formation and degradation of its main metabolites in flooded so...

show abstract

Section: 8ϫ10mentioning

confidence: 99%

“…For dissolution of the granule formulation, (17) (18) Where m ϭamount of the pesticide in the granule formulation (mg). When dissolution of the pesticide from the granule is completed (mϭ0), k s is set to zero in equations 9 and 10.…”

Section: Improvements Of Paddy Modelmentioning

confidence: 99%

Improved PADDY model including photoisomerization and metabolic pathways for predicting pesticide behavior in paddy fields: Application to the herbicide pyriminobac-methyl

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The concentrations of fipronil and isoprothiolane in each sample were determined. Daily UV-B irradiance values above the rice plants were estimated using the method of Kon et al 27) from daily solar irradiation observed by the NIAES in Tsukuba in 2008 and 2009 and the ratio of daily UV-B to daily solar irradiation. Experimental conditions, sampling, the analytical method, and the results are reported in detail in a separate paper.…”

Section: Validation Of the Improved Paddy Modelmentioning

confidence: 99%

An improved PADDY model including uptake by rice roots to predict pesticide behavior in paddy fields under nursery-box and submerged applications

2018

View full text Add to dashboard Cite

We developed an improved version of the PADDY model for predicting pesticide behavior in paddy fields, which includes pesticide uptake by rice roots. We applied the model to nursery-box and submerged pesticide applications. A paddy field was divided into root-zone and inter-plant areas, and paddy soil containing pesticides was vertically separated into three layers. Pesticide behavior was modeled with mass fractions of the pesticides in paddy water and the soil layers immediately after rice transplanting obtained from field experiments, and uptake by rice roots was described using the transpiration stream concentration factor. The improved model successfully simulated measured concentration changes in a paddy field, including rice plants, under nurserybox and submerged applications. The model evaluated the difference in the concentrations of nursery-box-applied pesticides between root-zone and inter-plant soil samples with several key parameters. Our study provides a useful solution for simulating the uptake of pesticides in soil by rice roots.

show abstract

A Compile of Climatic UV-B Mesh Map in Japan

Cited by 2 publications

References 4 publications

Improved PADDY model including photoisomerization and metabolic pathways for predicting pesticide behavior in paddy fields: Application to the herbicide pyriminobac-methyl

Improved PADDY model including photoisomerization and metabolic pathways for predicting pesticide behavior in paddy fields: Application to the herbicide pyriminobac-methyl

An improved PADDY model including uptake by rice roots to predict pesticide behavior in paddy fields under nursery-box and submerged applications

Contact Info

Product

Resources

About