Informatics Publishing Limited

A. Sireesha ¹, P. C. Rao ², S. Ramalakshmi ²

Affiliations
1 Andhra Pradesh Rice Research Institute and Regional Agricultural Research Station, Maruteru, West Godavari (A.P.), IN
2 All India Co-Ordinated Research Project on Weed Control, Acharya N.G. Ranga Agricultural University, Hyderabad (A.P.), IN

Abstract

Field experiment was conducted to study the residues of pendimethalin in edible parts of radish and its persistence in soil. At harvest in both the seasons of winter and summer more than 98per cent of initial deposit of pendimethalin was dissipated and observed half life in radish field was 6.45 days and 10.03 days for pendimethalin applied as pre emergence @ 0.5 and 0.75 kg a.i. ha^-1, respectively. In radish tubers the detected residues of pendimethalin were 0.0026 mg kg^-1 and 0.0063 mg kg^-1 during winter season and 0.0027 mg kg^-1 and 0.0056 mg kg^-1 when pendimethalin applied at 0.5 and 0.75 kg a.i. ha^-1, respectively.

Keywords

Pendimethalin, Persistence, Radish, Residues, Soil.

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J. D. Saritha ¹, T. Ramprakash ¹, P. C. Rao ¹, M. Madhavi ²

Affiliations
1 Department of Soil Science and Agril. Chemistry, College of Agriculture, PJTSAU Rajendranagar, Hyderabad, IN
2 Department of Agronomy, College of Agriculture, PJTSAU Rajendranagar, Hyderabad, IN

Abstract

Dissipation of metribuzin and its persistence in tomato fruits was studied by conducting on-farm research trials in three farmer’s fields in Ranga Reddy district of Telangana state. Farmer’s fields with widely varying soil characteristics were selected and metribuzin was applied at 500 g a.i. ha^-1. Soil samples were collected at 0, 7, 15, 30, 45 and 60 DAA (days after application) and fruit samples were collected at harvest and analysed on GC-ECD for metribuzin residues. Metribuzin persisted in the soils up to 45 DAA in coarse textured soils and 60 DAA in medium and fine textured soils. Metribuzin leached to 20-30 cm depth in all the soils and leaching was more pronounced in coarse textured soils than in fine textured soils. Organic carbon and clay content significantly influenced the residual life and leaching of metribuzin in soil. In soils, metribuzin dissipation followed a first-order decay process and exponential model was found to give better fit for field dissipation. Half life of metribuzin soil varied from 9.11 to 21.15 days. Metribuzin residues in tomato samples collected at the time of harvest were below the detection limit and MRL of 0.05 mg kg^-1 in all the farmer’s fields.

Keywords

Metribuzin Persistence, Soils, Tomato Fruits.

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