Development of a Model on the Fate and Transport of Pesticide in a Lowland Rice Area

Samuel  R. Simon,

Development of a Model on the Fate and Transport of Pesticide in a Lowland Rice Area

Abstract:

For fast, effective and economical assessment and continuous monitoring of the level of concentration of pesticide in a lowland rice area, the development and use of a model play a very important role. The study aimed to assess the extent of pesticide contamination of water in the paddy field and drainage channel and develop a model that can be used to determine the fate and transport of pesticide in an irrigated rice area. Three - 144 sq. m. experimental paddy plots planted with MS 16 variety of rice and applied with Lambda cyhalothrin insecticide was used in the study. A computer based transport model was developed that will be used to simulate the concentration of pesticide residue in the ponded water and drainage channel in an irrigated rice area by mathematically tracking the total mass of chemical residues from the loading point to the drainage stream in terms of mass balance. Results of simulation of the model revealed that concentration of Lambda cyhalothrin insecticide applied in the paddy field diminished at the rate of 42.38% on the first day, 90.64% on the second day, 98.26% on the third day, 99.10% on the fourth day and completely diminished on the fifth day. As indicated by the correlation analysis and test of significance between the observed and predicted data, the model can accurately simulate the actual pesticide concentration in the ponded and drainage water of an irrigated rice area. The study recommends the enhancement of the model by taking into consideration the advection process in the drainage stream and linking of the model to other available models by either using the input/output of the model as an input/output to the other model or vice versa.