Application of the Root Zone Water Quality Model (RZWQM) to pesticide fate and transport: an overview

• Published in: Pest management science Vol. 60; no. 3; pp. 205 - 221
• Main Authors: Malone, R.W, Ahuja, L.R, Ma, L, Wauchope, R.D, Ma, Q, Rojas, K.W
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-03-2004; Wiley
• Subjects: Agriculture - methods; Biological and medical sciences; chemical degradation; evapotranspiration; Fundamental and applied biological sciences. Psychology; infiltration (hydrology); kinetics; literature reviews; model validation; Models, Biological; pesticide degradation; pesticide kinetics; Pesticide Residues - chemistry; Pesticide Residues - metabolism; pesticide sorption; pesticides; Phytopathology. Animal pests. Plant and forest protection; plant growth; Plant Roots - growth & development; Plant Roots - metabolism; rhizosphere; runoff; RZWQM; simulation models; Soil - analysis; soil transport processes; soil water content; sorption; Water - chemistry; Water - metabolism; Water Movements; water pollution; water quality; Validation; RZWQM; Pesticides; Pesticide fate; Review; Modeling; pesticide kinetics; Sorption; Rhizosphere; model validation; pesticide degradation; Water quality; Kinetics; pesticide sorption
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.789

Pesticide transport models are tools used to develop improved pesticide management strategies, study pesticide processes under different conditions (management, soils, climates, etc) and illuminate aspects of a system in need of more field or laboratory study. This paper briefly overviews RZWQM history and distinguishing features, overviews key RZWQM components and reviews RZWQM validation studies. RZWQM is a physically based agricultural systems model that includes sub-models to simulate: infiltration, runoff, water distribution and chemical movement in the soil; macropore flow and chemical movement through macropores; evapotranspiration (ET); heat transport; plant growth; organic matter/nitrogen cycling; pesticide processes; chemical transfer to runoff; and the effect of agricultural management practices on these processes. Research to date shows that if key input parameters are calibrated, RZWQM can adequately simulate the processes involved with pesticide transport (ET, soil-water content, percolation and runoff, plant growth and pesticide fate). A review of the validation studies revealed that (1) accurate parameterization of restricting soil layers (low permeability horizons) may improve simulated soil-water content; (2) simulating pesticide sorption kinetics may improve simulated soil pesticide concentration with time (persistence) and depth and (3) calibrating the pesticide half-life is generally necessary for accurate pesticide persistence simulations. This overview/review provides insight into the processes involved with the RZWQM pesticide component and helps identify model weaknesses, model strengths and successful modeling strategies.