Agronomy Research Expertise in Montpellier and Languedoc-Roussillon (South of France)

Agronomy : crops and cropping systems

Keywords :

Hydrological functioning on plot and catchment scales in tropical environments–a case study of banana

4. Preserving water resources

4. Preserving water resources

Features of the hydrological balance in the elementary catchment of Féfé (20 ha). Ignorance of the main mechanisms controlling the fate of pesticides used in tropical environments is partly responsible for environmental problems in the West Indies and most banana-growing areas worldwide. As part of a study to assess the fate of pesticides in volcanic tropical environmental conditions, environmental degradation which could be potentially induced by banana cropping was a special focus of attention.

The research (in collaboration with the INRA Unité Agropédoclimatique de la zone Caraïbe) was conducted in two phases:

  • Understanding how pesticides are mobilized from their application site (plot). The main runoff and drainage water flows were quantified along with changes in pesticide concentrations in different water and soil compartments.
  • Study of water resource pollution mechanisms in catchments, i.e. an environmental impact assessment scale. The hydrological functioning of a small banana growing area (20 ha) was characterized, while also determining water and soil contamination patterns.

Hydrological modelling was conducted on two scales using the MHYDAS model developed by LISAH.

On a plot scale, banana trees highly redistribute incident rainfall, mainly via stemflow. This results in a heterogeneous rainfall intensity distribution on the ground, which in turn promotes runoff, increases drainage flows at the foot of banana trees and fosters pesticide export. On a catchment scale, water circulation routes are mainly underground. The spatial hydrological model developed can be used to assess the impact of the landscape spatial organization on water flows.

A study of nematicide dispersion revealed two successive water contamination phases: event-based contamination with peaks lasting less than 30 days, associated with transport via surface runoff during rainstorms; and quantitatively greater chronic contamination associated with drainage of the contaminated surface water.

Pesticide inputs in banana plantations lead to soil and water pollution on different agricultural spatial scales. This warrants research to develop alternatives to pesticide treatments. The findings of this study provide a reference base on pesticide contamination and mobilization processes in tropical volcanic environments, especially with respect to the management of the chlodecone problem in the West Indies, as this persistent organochlorine pollutes water and soils for very long durations.



Contact(s):
Philippe Cattan, philippe.cattan@cirad.fr
Marc Voltz, voltz@supagro.inra.fr
& Roger Moussa, moussa@supagro.inra.fr

Publication date: 30/05/2010

Illustrations

Device for measuring the rainfall redistribution by banana leaves. © P. Cattan




 


 
 

Update on 19/04/12


 




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