Herbicide dissipation and runoff from soils under sugarcane in Mauritius
| MSI99P3269 | |
| Umrit, G Ng Kee Kwong, K F | |
| Herbicide dissipation and runoff from soils under sugarcane in Mauritius | |
| 73rd SASTA Congress, 2-4 August 1999, Durban, South Africa | |
| Periodical article | |
| 1999 | |
| Proc. S. Afr. Sug. Technol. Ass. | |
| 73: 24-29 | |
| En | |
| En | |
| Increasing concern about the potential pollution of surface and groundwaters by herbicides used in sugarcane cultivation in Mauritius is calling for a need to identify agricultural practices that would minimise the movement of herbicides to our water resources. In this context, the off-farm transport by surface run-off of atrazine, diuron, hexazinone and acetochlor were monitored on a plot scale (500 m2) as well as on a 40 hectare catchment at a site (Valetta) receiving an annual rainfall of about 3500 mm. The results showed that rapid dissipation of herbicide occurred in the top 0-2,5 cm layer of the soil and little herbicide was transported down the soil profile to below 30 cm depth. There was no evidence of on-farm build-up of herbicide residues. Mean herbicide concentrations in run-offs waters were low and did not exceed existing drinking water guidelines. The total mass of herbcide lost by run-off from 40 hectare catchment over one growing season represented not more than 0,02 per cent atrazine, 0,32 percent hexazinone, 0,07 per cent diuron and 0,19 per cent acetochlor with respect to the amount normally applied. Although at plot scale herbicide losses occurred mainly as sediment-bound residues, at the 40 hectare catchment, 70-95 per cent of herbicide lost occurred as dissolved residues. Based on visual observation of crystal clear watercourses becoming loaded with mud during and after a heavy rainfall event, the perception of the general public is that quantities of herbicides representing a hazard to human health are being moved during soil erosion. The data obtained therefore showed that this perception is unfounded. | |
| SUGARCANE HERBICIDES RUNOFF DISSIPATION WATER POLLUTION | |
| MAURITIUS | |
| Pollution | |
| Herbicides runoff | |
| 1999-11-09 | |
| En | |
| Cat | |
| CHEM |