An Assessment of Management Practices to Control Nutrient and Pesticide Levels in Vegetable Production Areas in the Rattaphum Catchment, Thailand
Tóm tắt
The over-use of agrochemicals may have adverse effects on soils along with surface and groundwater. An assessment of alternative management practices to reduce the application of agrochemicals and minimise the pollution of water resources was carried out in the vegetable agro-ecosystem in the Rattaphum Catchment. This paper details the factors that govern the volume of agrochemicals used on high intensity crops in this area, covering the choice of crop and cropping patterns, level of pest and weed infestation and the socio-economic status of farmers such as capital, size of holding and labour availability. Alternative management practices tested included (i) a reduction in the use of pesticides and chemical fertilisers; (ii) the use of bio-insecticides and bio-fertilisers; and (iii) the development of buffer zones near streams to reduce nutrient leaching into surface water systems. The results showed that when compared with bio-insecticides, synthetic insecticides were more effective in controlling major insect pests during chaisim vegetable production and were associated with higher net incomes. The high rate of application of chemical fertilisers in home gardens and commercial farms led to the accumulation of phosphorous and potassium in the top soil, with the traditional method of combining organic and chemical fertilisers producing the highest total nitrogen soil content. A fifty percent reduction in chemical fertilisers in the commercial farms produced the lowest total nitrogen soil content, without any apparent change in crop yield. The three types of tested buffers seem to be effective in reducing runoff and sediment load and were particularly efficient in lowering nutrient leaching to streams; the best results were obtained with an effective length of 2.5 m.
Tài liệu tham khảo
Chatupote, W. and Panapitukul, N.: 2001, ‘Landform, soil, water resource and landuse in Rattaphum Catchment’, in Proceedings of an International Workshop on Agrochemical Pollution of Water Resources Under Tropical Intensive Agricultural Systems, Hat Yai, Thailand, 3–7 May.
Chatupote, W. and Panapitukkul, N.: (This issue), Regional assessment of nutrient and pesticide leaching in the vegetable production area of Rattaphum Catchment, Thailand.
Department of Agriculture: 2000, Annual Report, Ministry of Agriculture and Co-operatives, Bangkok, Thailand.
Imphitask, S.: 1994, ‘Report on pesticides residues analysis on vegetable production at Rattaphum District’, Division of Toxic Substances, Department of Agriculture, Ministry of Agriculture and Co-operatives, Thailand.
Kamnalrut, A., Choto, S. and Pipithsangchan, S.: 2001, ‘Management practices in the agrosystems of Rataphum Catchment area’, in Proceedings of an International Workshop on Agrochemical Pollution of Water Resources Under Tropical Intensive Agricultural Systems, Hat Yai, Thailand, 3–7 May.
Pipithsagchan, S., Kanatharana, P., Siriwong, C., Kammalrat, A. and Chatupote, W.: 1994, ‘Impact of the use of agrochemicals on water resources in southern Thailand’, ACIAR Proceeding No 61, Agricultural Impact on Groundwater Quality, Canberra, Australia, pp. 71–76.
Pipithsangchan, S. and Choto, S.: 1999, ‘The use and abuse of pesticides in the Agrosystems of Rataphum Catchment Study Area, Thailand’, in Proceedings of an International Workshop on Agrochemical Pollution of Water Resources Under Tropical Intensive Agricultural Systems, Hat Yai, Thailand, 3–7 May.
Pipithsangchan, S., Sritungnan, S. and Choto, S.: 2001, ‘On-farm comparisons between bio-insecticides and synthetic insecticides in vegetable production’, in Proceedings of a Conference, Hat Yai, Thailand, 16–18 February 2000.
Songkhla Lake Basin Planning Study: 1985, Main Report, John Taylor & Sons.
Supasawatkul, P.: 1999, ‘Evaluation of hygienic fresh fruit and vegetable production pilot project: A case study of Khuan Niang District, Songkhla Province’, M.Sc. Thesis, Mahidol University, Bangkok.
Tikavatananon, S.: 1977, ‘Insect pests of vegetables in central region of Thailand and their control’, M.S. Thesis, Kasetsart University, Bankok, 89 pp. (in Thai, with English summary).