Estimating Nutrient Flux of an Integrated Agriculture-Aquaculture System in Peri-Urban Thailand

抄録

There has been little information available on nutrient and heavy metal contents of animal manure (cattle, poultry and pigs) in Integrated Agriculture-Aquaculture (IAA) farm systems in Thailand and Southeast Asia. Such systems have an important role in these areas. In this study the nutrient and heavy metal contents were measured so that metal budgets could be constructed and “typical” rates of the inputs to IAA-farming systems calculated. This study was carried out over a period of one year (2007- 2008) in a peri-urban area in Thailand. Small scale pig farms in the peri-urban Pathum Thani province near Bangkok were considered typical of up to a third of total pig farms of the country. The specific objective of this study was to quantify nutrient and heavy metal (nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), copper (Cu) and zinc (Zn)) fluxes in (i) the agricultural systems with small scale pig farms and (ii) the downstream aquacultural systems with piggery waste-fed fish ponds. We quantified the amount of nutrients released as a result of farming and estimated the assimilative capacity of the surrounding environment. Nutrient inputs (feed) and releases as pig manure were sampled monthly in the fattening period (about 6-7 months) to provide information on the environmental load in that period. Information about nutrient and heavy metal fluxes in the IAA system can be used for farm management decisions with a view to decreasing the environmental impact of piggeries and fish farms. Nutrient and heavy metal flux data can be used as a basis for developing a practical tool to estimate nutrient flux for an IAA system.