Theses and Dissertations


Title: Bottom soil quality in fish ponds of different ages in Thailand and suggestions for its management

Name: Taworn Thunjai

Degree: PhD

Chair: Claude E. Boyd

Resides:

University: Auburn University

Location: Auburn, Alabama

Date: 2002

Pages: 126

Keywords: Bottom soil quality,fish ponds,Thailand,management

Abstract:

This research was conducted to obtain data on bottom soil quality in ponds of different ages in Thailand. The annual application of liming materials has been a major feature in pond management. Thus, samples of liming materials were obtained from vendors for analysis of composition and quality. Samples from thirty-five ponds around Samutprakarn in the central region and the other seventeen ponds near Chiangrai in the northern region of the nation were collected. Production of tilapia has been practiced continuously in the same ponds for up to 40 years. The tilapia ponds at Samutprakarn are in semi-intensive production. Ponds are treated with about 2 tons/ha of liming materials and possibly up to 5 or 6 tons/ha of chicken manure per year in order to achieve this production. Ponds at Chiangrai are integrated with either chicken or pig production. The standard practice is to keep 90 to 120 pigs or 200 to 300 chickens per hectare of pond. The animals are kept in corrals such that animal feces and uneaten feed fall into the pond water. Average pond age is about the same at both locations. The averages of total alkalinity and total hardness concentrations in pond waters at Samutprakarn are greater than at Chiangrai, and total hardness in some ponds at Samutprakarn is greater than total alkalinity because of the reaction of sulfuric acid from acid-sulfate soils with liming materials that farmers apply to ponds. Soils in ponds at Chiangrai have a higher bulk density than those from Samutprakarn because they have lower clay content. Soils at Samutprakarn are naturally more acidic than those at Chiangrai, but use of liming materials has resulted in low exchangeable acidity, high pH, and the presence of substantial amounts of carbonate in bottom soils at both locations. Concentrations of total carbon and organic carbon seldom exceeded 3% and the relationship between pond age and soil organic matter concentration is not strong in ponds with or without sediment removal (p>0.05). Concentrations of nitrogen and phosphorus in pond soils did not differ with pond age at either site, and the carbon : nitrogen (C:N) ratio averaged 11 at both sites. Bottom soils of ponds in Chiangrai had greater concentrations of phosphorus than those at Samutprakarn. However, the phosphorus adsorption capacity of soil was much greater at Samutprakarn than at Chiangrai. Soil respiration was greater in soil samples from Samutprakarn than in those from Chiangrai even through soil carbon concentration, pH, and C:N ratio were similar between locations. This discrepancy could not be explained from available data. Liming materials sold as calcium carbonate contained 32.2% to 37.9% calcium, and magnesium concentrations were 1.07 to 5.28%. Neutralizing values and fineness ratings were between 81 to 100% and 55.2 to 100%, respectively. Liming materials sold as dolomite contained from 9.47 to 29.83% calcium and from 3.83 to 13.34% magnesium. Neutralizing values ranged from 41 to 108%. Liming materials sold as marl contained 21.14 to 35.68% calcium, and 0 to 13.72% magnesium. Neutralizing values and fineness ratings were between 71 to 107% and 56.13 to 99.67%, respectively. Liming materials sold as lime contained from 30.68 to 48.77% calcium and from 0.59 to 18.51% magnesium. Neutralizing values and fineness ratings were between 100 to 157% and 58.52 to 99.86%, respectively. Liming materials sold as ground shell contained from 25.95 to 41.13% calcium and from 1.07 to 5.29% magnesium. Neutralizing values and fineness ratings were 72 to 103% and 45.46 to 63.95%, respectively. About 50% of the liming materials were either identified incorrectly in regard to composition or of low quality. Carbon concentrations as measured by three different methods, carbon analyzer, sulfuric acid-dichromate oxidation, and dry ashing,

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