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    Cost and return analysis of milkfish operations in different farm sizes in Barotac Nuevo, Iloilo
    Belgira, Gay Nanette (Division of Social Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1996-07)
    Milkfish (Chanos chanos) is the most important pond cultured fish specie in the Philippines. Barotac Nuevo, where the study was conducted, is among the most productive in the province of Iloilo in terms of milkfish culture. Cost and Return Analysis of Milkfish Production evaluates the economic performance of 30 milkfish farms in Barotac Nuevo, Iloilo. The economic performance of milkfish farms were assessed using profit, revenue, return on investment, rate of return on operating cost, and payback period. Investment and cost structure were also presented. Comparative analysis was done by farm size namely; small farms (less than 5ha), medium farms (5.01 to 20ha) and large farms (above 20ha). Farm investment increased as farm size increased. The highest yield per hectare per crop was obtained by medium farms (708.86kg) followed by large farms (566.76kg) and small farms (394.16kg). For all farms, economic profit decreased as fann size increased on a per farm basis. Small farms had an economic profit of P7,525.25. Medium farms had P55,157.66 while large farms had P131,575.59. Results showed that variable cost of medium farms(21,056.97) on a per hectare basis was higher than that of the large farms(20,298.67) while fixed cost of all farms on a per hectare basis decreased as farms size increased. Opportunity cost of farms on a per hectare basis decreased as farm size increased. Small farms had the lowest return on investment (14.30%) followed by medium farms (30.68%) and large farms (42.31%). Rate of return on operating cost for small farms was 56.03% while medium farms had 26.53% and large farms had 13.14%. Payback period of all farms decreased as farms size increased. Small farms had 6.99 years, medium farms had 3.29 years and large farms had 2.36 years. From all economic indicators presented, milkfish pond culture remains a profitable business venture in Barotac Nuevo, Iloilo. Small farms were found to be productive due to the close farm supervision devoted by owners themselves, but medium farms were found to be most profitable farm size to operate in milkfish pond culture in Barotac Nuevo, Iloilo. Large farms has lower yield because of the large area it occupies that an operator can hardly check all areas.
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    Chemical changes in a limed and flooded acid sulfate fishpond
    Baylon, Carlos C. (University of the Philippines at Los Baños, 1981-10)
    Field and laboratory studies were conducted on an acid sulfate soil in Carles, Iloilo with the following objectives: a) to characterize the soils in the pond bottom and along the dikes of an acid sulfate fishpond; b) to follow-up some chemical changes occurring in the flooded acid sulfate ponds, and c) to evaluate the effect of liming on these chemical changes. The pH (1 :1 soil-water) of the air-dried soil samples collected from the pond bottom and along the dikes of the nursery ponds ranged from 2.2 to 4.6. This was significantly correlated with the lime requirement, extractable Al, active Fe and Mn, acetate-soluble sulfate and total sulfur content of the soil. In the field experiment, before lime treatment, the waters of the nursery ponds exhibited decreasing pH with time as well as increasing concentrations of dissolved Al and Fe. The level of Mn in the water was low due to the small amount of active Mn present in the soil. Acidity in the pond waters after a heavy rain was mainly due to the leaching of sulfuric acid from the dikes. Three lime treatments were used in the study: I-lton/ha of lime applied along the dikes and 3 tons/ha on the pond bottom, II - 3 tons/ha of lime on dikes and 1 ton/ha on the pond bottom, III - 4 tons/ha of lime on dikes and no lime on the pond bottom. Treatment II could be considered the most effective way of applying lime since the ponds in this treatment exhibited the highest mean water pH compared to the ponds of the other treatments. Fish mortalities were observed in one of the ponds (NP10 in Treatment III) which may be traceable to the low pH and high Al concentration in the pond water. The applied lime on the dike was not able to control the acidity because it washed down by the rains and covered with eroded soil. The SMP buffer method of determining lime requirement overestimated the lime required to control the acidity of the water in acid sulfate ponds.