A study was conducted at the Bangladesh Agricultural University (BAU) Farm in order to determine the seepage and percolation (S and P) loss in the transplanted Aman (T. Aman) rice field during the period from 23 August to 6 November 2010. The variety of rice was BRRI dhan49. The soil was silty loam having 78% silt, 12% sand and 10% clay. The study was conducted following two cylinders method for measuring seepage and percolation and Blaney-Criddle method for estimating evapotranspiration. This loss (S and P) was combined with evapotranspiration to determine the total water requirement. It was observed that the seepage and percolation loss in the study area varied from 1 to 8.50 mm day-1 with an average of 4.18 mm day-1. Total seepage and percolation loss was 307 mm for the whole growing season. The estimated evapotranspiration for the total growing season was found to be 538 mm with an average of 6.49 mm day-1. The total water requirement was 845 mm for the study period. During the study period seepage and percolation and evapotranspiration was 37% and 63% of total water requirement, respectively. Land soaking, land preparation, and surface drainage loss was not considered to determine water requirement.

Keywords: Seepage and percolation loss, T. Aman rice, water requirement, yield

This study was designed to assess the comparative profitability of T. Aman rice farming in saline and nonsaline area at Dacope upazila of Khulna district of Bangladesh. In total, 240 farmers were randomly selected for the study among which 120 from saline area and rest 120 from nonsaline area. Descriptive statistics, activity budgets, Cobb-Douglas production function model were employed to achieve the objectives of the study. The study confirmed that T. Aman rice production of nonsaline area were profitable than saline area. Per hectare total cost, gross return and net return of T. Aman farming in nonsaline area were Tk 33,097.00; 59,723.00 and 26,626.00, respectively. Similarly, Per hectare total cost, gross return and net return of T. Aman farming in saline area were estimated at Tk 37,003.00; 50,666.00and 13,663.00, respectively. It was observed that the coefficient of human labour, power tiller and insecticide were positive and had significant impacts on gross returns of T. Aman rice production in nonsaline area. Similarly, the coefficient of seedling, power tiller, human labour, TSP and insecticide were positive and had significant impacts on gross returns of T. Aman rice production in saline area.

Keywords: T. Aman rice, saline, economic and comparative analysis