Turkish Journal of Fisheries and Aquatic Sciences
2008, Vol 8, Num, 1 (Pages: 15-23)
Effect of Inclusion of Prawn and Mola on Water Quality and Rice Production in Prawn-Fish-Rice Culture System
2 Hajee Mohammad Danesh Science and Technology University, Department of Fisheries Biology and Genetics, Dinajpur, Bangladesh Viewed : 5288 - Downloaded : 2666 A long term experiment for a period of sixteen weeks was conducted from August to November, 2005 to observe the effects of inclusion of prawn (Macrobrachium rosenbergii) and mola (Amblypharyngodon mola) on water quality and rice production. To achieve the target, four treatments each with three replications were set in the experiment. In all treatments, prawn was stocked with mola in the rice field. The stocking densities of prawn were 10,000, 15,000, 20,000 and 25,000/ha in treatments T1, T2, T3 and T4 respectively. The stocking density of mola was 20,000/ha in all the treatments. All rice plots were fertilized with urea (200 kg/ha), TSP (150 kg/ha) and MP (75 kg/ha). The mean values of water quality parameters such as temperature, transparency, dissolved oxygen, pH, alkalinity, ammonia, nitrate-nitrogen, phosphate-phosphorus and chlorophyll-a in all the plots showed very small variations among the different treatments except chlorophyll-a which was relatively higher in all treatments. All the parameters were found within the suitable ranges for prawn and mola culture and with respect to cultural suitability, prawn performed comparatively higher growth rate and survival rate in treatment T2, where stocking density was 15,000 kg/ha. The highest production (456.16 kg/ha) of prawn was also recorded in the treatment-T2 compared to other treatments. The yields of rice grain recorded were 3.71 mt/ha, 2.88 mt/ha, 3.33 mt/ha and 3.04 mt/ha in T1, T2, T3 and T4, respectively. The highest yield of rice grain obtained was 3.71 mt/ha in treatment-1. The study provided evidence that the introduction of prawn and mola in rice fields has profound impacts on the availability of nutrients in the water and soil which ultimately increases the yield of rice grain and straw and at the same time provides an additional yield of prawn and mola from the same land and ultimately the rural poor farmers would benefit economically and nutritionally by adopting rice-prawn-mola integrated culture system. Keywords : integration, fresh water, Macrobrachium rosenbergii, Amblypharyngodon mola, rural farmer