tailieunhanh - BÁO CÁO " ĐÁNH GIÁ MỨC ĐỘ TÍCH LŨY ĐẠM, LÂN TRONG MÔ HÌNH NUÔI TÔM SÚ (Penaeus monodon) THÂM CANH "

Nghiên cứu về mức độ tích lũy đạm, lân trong mô hình nuôi tôm sú thâm canh được thực hiện tại tỉnh Bạc Liêu nhằm xác định mức độ và sự phân bố dinh dưỡng của chất thải trong mô hình này. Thí nghiệm được bố trí với hai mật độ nuôi (27 con/m2 và 35 con/m2 ) trong ao đất ( m 2 /ao) với hai lần lặp lại. Kết quả cho thấy các chỉ tiêu môi trường nước biến động trong thời gian nuôi tôm sú (168 ngày) nhưng trong giới hạn cho phép. Gần cuối vụ. | Tạp chí Khoa học 2008 1 44-52 Trường Đại học Cần Thơ ĐÁNH GIÁ MỨC ĐỘ TÍCH LŨY ĐẠM LÂN TRONG MÔ HÌNH NUÔI TÔM SÚ Penaeusmokodon THÂM CANH Nguyễn Thanh Long1 và Võ Thành Toàn1 ABSTRACT A study on nutrient mass balance in the shrimp intensive culture system was conducted in Bac Lieu province. The aim of the study was to determine the accumulation and dispersal levels of nitrogen and phosphorus in this culture model. Two shrimp stocking densities 27 PL m2 and 35 PL m2 were designed in two earthen ponds 2 000 m2 pond with two replicates each. The results indicated that all measured parameters were fluctuating during the culture period 168 days . However these values varied within the acceptable ranges. The quality of culture water reduced towards the end of the culture period in both treatments. Concentrations of TAN NH3 NOf NO3- TKN chlorophyll-a and TSS increased during this period. DO concentration at 6 AM was decreasing after one month of culture period. There were no significant differences in yields between treatment 1 4 953 413 kg ha crop and treatment 2 4 842 850 kg ha crop however survival rate in treatment 1 was significantly higher than that in treatment 2 while daily weight gain in treatment 1 g shrimp day was significantly lower than that in treatment 2 0 01 g shrimp day p . FCRs in two treatments were high but no significant difference found between treatment 1 and treatment 2 P . Nitrogen accumulated in shrimp water and sediment was 16 29 and 28 respectively. Similarly 9 2 and 40 were found for phosphorous in these sources respectively. In addition significant uncountable amounts of nitrogen and phosphorus considered loss were 27 and 49 respectively. Results of nutrient mass balance asl indicated that to produce 1 ton of shrimp approximate 118 120 kg N of nitrogen and 30 33 kg of phosphorus were released into the environment. Keywords nitrogen phosphorus intensive tiger shrimp culture .