| Popis: |
Different soil types were studied for supplementing ponds with fertilizers and their effect on water quality parameters with two culture systems. The pond soils were clayey, claysandy, and sandy in three different locations in Egypt. The fish ponds were fertilized with organic fertilizers (compost) and inorganic fertilizers with a rate of 500 kg/feddan/week and14(nitrogen: phosphorus with ratio of 4:1) kg/feddan/week, respectively. Nile tilapia Oreochromis niloticus was reared with initial body weight of (5.31g±0.03) in monoculture system with density of 22,000 fish/feddan and with grey mullet Mugil cephalus with initial body weight of (9.88g± 0.06) in polyculture system fed on commercial diet (25% crudeprotein) for 240 days. The results revealed that the dissolved oxygen, total alkalinity, total hardness, and total dissolved solids increased insignificantly in clayey soil more than claysandy and sandy soil. In addition, fertilization and monoculture system raised the values not significantly. Total ammonia, unionized ammonia, nitrates (NO3), and nitrites (NO2) followedthe same trend. Total phosphorus, orthophosphate, chlorophyll”a” and zooplankton (animal/L) were significantly (P |
