Biodegradability and Nutritional Value to Zooplankton of Selected Organic Fertilizers

Abstract

Abstract In laboratory studies we compared the biodegradability and nutritional value to zooplankton of four organic fertilizers. Degradability rates and ultimate biochemical oxygen demand of wheat shorts, cottonseed meal, alfalfa meal, and chicken manure were computed. The nutritional values of the three meals, and of combined trout chow–yeast–CEROPHYL® (TCYC) food, were compared by ability of Ceriodaphnia dubia and Daphnia magna to survive and reproduce in culture media prepared from them. Decomposition rates and decomposable organic matter for the three meals were similar. Chicken manure oxidized more rapidly than the vegetable meals, but contained less decomposable organic matter. Both C. dubia and D. magna survived better and produced more neonates in cultures with alfalfa meal than in those with wheat shorts or cottonseed meal. Daphnia magna in cultures with wheat shorts or cottonseed meal did not reproduce. Daphnia magna reproduced about 19 h earlier in the alfalfa meal culture than in the TCYC med...