Research On Nutrients Absorption Character Of Two Kinds Of Fish Grasses And Balanced Fertilization

Along with the adjusting of country industry structure, it has been developed rapidly of limnetic fish culture in Jianghan plain. In order to save cost and make use of the local resource predominance, it is coming into being gradually production mode of planting grass for fish in the pisciculture region. Farmers did not know the nutrition character and nutrients management measures of fish grasses for it was a new "crop". The yield of fish grasses often can not content the demand of actual production though the areas of planting grass are enlarged constantly. So we had carried out a series of research works about fish nutrients management in Hubei province in recent years for probing into the nutrients absorption characters of sudangrass and ryegrass, and had done some field trials about fish grasses fertilization to provide scientific evidences for reasonable fertilization methods in planting grass. The main results were as following:1 It needed to absorb N 2. 56 kg, P₂O₅ 0. 76 kg, K₂O 3. 30 kg, Ca 0. 66 kg, Mg 0. 20 kg, N: P₂O-5: K₂O: Ca: Mg=l: 0. 30: 1. 29: 0. 26: 0. 08 and needed to absorb Fe 39. 7 g, Mn 8. 3 g, Cu 1. 4 g, Zn 8. 4 g, N: Fe: Mn: Cu: Zn=1000: 15. 5: 3. 3: 0. 5: 3. 3 by producing 1 ton fresh sudangrass in the treatment of accustomed fertilization. For the treatment of recommended fertilization, it needed to absorb N 2. 59 kg, P₂O₅ 0. 65 kg, K₂O 3. 13 kg, Ca 0. 55 kg, Mg 0. 20 kg, N: P₂O₅: K₂O: Ca: Mg=1: 0. 25: 1. 21: 0. 21: 0. 08 and needed to absorb Fe 34. 2 g, Mn 7. 8 g, Cu 1. 3 g, Zn 8. 0 g, N: Fe: Mn: Cu: Zn=1000: 13. 2: 3. 0: 0. 5: 3. 1. It can be a fertilization reference as planting sudangrass.2 It needed to absorb N 3.42 kg, P₂O₅ 0.85 kg, K₂O 3.46 kg, Ca 0.18 kg, Mg 0.19 kg, N : P₂O₅: K₂O : Ca : Mg=l : 0.25 : 1.01 : 0.05 : 0.06 and needed to absorb Fe 38.4 g, Mn 13.9 g, Cu 0.9 g, Zn 9.3 g, N : Fe : Mn : Cu : Zn=1000 : 11.2 : 4.1: 0.3 : 2.7 by producing 1 ton fresh sudangrass in the treatment of accustomed fertilization. For the treatment of recommended fertilization, it needed to absorb N 3.45 kg, P₂O₅ 0.96 kg, K₂O 3.73 kg, Ca 0.22 kg, Mg 0.20 kg, N : P₂O₅: K₂O : Ca : Mg=l : 0.28 : 1.08 : 0.06 : 0.06 and needed to absorb Fe 31.7 g, Mn 11.7 g, Cu 0.9 g, Zn 8.5 g, N: Fe : Mn : Cu : Zn=1000 : 9.2 : 3.4 : 0.3: 2.5. It can be a fertilization reference as planting ryegrass.3 In the rotation system of sudangrass-ryegrass, the total yields of the treatments...