草基—鱼塘生态系统的能量转化与养分循环研究

应用模拟试验的方法，研究了“草基-鱼塘”系统中的能量转化与养分循环．结果 表明，该系统中饲草对太阳能的利用率为 ０． ８３％，鱼对饲料能的转化率为 ７． ３％．与以粮 食作为鱼饲料比较，单位面积草地的产鱼当量是粮食作物的１．６倍．鱼对饲料Ｎ、Ｐ、Ｋ的 转化率分别为１６．８％、３２．３％和２．０％．塘泥沉积的Ｎ、Ｐ分别占饲料的２３．４％和５６．１％； 猪对饲料 Ｎ、 Ｐ、 Ｋ的转化率分别为 ２０． ５％、 ３３． ７％和 ４． ６％，猪粪尿回收饲料 Ｎ为 ３６． ４％、 Ｐ为 ６３． ８％、 Ｋ为 ３９． ４％．猪-草-鱼结合的基塘系统其能量和养分转化效率均高于单一的 养鱼系统．

Energy conversion and nutrient cycling in grassdyke-fish pond ecosystem.

The simulation study on the energy conversion and nutrient cycling in the grndyke-fishpond ecosystem shows that for this ecosystem, the photo-utilization rate of forage is 0. 83%, and the conversion efficiency of feed energy into fish is 7. 3 %. Comparing with grain for fish farming, the efficiency of forage is 1. 6 times greater. The conversion efficiency of feed nutrients (CEFN) to fish is 16. 8, 32. 3 and 2. 0 % respectively for N, P and K. The recovery of nutrients in fishpond sediment is 23.4% for N and 56. 1 % for P, and the CEFN to hog carcass is 20.5, 33.6 and 4. 6 %, respectively for N, P and K. The recovery of nutrients in the feces is 36. 4 % for N, 63. 8 % for P and 39. 4 % for K. The conversion efficiency of fed energy and nutrients to fish is higher in compound system than in single one.