微量元素对水库初级生产力的影响

采用生氧量生物测验法对影响水库初级生产力的微量元素进行了测定。结果表明，当氮、磷充足时，锰的限制作用较普遍，而锌、铜的抑制作用也常出现，铁、硒等其他元素在某些条件下也会起限制作用。围隔试验的结果也表明，在施氮、磷的基础上，加施锰剂后，浮游植物生物量（以活性叶绿素ａ表示）增高１．７倍以上，较之单纯施氮、磷肥，生物量亦增高了３５％以上，高峰持续时间约１０ｄ，浮游动物生物量亦有所增加。这些结果都表明锰在提高水库鱼产力中有重要作用，同时也说明在大水域施肥养鱼中添加微量元素是可行的。

Effects of Microelements on Primary Productivity of Reservoirs

The limiting micronutrients such as Fe, Mn, Zn, Cu, Co, Mo and Se in reservoir were determined with the oxygen evolution bioassay method. The results indicated that when N and P are enriched sufficiently, Mn was limiting frequently, whereas Fe ad Se were limiting occasionally; on the contrary, Zn and Cu acted as an inhibiting at most times. Furthermore, an enclosure experiment was carried out to determine the effect of Mn as a fertilizer. The results showed that the phytoplankton biomass (indicated by the active chlorophyll a concentration) in the enclosure fertilized with N, P and Mn increased 1.7 times as compared with the control, and increased by 35% as compared with that in the enclosure fertilized with N and P only, and the high level of phytoplankton biomass continued for about 10 days. The zooplankton biomass also increased to some extent. All of the results indicated that Mn plays an important role in increasing the fish productivity of reservoirs and it is feasible for fertilizing large water bodies as a micronutrient.