鸡粪和牛粪对罗非鱼养殖水体中浮游植物群落结构的影响

为探讨在罗非鱼Oreochromis niloticus养殖水体中施用鸡粪、牛粪等有机肥对浮游植物群落结构的影响,在容积为1.2 t的塑料桶(直径为1.3 m,高为1.0 m)中,装入1 t曝气20 d的自来水和从周边池塘水源水中用25#浮游生物网捞取的含有浮游生物的水体1000 m L,每个桶中放养体质量为(2.49±0.58)g的吉富罗非鱼GIFT Oreochromis niloticus 50尾,投喂约为鱼体质量5%的配合饲料,分别施发酵的腐熟鸡粪、牛粪、鸡粪-牛粪(1∶1)混合肥,以不施肥作为对照组,养殖试验为期60 d,前20 d每10 d施肥1次,后40 d每20 d施肥1次,共施肥4次,研究施用有机肥对罗非鱼养殖水体中浮游植物群落结构的影响。结果表明:对照组、鸡粪组、牛粪组、鸡粪-牛粪混合组的藻类总生物量变化范围分别为(1525~6990)×104、(1472~4299)×104、(1355~8795)×104、(575~9104)×104cells/L,藻类总生物量均呈升高趋势;各组蓝藻生物量变化范围分别为(1300~4095)×104、(702~3278)×104、(700~4080)×104、(328~3278)×104cells/L,对照组的蓝藻生物量高于同期有机肥组;蓝藻比例表现为对照组牛粪组鸡粪-牛粪混合组鸡粪组,绿藻比例总体表现为对照组牛粪组鸡粪-牛粪混合组鸡粪组;多样性指数和均匀度指数的大小顺序均表现为对照组牛粪组鸡粪-牛粪混合组鸡粪组。研究表明,在养殖水体中添加鸡粪、牛粪,具有抑制蓝藻生长、促进绿藻生长和改善浮游植物群落结构的功效,且鸡粪优于牛粪。

Effect of chicken manure and cow dung on phytoplankton community in tilapia Oreochromis nicoticus culture water

The 1. 2 t round plastic tanks (1. 3 m in diameter, and 1. 0 m in height ) were supplied with dechlori-nated tap water aerated for 20 days and 1000 mL pond water containing plankton collected from the water supply a-round aquaculture ponds by phytoplankton net. Fifty tilapia GIFT Oreochromis niloticus with body weight of (2. 49± 0. 58)g were stocked into the tanks at stocking rate of 50 fish, and fed commercial diet at 5% of the tilapia biomass daily for 60 days. The tanks were applied fermented chicken manure ( chicken group M) , cattle manure ( cattle M group) and chicken-cattle mixture (chicken-cattle M, chicken manure : cattle manure = 1 : 1), once every 10 days during the first 20 days, and then once every 20 days during the later 40 days and the tanks were not applied any chicken manure and cattle manure as control group, to study the effects of organic fertilizer on community struc-ture of phytoplankton in tilapia culture water. The results showed that the biomass of total phytoplankton was changed from 1525×104 to 6990×104 cells/L in control group, 1472×104 to 4299×104 cells/L in chicken M group, 1355×104 to 8795×104 cells/L in cattle M group, and 575×104 to 9104×104 cells/L in chicken-cattle M group, increase in the total biomass of phytoplankton in all test groups during the experiment. The biomass of cyanophyta was found to be from 1300×104 to 4095×104 cells/L in control group, 702×104 to 3278×104 cells/L in chicken M group, 700×104 to 4080×104 cells/L in cattle M group, and 328×104 to 3278×104 cells/L in chicken-cattle M group, higher biomass of cyanophyta in control than in the fertilizer groups. The order of proportion of cyanophyta in the total phytoplankton was followed by control group>cattle M group>chicken-cattle M group>chicken M group, while the order of proportion of chlorophyta in the total phytoplankton was described as chicken M>group chicken-cattle M group>cattle M group>control group. The order of biodiversity index and uniformity index were expressed as chicken M group>chicken-cattle M group>cattle M group >control group. The findings indicate that application of chicken manure and cattle manure in tilapia culture water leads to inhibit cyanophyta growth, facilitate chloro-phyta and improve phytoplankton community structure, especially, chicken manure.