自然沟渠与水泥沟渠水生植物群落结构及净水效果研究

Study on the community structure of aquatic plant and the effect of water purification in natural ditch and cement ditch

采用野外调查法,对养殖场自然沟渠与水泥沟渠的水生植物群落结构、生物量及其对水质的影响进行比较研究。结果表明:自然沟渠全年水生植物种类7科23属24种,以空心莲子草-菰群和空心莲子草-莲群为主,平均生物量为2 633.85 g/m2,真盖度>50%;水泥沟渠7科7属7种,以苦草群、金鱼藻群为主,真盖度<20%;自然沟渠生物多样性显著高于水泥沟渠。自然沟渠和水泥沟渠的TN分别为(0.97±0.32)mg/L和(1.48±0.61)mg/L,TP分别为(0.13±0.06)mg/L和(0.16±0.07)mg/L,Chl-a分别为(35.12±17.73)μg/L和(69.24±17.31)μg/L,DO分别为(3.67±2.17)mg/L和(6.12±1.95)mg/L。自然沟渠的水生植物丰富,净化水质效果显著,但溶氧显著低于水泥沟渠。从系统稳定性、构建费用、净化效果综合考虑,建议采用自然沟渠。

Through field investigating, the community structure and biomass of aquatic plant and the effect of Natural Ditch （ND） and Cement Ditch （CD） on water quality were studied to improve basis for building ecological ditch in the aquaculture farm. Studies showed：it comprised 17 families, 23 genus, 24 species, and consisted of Alternanthera philoxeroides-Zizania latifolia community, Alternanthera philoxeroide-Nelumbo nucifera community in ND, where the basal coverage of aquatic plant is more than 50% and the average of biomass is 2 633.85 g/mE ; it comprised 7 families, 7 genus, 7 species, and composed of Valisneria batans community, Ceratophyllum demersum community in CD, where the basal coverage is less than 20% and the biodiversity is greater than CD. The concentration of TN in ND and CD are 0.97±0.32 mg/L, 1.48±0.61 mg/L respectively ; the concentration of TP is （0.13 ± 0.06 ） mg/L, （0.16 ±0.07 ） mg/L respectively ; the concentration of Chl-a is（35.12± 17.73） μg/L, （69.24 ± 17.31 ） μg/L respectively; the concentration of DO is （3.67±2.17）mg/L, （6.12 ± 1.95）mg/L respectively. The aquatic plant is rich and the effect of water quality purification is obvious in ND, but DO is substantially lower than CD. Considering system stability, cost of building and effect of water quality purification, suggest to employ ND.