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- Title
种植密度对鱼菜共生系统氮素转化的影响.
- Authors
蔡淑芳; 陈 敏; 陈永快; 包兴胜; 张 钟; 雷锦桂
- Abstract
This study aims to discuss the effects of plant density on nitrogen transformation in aquaponics system, the purpose is to obtain the suitable arrangement of plant density for greenhouse aquaponics in Fuzhou. The experiment was conducted in a solar greenhouse in Fuzhou China-Israel Demonstration Farm in Fujian province from July to August in 2017. An experimental aquaponics system based on NFT (Nutrient Film Technique) cultivation was set up in the greenhouse. The cultivated variety of vegetable in the experiment was Ipomoea aquatica. The aquacultured variety of fish in the experiment was Carassius auratus gibelio. The cultivated area was 1.0 m2 and the aquaculture water amount was 350 L. The treatments comprised three plant densities(A(60 plants/m2), B(45 plants/m2),C(30 plants/m2)) with 10kg/m3 aquaculture density. The three treatments were experimented totally and every treatment was replicated three times. There were three harvests of vegetables without root during these experiments. The water quality and the growth of fish and vegetable during the 33d operation of system were investigated. The conversion of added nitrogen and the influence of time and plant density on the mass concentration of nitrogen compounds were discussed. The results showed that the water quality of different plant density systems, including water temperature, pH, DO and EC, was relatively stable and suitable for the growth of fish and vegetable. The main index of biological characteristics of fish and vegetable increased to different degrees. By analysis of variance, plant density had positive impact on the increment of total fresh quality of vegetables (P=0.000) and the increment of total nitrogen accumulation in vegetables (P=0.002), which indirectly meant the plant areas could be expanded. There was no significant interaction between plant density and relative growth rate of the main index of biological characteristics of fish and vegetable. Regardless of loss of nitrogen such as N2O, N2, 49.32%-68.41% of added nitrogen from feed were accumulated in fish and vegetable. Nitrogen content in fish and vegetable were negative increased and not better than that in ordinary aquaculture and NFT cultivation, which meant optimization measures such as biological filter and medium culture could be adopted. Mass concentrations of ammonia, nitrite and nitrate nitrogen changed significantly with time (P=0.000). Under the action of nitrification and denitrification, the mass concentration of nitrogen compounds fluctuated and ammonia nitrogen was converted to nitrate nitrogen. At the late stage of the system operation, the mass concentration of nitrogen compounds was basically stable, and the mass concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen were about 2.50, 0.20 and 5.00 mg/L, respectively. The mass concentration of nitrate nitrogen in different plant density systems was significantly different (P=0.028), and the system with plant density of 45plants/m2 had a higher accumulation advantage of nitrate nitrogen. Plant density had no significant impact on the mass concentrations of ammonia nitrogen and nitrite nitrogen. Nitrogen conversion can be further enhanced by expanding cultivation area, installing biological filter and adjusting cultivation mode. In conclusion, the plant density of 45plants/m2 for Ipomoea aquatica is an appropriate plant density for greenhouse aquaponics in Fuzhou and other measures should be combined to improve the nitrogen conversion effect.
- Publication
Transactions of the Chinese Society of Agricultural Engineering, 2019, Vol 35, Issue 4, p132
- ISSN
1002-6819
- Publication type
Academic Journal
- DOI
10.11975/j.issn.1002-6819.2019.04.016