| The experiment was conducted to screen the species of three vegetables (Ipomoea aquatica, Brassica oleracea var acephala, Lactuca sativa) and the best planting way with three cultivations planted in the shrimp aquaculture water. And then, the best variety was planted with the best planting way in the large-scale shrimp ponds to study the vegetable growth condition and the purification effect of the vegetable on the water quality in shrimp ponds. The results
showed that I. aquatica was the best vegetable for planting in shrimp ponds, and the knot planting pattern was the best way to plant water spinach. After that, I. aquatica was planted by knotting cultivation, the effects of I. aquatica on survival,growth characteristics of Litopenaeus vannamei and water quality were analyzed. The results showed that at the end of the experiment, the concentrations of TAN, NO2--N, NO3--N, TP, PO43--P, and CODMn in the planting ponds were lower than those in the control ponds. The percentage removal of total nitrogen (TN) and total phosphorus (TP) in the planting ponds and in the control ponds were 38.50% and 22.03%, 34.82% and 19.02%, respectively. In the planted pond, the feed
conversion rate was higher, the fresh weight of I. aquatica was 2 441 (±183) kg, the removal rates of TN and TP were
6.23% and 3.9%, respectively, the average product of shrimp was 4 768.75 (±111.69) kg/hm2, while higher than that in the
control ponds with 4 120.46 (±90.00) kg/hm2. The results suggested that the ecological aquaculture mode could not only
effectively purify water quality, reduce the environmental pollution of aquaculture waste water, but also improve the
economic benefits of shrimp aquaculture. |
