Using fish culture water and sludge may benefit vegetable production by reducing the need for high-quality irrigation water in areas where water is a limiting resource for agriculture. Fish water and sludge contains nutrients, thereby reducing the need for chemical fertilizers. A study was conducted to integrate fish (tilapia) culture with field production of Pak choi (Brassica rapa L. Chinensis). Water from tilapia culture tanks from which solids were removed (SR) and from tanks with no solid removal (NR) were applied to pak choi 2 to 3 times weekly through a drip system. These treatments were compared with sludge (FS) removed from culture tanks using three methods of irrigation. Conventional methods of fertigation (F) and band fertilizer (B) application were included as control treatments. The trial was conducted for 2 seasons. In the first season, pak choi applied with (FS) produced total yields ranging from 21 to 26 t·ha–l. Pak choi applied with fish water from tanks with (SR) and (NR) produced yields of 19 and 20 t·ha–l, respectively. Pak choi grown with (F) and (B) applications yielded 21 and 20 t·ha–l, respectively. There were no significant yield differences between the (FS) treated and (F) plots. Yield from (FS) treatment was significantly higher than all other treatments except (F). Similar results were obtained during the second season, but total yields from various treatments were 50% higher than the first season. Fish culture water and sludge are therefore good alternative sources of irrigation and fertilizer for pak choi.
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