| Author | Lam My Lan |
| Call Number | AIT Thesis no. AS-99-03 |
| Subject(s) | Sewage as fertilizer
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree
of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AS-99-03 |
| Abstract | A feasibility study was conducted from December 1998 to April 1999 to use wastewater
from intensive hybrid catfish (Clarias macrocephalus x Clarias gariepnus) pond culture as
fertilization for rice crop at the Center of Aquaculture Development and Training of
Freshwater Aquaculture Department, Cantho University, Vietnam. In this experiment, hybrid
catfish fingerlings with individual mean weight of 16.7 ± 4.0 g were stocked at density of 10
fish/m2 in a 400-m2 earthen pond. Hybrid catfish were fed with home-made feeds twice daily
at feeding rates of 5 - 10% of body weight per day for 105 days. Water from the pond was
pumped through a hose system to irrigate the rice fields. The quality of effluents from the
pond was determined when supplying the rice fields.
Rice plots in four treatments of rice cultivation with three replications each were
conducted in twelve 50-m2 rice plots. Treatment 1 was irrigated with canal water without
fertilizer input; Treatment 2 was irrigated with canal water and inorganic fertilizer inputs
(nitrogen, phosphorus and potassium); Treatment 3 was irrigated with water from the catfish
pond as the only fertilization input; Treatment 4 was irrigated with water from the catfish pond
supplemented with phosphorus and potassium fertilizers.
The nutrient contents in water from the hybrid catfish pond were higher than those of in
the canal water. Total nitrogen and total phosphorus in pond water and were applied to the rice
crop was 31.85% and 24.43% of total nutrient loading from feed to the pond water,
respectively. The grain yields in Treatments 2, 3 and 4, ranging from 2.86 to 3.08 t/ha, were
not significantly different (P>0.05). The highest filled grain yield was achieved in Treatment
4, which was not significantly different (P>0.05) from that in Treatment 3, but significantly
higher (P<0.05) than that in treatments 1 and 2. There was no significant difference (P>0.05)
in apparent nitrogen recovery from total nitrogen applied to Treatment 2 (17.32 ± 4.81 %),
Treatment 3 (35.96 ± 22.21 %) and Treatment 4 (32.11 ± 20.63%). Apparent phosphorus
recovery from total phosphorus applied in Treatment 3 (128.71 ± 73.97%) was significantly
higher (P<0.05) than that in treatments 2 (25.35 ± 9.6%) and 4 (21.99 ± 8.97%). Nitrogen and
phosphorus recovery was highest in Treatment 3 among all four treatments. Therefore,
wastewater from the catfish pond can be reused for rice crop to reduce environmental impacts
of intensive aquaculture effluents and lower fertilizer costs. |
| Year | 1999 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AS-99-03 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Aquatic Systems (AS) |
| Chairperson(s) | Lin, Chang Kwei;Yi, Yang; |
| Examination Committee(s) | Hansen, Gunner Kjer; |
| Scholarship Donor(s) | Swedish International Development Cooperation
Agency (Sida); |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1999 |