| Author | Dao Huy Giap |
| Call Number | AIT Thesis no. AS-99-07 |
| Subject(s) | Shrimp culture
|
| Note | A thesis submitted in partial fulfillment of the requirements
for the degree of Master of Science, School of Environment and Resources Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AS-99-07 |
| Abstract | Comparison between fertilization and feeding for culture of freshwater prawn
(Macrobrachium rosenbergii) in ricefields was conducted during a 90-day experiment at the
Asian Institute of Technology, Bangkok, Thailand. The experiment consisted of four
treatments in 3 replicates: Treatment 1 was rice with normal fertilization, Treatment 2 riceprawn
with normal fertilization, Treatment 3 rice-prawn with feeding, TSP and half of normal
urea fertilizer, Treatment 4 rice-prawn with feeding and normal fertilization. There were
significant (P<0.05) differences among Treatments in overall mean concentration of DO, N02-
N, N03-N and chlorophyll-a in trench. At the end of experimental period, only DO
concentration was significantly (P<0.05) different among Treatments. The gross and net
primary production of water and periphyton in ricefields were not significantly (P>0.05)
different among Treatments. Overall, primary production decreased toward the end of
experiment. There were no significant (P>0.05) differences among Treatments in number of
tiller per hill; the maximum number of tiller per hill was about 16 tillers on the 601
h day after
transplanting. Rice yields were significantly (P<0.05) different among Treatments. Rice yield
in Treatment 4 (0.42 kg/m2
) was not significantly different from that in Treatment 1 (rice
monoculture), although the planted area in Treatment 4 was reduced by 20%. Treatments 2
and 3 gave significantly lower yields than that in Treatment 1. There were significant
differences among Treatments in prawn growth rate and prawn production (P<0.05) but not in
survival rate (P>0.05). Treatments 3 and 4 gave significantly (P<0.05) faster growth than
Treatment 2. However, the prawn yield in Treatment 4 was not significantly (P>0.05) higher
than that in Treatment 2. Average prawn weights increased at higher growth rates during the
first 60 days after stocking, and then increased with lower growth rates toward the end of
experiment. There was no significant difference in FCR between Treatments 3 and 4. The
average individual weight of prawn at harvest ranged widely from 5 to 54 g/prawn. The size
distribution of prawn weight in Treatment 3 was larger than that in other Treatments, indicated
by larger standard deviation of 7.4 g in Treatment 3 compared with 4.9 g and 5.8 g in
Treatments 2 and 4, respectively. The average water requirement for rice-prawn culture fields
from transplanting to harvest was 948 mm ranging from 858 mm to 1073 mm. The main
source of nutrient input for rice was fertilizers, which accounted for about 59% to 98% of the
nitrogen, and 89% to 98% of the phosphorus input. Feed for prawn also contributed 30% in
Treatment 3 and 19% in Treatment 4 in terms of nitrogen and about 8. 5% in both Treatments
in terms of phosphorus. Rice-prawn culture required higher investment (740 to 1023
USD/ha/crop) than rice monoculture (260 USD/ha/crop ). In rice monoculture, return to total
variable cost was significantly (P<0.05) higher than that in rice-prawn culture. However,
return per family labor was significantly higher (P<0.05) in rice-prawn culture (2.4 to 2.8
USD/person/day) than that in rice monoculture (1.6 USD/person/day). Treatment 3 gave the
highest value of 2.8 USD/person/day. |
| Year | 1999 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AS-99-07 |
| 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, C. Kwei;Yi, Yang; |
| Examination Committee(s) | Edwards, Peter;Shivakoti, G. P.; |
| Scholarship Donor(s) | Government of Japan; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1999 |