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On-Station and On-Farm Trials of Different Fertilization Regimes Used in Bangladesh 10ATR4

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On-Station and On-Farm Trials of Different Fertilization Regimes Used in Bangladesh

Appropriate Technology Research 4 (10ATR4)/Study and Activity/Bangladesh and Thailand

Collaborating Institution
Asian Institute of Technology, Thailand
     C. Kwei Lin
     Yang Yi

Bangladesh Agricultural University, Bangladesh
     Md. Abdul Wahab

The University of Michigan
     James S. Diana

Objectives
1) Evaluate the different fertilization regimes currently used for aquaculture in Bangladesh.

2) Compare effects of different fertilization regimes on fish production, water quality, pond effluents and economic returns.

3) Recommend best fertilization regimes to small-scale rural farmers.

Significance
Bangladesh is one of the most densely populated countries in the world. Fisheries and aquaculture in particular are vital to Bangladesh's national economy in terms of nutrition, income, employment generation and foreign exchange earning (Alam et al., 1996). Currently approximately 80% of the animal protein supply for residents is provided by fish, but population growth is rapidly overwhelming the productive potential of the Bangladesh fishery (O'Riordan, 1992). Since the 1960s, per capita availability of fish has dropped from 12 kg to only 7 kg, moreover among lower income groups per capita consumption is only 4.4 kg. For the poorest of the poor, fish is simply unaffordable (O'Riordan, 1992). Thus, aquaculture plays more and more important roles to meet the nutritional needs of Bangladesh people.

Bangladesh has a variety of aquaculture and fisheries projects that have been funded by international aid. Many non-government organizations (NGOs) such as PROSHIKA, BRAC, CARE and CARITAS have been promoting aquaculture development independently through their own extension networks in Bangladesh.

Aquaculture is commonly practiced using polyculture of 4-7 species of Indian and Chinese carps in manured and/or fertilized ponds (Wahab et al., 1991). In spite of extensive research has been conducted on fertilization in carp polyculture ponds in many parts of the world, such information in Bangladesh is rather scanty (Haq et al., 1993). Fish production is quite low in Bangladesh, averaging 2,800 kg ha-1 yr-1 (DOF, 1999). In rural aquaculture ponds, fish production is often lower than 1,500 kg ha-1 yr-1. NGOs have been working with farmers to increase fish production, however, different NGOs recommend different fertilization regimes to farmers, and these regimes do not all seem to increase yields. Fertilization regimes should vary with different local conditions such as soil and source water. In some cases, the same farmers receive very different recommendations on fertilization regimes from different extension partners. Both over- and under-fertilization may cause adverse effects on fish production, water quality, pond effluents and economic returns. It is necessary to evaluate fertilization regimes and recommend appropriate fertilization strategies to farmers in order to maximize fish production, maintain good water quality, reduce environmental impact and maximize economic returns.

Anticipated Benefits
The results of this study will provide an appropriate fertilization strategy to polyculture Indian carps and Chinese carps for small-scale rural farmers. It will benefit fish culturists in Bangladesh and other countries in the region where carps are commonly polycultured.

Research Design

This study would consist of two main components, i.e., on-station trials and on-farm trials.

On-Station Trials
Location: Bangladesh Agricultural University (BAU), Field Laboratory, Mymensingh, Bangladesh (on-station trials)

Methods: Pond research

Pond Facility: Fifteen 100-m2 earthen ponds will be used.

Culture Period: 150 days

Stocking Density: 1 fish/m2; stocking size: 8-10 g

Test Species: silver carp Hypophthalmichthys molitrix, mrigal Cirrhinus mrigala, rohu Labeo rohita, catla Catla catla, grass carp Ctenopharyngodon idella, and common carp Cyprinus carpio; species ratio: 6:5:4:2:2:1.

Nutrient Inputs: Varying with treatment.

Water Management: Maintain at 1.0-1.2 m depth.

Sampling Schedule:

Statistical Design, Null Hypothesis, Statistical Analysis: Experimental design: The experiment design is a randomized complete block design (due to different size of pond surface area). There will be five fertilization regimes with three replicates each. (A) PROSHIKA fertilization regime: weekly application of 1,250 kg cow manure, 15 kg urea and 22.5 kg TSP per hectare (personal communication). (B) BRAC fertilization regime: weekly application of 156 kg cow manure, 27.5 kg urea and 13.1 kg TSP per hectare (personal communication). (C) CARITAS fertilization regimes: fortnight application of 1,500 kg cow manure per hectare. (D) BAU fertilization regime: fortnight application of 5,000 kg cow manure, 50 kg urea and 50 kg TSP per hectare (Wahab et al. 1999). (E) CRSP organic fertilization regime developed from Nile tilapia ponds: 250 kg cow dung (DM) ha-1 wk-1 supplemented with urea and TSP to give 28 kg N and 7 kg P ha-1 wk-1 (Knud-Hansen et al. 1991a).

Null hypothesis: Different fertilization regimes in carp polyculture ponds have no effect on the growth, water quality and pond effluents.

The results of fish growth and water quality will be analyzed for significant differences among treatments using ANOVA.

On-Farm Trials
Location: Working sites of four NGOs (PROSHIKA, BRAC, CARE, and CARITAS), Bangladesh (on-farm trials)

Methods: Pond research

Pond Facility: 6 earthen ponds in each of four NGO sites will be used.

Culture Period: 180 days

Stocking Density: 1 fish/m2; stocking size: 8-10 g

Test Species: silver carp Hypophthalmichthys molitrix, mrigal Cirrhinus mrigala, rohu Labeo rohita, catla Catla catla, grass carp Ctenopharyngodon idella, and common carp Cyprinus carpio; species ratio: 6:5:4:2:2:1.

Nutrient Inputs: Varying with different treatments

Water Management: Maintain at 1.0 to 1.2 m depth

Sampling Schedules: All water quality parameters mentioned before will be analyzed at beginning and end of the experiment. Fish growth at final harvest. Partial budgets will be estimated to assess costs and value of fish crops.

Statistical Design, Null Hypothesis, Statistical Analysis

Experimental design: The experiment is a randomized complete block design. In each NGO site, the best fertilization regime from on-station trial will be compared with the respective NGO fertilization regime, three replicates each.

Null hypothesis: Different fertilization regimes in carp polyculture ponds have no effect on the growth.

The results of fish growth and water quality will be analyzed for significant differences between treatments using ANOVA.

Regional Integration
Polyculture of Indian major carps and Chinese carps is commonly practiced in South Asia. Improvements in fertilization regimes for polyculture ponds will provide an appropriate polyculture strategy for small-scale rural farmers in terms of technical, environmental and economic aspects. It will be of interest to all NGOs involved in aquaculture outreach.

Schedule
July to December 2001 and June to December 2002
Report submission: March 2002 for on-station trials and March 2003 for on-farm trials

Literature Cited
Alam, M.S., M.R. Amin, M.R. Hasan, S.M. Rahmatullah, and M.I. Miah, 1996. Effects of fertilizers and supplementary feeds on physico-chemical parameters of ponds. Bangladesh Journal of Fisheries, 19(1­2):9­16.

DOF, 1999. Fish weekly compendium. Department of Fisheries, Dhaka, Bangladesh, 109 pp.

Haq, M.S., M.A. Wahab and Z.F. Ahmed, 1993. Optimization of fertilization rate in the pond fish culture systems. Bangladesh Agricultural University (BAU), Mymensingh, Bangladesh, BAU Res. Prog. 7:635­642.

Knud-Hansen, C.F., T.R. Batterson, C.D. McNabb, and K. Jaiyen, 1991a. Yields of Nile tilapia (Oreochromis niloticus) in fish ponds in Thailand using chicken manure supplemented with nitrogen and phosphorus. In: H. Egna, J. Bowman, and M. McNamara (Editors), Eighth Annual Administrative Report, Pond Dynamics/Aquaculture CRSP. Pond Dynamics/Aquaculture CRSP, Oregon State University, Corvallis, Oregon, pp. 54­62.

Knud-Hansen, C.F., C.D. McNabb, and T.R. Batterson, 1991b. Application of limnology for efficient nutrient utilization in tropical pond aquaculture. Proceedings of the International Association of Theoretical and Applied Limnologists. 24:2541­2543.

O'Riordan B., 1992. NGOs in Bangladesh Fisheries Workshop: Strategies towards benefiting the poor. Association of Development Agencies in Bangladesh (ADAB) and Intermediate Technology Development Group (ITDG), Dhaka, Bangladesh.

Wahab, M.A., M. Begum, and Z.F. Ahmed, 1991. The effects of silver carp introduction in the polyculture of major Indian carps. Bangladesh Agricultural University, Mymensingh, Bangladesh, Proc. BAU Res. Prog., 5:429­437.

Wahab, M.A., M.E. Azim, M.H. Ali, M.C.M. Beveridge and S. Khan, 1999. The potential of periphyton-based culture of the native major carp calbaush, Labeo calbasu (Hamilton). Aquaculture Research 30:409­419.

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