KENYA RESEARCH

Objectives
1) Characterize the productive capacity of the new Africa site in response to high inorganic nutrient loading rates;
2) Evaluate the relative contributions of inorganic fertilizers and supplemental feeds to fish production.

Significance
Tilapia production with high inorganic inputs provides a basis for global site comparisons of fish production. This will help characterize the new African site. Comparison of the relative contributions of fertilizer and feed provides a basis for development of efficient input strategies in tilapia culture.

Anticipated Benefits
Characterization of the African site at high nutrient levels provides a global comparison with other CRSP sites. Reliable data on the value of low cost supplemental feeds and comparative benefits of fertilization for semi-intensive tilapia production can provide a basis for more efficient production strategies in Kenya and similar areas of Africa.

Identification of Beneficiaries
Fish farmers, extension agents, lending agencies for small businesses. Users of CRSP models and databases.

Collaborative Arrangements
OSU, AU and UAPB will collaborate with host country researchers in Africa. The production trial will be conducted at Sagana by OSU/AU. If funded, fish and feed samples will be sent to UAPB and carbon isotope analyses will be conducted for samples sent to (UAPB) to partition the nutritional contribution of natural foods and rice bran.

Experimental Design
Completely randomized design, 4 treatments in triplicate.

Site: Sagana Fish Culture Farm, Kenya.

Pond Facilities: 12 ponds

Stocking Rate: 2 juvenile (about 50 g each) male Oreochromis niloticus per m2, and 10% Clarias. (about 10 g each).

Water Management: Replace water losses weekly.

Other Inputs:

Treatment 1: 16 kg N/ha/wk, 4 kg P/ha/wk as DAP, urea or KNO3;

Treatment 2: Inorganic fertilizer at 8 kg N and 2 kg P/ha/wk plus rice bran feed to bring total N input to 16 kg/ha/wk (about 55 kg RB/ha-d);

Treatment 3: Rice bran feed only at a rate sufficient to be isonitrogenous with treatments 1 and 2 (about 110 kg RB/ha-d which is similar to quantities used in Rwanda);

Treatment 4: Rice bran fed as in Treatment 3 and inorganic as in Treatment 2 (total N will be 24 kg/ha/wk).

Note: P will be added at N:P=4:1 whenever inorganic N is added in any treatment.

Test Species: Oreochromis niloticus and Clarias.

Sampling Plan: 5 month experiment, sampling as per CRSP protocol.

Statistical Methods and Hypotheses: ANOVA, Regression. At the tested rates inorganic fertilization does not affect water quality, fish growth, production, feed conversion ratio, net protein utilization or profitability of supplemental feeding with rice bran.

Identification of Deliverables
The capacity of the new Africa site in response to high inorganic nutrient loading rates will be characterized. The relative contributions of inorganic fertilizers and supplemental feeds to fish production will be evaluated for the above mentioned input combinations.

Schedule/Time Line
Start 9/97, end 3/98.

Final Report Submittal: 8/98.