This section presents a description of the set-up of the field trials in Kenya. The set-up of the field trials, application, and evaluation of the modern technologies were conducted by an independent research institution, namely the International Potato Center (CIP). There were a total of eight demonstration sites in Nyandarua, Meru, Bungoma, and Nakuru County.

Demonstration Design of the Field Trials

Nyandarua County
Nyandarua County is the leading potato-producing county in Kenya, with about 33% of the national potato production on about 36,446 ha annually. However, farmers in this county have limited access to options to improve productivity (yield per hectare), resulting in yields averaging 8–10 t/ha, much below attainable yields of 20–30 t/ha.

Meru County
In Meru County potatoes are mainly produced on the northern slopes of Mount Kenya. Planting for the long rains is done in October and November, followed by harvesting in January and February. The short-rain crop is planted in March and April and harvested in July and August.

Bungoma County
Bungoma County has three agro-ecological zones: Lower Midland (LM1), Lower Highland (LH), and Upper Highland (UH). There is high potential for potato production, especially in the UH zone. The county finds potato as the most suitable crop for rotation with maize.

Nakuru County
Naivasha sub-county in Nakuru County is not popular for potatoes as it is for the floriculture industry; however, the area has great potential due to availability of irrigation water and the ability to produce year round.

For all areas there is fast soil degradation, through loss of soil organic matter content, erosion, limited crop rotation, and use of inadequate fertilizers. The main production problem affecting potato farmers in the counties is limited certified seed potatoes. This means that the same seed is used for many years, thus reducing the yields, as it encourages disease multiplication. Another important constraint is the limited choice of fertilizers and fungicides. This has resulted in increased soil acidity, lowering the productivity of those soils. These challenges provided an opportunity for demonstrating new production technologies.

The demonstration design for the Kenyan field trials included the comparison of three different technology settings:

Demonstration Design of the Field Trials

1. Modernized package: Mechanization, specific fertilizer suitable for potatoes, crop protection measures (with spray program 1 and spray program 2), and certified seed potatoes. For the modernized package certified seed potatoes of the varieties Variety 1, Variety 2, and Variety 3 were used as well as certified seed potatoes of the local variety Shangi.

2. Recommendations from KALRO (Kenya Agricultural and Livestock Research Organization): Hand labor, fertilizer that is applied by farmers (DAP) but a higher rate (500kg of DAP), crop protection measures (4 sprays of Ridomil/Mancozeb), and certified seed potatoes of the local variety Shangi.

3. Farmers’ practice: Hand labor, DAP fertilizer (150kg of DAP), crop protection measures (3 sprays Ridomil/Mancozeb), and uncertified seed potatoes of the local Shangi in Nyandarua County and other local varieties in Meru and Bungoma. Uncertified seed potatoes of the local varieties Asante, Alcar, and Unica partially were used in Meru and Bungoma Counties.