Inoculation and staking systems of climbing bean in Kenya

Climbing bean is one of the legumes under study in Kenya. In contrast to bush beans commonly grown by farmers, climbing beans are higher yielding, have a longer growing period and require support. A field evaluation was conducted with climbing bean (cv. Kenya Mavuno) at 19 locations by project Master Farmers to assess the inoculation (BIOFIX containing CIAT 899) and three alternative staking systems of climbing beans (single staking, tripods and string trellises) during the 2011 long rains (March to July). Inoculation increased nodulation by 15% and yields by only 6%. Nonetheless, yield increases of only 42 kg/ha provide a return of over $25 after investing only $6 on BIOFIX and may be regarded as a form of inexpensive "crop insurance". Tripods were the highest yielding staking system, increasing yields by 40% above single staking. Interestingly, tripods require 33% less stakes and the availability of staking materials often controls farmer’s willingness to adopt climbing bean. String trellises were variable, with each Master Farmer provided two rolls of nylon line that were arranged as they saw fit. Strings arranged vertically performed better. These trials were conducted entirely by Master Farmers, not randomized and irregularly replicated, and yield and nodulation assessments conducted by them, so these findings are regarded as preliminary. More detailed assessment of climbing bean management is underway by the Kenyan Legume Agronomy team and will be reported in a future Podcaster.

Table 1. Effect of inoculation and staking system on climbing bean in west Kenya (± Standard Deviation).

Paul Woomer