Modeling potential impact of climate change on Sorghum (Sorghum bicolor) and Cowpea (Vigna inguiculatas growth and performance under different tillage and cropping systems in semi-arid areas of Eastern Kenya
Abstract
Crop models can be used to assess risk associated with climate change and variability. The
output can be more useful to farmers if the process involves their input. This study was hinged
on a participatory concept and therefore a survey in the study area (Makueni County, in Eastern,
Kenya) was conducted to capture farmers experience, knowledge- and adaptation strategies
employed in response to climate change and variability. A field trial was carried at Kambi ya
Mae location in Eastern Kenya, to evaluate the effect of tillage and cropping system on
performance of sorghum and cowpea. The trial was done during long rains (LRS) 2010 and short
rains (SRS) 20 10/20 11 and consisted of three tillage (Tie-ridge, sub soiling and ox plough) and
four cropping systems (sole sorghum and cowpea, sorghum-cowpea intercrop and rotation). The
treatments were arranged in split plots with tillage practices as the main plots and cropping
systems as the sub-plots in a Randomized Complete BIC!'CkDesign (RCBD).The APSIM model was used to assess the potential impact of~limate change on sorghum and cowpea yields under
semi-arid conditions with the following future climate scenarios considered, current temperature .
(To) and rainfall (Ro) provided the baseline, To+2°C (T2), To+3°C (T3) and To+10% R
reduction (R2) and a combined effect of T2 and T3 and R2 was examined for both crops. For
Cowpea, CO2 fertilization at 450ppm and 700ppm and their combination with T2 and T3 and R2
was also examined. Rainfall unreliability and low amount was ranked top as the most important
challenge farmers face and on average constituted 58% of the risks in their farming system.53%
alleging that significant change in climate will manifest in 10 -20 years. CCV as an issue was
rated very high by 72% of the farmers who solely depended on farming as their only source of
livelihood compared to just 15% who had diversified; income sources. This gave an insight into and confirmed farmer's vulnerability.
Citation
Masters of Science in Land and Water managementPublisher
Department of land resource management and agricultural technology, faculty of agriculture university of Nairobi