Spatio-Temporal Trends in Major Food Crop Yields in Rwanda
This study uses various statistical techniques in an attempt to quantify the magnitude and to determine the significance of trends in the yields major food crops at seasonal and annual timescales over Rwanda for the period 2000-2010. The magnitude derived from the slopes of the regression lines is presented spatially in the form of maps. A steady rise in major food crops yields was registered. There was a higher non-significant increase in beans yields in the east, northern and southwestern regions; and a higher nonsignificant decrease in the southern and northwestern regions. A significant increase in cassava yields was observed in the central region. The east southern and southwestern regions had significant decreases in cassava yields in 2000-2005. The same was witnessed in the northwestern region in 2006-2010. The central and northwestern regions had a significant increase in Irish potato yields, especially in 2000-2005 and a significant reduction was registered over the southwestern, western and eastern regions. However, the southeastern region recorded a decrease in 2000-2005, and an increase in 2006-2010. A significant decline in maize yields was observed in the western region in 2000-2005, while the rest of country had an increase especially during the period 2006-2010. A significant decrease in sweet potato yields was recorded in the southwestern and western regions in 2000-2005; and in the western, northwestern and southeastern regions in 2006-2010. A significant increase in sweet potato yields was recorded in central Rwanda. These spatio-temporal trends in the yields major food crops may be influenced by the variability in precipitation intensity and frequency observed recently over Rwanda in combination with the agricultural reforms undertaken since 2007.
