Effects of climate variability on large scale coffee production in Kigutha coffee estate in Kiambu County, Kenya
Koge, Jessica Wangui
MetadataShow full item record
Dealing with declining coffee amidst challenges occasioned by climate variability is a problem affecting large-scale coffee production in Kenya. Climate variability has affected coffee output by changing distribution of pests and diseases, hindering growth and affecting amount of water supplied for irrigation. Kiambu is a major coffee producer in Kenya and coffee is mostly grown in estates. Climate variability makes it difficult for farmers to predict when to plant and interferes with coffee development cycles. Since plantations in Kiambu are within the same geographical zone with similar rainfall and temperature patterns, a study on this plantation may serve as an example on how climate variability is generally affecting large-scale coffee production in the county. Objectives of this study were; to investigate variability in rainfall and temperature patterns (1991-2010), how this has affected yield, spread of pests and diseases associated with changes in rainfall and temperature patterns, how water supply for irrigation has been affected and coping mechanisms adopted. The study was carried out in Kigutha Coffee Estate in Kiambu County and took 16 months (January 2012-April 2013). Purposive sampling was used to select 10 permanent workers and 20 casuals. Questionnaires were distributed to permanent workers and interviews conducted. Focus group discussions were conducted with casual workers who have been there for not less than 10 years. Statistical analysis was used to calculate Pearson correlation(r) with significance of 0.05 using SPSS to determine relationship between the two climate parameters and yield and water supplied for irrigation. Negative correlation (r = -0.7) suggests that when temperature increases, yield reduces and positive correlation (r = 0.494) shows when rainfall reduces, yield also reduces. Temperature has generally increased (1991-2010), with annual temperatures falling below overall mean with lows of 17.7˚C in 1995 and 17.89˚C in both 1992 and 1993, then rising above the mean from 2002 to 2010 with highs of 19˚C in 2008 and 18.75˚C in 2009. Erratic rainfall, dry spells and high temperature affect water supplied for irrigation; r = 0.411 suggests that when temperature increases, water supplied to the estate for irrigation increases and r = -0.477 shows when rainfall increases, water supply for irrigation reduces. Time series graph shows fluctuations in rainfall averages with 5-year moving average; from 84.19mm (1991-1995), to 94.41mm (1996-2000), to 84.38mm (2001-2005) to 96.95mm (2006-2010). Spread of pests and diseases changes with changing rainfall and temperature patterns; thrips and sun-scorch associated with increase in temperature, yellow-headed borers and drought disease in dry spells and tip borers and Coffee Berry disease in wet conditions. From this study, it was concluded that fluctuations in rainfall and increase in temperature have occurred and have lowered yields by hindering growth of coffee at each of the 5 growth stages, putting pressure on water supply for irrigation and spread of pests and diseases. Recommendations include increasing yields by growing the batian variety which is resistant to Coffee Berry Disease, constructing rainwater harvesting facilities, growth of shade trees in between rows of coffee bushes and the need to conduct research on effective copying mechanisms particular to each climatic condition.