Effect of Intercropping Coffee With Fruit Trees on Coffee Eco Physiological and Soil Factors at Coffee Research Foundation in Ruiru, Kiambu County, Kenya

ABSTRACT

The coffee plant (Coffea Arabica L) originated in the forests of Ethiopia, where it evolved as an understory tree species. Mimicking this native growth habit, coffee farmers have for centuries grown coffee under shade and intercropped with various fruit tree species to provide shade, foods, and income. The impact of these intercrops on coffee production is little known hence the need for this study. The study was carried out in an existing coffee intercropping plot at Coffee Research Foundation (CRF) in Ruiru District, Kiambu County, Kenya between 2010 and 2011. The broad objective was to establish the effect of coffee intercropping with selected fruit trees on coffee eco-physiological and soil factors of production. The specific objectives were to investigate the impact of intercropping coffee with fruit trees on photosynthetic active radiation (PAR), temperatures, rate of transpiration, stomatal Conductance, relative humidity (RH), soil nutrients, soil moisture content and soil organic matter. The study involved matures coffee trees, cultivar SL 28 planted at 2.74m x 2.74m inters and intra rows, intercropped with avocadoes (Persea americana), macadamia (Macadamia ternifolia), mangoes (Mangifera indica), guavas (Psidium guajava), loquats (Eriobotrya japonica), bananas (Musa sapientum), and a sole coffee (Coffea arabica l.) as a control plot. Data collected was subjected to analysis of variance using Cohort Stat 2010 statistical analysis programme. Means separation was done using Duncan’s Multiple Range Test (DMRT) significance test at P≤0.05. Results indicated that intercropping coffee with fruit trees significantly reduced coffee PAR and did not significantly influence the leaf temperatures, during the cold season (June 2010) but was higher than the sole coffee. During the dry season, coffee intercropped with all fruit trees depressed the leaf temperatures with mangoes and avocados being significantly low. Intercropping coffee with Mangoes and macadamia gave significantly higher potassium, calcium and magnesium to sole coffee while avocados led to significantly higher phosphorus to sole coffee and coffee intercropped with bananas. Intercropping coffee with fruit trees significantly depressed coffee yields to sole coffee but gave higher Percentage (%) grade A, with mangoes being significantly higher. Intercropping coffee with guavas significantly depressed soil moisture content, organic matter, Potassium and Calcium, coffee yields and percentage grade A. The study concludes that intercropping coffee with fruit trees depressed coffee PAR and coffee yields but improved on percentage (%) grade A and soil nutrients. Intercropping coffee with avocados, mangoes and macadamia ameliorated the leaf temperatures to near optimum required during the two distinctive seasons (June 2010 and February 2011). Both eco-physiological and soil factors improved with distance from the tree. In this regard the study recommends that coffee can be intercropped with avocados, macadamia and mangoes at a distance longer than the study distance used. For this practice to succeed all agronomic practices for both coffee and the fruit trees must adhered to recommendations. Further studies are recommended on coffee fruit trees, intercropping arrangements, appropriate distance from the fruit tree and an economic analysis.