Coffee Board of Kenya Monthly Bulletins February 1956

Abstract

The problems to be studied.-The main coffee-producing areas of Ken a lie on the south-east slopes of the Aberdare range.The soils are very deep, friable, lateritic clays, derived from festive sheet lava and classified as the Kikuyu Red Loam series.The lava has been dissected by streams into characteristic steep-sided ridges.Most of the /plantations were established in the early years of the present century,the trees being planted in straight lines without regard to the contours, so that cultivation has been up and down slopes which sometimes exceed 20 per cent. Although these soils are inherently stable sheet-erosion has been general and lying has occurred on many plantations.This erosion has taken place mainly the hotter and drier areas below an altitude of about 6,000ft. Here coffee is grown without shade protection, and thirds of the soil surface is exposed alternately to severe desiccation and to the impact of tropical rainstorms. The steady decrease in the supply and reliability/y of manual labour intensifies the dahgel1s of soil erosion, as the coarse cloddy tilth of the hand-hoe is replaced by continuous off-contour furrows of the disk harrow or plough.