Some agronomic practices affecting the quality of Kenya coffee

Abstract

Quality samples from field trials at the Coffee Research Station at Ruiru and from Substations in other parts of Kenya were submitted to the Coffee Marketing Board Liquorer for his comments. These were then subjected to frequency: analysis. 2. Prolonged mulching with Elephant Grass had adverse effects on the quality of the coffee. The number of samples with brown colours increased and this resulted in poorer raw quality. There was also a reduction in the number of samples with bright roasts in some trials and an overall tendency for the mulch to reduce acidity. 3. Magnesium applications of 50 lb. Mg/acre per year improved the quality of mulched coffee in one trial, but not in two other trials, where mulch had been applied for 6 years or less. 4. The effects of mulch on quality show some similarity to those of cattle manures. Both cultural practices increase the potassium status of the soil which leads to imbalance in the magnesium and possibly iron nutrition of the tree and results in the production of poorer quality of coffee.