YIELD AND LEAF NUTRIENT CONCENTRATIONS OF ARABICA COFFEE DURING THE 2ND PRODUCTION CYCLE AFTER ESTABLISHMENT AS INFLUENCED BY NITROGEN RATES AND PLANT-DENSITY

Influence of nitrogen application rates; 0, 50, 100, 200 and 400kg N/h a/year and plant densities, (1332, 2664 and 5330 trees/ha of Arabica c offee cv. 'SL 283, were investigated at Coffee Research Station, Ruiru and its sub-station at Koru, Kenya during the second production cycle after establishment. Leaf nitrogen concentrations increased with incr easing rates of applied nitrogen, but was not influenced by coffee tre e densities. Yields of clean coffee increased with the application of nitrogen, with points of technical and economic inversion being 50kg N /ha for the three densities at Ruiru; and 100kg N/ha for 1332 and 5330 trees/ha, and 200kg N/ha for 2664 trees/ha at Koru, West of the Rift Valley. Yields of clean coffee increased with increase of plant densit y up to 2664 trees/ha and then dropped at 5330 trees/ha. Higher propor tion of large beans were observed under the highest tree density where total clean coffee was low.