Suzana Mbwambo^1,, Godsteven Maro¹, Emmanuel Nkya¹

The growth and yield response of some of TaCRI’s improved tall Coffea arabica hybrids to applied N, P and K were assessed in this work; since, in addition to resistance to CBD and CLR, they are also high yielding (up to 3 t ha^-1 against 1.5 t ha^-1 of the traditional varieties) and assumed also to be highly nutrient demanding. A split plot RCBD was applied with three replications, five coffee varieties (N39-8, N39-9, N39-11, N39-12 and KP 423 old variety check) as main factors and 4 fertilizer rates (75, 112.5 and 150 g tree^-1, together with 37.5g + 10 kg of FYM) as sub factors. Each rate was applied three times per year except FYM which was applied once in two years. Data on canopy width, stem girth, number of bearing primaries, plant height, berry clusters and yields were collected and subjected to ANOVA using Statistica V7 software with means separated using Fisher LSD method at α = 0.05. Variety KP 423 showed a significantly (p<0.05) wider canopy and more berry clusters than the test varieties. N39-8 excelled in number of branches, stem girth and tree height. It also gave higher yield (1894 kg clean coffee ha^-1) which was significantly different (p<0.05) from other varieties. Plant height, stem girth and yield response to the fertilizer options showed an asymptotic relationship with the turning point at 112.5 g tree^-1. Interaction between Variety N39-8 and 37.5g tree^-1 + FYM resulted into significantly higher yield (2436 Kg clean coffee ha^-1). It is tentatively concluded that the assumed high nutrient demand for the new varieties is unlikely, at least in the first four years. As such, 37.5g tree^-1 of NPK (20:10:10) applied three times per year + 10 kg of FYM per tree applied once in two years; or 75g of NPK (20:10:10) per tree if applied three times per year is enough for the test varieties under this age.

NPK nutrients, Farm Yard Manure (FYM), Coffea arabica, Tanzania