Abstract:
Abstract. The effect of cultivation of Coimbatore 3 (CO3; Pennisetum perpureum x Pennisetum
americarnum) grass under coconut has not been researched in Sri Lanka. We examined the effect ofdifferent
levels of nitrogen fertilizer and the spread of CO3 roots in the soil. CO3 root slips were cultivated under
coconut in two rows with lx2 m within and between row spacing in a Randomized Complete Block Design
with thee replicates. Treatments were four NitroCen (N) levels- O,14,2l and 35 kg N/ha/year. There were
sixteen effective palms per treatment. CO3 bushes'were harvested at 15 cm height from ground level at 6
monthly intervals. Application of2l and 35 kg ofNlha/year gave the highest (.D0.05) dry matter yield (DM)
of 216 and225 kg per ha per year respectively compared to other treatments. An average nut yield of 55, 53
and 56 nuts per tree per year were observed in plots receiving 14,21 and,35 kg N/halyear respectively. CO3
roots were spread in an area of 0.94 m (width) and 0.65 m (depth). Application of 2l kg of N/ha/year was
determined as the best rate of nitrogen to be applied after each pruning of CO3 cultivated under coconut. lt is
advisable to cultivate only 3 rows of CO3 within a coconut square to avoid CO3 roots invading into the
mamre circle of the coconut palm.
