Abstract:
This study was conducted at one of the estates in Kilimanjaro Plantation to assess the
performance of the drip irrigation system on coffee yield. Climatic, plant and soil factors
were used for the calculation of monthly crop water and irrigation requirements and results
compared with actual performance of the irrigation system. Further evaluation of the
system performance was carried out using catch cans. The experiment was carried out on a
3-year-old coffee cultivar N39 at 3m spacing between lines of plants and 1.5 m between
plants. The experiment was laid out in a randomized complete block design with five
treatments replicated four times. The treatments included five irrigation application
levels: T1, T2, T3, T4 and T5 corresponding to flow rates of 0, 0.6, 1.2, 1.8 and 2.4
lph/emitter respectively. The results from calculations showed that the daily irrigation
requirement is 18 litres per tree, or applying 90 litres at an irrigation interval of 5 days at
peak demand. The EU in the selected block was found to be 94%, which is within the
acceptable standards. The wetted area ranged from 0.12 to 0.21 m 2 . The relative water
supply ranged from 0.45 to 0.98 indicating that the crop demand was not met by both
rainfall and irrigation. Coffee yield and water productivity was also investigated. The best
treatment towards the yield of coffee was T5 which produced mean yield of 2945 kg/ha
while treatment T1 produced the least yield of 2045 kg/ha. The best WP was 1.56 kg/m 3
found in T1 and lowest was 0.95 kg.m 3 in T5. There were significant differences in yield
and irrigation water productivity between treatments. T1 and T2 were not significantly
different. It is recommended that further research covering other parts of the plantation
should be conducted to confirm the results from this study.
