Abstract:
A study was conducted in a glasshouse at Sokoine University of Agriculture Morogoro,
Tanzania to investigate the effect of coffee pulp compost (CP), Minjingu phosphate rock
(MPR) and coffee pulp composted with Minjingu phosphate rock (CPMPR) on
phosphorus availability and response of Tomato (Lycopersicon esculentum M.) var. Carl J
in 3x8 completely randomized block design experiment. The P sources were applied on a
P deficient Chromic Acrisol at eight equivalent rates of 0, 40, 80, 100, 120, 140, 160 and
200 kg P ha -1 . Five tomato seeds were directly sown in each pot then thinned to three
seedlings at 30 days after planting (DAP). Two out of the three plants were harvested from
each pot 60 DAP for assessment of dry matter yield response to the three P sources and
nutrient concentrations in the plants. One plant was maintained per pot to harvesting
maturity for assessment of growth and yield responses. Crop responses were further
assessed in terms of plant heights and number of true leaves per plant, number of flowers,
fruits and trusses per plant as well as numbers and weights of marketable fruits harvested
per plant. Experimental soil was analyzed at the end of the experiment to assess the effect
of the three P sources on residual P and other chemical properties of the soil. The
application of CP, MPR and CPMPR at 40 to 200 kg P ha -1 increased the overall P uptake
11, 13 and 18 folds while the overall plant P contents increased by 23%, 36% and 110%,
respectively above the control. The average number of flowers increased from 0 to17, 0 to
23 and 0 to 29 per plant, while the average number of fruits increased from 0 to 6, 0 to 19
and 0 to 24 fruits per plant, respectively. The average number of marketable fruits
increased by 4, 5 and 7 fruits per plant while the average fruit weight increased by 152.2 g,
168.2 g and 242.0 g per plant, respectively. CPMPR thus, significantly (p=0.05) increased
P uptake and concentrations in plant tissues, the numbers of flowers, fruits, marketable
fruits and weight of tomato fruits; while its effect on residual soil P at the end of theiii
experiment was
comparable to MPR. Composting coffee pulp with MPR was thus
concluded as a potential technique for improving MPR dissolution, P and other nutrient
supply as well as the physical, chemical and biological properties of the soil.
