Characterization of Compost Made from Chicken Droppings and Fish Bones, and Its Application to Tomato Cultivation

The effect of compost made from chicken droppings and fish bones on soil quality and tomato production was evaluated. The soil of Bokito (Central Region-Cameroon) was amended with four variants C1, C2, C3 and C4 of compost at 5%, 10%, and 15% compost/soil (w/w). The experimental device was completely randomized en bloc with 5 repetitions for each treatment. The physicochemical, biological and biochemical parameters of compost and amended soils, as well as tomato production were evaluated. The highest concentrations of nitrogen, phosphorus and potassium were obtained with C3 (1.96g/Kg) and C2 (0.42 g/Kg; 0.08 g/Kg) respectively. The different compost variants had a C/N ratio between 21.88 (C1) and 30.27 (C2) and their pH was basic. They were rich in exchangeable ions (Mg2+, Ca2+, K+, Na+) and poor in heavy metals (Pb, Zn, Cu). A significant increase in the C/N ratio was noted in all the amended soils compared to the unamended soil. It varied from 12.50±0.10 (unamended soil) to 30.55±2.04 (C1 10%). Exchangeable ion concentrations (Mg2+, Ca2+, K+, Na+) were higher in amended soils. The bacterial biomass varied from 347 x 105UFC/g (C4) to 609 x105UFC/g (C2) values significantly higher than that of the unamended soil (100 x105UFC/g). The fungal biomass varied from 470 x105UFC/g (C1) to 781 x105UFC/g (C2) values significantly higher than that of the unamended soil (120 x105UFC/g). The 15% C2 component presented the highest cellulase and protease activities with values 3 and 9 times higher than the unamended soil respectively. The compost variants C2 and C1 (15%) were generally more productive with respective values of 85 and 69 fruits, the tomato amended with the chemical fertilizer having given 24 fruits. These results show that compost made from chicken droppings and fish bones could contribute to the development of green manure to enrich the soil, thus improving tomato production.