Effects of Pot Sizes and Biochar Base Media Composition on Nutrient Uptake of Coffee (Coffea arabica L.) Seedlings in South Ethiopia

Modern coffee farming is essentially based on the production of quality seedlings with the desirable shoot and root growth mainly determined by nutrient uptake of the seedlings. Therefore, this study was conducted to evaluate the effects of pot size and biochar-based media composition on the nutrient uptake of coffee seedlings. The experiment was laid out in a factorial experiment arranged in RCBD with three replications. The treatment combination included four levels of pot size (P1=7x13cm, P2=10x16cm, P3=13x19cm and P4=16x22cm) and five biochar to topsoil ratios (0:1, 1:1, 1:2, 1:3, and 1:4 v/v). All soil and seedling leaf tissue laboratory results were computed using SAS software and treatment means separation was compared using LSD at 5%. The results revealed significant variation in seedling nutrient uptake due to treatments and their interaction effects. Nitrogen uptake of the seedlings treated by 13x19cm pot size and one to three ratios of biochar to topsoil was increased by 58.00% over the farmers practice representing treatment. Phosphorus uptake of the seedling raised in 16x22cm pot size with 2g DAP/pot and one to three biochar to topsoil ratio were increased by 46% and 43% over the local control, respectively. Potassium uptake of the seedling raised in 16x22cm pot size with one to three biochar to topsoil ratio was increased by 180.00%, over the local control, respectively. Therefore, nutrient uptake of the seedling through the use of biochar as a fertilizer at a lower rate provides alternative enhancement media options to coffee seedling growth.

Keywords:Biochar-ratio; Coffee seedling; Interaction effects; NPK; Pot size