Abstract A greenhouse study was carried out at Cocoa Research Institute of Nigeria (CRIN), Ibadan to investigate growth factors, dry matter yield and P-uptake of cashew seedlings of different nut sizes using organo-mineral and inorganic fertilizers. The fertilizers were applied at rates of 0, 10, 20 ton/ha and 0, 10, 20kg N/ha for seven treatments using a completely randomized block design.
The results showed that for PCA (Organo fertilizer (fortified with Urea)), an increase in level of fertilization led to an increase for all the parameters measured having the most significant effect on plant height whereas for PCB (Organo fertilizer (non-fortified)) an increase in level of fertilization generally led to a reduction in growth factors except for P-uptake. An increase in fertilizer application for the Inorganic fertilizer (NPK) gave marginal increases in the growth factors measured although this increase is not proportional to the amount of fertilizer used. All the values were found not significantly different (at P>0.05) compared with the control measurement values for jumbo nut sizes of cashew seedlings. It can be deduced that optimal results for the parameters measured would be obtained at 20 t/ha PCA and 10t/ha PCB for jumbo nut sizes.
For small nut sizes, application of PCA, PCB and NPK fertilizers did not significantly affect the measured parameters. However, PCB at 20ton/ha had the highest P-uptake (30.12mg/kg) and this was found significantly different (at P>0.05) amongst other treatments for small nut sizes.
Thus, PCA and PCB applied at 10 and 20ton/ha could be used to enhance the growth and P-uptake of cashew seedlings and would serve as viable alternatives to mineral fertilizers.