The effect of oil palm decanter cake on the accumulation of nutrients and the stomatal opening of Solanum melongena (brinjal) plants

Purpose Research has shown that oil palm decanter cake(DC) serves as a potential source of nutrients for plantgrowth. This study therefore investigated the applicabilityof decanter cake (DC) as an amendment to soil for thegrowth of Solanum melongena (brinjal) at three ratios 10,20, 30 % DC and suitable controls (0 %).Methods Seeds of brinjal were sown in soils amendedwith decanter cake at 10, 20, 30 % w/w and 0 % as control.Nutrient enrichment factors were calculated from theconcentration of selected metals (Cu, Ca, Fe, Zn and Mg)in plant parts. The scanning electron micrographs were alsotaken to measure the stomatal opening/closing due to theeffect of excess nutrients on the leaf structure.Results Enrichment factor (EF) values in this study wereall below 3 indicating low enrichment of metal ions fromsoil to plants. SEM studies of the leaf epidermis of the testplants revealed the closure of guard cells with increasingdecanter cake treatments.Conclusions Decanter cake at 20 % amendments withsoil could serve as a source of soil amendment for cultivationof S. melongena plants.