Residual Effect of Organic Wastes on Productivity of an Ultisol in Abakaliki, South Eastern Nigeria

An experiment was carried out to study residual effect of organic wastes amendment on productivity of an ultisol.The field was laid out in a Randomized Complete Block Design with four treatments of 20 t ha equivalent to 8kg/plot of burnt rice mill waste (BRMW), unburnt rice mill waste (URMW), sawdust (SD) and control which were replicated five times to give a total of twenty experimental units. The treatments were applied in 2006 and 2007 cropping seasons and residual effect studied in the third season. A hybrid of maize (Oba super II hybrid) variety was used as a test crop. Data obtained were subjected to analysis of variance (ANOVA) while means were separated with Fisher’s Least Significant Difference. The results showed that the textural class remained sandy loam. Hydraulic conductivity of organic wastes amended soil was significantly (P<0.05) higher when compared to control. While bulk density of SD amended plot was 7% lower, total porosity and hydraulic conductivity in same treatment were higher by 16 and 6% when compared to control, respectively. Total porosity, hydraulic conductivity. Available phosphorus and CEC of organic wastes amended soil were significantly (P<0.05) higher than control. Grain yield of maize was higher in BRHD, URHD and SD amended plots by 5, 9 and 13% respectively than control. Residual effect of organic wastes improved the productivity of ultisol more than control, and thus, could be recommended for sustainable soil productivity in Abakaliki agroecological farming system.