The effect of tillage methods and rates of wood ash on soil chemical properties and castor bean plant performance was studied in field trial at Abakaliki in three planting seasons. The experiment was a split plot in randomized complete block design with three tillage methods (mound, ridge, flat) and four rates of wood ash (0, 2t, 4 and 6 tha -1 ) replicated three times. Crop start version 7.2 was used to analyze data collected and mean separation was done using least significant difference (LSD) at 5% alpha level. The results of soil pH and available P showed that tillage method (TM) increased the values of the nutrients in 2 nd year, but decreased in the 3 rd year planting. The values of these parameters observed in Ridge method was found to be higher when compared to the values of Mound and Flat except for the result of available P in 1 st and 3 rd year planting periods. The wood ash (WA) amendment was found to change the soil from slightly acidic in 1 st year to alkaline in 2 nd year to slightly acidic in 3 rd year. The control soil remained acidic throughout the three years of study. The available P obtained from Rd6 consistently gave the highest values among the TM and rates of WA. Tillage methods had no effect on leaf area index (LAI) at 50 days after planting (DAP) and 100 DAP in 1 st and 2 nd year planting periods, but had significant effect on the parameters in 3 rd year planting season. Flat showed highest plant height in 1 st and 2 nd years but decreased in the 3 rd year. While the least value in plant height for the 3 years' of study was recorded in Mound. The findings from this study has clearly shown that soil application of wood ash and tillage practices has the potential to cause positive and useful changes in the fertility and productivity status of the soil by improving the soil properties and yield component of castor.

Abstract-The observed values of these tested parameters (Cu, B, Pb) in wood ash amended plots in the three planting seasons were within acceptable limits.