In this study, we investigated the fruit, seed yield and biofuel production potentials of Jatropha curcas in soils fertilized with different rates of rice husk dust (RHD) and NPK 10:10:10. This study took place at the Teaching and Research Farm of the Department of Horticulture and Landscape Technology, Akanu Ibiam Federal Polytechnic, Unwana from April 2020 to March 2021. Treatments comprised of six rates (0, 1,2,3,4 and 5 ton ha-1) each of RHD and NPK, arranged in Randomized Complete Block Design (RCBD in Randomized Complete Block Design (RCBD) in a factorial pattern. Nursery Jatropha seedling of average heights of about 30 cm and 5-6 true leaves were transplanted to the field a month after treatment application. Our measurement between 10 to 12 months of Jatropha growth focused on the number of fruits, weight of fruits, number of seeds, weight of seeds and quantity of oil per plant. Analysis of variance (ANOVA) and Least Significant Difference (LSD) tools were used to analyze the obtained data and separated the significant means respectively. The relationship between yield parameters and selected soil chemical properties was determined using correlation analysis. Results indicated that relative to control, addition of RHD and NPK as lone and combined treatments increased the fruit, seed yield and oil quantity of Jatropha. Relative to control, fruit number increased by 72.80%, fruit weight by 79.81% and number of seeds by 80.73%. Similarly, the seed weight and oil content increased by 28.11% and 21.485 respectively. Organic matter, available phosphorus and total nitrogen had highly significant correlation with fruit, seed yield and oil quantity. Treatments combination of 5tonha-1 RHD and 5tonha-1 relatively gave the most appreciable result in fruit, seed yield and oil quantity and therefore recommended.

Nine genotypes of castor oil bean (Ricinus cumunis) were evaluated in 2011 and 2012 cropping seasons to determine their consistency of performance at the Enugu State University of Science and Technology, Enugu State. Eight (8) accessions were selected from various locations in the south east, while a standard check was obtained from Ahmadu Bello University Zaria. The study was carried out using a randomized complete block design with four replications. Data was collected on number of days to germination, days to 50% flowering, plant height at maturity, length of primary raceme, length of pistillate region, length of staminate region and number of leaves. The findings from the study showed that Zaria accession flowers within 80 days and significantly (P < 0.05) different from the other eight (8) accessions studied, except Udi for plant height at maturity the significant and comparable large genotypes for all the characters except number of days to germination; number of nodes and length of staminate region implies that there would be adequate gains in selecting the characters. The phenotypic coefficient of variation was found to be higher than the genotypic coefficient of variance for all the character studied indicating the influence of environment towards the total variance. The short height recorded in Zaria and Udi accessions which are at par is of a desirable trait for shorter plants are easier to manage agronomical and it also withstands lodging better than all plants. These accessions based on the agronomic characters studied were found to perform very well in Enugu south-east, Nigeria and is therefore, recommended to be grown in this region.

The effect of tillage methods (Mound, Ridge, Flat) and rates of wood ash on soil properties and yield of castor bean plant were studied in field trial at Abakaliki for 3 years cropping seasons. The experiment was a split plot in randomized complete block design with three tillage methods and four rates of wood ash (0 t•ha ), replicated three times. CropStat Version 7.2 computer software for data management developed primarily for the analysis of data from agricultural field trials was used to analyze data collected from the study and mean separation was done using least significant difference (LSD) at 5% alpha level. The findings from the study showed for soil heavy metal contents, it was observed that tillage methods had no effect on the heavy metals except for 1 st year cropping result of Zn and 2 nd year cropping result of Fe. The effect of tillage methods on heavy metal contents of castor shoot showed a significant difference P < 0.05 except for 3 rd year result of Fe. The values obtained from Ridge and Flat were higher when compared with the value of Mound with regard to soil and castor shoot; heavy metal content with higher values was more observed in Flat method. The result of heavy metal content of seed indicated that tillage method had no effect on the heavy metal contents of the castor seed; the results of Fe, Zn in 1 st and 2 nd year planting season were not significant among the rates of wood ash applied. The effect of tillage and wood ash on heavy metal content of soil, castor shoot and seed was found to be significant (P < 0.05). The values obtained decreased as the planting season increased, and the amount was found to increase as the rates of wood ash application increased. The effect of Ridge and wood ash at the rates of 2 t•ha −1 (Rd 2 ), 4 t•ha −1 (Rd 4 ) and 6 t•ha −1 (Rd 6 ) on Fe 2 nd year planting result of castor seed was statistically similar, while the result from Mound method was found to increase the seed uptake of the tested parameters.The observed values of the tested parameters (Fe, Zn) in wood ash amended plots in the three years' study were beyond acceptable limits; hence reservation in the use of wood ash How to cite this paper: Nweke, I.A., Mbah,