Effects of organic supplement on growth, leaf chlorophyll and nitrogen index of cassava (Manihot esculenta Crantz) cultivated in crude-oil- contaminated soil in Nigeria

Abstract

A field study was conducted in the 2015-2016 cropping season to investigate the effect of soil amendment on the growth, leaf chlorophyll and nitrogen index of cassava (Manihot esculenta Crantz) cultivated in crude oil contaminated soil located at Ikot Ada Udo, Ikot Abasi Local Government Area LGA) of Akwa Ibom State, Nigeria. The soil samples were amended with organic supplement (palm bunch ash, PBA and dried poultry litter, DPL) singly and in combination using three different cassava cultivars (TMS 30572, NR 8082 and Local variety) where the growth parameters, chlorophyll content and nitrogen index were monitored at eight (8) weeks intervals for twenty-four (24) weeks. The mean results obtained showed that plant height, leaf area and stem girth increased with increase in the number of weeks with PBA+DPL and DPL amended soil showing significant increase in plants height as compared to the PBA amended soil and the control soil. The same trend was observed with other growth parameters. For the plant varieties, growth in TMS 30572 was significantly higher than others except for the 8th week where the local variety was highest with NR 8082 being the least in all growth parameters. After 16 weeks of sprouting, plots treated with PBA had higher number of Nodes and Leaf Nitrogen Index while plots treated with DPL had higher Chlorophyll A and B contents. This study recommended that varieties TMS 30572 and the Local (Nsak Idaha) should be planted on a crude-oil-polluted site and the soil should be amended with organic nutrients to improve the crop growth performance.

Keywords: Soil Amendment, Leaf Chlorophyll, Nitrogen Index, Manihot Esculenta Crantz and Contaminated Soil