NEW RADIOCARBON DATES FROM ARCHAEOLOGICAL SITES IN PARTS OF IGBOLAND, SOUTHEASTERN NIGERIA

ABSTRACT This paper presents new results of radiocarbon (14C) ages from archaeological sites in northern Igboland. The study was designed to shed more light on early human occupation and activities in the study area based on sediments from cave and iron-smelting sites. The approach consisted of ethnographic, archaeological, palynological, and slag analyses; these were complemented with 14C dates. The technology adopted as well as the paleoenvironmental conditions that prevailed during the period of human settlement in both sites was revealed. These data, complemented by 14C dates, highlight the human behavioral and subsistence patterns within the region and are comparable to those from similar sites in southeastern Nigeria.

Comparative effect of fertilization on cocoyam and component crops on Cocoyam-based intercropping systems in Uyo, Southeastern Nigeria

Field experiment was conducted at University of Uyo Teaching, research farm during the 2018 and 2019 cropping seasons to assess the effect of fertilization on cocoyam-based intercropping systems. The experiment was laid out in a randomized complete block design with three replications. Treatments were six fertilizers rates - 0kg/ha, NPK200kg/ha, NPK400kg/ha, PM2.5t/ha, PM5.0t/ha, Mixture (NPK200kg/ha + PM2.5t/ha) and six crop mixtures - Sole Cocoyam, Sole Melon, Sole Maize, Cocoyam + Maize, Cocoyam + Melon and Cocoyam + Melon + Maize). Result analysed with analysis of variance revealed PM2.5t/ha, NPK400kg/ha and Mixture (NPK200kg/ha + PM2.5t/ha) gave higher plant height, leaf area, stem girth in sole cocoyam, maize and melon respectively. PM2.5t/ha favoured leaf area, stem girths of cocoyam, maize with cocoyam + maize, cocoyam + melon and cocoyam + melon + maize crop mixtures. PM5.0t/ha gave higher values of corm, cormels, cormels weight, cormels number and cormels length in both sole cocoyam and mixtures (cocoyam + melon, cocoyam + maize, cocoyam + melon + maize) in both seasons respectively. PM2.5t/ha gave higher values of maize grain yield with cocoyam + maize, cocoyam + melon + maize crop mixtures. PM5.0t/ha and NPK400kg/ha gave higher melon seed values with cocoyam + melon and cocoyam + Melon + maize. Conclusively, it is recommended that application of organic fertilizer promotes higher yields and yield components in both sole and crop mixtures of cocoyam and maize respectively.

Performance of cement-stabilized weak subgrade for highway embankment construction in Southeast Nigeria

Soils with poor shear strength and high compressibility underlie the wetlands of southern Nigeria. They are susceptible to intolerable settlements and account for greater than 60% of the soils in the region. While requiring embankments for any infrastructure construction, these weak soils pose significant threat to the construction and service life of highway pavements in southeastern Nigeria. Therefore, this research investigates shear strength improvement of a highway embankment’s weak subgrade soil after mass stabilization of soil with 6 and 10% Portland cement. The factor of safety against shear failure of the embankment was analyzed for un-stabilized subgrade and then cement-stabilized subgrade. The analysis was carried out for embankment heights of 4, 5, 6 and 7 m using the limit equilibrium method. Thick soft clayey silt with Cu range of 9 to 15 kPa underlay the embankment, upon improvement, the Cu of 154 and 208 kPa was obtained for 6 and 10% stabilization respectively. The FoS for the embankment on Un-stabilized soil ranged from 0.88 for a 7 m embankment to 1.2 for a 4 m embankment. The FoS after mass stabilization of 1 to 5 m soil ranged between 1.77 and 5.22 for the different embankment heights. Stability was better improved as depth of mass stabilization and cement content increased. A linear relationship was observed to exist between the cement content, strength of the improved soils, stabilization depth and the factor of safety.

Water Quality as Affected by Quarry Activities in Ebonyi State, Nigeria

The study was done in 2018, 2019 and 2020, during which quarry activities effects was determined on water qualities in Ebonyi State, Southeastern Nigeria. The following locations were selected: 0 – 50 m from quarry locations at Ishiagu, Umuoghara and Ngbo were selected with Non quarry location situated 3 km away from each location as control. Collected water samples were analysed for selected physical properties, chemical properties and heavy metal concentrations. The experimental design was carried out in a Completely Randomized Design (CRD) with F-LSD at (p < 0.05). The results obtained were compared with the established standards. Physical parameters studied in the sites within 0 – 50 m from quarry sites were higher than that of control and are within the recommended standards. Similarly, chemical parameters were higher the sites within 0 – 50 m from quarry sites than that of control and are within the standard, except pH in 2018 at Ishiagu and Umuoghara and pH of control in the three years of studied. Lead, cadmium and iron recorded values in sites within 0 – 50 m which were higher than that of control and the recommended standards whereas zinc observed in Ishiagu in 2018, 2019, 2019 were above standard and control. Zinc observed in Umuoghara and Ngbo were within standard but some values are either higher or lower than control. Based on the results water bodies in quarry sites should be subjected to treatment processes before domestic use to avoid ailments associated with water polluted with quarry activities.

Stem portion and number of stakes influence on growth and yield of cassava variety in the South East, Nigeria

Investigations were conducted to study the effect of stem portion and number of stakes per stand on crop establishment, growth and yield of cassava variety NR 8082 in Umudike Southeastern Nigeria during the 2016/17 and 2017/18 cropping seasons. In each year, the experiment was laid out as a 3 × 3 factorial, in randomized complete block design with three replications. Treatments consisted of three stem portions of different physiological ages (top, middle and basal) and three numbers of stakes per stand (1, 2 and 3). The middle and basal stem portions significantly increased percent establishment, plant height and leaf area index at 3 months after planting (MAP) but had no effect on number of storage roots per plant. The best stem portion for storage root yield was, however, the top portion which produced the highest yield on average. Number of stakes per stand did not significantly affect stem girth, number of nodes per plant and leaf area index, but the use of 1 stake per stand increased number of storage roots per plant, root weight and storage oot yield in 2017/2018 cropping season. Number of stakes per stand did not significantly influence storage root yield across the two seasons of evaluation. Interactions between stem portion and number of stakes per stand did not significantly affect storage root yield of NR 8082 high cassava variety in both cropping seasons. Based on the findings, the use of 1 stake per stand is recommended for high root yields of NR 8082 cassava variety under conditions of low soil fertility in Umudike, South East Nigeria. Although the top portion enhanced root yield, farmers could use any of the stem portions, since the middle and basal parts gave satisfactory yields and had better establishment than the former.