DEPARTMENT OF SOIL SCIENCEANDLAND MANAGEMENT

The present study evaluated the physical, chemical, and heavy metals content (Fe, Zn, Mn, and Cu) and fertility status of soils from three dumpsites within the Benin city metropolis and the effect of NPK (15:15:15) fertilizer on the growth and yield of Okra and Garden Egg. Soils samples were collected processed and analyzed using standard laboratory methods. The experiment was a 3 x 4 factorial fitted in a Completely Randomized Design (CRD), with three levels of fertilizer (0 g NPK, 14 g NPK and 28 g NPK) and (3) dumpsites (Benin Sapele Road Dumpsite (BSD), Benin Agbor Road Dumpsite (BAD) and Benin Oluku Bypass Dumpsite
(BOD) and the control with three replications. Growth parameters (plant height, number of leaves; stem girth; leaf area) and yield were collected. The fruit yield per hectare was derived by estimating the fruit yield per poly bag. Data were subjected to Analysis of Variance (ANOVA), and treatment means were separated using Duncan’s Multiple Range Test at 5% probability level. Results showed that, physical and chemical properties of the dumpsite soils were slightly alkaline with pH range of 7.28 to 7.56. The organic carbon ranged between 11.6 and 13.7 g/kg. The fertility status of the soils from the different dumpsites revealed that soils
from Agbor Road ByePass were high in potassium while soils from Oluku and Sapele ByePass dumpsites were high in phosphorus and nitrogen. The total N from the dumpsites ranged between 0.065 to 0.199 %. The heavy metal content of dumpsite soils varied significantly, but was within the limits recommended by FAO/WHO. The application of 28 g NPK fertilizer enhanced the growth and yield of Okra and Garden Egg compared to the control. This study suggest that dumpsite soils amended with NPK fertilizer improved soil nutrients status and enhanced the yield and growth of Okra and Garden Egg plant.

This study investigated the residual effects of selected organic amendments on the physical, chemical, and microbial properties of soils previously cultivated with bell pepper (Capsicum annuum L.).The experiment was laid out in randomised block design (RCBD) with twelve different treatment representing sole treatment(T1(control) T2 (Poultry manure) T3 (Mychorriza) T4( Black soldier flyfrass)T5 (Digestate) and the rest as combined treatments. This research compared data from soil samples collected from the previous cultivation season in 2024 with soil samples of the post harvest period (2025) to evaluate changes in soil quality, the continuous and sustained effects of amendments over time. The results from the analysis shows that There was a decrease in pH from 2024 to 2025, from(6.47to6.00) in T2(PM), while organic matter and organic carbon showed a general increase from (5.30 to 34.60 g/kg) and (3.10 to 20.10 g/kg) in T12(DIG+PM) respectively. In comparing 2024 and 2025, bacterial counts increased across all treatments, while fungal counts declined. Results revealed that while some nutrient parameters declined compared to the initial season (2024 cropping season), soils that previously received combined organic treatments maintained significantly improved fertility indices relative to the control. These findings demonstrated that the amendments not only improved soil fertility during the first year but also had lasting residual benefits that continued enhancing the soil even without re-application. Also this study recognizes T12(DIG +PM) as the best most sustainable amendments because it effectively balanced nutrient supply, organic matter input, and microbial stimulation leading to enhanced soil fertility and lasting residual effects. Keywords: Poultry manure, Digestate.