Evaluation of Dump Site Soil on the Growth Parameters and Yield of Okra (Abelmoschus Esculentus (L) Monech).

Abstract:

The use of urban waste as soil amendment is increasingly gaining attention in developing countries due to its potential to improve soil fertility and reduce waste accumulation. This study evaluated the effect of dumpsite soil manure on the growth and yield of okra (Abelmoschus esculentus) in Owerri, Southeastern Nigeria. A field experiment was conducted during the 2020 cropping season using a Randomized Complete Block Design (RCBD) with six treatments (0, 5, 10, 15, 20, and 25 t/ha of dumpsite manure), replicated three times. Data were collected on percentage emergence, plant height, stem girth, number of leaves, leaf area, leaf area index, fruit number, fruit weight, and fruit yield. Results revealed that dumpsite soil manure contained higher organic matter, nitrogen, phosphorus, and potassium compared to the topsoil, but also elevated levels of heavy metals such as Pb, Cd, and Zn. Application of manure significantly (P<0.05) enhanced growth parameters and yield attributes relative to the control. The highest manure rate (25 t/ha) consistently recorded superior performance in plant height (49.30 cm at 8 WAP), stem girth (3.30 cm at 10 WAP), leaf number (9.67 at 6 WAP), leaf area index (7.38 at 10 WAP), and fruit yield (75.67 kg/ha). Although heavy metals were present in the manure, their concentrations in okra leaves and seeds remained below FAO/WHO permissible limits, and no visible toxicity symptoms were observed. The findings demonstrate that dumpsite manure is a valuable low-cost organic fertilizer that improves soil fertility, growth, and productivity of okra. However, the elevated heavy metal content raises concerns about long-term food safety and soil health. The study recommends manure application at 20–25 t/ha for optimal yield, alongside regular monitoring and co-composting with safer organic residues to mitigate heavy metal risks.