The effect of soil contamination by oil hydrocarbons on the growth and yield of beans

Abstract

The energy sector through the exploration of oil and gas plays an essential role in the global economy. Uganda began oil exploration activities in the Albertine Graben in 1938 and recent developments include the establishment of the East-African Crude Oil Pipeline. However, the transportation of oil leads to oil spillages and related hydrocarbons on productive agricultural lands which have different effects on soil properties and plant growth. In Uganda, most studies conducted relating to crude oil exploration effects have focused more on health and biodiversity but, few studies have been done on the effects of oil on plant growth, therefore, this study aimed to bridge this information gap. Specifically, the research aimed to i) compare the effect of different levels of oil on plant height, number of pods, seeds per pod, subjected to different oil contamination levels, and ii) compare root nodules produced by bean plants subjected to different oil contamination levels. The research was conducted using an experiment which was setup on the 12th October 2019 and it involved a Completely Randomized Block Design (CRBD) with three (3) replicates. The treatments, T1, T2, T3, T4, T5, and T6 contained 0, 2, 4, 6, 8, 10 millilitres of used engine oil respectively and T1 was the experimental control. Eight (8) bean seeds of K131 species were planted in buckets at four spots and routine management practices of weeding, insecticide control, and watering were done to enable plant growth. Data was collected after the flowering of plants and responses such as the number of leaves and number of root nodules were visually counted in November of 2019 whereas the number of pods and the seeds per pod were visually counted in January of 2020. Data was recorded in Excel Worksheet and analyzed using Genstat software at 5% significance level and farmers will use this knowledge to enhance their yields amidst oil pollution in the Albertine region. Results showed significant better growth and yield than the control(T1) at minimum oil level concentration, hence adverse effects of oil pollution was dose dependent .Number of leaves p=0.529 was due to anaerobic conditions that led to an increase in calcium ions within the cytosol though they experienced chlorosis, root nodules p=0.204 as a result of low nitrogen but were whitish in colour, height p=0.209, seeds p=0.369 due to extreme temperatures caused by the dark nature of oil that stimulated accumulation of osmolytes, number of pods p=0.481.