1. Comparative Assessment of Soils in Automobile Repair and Non-Automobile Repair Sites in Abakaliki, Southeastern Nigeria By Njoku, C. and Ngene, P.N. Department of Soil Science and Environmental Management, Ebonyi State University, P.M.B. 053, Abakaliki, Nigeria

2. ABSTRACT An experiment was conducted at automobile repair and non- automobile repair sites in Abakaliki to compare the selected chemical properties of soils of automobile repair and non-automobile repair sites. A survey of the study area was carried out and automobile repair and non-automobile repair sites were selected. Five replicates soil samples each were collected at 0 – 30 cm depth in each sites. Data collected were analysed using standard error of the mean. Results of the study showed that automobile repair site recorded higher total organic carbon, C/N ratio and total exchangeable acidity than non-automobile repair site. On the other hand, lower pH, total N, available P, Ca, Mg, K, Na, total exchangeable bases, effective cation exchangeable capacity and base saturation were observed in automobile repair site than non-automobile repair site. Soils of automobile repair sites are not good for crop production since they are low in plant nutrients

3. Key Words Automobile repair site Oil Plant nutrient Soil Wastes

4. Aims The aim of this study is to compare the selected chemical properties of soils of automobile repair and non-automobile repair sites in Abakaliki, southeastern Nigeria.

5. Materials and Methods Site description and soil sampling Laboratory Analysis Data Analysis

6. Site Description and Soil Sampling Ten automobile repair sites spreading within Abakaliki metropolis were surveyed and the automobile repair site at Ogoja road, opposite Abakaliki rice mill and adjacent College of Agricultural Science, Ebonyi State University was selected. This site is a major and the biggest automobile repair site in Abakaliki. An arable land at Ebonyi State University, Faculty of Agriculture and Natural Resources Management Research Farm was used as non-automobile repair sites. Abakaliki lies at latitude 6 o 19’ N and longitude 8 o 06’ E in the derived savannah of the southeast agro-ecological zone of Nigeria. It has a mean annual rainfall of 1700 – 1800 mm. The rainfall pattern is bimodal between April – July and September – November with short spell in August. According to Ofomata (1975) the minimum and maximum temperatures of the area are 27 o C and 31 o C respectively. The relative humidity of the area is between 60 – 80%. The soil belongs to the order Ultisol and is classified as Typic Haplustult (FDALR, 1985). Soil samples were obtained in five replicates at each site at depths of 0 to 30 cm using soil auger. Each sample was immediately placed in a fresh plastic bag and tightly sealed. All the samples were transported to the laboratory where on arrival, analytical procedure commenced in earnest.

7. Laboratory Analysis The pH of the soil was determined using a suspension of soil and distilled water in the ratio of 2:5 – soil: water (McLean, 1982). Total nitrogen was determined using modified kjeldahl digestion procedure (Bremmer and Mulvaney, 1982). Organic carbon was determined by the method of Nelson and Sommers (1982). Available phosphorus was determined by Bray 11 method (Olsen and Sommers, 1982). Exchangeable bases were determined using Chapman (1982) method. Exchangeable acidity was determined by the titration method (Juo, 1979). Effective cation exchange capacity and base saturation were determined by the summation and calculation, respectively (Njoku and Mbah (2012)

8. Data Analysis Statistical analysis of the data was carried out using standard error of the mean (Steel and Torrie, 1980).

9. Result and Discussion The results of selected chemical properties of soils of automobile repair and non-automobile repair sites are presented in table 1.

10. Table 1: Selected chemical properties of soils of automobile repair and non-automobile repair sites Parameter Automobile Repair site Non-automobile Repair site pH (H2O) 4.31+0.011 5.96+0.005 Organic Carbon (%) 1.95+0.015 0.94+0.020 Total Nitrogen (%) 0.15+0.017 0.17+0.011 C/N Ratio 13.00+0.012 5.23+0.003 Available P (mgkg -1 ) 7.08+0.05 10.26+0.015 Ca (cmol(+)kg -1 ) 4.64+0.005 5.07+0.005 Mg (cmol(+)kg -1 ) 1.56+0.017 3.71+0.017 K (cmol(+)kg -1 ) 0.11+0.005 0.18+0.003 Na (cmol(+)kg -1 ) 0.18+0.009 0.25+0.013 TEA (cmol(+)kg -1 ) 1.39+0.006 1.22+0.012 TEB (cmol(+)kg -1 ) 6.49+0.013 9.21+0.014 ECEC (cmol(+)kg -1 ) 7.88+0.003 10.43+0.011 BS (%) 82.36 +0.011 88.30+0.006

11. pH Automobile repair site recorded the lower pH value of 4.31. This observed pH value in automobile repair site was lower than that of non-automobile repair site by 28%. This lower pH observed in automobile repair site than non-automobile repair site may be as a result of acidic automobile wastes that entered the soil and increasing its acidity.

12. Organic Carbon and C/N Ratio On the other hand, higher organic carbon, and C/N ratio were recorded in automobile repair site than non- automobile repair site. These higher values of organic carbon and C/N ratio may be attributed to the presence of spent lubricant oil and petroleum products that are among the wastes produced in automobile repair sites. The high amount of organic matter in the studied soil samples is quite obvious since the soil is contaminated with automobile fuels that are composed of hydrocarbon and PAHs (Atlas, 1981; McMurry, 2000; Clayden and Greeves 2001). Similarly, this result was inline with Bahuguna et al. (2011) who noted that the soil samples from automobile repair work stations demonstrated significantly higher total organic carbon, total PAHs contents and soil temperature while showing lower moisture contents and bacterial counts.

13. Total N, Available P, Exchangeable bases and Total Exchangeable acidity The results also showed lower total N, available P, Ca, Mg, K, Na, TEB, ECEC, BS and higher TEA in automobile repair site than non- automobile repair site. These are plant nutrients which when they are lacking in soils will reduced the quality of the soils and the yield of crops growing in that soil. Thus, the soils of automobile repair site are not good for crop production and should be put into alternative use.

14. Conclusion This study showed that the soils of automobile repair site are of low quality. It is high in organic carbon, low in soil major nutrients and pH. Therefore, such soils should not be used for crop production but should be used for other non-agricultural ventures.

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