IOSR Journal of Pharmacy and Biological Sciences (IOSR-JPBS) e-ISSN: 2278-3008, p-ISSN:2319-7676. Volume 9, Issue 3 Ver. II (May -Jun. 2014), PP 40-44 www.iosrjournals.org www.iosrjournals.org 40 | Page Effect of Biostimulation with Organic Amendment on the Growth and Yield of Maize (Zea Mays) In Diesel Oil (Ago) Polluted Soil Okechalu, O.B, Oke, F.M, Egbere, O.J and Juliet N. Okechalu. Department of Plant Science and Technology University of Jos Abstract: The effect of poultry manure and cow dung amendment of diesel oil polluted soil on the growth of Zea mays (Maize) was carried out in a green house at Lamingo area of Jos. The experiment was set up in a randomize block design (RBD) of five (5) replicates for each treatment. Loamy soil (500g) was polluted with 250ml of diesel oil in perforated polyethene bags size (64x21cm) and amended with poultry manure and cow dung at 0%.10%, 20% and 30% soil weight. Three (3) seeds of maize were planted in each pot. Two types of control were set up to validate this experiment: a positive control (500g of soil + 0ml of diesel + 0% manure) and a negative control (500g of soil + 250ml diesel + 0% manure). These were observed for germination and growth parameters for 13 weeks. The results showed that maize seeds in the positive control had the shortest day to germination (6day), an average of 12 and 13 days to germination was observed in plots treated at 30% poultry manure and cow dung respectively. No germination was observed in both the negative control and at 10% organic manure treatment. Maize plants in the positive control plots had highest mean leaf count (13) followed by those at 30% manure treatment (11) and (12) respectively, while those at 20% manure treatment had the least number of leaves. Results on stem girth followed a similar trend with the aforementioned parameters. Plant height at weeks 10 and 12 were significantly higher than those of all other weeks, but do not differ from each other at 0.05 level of probability. Plant in the control had the highest number of kernels per cob (187) followed by plot at 30% manure treatment 150 and 180 respectively for poultry manure and cow dung. The study has shown that diesel contamination affected growth and yield of maize plant adversely. However among the manure treated plots those exposed to higher fraction of poultry manure strived better than those treated with equal fraction of cow dung. Poultry manure can therefore be recommended as a biostimulant in diesel oil polluted soil. I. Introduction The earth has faced many disasters that have been caused by humans throughout history. One of the most important hazard jeopardizing our environment today is petroleum pollution which occurs as a result spills during extraction, processing, transportation and pipeline rust or damage (Yakubu, 2007) Crude oil and petroleum products such as gasoline, fuel oil and diesel fuel are complex mixture of organic compounds and have been shown to be toxic to plants, in addition to their adverse effects on soil ecosystem through adsorption to soil particles (Anonymous, 2003). In Nigeria most of the terrestrial ecosystem and shore lines in oil producing community are important agricultural land under cultivation. Any contact with crude oil usually results in damage to the soil, microorganism and plants (Adedokun & Ataga, 2007). Agbogidi et al. (2005) reported that oil spillage constitute the most significant source of oil pollution in the Niger Deltal region of Nigeria. Oil spillage also destroys farmlands and has significant effect on plant growth. Bioremediation’s role is to optimize conditions for natural microbes to degrade environmental pollutant (Penny et al., 2003). There are two main approaches to oil spill bioremediation, which are; bioaugmentation and biostimulation (Yakubu, 2007). Bioaugmentation deals with the use of beneficial microbes that have an affinity towards specific pollutants (Venosal et al., 1996; Mekec & Mendelssilni, 1995). While biostimulation involves the aeration and addition of selected micronutrient and sometimes top soil to appropriate quantities (Shekwolo, 2005; Swannell et al., 1999) i.e the modification of the environment to stimulate exiting bacteria capable of bioremediation. The primary advantage of biostimulation to bioaugmentation is that bioremediation will be undertaken by already present native microorganism that are well suited to subsurface environment and are well distributed spartially within the subsurface (Mishra et al., 2001). Maize (zea mays L, 2n= 20) is an important cereal crop of the world and household staple food in Nigeria, it has worldwide significance as human food, animal feed and as a raw material for the manufacture of hundreds of industrial product. These products include corn starch, matodexrins, corn flour, corn oil, corn syrup and products of fermenting and distilling industry, and is grown across the country (Nigeria) (Miracle, 1996). There is a dire need to prevent, control and clean up hydrocarbon polluted soil. Although excavation and chemical treatment of the polluted soil seems the most definite measure, cost of such operations and damage to