Bulgarian Journal of Soil Science

99 - 115

Authors: Ognyan Stoyanov Kostov and Oswald Van Cleemput

There is a lot of concern about climate change, nature and quality of life of people. Human activities directly affect more than 70% of the global ice-free land surface. Land also plays an important role on climate. Sustainable land and forest management can prevent and reduce land degradation, maintain soil fertility and productivity and reverse the adverse impact of climate change and land degradation. The present state of our environment, problems and future for EC science and science policy are presented in this paper. The actual status with regard to agriculture, industry, food, environmental microbiology, production and consumption of greenhouse gasses and how microorganisms will be affected by climate change and how microorganisms affect climate changes and other human activities are shown. Quality of life and suitability of environmental policies are discussed. Analyzes, contribution and problems of environmental policy are demonstrated. Future purposes, priority areas and directions of the environmental EU policy are also presented. In addition, polices for implementation of bio-environmental strategy as complex purpose are discussed. Supporting of scientific personals involved in this policy, enough financing of environmental sciences and identifying priority areas were shown. Financial regulation for environmental policy and priority areas are being underlined. The following aspects are also handled: protection of intellectual property, science infrastructure, government and private science units, updated supply of science policy information, as well as cooperation and coordination between EC members. Building scientific centers to study the relationship among environmental science and policy and business are presented. Actions for implementation of the environmental strategy are recommended. More and more stronger standards for protection and maintenance of environmental quality are recommended. The EU countries have to initiate the introduction of new laws for protection of humanity and environment. The discussion of the above-mentioned problems strongly supports the paper: “scientist’ warning to humanity: microorganisms and climate change”. Some scientists predict environmental collapses at different periods. Bio, organic low impute and sustainable agricultural practices reduce the negative tendencies for natural processes, soil fertility, rate of contamination of soils, waters and air and climate changes. Poverty, soil contamination, ways of soil exploitation, low rate of waste management, rate of concern of nature by political leaders and governments have influenced the rate of climate changes. Better and stricter standards are needed for protection and maintenance of our environment. The EU countries can take an initiative for new laws to protect humanity and maintain our environment at the present level.

132 - 139

Authors: Stanley Uchenna Onwudike, Olivia Oluebube Egbufor, Ugochukwu Nnamdi Nkwopara and Leonard Chimobi Agim

Understanding the fertility status of soils under different agricultural systems is imperative for sustainable crop production and ecological sustainability. This study examined the fertility levels of soils under silvopastoral system of two soil types in Southeastern Nigeria. Two towns in two states with two parent materials in the region were covered namely Owerri in Imo State with coastal plain sand and Uturu in Abia State with false bedded sand stone. Surface soil samples collected within 30 cm depth were analyzed using standard methods. Silvopastoral system and parent materials guided the sampling points. Data obtained from analyzed soil samples were statistically analyzed. Significant variations existed in the particle distribution of the soil while highest gravimetric moisture content (249.7 g/kg),total porosity (67.5%) and lowest soil bulk density (0.85 g/cm3) were recorded in the silvopastoral lands than in non silvopastoral lands. Silvopastoral lands contained higher soil organic matter (36. 88 g/kg), total nitrogen (1.87 g/kg) and exchangeable bases than non silvopastoral lands. There was higher clay content (274 g/kg) in false bedded sandstone than in coastal plain sand silvopastoral lands. The highest value of soil organic matter (36.88 g/kg) and total nitrogen (8.7 g/kg) were recorded in false bedded sandstone under silvopastoral system. There was significant negative correlation between bulk density and base saturation (r = -0.946) and positive relationship between total exchangeable acidity and soil bulk density (r = 0.865). This work revealed that parent materials under silvopastoral systems differ in soil physical, chemical and plant nutrient concentration. Therefore it is recommended that silvopastoral system should be adopted under coastal plain sand for soil fertility improvement due to its poor soil quality.

150 - 165

Authors: V. T. Jason-Ogugbue, P. C. Mmom, I. Etela and J.A. Orluchukwu

This study was carried out to evaluate the physicochemical statuses of bioremediated sites in Ogoniland (K-Dere, Bodo, and Biara), Rivers State, Nigeria after a certified bioremediation protocol. Three bioremediated soils of different fallow ages (6 months, 12 months, and 18 months after bioremediation-AB) and an uncontaminated soil (Bera) were collected and analyzed for various parameters- pH, electrical conductivity (EC), total organic matter (TOM), particle size distribution, cation exchange capacity (CEC), nitrogen and phosphorus, heavy metals (lead, cadmium, nickel and copper), total petroleum hydrocarbons (TPH), poly aromatic hydrocarbons (PAH), and intermediary metabolites. Results obtained indicate that the particle size distribution of the four soil samples were similar in terms of their content of sand, silt and clay. The pH of 12m-AB and 18m-AB bioremediated soil samples were 6.34 and 6.50 respectively and were slightly lower than pH of uncontaminated soil. The EC as well as the CEC of the bioremediated soil samples were considerably lower when compared to the uncontaminated soil sample. The range of values for TOM was between 0.095 – 1.232 % with 6m-AB soil having the least value; whereas 0m-AB and 12m- AB had the highest value of 1.232 %. Sample 18m-AB had the highest concentration of nitrogen whereas, 12m-AB sample had the least concentration. The phosphorus content in each bioremediated soil was significantly lower than in uncontaminated soil. The residual TPH content of each bioremediated soil sample was above the recommended EGASPIN target TPH value of 50 mg/kg but below the intervention level of 5,000 mg/kg. The TPH contents in bioremediated soil samples were 161.25 mg/kg (6m-AB), 51.72 mg/kg (12m-AB) and 91.50 mg/kg (18m-AB). TPH was not detected in the uncontaminated soil sample. All four samples had no trace of PAH. Heavy metals were below detectable limits in all soil samples. Screening of the soil samples using gas chromatography-mass spectrometer revealed a number of metabolic intermediates in bioremediated soil samples when compared to the uncontaminated pristine soil (control). Some of the identified metabolites are known carcinogens and are deleterious to plant growth thus suggesting the unhealthy status of the bioremediated soils for agricultural productivity.