Growth and development of common vetch ( Vicia sativa L.) in a gasoline-polluted soil amended with organic or inorganic amendments

Abstract

The ability of various crops to grow and maintain its average yield when they are cultivated in contaminated soils should be better explored to choose the most appropriate crop when suddenly a gasoline-pipeline collapse on soils of subsistence agricultural systems. The aim of the present study was to evaluate the effect of organic or inorganic amendments on plant characteristics, biomass yield, colony-forming units (CFU), and on biological and chemical soil characteristics when it was cultivated, under greenhouse conditions, in a soil artificially polluted with gasoline and amended or not with sludge, compost, manure or inorganic fertilizers. Our results suggest that the electrolytic conductivity, organic matter, inorganic N, extractable P and exchangeable K were strongly influenced by the organic or inorganic amendments but not by the gasoline. Gasoline contamination reduced seedling emergence, shoot length, root volume, root dry weight, shoot dry weight and abundance of nodules but organic or inorganic amendments increased them. In addition, gasoline-polluted soil amended with sludge had the highest seedling emergence, shoot length, root volume, root dry weight and shoot dry weight. The soil used in this experiment contains autochthonous microorganisms able to grow in a gasoline-polluted soil while gasoline-spiked soil amended with manure or compost maintained their CFU and even increased using gasoline as a sole carbon source, suggesting that manure or compost contains indigenous microorganism that uses gasoline as a sole carbon source. Plant characteristics and yield were increased in the order of sludge > compost = manure > inorganic fertilizer > unamended and unpolluted soil > unamended polluted soil. Hence, a gasoline-spiked soil amended with sludge can be successfully cultivated with common vetch. Key words: Biomass yield, colony-forming unit, greenhouse conditions, indigenous microorganisms, organic or inorganic amendments, plant characteristics.