Effect of Tolypothrix tenuis and Microchaete tenera on biochemical soil properties and maize growth

Exopolysaccharide (EPS) and biomass from strains Tolypothrix tenuis and Microchaete tenera were added to the soil and the activity of beta-glucosidase, urease, protease, phosphomonosterase, arylsulphatase, and dehydrogenase were determined. Both treatments induced a promotion of microorganisms growth, indicated by a constant increase of dehydrogenase activity. Protease and dehydrogenase activity increased with time up to day 400. beta-gluosidase, urease, and phosphomonoesterase activity changed from a maximal increase at day 90 to lower values at day 400. Arylsulphatase activity decreased with T tenuis and increased with M. tenera biomasses, after 400 days. Changes of activity were higher when EPS from both strains were added to soil compared with the effect of the corresponding biomasses. In order to establish whether EPS effect on soil affects plant growth, maize seedlings were grown in soils treated with EPS. The treatments increased dry weight (72-47% for shoots and 47-81% for roots), respectively, nitrogen (N) (428 and 464% for T tenuis and M. tenera) and phosphorus (P) (200% for both strains) content.