Effects of manure enriched with algae Chlorella vulgaris on soil chemical properties

Abstract

The effect of the algal species Chlorella vulgaris at six different ratios (0, 1, 2, 3, 4, 5 g) of air dried algae biomass, mixed with 10.18 g of sheep manure, added to 50 g of soil, and incubated for a period of 15 weeks was studied in a laboratory in order to detect the role of adding small amounts of admixed algal biomass to soil in biodegradation of soil organic carbon. The obtained data showed that mineralization of soil organic carbon increased by 16.2-35.9% at all rates of algae addition compared to the control, while the highest increase was observed at the highest rates of algae addition. There was a 40-50% increase in the available form of potassium, while the highest increase was also observed at the highest rates of algae addition. The four times higher rates of added algae increased the corresponding content of nitrate nitrogen by 20-30%, while ammonium nitrogen contents decreased by 9.5-35.7% for all amounts of added algae in comparison with the control. The available forms of copper, manganese, and zinc were also increased for all amounts of added algae by 56.8-61.9%, 55.8-67.3%, and 34.1-40.6%, respectively. On the contrary, the addition of algae did not indicate significant differences among treatments as concerns organic or available phosphorus contents. The results proved the effect of the algae Chlorella vulgaris as an accelerator agent in biodegradation of soil organic matter, without any significant negative impact on soil chemical properties.