Increasing carbon stock potential in degraded lands and reducing atmospheric CO2 through field inoculation of cyanobacteria

Abstract

Micro-organisms of biological soil crusts have a major role in carbon (C) cycling and atmospheric CO2 removal. Currently, the ability of erodible soils to store atmospheric C is reduced. Thus, we assessed how inoculating soil cyanobacteria onto degraded soil affects C sequestration from the atmosphere. The existing cyanobacteria (Nostoc sp., Oscillatoria sp. and Lyngbya sp.) for the C sequestration were proliferated. They were inoculated on the 40 m2 plots located in degraded land. After 83 (middle of the period) and 172 (end of the period) days, we measured the effect of this inoculation on soil organic C, calculated potential C sequestration, and potential CO2 removal from the atmosphere. The results showed that in the control treatment, the sequestrated carbon in the middle and at the end of the experiment was 0.25 and 0.27 g.m-2.day-1, respectively. Inoculation of cyanobacteria led to a significant increase of 312% and 226% of C sequestration in the middle and end of the experiment, respectively. After 172 days, the rate of C sequestration and removal of CO2 by inoculation of cyanobacteria was estimated to be 3.59 and 13.17 ton.ha-1.year-1, respectively, which was 1.10 and 4.03 ton.ha-1.year-1 in control. The results showed that inoculation of cyanobacteria by hydro-seeding technique before the wet season (early autumn) and at least 1.5 g.m-2 of biomass has the desired effect, and is also approved economically. Eventually, field-scale inoculation of cyanobacteria could be considered as a bio-based tool for sustainable development goals through carbon sequestration and rehabilitation of lands.

Keywords

• biological soil crust
• global warming
• greenhouse gases
• land rehabilitation
• organic carbon