Coupling Sewage Sludge Amendment with Cyanobacterial Inoculation to Enhance Stability and Carbon Gain in Dryland Degraded Soils

Lisa Maggioli, Sonia Chamizo (), Raúl Román, Carlos Asensio-Grima and Yolanda Cantón
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Lisa Maggioli: Agronomy Department, University of Almería, 04120 Almería, Spain
Sonia Chamizo: Agronomy Department, University of Almería, 04120 Almería, Spain
Raúl Román: Agronomy Department, University of Almería, 04120 Almería, Spain
Carlos Asensio-Grima: Agronomy Department, University of Almería, 04120 Almería, Spain
Yolanda Cantón: Agronomy Department, University of Almería, 04120 Almería, Spain

Agriculture, 2022, vol. 12, issue 12, 1-19

Abstract: Sewage sludge (SS) is widely used as a soil conditioner in agricultural soil due to its high content of organic matter and nutrients. In addition, inoculants based on soil microorganisms, such as cyanobacteria, are being applied successfully in soil restoration to improve soil stability and fertility in agriculture. However, the combination of SS and cyanobacteria inoculation is an unexplored application that may be highly beneficial to soil. In this outdoor experiment, we studied the ability of cyanobacteria inoculum to grow on degraded soil amended with different concentrations of composted SS, and examined the effects of both SS concentration and cyanobacteria application on carbon gain and soil stability. We also explored the feasibility of using cyanobacteria for immobilizing salts in SS-amended soil. Our results showed that cyanobacteria growth increased in the soil amended with the lowest SS concentration tested (5 t ha −1 , on soil 2 cm deep), as shown by its higher chlorophyll a content and associated deeper spectral absorption peak at 680 nm. At higher SS concentrations, inoculum growth decreased, which was attributed to competition of the inoculated cyanobacteria with the native SS bacterial community. However, SS significantly enhanced soil organic carbon gain and tightly-bound exopolysaccharide content. Cyanobacteria inoculation significantly improved soil stability and reduced soil’s wind erodibility. Moreover, it led to a decrease in the lixiviate electrical conductivity of salt-contaminated soils, indicating its potential for salt immobilization and soil bioremediation. Therefore, cyanobacteria inoculation, along with adequately dosed SS surface application, is an efficient strategy for improving carbon gain and surface stability in dryland agricultural soil.

Keywords: organic waste; biocrust cyanobacteria inoculation; organic carbon content; aggregate stability; wind erosion susceptibility; agricultural soil (search for similar items in EconPapers)
JEL-codes: Q1 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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