Ecological Engineering Using Biological Crusts: Effects on Soil Physicochemical Properties in West-Central Region of Burkina Faso

The land degradation in Burkina Faso is one of the major development challenges in the agricultural sector. Among the various existing means of soil recovery and improvement, the use of ecological engineering based on soils microorganisms also appears as a tool for sustainable land management. For this purpose, a trial was set up in Péyiri in the West-Center region of Burkina Faso and focused on studying the effects of induced biological crusts on the physicochemical properties of degraded soils. A split-plot design with three replications was set up on three types of soil environment with increasing degradation level, namely "Soil environment with a dense herbaceous layer and some shrubs" (Site 3), "Soil environment with a less dense herbaceous layer" (Site 2) and "Bare soil environment" (Site 1). On each replication plot, three samples core were taken from the 0-20cm layer along the diagonal and were subjected to physicochemical analysis. The organic status (Total C, N and C/N ratio), physical properties (particle size distribution, texture, moisture content), chemical indexes (Séch, CEC, pH, V, Conductivity) and major nutrients (NO3-, NH4+, K+, Mg2+, Ca2+, Total P) were evaluated. The results obtained revealed that the treatment with the induced biocrust increased the rates of C, N, Séch, CEC, V, pH, NH4+, P and clay fraction, with much higher moisture. Taking into account the level of soil degradation, the balance on the site 1 presented the highest positive values in N, clay, pF4.5, Sech, CEC, pH, and P. On the site 2 and site 3, the results balance is sometimes positive or negative depending on the considered soil properties. Then the level of soil degradation influenced the biocrust efficiency, but in general the use of induced biocrust led to an improvement in the physicochemical properties of degraded soils especially on some major nutrients such as N and P. Soils in Burkina Faso like the others Sahelian countries are mostly deficient in these major nutrients. The induced biocrusts seem to be as a sustainable management tool for drylands agrosystems.