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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.
Short Term Impact of Andropogon gayanus Kunth. on Soil Fertility and Legume Crop Rotation in West Central Region of Koudougou, Burkina Faso
The low productivity of land in Burkina Faso is one of the major threats of the agricultural sector. This study aims to evaluate the short-term legume crop impact in a sequence with a short term Andropogon gayanus fallow rotation in order to propose means of degraded lands recovery and their sustainable management. To achieve this goal, a test was set up in Péyiri village in West-Central region of Burkina Faso. The test which is made up of a completely randomized block of three plots, was installed on two area of a transect taking into account the microtopography (1.35%) effects. The first area which is called geomorphological unit I (UGI) consisted of a block of three replications plots and this area was used for legume crop (MC) during five (05) years. The legume crop was followed in rotation with a short-term Andropogon gayanus fallow (MA) for three (03) years. Following the micro-slope (1.35%), the same test was repeated on the second area of the transect called geomorphological unit II (UGII). On each plot of each UG, three (03) replications soil samples were collected on 0-20 cm soil layer at the end of legume crop and at the end of Andropogon gayanus short-term fallow for the soil physico-chemical properties assessment. The results obtained revealed that the MA treatment increased the contents of N, C, Sech, CEC, V, pH, NH4+, P, K, Mg, Ca respectively by 33%, 51.72%, 20.55%, 16.43%, 3%, 7%, 192.71%, 18.61%, 98.68%, 1095.8% and 353% on UGI except NO3- compared to the MC treatment results which increased the content of NO3- by 5% compared to MA. The slope of 1.35% observed between UGI and UGII caused a deterioration of the organic status, physicochemical properties and major nutrients on the UGII. These results suggest that even for small slopes, soil conservation measures are still necessary. In conclusion, the study showed that on small family farms systems in Burkina Faso, legume crop rotation with Andropogon gayanus short-term fallow constitutes a means of agricultural lands sustainable management.