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.