No-tillage and agroforestry decrease sediment loss from a hilly landscape in northern Morocco

No-tillage agriculture and agroforestry have many environmental benefits, such as maintaining soil productivity, storing water and reducing labor and energy. These practices may also reduce soil erosion in hilly landscapes with a Mediterranean climate by leaving more crop residues on the surface that allow rain and irrigation water to infiltrate the soil profile rather than run off the soil surface. Based on this concept, the objective was to determine how no-tillage and agroforestry techniques affect hydrology and sediment loss from the 180 km2 Tleta watershed in northern Morocco. Land cover and precipitation impact on hydrological processes were quantified with the calibrated Kinematic Runoff and Erosion (KINERO2) model. The KINEROS2 model was validated with data from 7 rainstorms from 2014 to 2018, then soil erosion rates were simulated under extreme rainfall events, consid-ering storm recurrence intervals of 5, 10, 15, 30, 50 and 100 years. The model performed well in the calibration (R2 = 0.8 and Nash-Sutcliffe model efficiency coefficient, NSE = 0.6) and validation (R2 = 0.9 and NSE = 0.7) steps. Then, land use scenarios were tested with the Automated Geospatial Watershed Assessment (AGWA) tool for conventional agriculture (baseline scenario), no-tillage agriculture, agroforestry and combined no-tillage and agroforestry (alternative scenarios). Annual sediment loss of 5.7 t. ha-1 with conventional farming declined by 63 %, to 2.1 t. ha-1 for the combined no-tillage and agroforestry practices. We conclude that adopting no-tillage plus agroforestry on vulnerable farmland has the potential to significantly reduce soil erosion and diminish the sediment yield at the Tleta watershed outlet.

Automated summary

No-tillage and agroforestry techniques have been found to have positive impacts on hydrology and sediment loss, reducing soil erosion and sediment yield in the Tleta watershed in northern Morocco. The adoption of these practices can help maintain soil productivity, store water, and reduce labor and energy consumption.