Medium and long-term effect of direct sowing on organic matter, structural stability and compaction of clay soils in Morocco
In Morocco, the effects of climate change coupled with the degradation of soil resources are major factors limiting socio-economic development. Among these factors, intensive plowing practiced by Moroccan farmers causes depletion of soil organic matter (OM) and affect their physical properties (structural stability, apparent density) which promotes their erosion. The purpose of this paper is to assess the extent to which no-till (SD) can be used to address these various challenges. The adopted methodology consists of monitoring the OM contents at different depths in two sites on soils of Central Morocco with mixed plowing practices in the medium and long term: direct seeding (SD) and conventional seeding (SC). In addition, we studied the effect of SD on two physical properties of the soil: structural stability and apparent density (Da). The results obtained showed the favorable effects of the EA system on these soil properties. Differences between the two treatments were recorded on the one hand on the soil surface after 10 and 11 years of testing (first site) and on the other hand, at depth after 32 years of testing (second site) . These differences were significant (P-value <0.05) for all parameters except Da. It is concluded that EA has improved soil quality over the medium and long term, which contributes to reducing its vulnerability to erosion.
Keywords: direct sowing, organic matter, structural stability, apparent density, Central Morocco