Short-term effects of conversion from reduced tillage to direct-seeding mulch-based cropping systems

Conservation tillage is one strategy whereby both sustainability and productivity can be achieved by improving the soil quality. Although reduced tillage (RT) is widely practiced, more conservative strategies, such as direct-seeding mulch-based cropping systems (DMC), are less frequent. Here we assessed the effect of conversion from RT to DMC in three commercial fields in southern France (inland Mediterranean climate). Two fields were cropped with maize (Zea mays L.) and one with sorghum (Sorghum bicolor L.), and monitored during 15 months. We found higher soil water potential retention in DMC than in RT at 10, 30, and 60 cm soil depth. Conversely, nitrogen availability was slightly higher in the RT treatment. Crop development was not affected by the soil practices, but crop yields were higher in the DMC treatment for one maize field and the sorghum field (plus 3.04 t/ha harvested in the DMC treatment when compared to the RT treatment in the maize field and plus 2.105 t/ha in the sorghum one). This study demonstrates that DMC can provide short-term benefits in farm fields in southern France, but these benefits are not automatic and the conditions under which they are obtained remain to be clarified.