Is it Sustainable to Cultivate a Monoculture of Durum Wheat with Prolonged No-Tillage Management?

The prolonged effect of no-tillage (NT) and conventional tillage (CT) treatment on durum wheat (Triticum durum Desf.), continuously grown in Southern Italy, has been evaluated in experimental fields for sixteen years (1994/95-2009/10) to ascertain whether the yields and quality of the grain as well as some soil characteristics had changed. The average grain yield in CT (2.70 ± 0.96 t ha-1) and NT (2.63 ± 0.74 t ha-1) treatment was not significant. CT treatment showed higher values of plant height and grain weight (74.2 cm and 43.2 g) than NT (71.0 cm and 41.8 g). Regarding to the semolina quality, the values of the gluten index and the dough strength (W parameter) as well as the protein content and the yellow index were not significantly different for the NT and CT treatments. As for soil moisture, the NT treatment stored in the soil profile, and over time, about 13% more water than the CT one. In the upper soil layer of the NT treatment the SOC value (16.0 ± 2.2 g kg-1) was 13.2% higher than CT one (14.2 ± 1.2 g kg-1) while the CT treatment (13.7 ± 0.5 g kg-1) showed in the lower soil layer a SOC value of 30.2% higher than the NT one (9.6 ± 1.9 g kg-1). Hence the prolonged no-tillage adoption in conditions of continuous durum wheat cultivation, even with slight losses in yield but not in the quality of grain or semolina, would seem sustainable.