Rainfed wheat and soybean productivity in a long-term tillage experiment in central Italy

Tillage plays a key role in cropping system sustainability due to its impact on soil properties, crop yields, economic returns, labor, and energy requirements. Th e objective of our research was to compare the eff ects of no-tillage (NT) and conventional tillage (CT) on durum wheat (Triticum durum Desf.) and soybean [Glycine max (L.) Merr.] productivity in a long-term, 2-yr rotation fi eld experiment initiated in 1986 under a Mediterranean climate. Th e 16-yr (1990–2005) average grain yield for NT wheat was 8.9% lower than that for CT wheat (3.97 vs. 4.36 Mg ha–1). Diff erences between tillage systems were signifi cant in 6 out of the 16 seasons and were small when planting was early, weed control was good, and rainfall defi cit occurred during the grain fi lling period. Th e 16-yr average grain yield for soybean was signifi cantly lower under NT than under CT (2.60 vs. 3.08 Mg ha–1) but diff erences between tillage systems were small and not signifi cant in 12 out of the 16 seasons. In comparison to wheat, NT soybean had higher weed pressure. Nitrogen concentrations in wheat and soybean were little aff ected by tillage. Phosphorus concentrations in wheat grain and straw were generally higher under NT, while diff erences in soybean tissue P due to tillage were negligible