Durum wheat yield uncertainty under different tillage management practices and climatic conditions

In the field of conservative agriculture, no-till (NT) management has been receiving increasing interest, with 45 million ha of land under no-till management in 1999 to 155 million ha in 2014. Up until now, no-till has only been observed to perform better under rainfed conditions, especially in dry climates mainly because the reduced tillage system retains more soil moisture. However, the adoption of alternative agricultural practices (NT) can be improved only if uncertain and consequent assumption of risk is well known and accepted. For these reasons, the aim of this research is (i) to define durum wheat suitability under NT soil management in terms of yield success probability and (ii) to determine the suitable area for NT wheat cultivation within three climatic periods (the past, present, and future). The probability distribution of the aridity index (AI) was used to derive the non-exceedance conditional probability of NT yield success in comparison to conventional tillage (CT) on arable land in the Sicilian Region (southern Italy). The probability of NT management resulting in a higher yield than CT management for each specific environment was predicted. The latter made it possible to determine the probability of a higher yield under NT practice in comparison to CT, considering both the environment (aridity index) and different management practices (cropping system and residue management). An analysis of the relationship between the crop yield and the AI showed that the probability of NT success in durum wheat yield is affected by cropping systems and residue management and that Sicilian climatic trends will determine an increase in the areas suitable for NT durum wheat management. The uncertainty quantification or the success yield probability of NT could be used to target incentives for NT durum wheat cultivation in areas (within a region) where the mean yield and non-exceedance probability are low.