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Abstract: This study investigated whether the choice of a tillage system (no-tillage, minimum tillage or traditional tillage) affected weed diversity in a 23 years cereal–leguminous rotation system in Spain. Weed diversity was assessed using common diversity indices: species richness, Shannon''s index and Pieloús evenness. Linear mixed-effects models were employed to compare the tillage systems. It was found that after 23 years no large differences between tillage systems have arisen related to weed diversity. Only minimum tillage appeared to support, on average, more species than the two other tillage systems. Richness, Shannon diversity index and evenness varied largely through the years in all tillage systems but this variation was not related to type of crop sown (cereal or leguminous). Our results highlight that conservation tillage practices did not represent any concern for weed diversity conservation in cereal–leguminous rotations in the conditions of central Spain. [Copyright &y& Elsevier]

Abstract: Correct estimation of leaf-level stomatal conductance (g sto) is central for current ozone (O3) risk assessment of wheat yield loss based on the absorbed O3 phytotoxic dose (POD). The g sto model parameterizations developed in Europe must be checked in the different climatic regions where they are going to be applied in order to reduce the uncertainties associated with the POD approach. This work proposes a new g sto model parameterization for estimating POD of Triticum aestivum and Triticum durum under Mediterranean conditions, based on phenological observations over 25 years and g sto field measurements during 5 growing seasons. Results show that POD in the Mediterranean area might be higher than previously estimated. However, caution must be paid when assessing the risk of yield loss for wheat in this area since field validation of O3 impacts is still limited. [Copyright &y& Elsevier]