Cover crops support ecological intensification of arable cropping systems.

A major challenge for agriculture is to enhance productivity with minimum impact on the environment. Several studies indicate that cover crops could replace anthropogenic inputs and enhance crop productivity. However, so far, it is unclear if cover crop effects vary between different cropping systems, and direct comparisons among major arable production systems are rare. Here we compared the short-term effects of various cover crops on crop yield, nitrogen uptake, and weed infestation in four arable production systems (conventional cropping with intensive tillage and no-tillage; organic cropping with intensive tillage and reduced tillage). We hypothesized that cover cropping effects increase with decreasing management intensity. Our study demonstrated that cover crop effects on crop yield were highest in the organic system with reduced tillage (+24%), intermediate in the organic system with tillage (+13%) and in the conventional system with no tillage (+8%) and lowest in the conventional system with tillage (+2%). Our results indicate that cover crops are essential to maintaining a certain yield level when soil tillage intensity is reduced (e.g. under conservation agriculture), or when production is converted to organic agriculture. Thus, the inclusion of cover crops provides additional opportunities to increase the yield of lower intensity production systems and contribute to ecological intensification.

Identification of pheromones and optimization of bait composition for click beetle pests (Coleoptera: Elateridae) in Central and Western Europe.

Based on analysis of pheromone gland extracts, highly attractive new baits have been developed for three click beetle pests. That for Agriotes brevis is a mixture of geranyl butanoate and (E,E)-farnesyl butanoate, and that for A rufipalpis and A sordidus contains geranyl hexanoate alone. From known data from species populating Russia, optimized bait compositions for species in Central and Western Europe were developed as follows: geranyl octanoate + geranyl butanoate for A lineatus, geranyl isovalerate for A litigiosus, geranyl hexanoate + geranyl octanoate for A obscurus, geranyl butanoate alone for A sputator and (E,E)-farnesyl acetate alone for A ustulatus. Although slight differences were found in gland contents with A litigiosus var laichartingi and fenotypus typicus, nevertheless there were no differences in response to the optimum bait. There were no differences in pheromone composition or response to the optimized bait between the two morphological forms ('black' and 'red') of A ustulatus. As a result of these studies, highly effective pheromone baits are now available for monitoring and population reduction in all important pest click beetle species in Central and Western Europe.