Soil and crop responses in legume/barley intercropped systems

In a modern agriculture, cropping systems are addressed to provide ecosystem services. Legume crops are known to contribute more to the farming system than simply the harvested part: they fix atmospheric nitrogen into chemical forms available for plant metabolism, they break the cycles of diseases that attack the major cereal crops, and they can replace other food, feed, fiber and fuel crop products that are imported from other countries. This work contributes to the European research programme “Legume Futures” (FP7, KBBE), aimed at delivering an improved understanding of the range of ecosystem services provided by legume-containing systems. The present study was focused on investigating the environmental effects (C and N cycling, soil bacterial diversity, weed control, N use efficiency) of farming systems based on legume/barley intercropping and grown in a Mediterranean environment. Six-row barley (Hordeum vulgare L.) cultivar was cultivated both in additive or replacement combination with pea (Pisum sativum L.) or faba bean (Vicia faba L.). Soil chemical (EC, TOC, TN, NH4+-N, NO3--N, total soluble N, EON), biochemical (basal respiration, MBC and MBN, potentially mineralizable N, mineralization quotient), ecophysiological (qCO2, MBC/TOC, qCO2/TOC) variables and bacterial community molecular structure were monitored at three sampling times (tillering, flowering, harvest) over the growing cycle. The ecological services provided by intercropped legumes were also evaluated in terms of weed control and complementary use of soil nitrogen supply. Results show that even in the short-term legume/barley intercropping selectively affected biochemical variables linked to soil C cycling, and some related soil quality attributes.