Introduction: Legumes in Sustainable Agriculture

World population is predicted to double by 2050 (http://www.fao.org), imposing an increasing demand for food that comes together with an increasing concern on environment and food security. Under this pressing scenario for agriculture, the widely acknowledged beneficial role of legumes in cropping systems, by increasing biological nitrogen fixation, reducing energy costs, improving soil physical conditions and biodiversity, is more needed than ever (Curty et al., 2014; Peix et al., 2014). In addition to this, legumes are important food and feed crops, being key components of the Mediterranean diet, and even staple crops in other regions (Vaz Paatto et al., 2014), with an increasing role as forage producing high-quality meat and milk (Boelt et al., 2014). Legumes are also gaining importance for their health benefits (Arnoldi et al., 2014).