Conventional Agricultural Production

Over the decades from 1960 to 2010, agricultural pro­duction has increased more than threefold and per cap­ita provision of calories has increased by one-third (FAOSTAT, 2013). This has greatly contributed to feeding an ever-increasing population (from 3×109 to 6.7×109 billion over this period). This development is usually subsumed under the label "Green revolution" (IFAD, 2001; Evenson and Gollin, 2003). Starting in the 1960s, this development was based on a strict focus on monocropping with high yielding species and varieties, irrigation and mechanization where available and increased use of mineral fertilizers, pesticides and herbi­cides. The successes of the green revolution are evident, but so are the downturns related to it (Matson et al., 1997; DFID, 2004). The focus on monocropping, chemi­cal fertilizers, pesticides, irrigation and mechanization has left an increasingly negative legacy regarding adverse effects on soil fertility, i. e. increased soil degra­dation, salinization and depletion of water bodies, on intoxication of the environment, biodiversity loss, loss of ecosystem services, on eutrophication of water bodies and animal health (Matson et al., 1997). Current agricul­ture is well able to feed the world and will be able in 2050 to feed more than 9 billion people, given projected yield increases realize (Alexandratos and Bruinsma, 2012). The challenge is not the average supply of calories per capita but their distribution globally and the fact that a third is lost or wasted globally (Godfray et al., 2010). However, in the light of the adverse effects of the green revolution and climate change, such yield increases may be compromised and sustained agricultural production calls for alternative cropping practices and a funda­mental shift in the agricultural production system (IAASTD, 2009; Muller et al., 2010).

Sustainable Agricultural Production

A new revolution in agricultural production is thus needed. On the production level, a sustainable future agricultural system needs to focus on mitigating and avoiding the adverse effects of current agricultural prac­tices. It needs to focus on crop diversity, ecosystem ser­vices, soil protection and fertility, nutrient and water use cycling, biocontrol of pests, diseases and weeds and reduced pesticide use. A range of alternative pro­duction approaches are available (Eyhorn et al., 2003; Pretty et al., 2006; Rossi, 2012), such as agroecology — based approaches, focusing on utilization of ecological concepts (Altieri, 1995), or integrated pest management, focusing on reducing pesticide use via managing pest populations in such a way that damages remain low (Bajwa and Kogan, 2002). The role model for these alter­native approaches is organic agriculture with its ban on most pesticides, focus on soil fertility, plant health and closed nutrient cycles, utilization of optimized crop rota­tions and crop diversity, organic fertilizers and ecosystem functions for pest and weed control (FAO, 2002; Eyhorn et al., 2003; IFOAM, 2006). Organic agricul­ture is the role model as it addresses all adverse effects of conventional production, adopts a systemic approach and is well established and tested for decades and embedded in a context of governance, information pro­vision, training and extension institutions that make it the best-developed alternative production system. Organic agriculture performs better than conventional agriculture with respect to most environmental indica­tors on a per-hectare basis (Schader et al., 2012). The biggest drawback is its generally lower yields (Seufert et al., 2012; De Ponti et al., 2012; Badgley et al., 2007). Lower yields predominantly manifest in comparison to high-yielding intensive conventional agriculture. In developing countries, in a context of currently no­optimal conventional production systems, organic yields are on par or even higher for well-managed organic farms. The lower yields can result in a less favor­able per kilogram produce assessment of environmental impacts for some products in organic agriculture (Schader et al., 2012). We emphasize that we do not address socioeconomic aspects of organic production here, such as the need for information and extension ser­vices to train farmers and potential challenges of the conversion from organic to conventional agriculture.

Interestingly, the key principles and practices of organic agriculture become increasingly important in conventional agriculture, mainly due to the increasing need to contribute to climate change mitigation and adaptation but also due to the increasingly important discussion on global biodiversity losses. Optimized crop rotations with deep-rooting forage legumes and use of organic fertilizers, for example, are promoted in the context of climate change mitigation and adaptation to improve soil fertility and increase soil organic carbon levels (Smith et al., 2008) and reducing nitrogen loads are key to protect biodiversity.