A cultivated planet: closing yield gaps

By Tibor Hartel and Joern Fischer

The challenge of sustainably increasing global food production was recently addressed by Foley et al. in Nature. Among other solutions, they suggested closing yield gaps in existing agricultural land, rather than converting new areas for agriculture. A yield gap is the difference between the actual agricultural productivity of land and its potential productivity. Foley et al. considered that much farmland in Eastern Europe had high yield gaps (see also Licker et al. 2010).

We broadly agree with Foley et al., but we also think we shouldn’t be too enthusiastic about closing yield gaps. In the case of Eastern Europe, three questions must be addressed: (i) What should be the reference point for closing yield gaps? (ii) Which specific management and land use should be used to close yield gaps? (iii) How will the closure of yield gaps affect the biodiversity and resilience of agro-ecological systems?

Yields obtained by ‘organic farming’ may constitute a reference point for assessing yield gaps, and organic farming may be a desirable new type of land use. However, organic farming as it is practiced in Western Europe may still constitute more intensive land use than the traditional agriculture practiced until today in some of Eastern Europe. Traditional agriculture has been tested over centuries, and has resulted in species-rich, virtually unfragmented rural landscapes (e.g. in Central Romania). While organic farming tends to support greater biodiversity than conventional (industrialised) agriculture, its consequences for biodiversity relative to traditional agriculture are poorly understood.

Closing yield gaps could easily be interpreted as analogous to ‘optimal harvesting’ as it has been applied in forestry. However, an overly narrow focus on efficiency in production can risk an system’s biodiversity and resilience (Holling and Meffe 1996). The costs to resilience of closing yield gaps are currently unknown.

Before policy aims to close yield gaps, society needs to consider the unique circumstances of the systems targeted. Otherwise, there is a risk to erode the resilience and biodiversity of some of the world’s most notable rural landscapes.

 

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12 thoughts on “A cultivated planet: closing yield gaps

  1. I quite agree. The idea of intensified agriculture with biodiversity islands is (I thought) rather 20th century! Have we not moved on to the idea if sustainable agriculture everywhere – that is supported by the EU’s proposal of 7% ecological focus areas on every farm in Europe – a more effective way of sustainable food production and biodiversity conservation than the Foley et al. polarised model.

  2. Hi Nat – many thanks! I am outsider of EU policies, but still, I wonder how that 7% was decided, on which scientific evidences. In EE, at least in the Saxon area, the ecological focus area is region wide.

    I would like to see policies made for Eastern Europe – to fit landscape European landscapes.

    I read a farmland conservation & policy (proposal) paper recently published in TREE, and here (i.e. in a top journal) Eastern Europe is still refered as ‘marginal’ area. I would say that considering the western state of farmlands, versus the eastern farmlands, everything else is marginal but not EE.

    If I would make a caricature map of Europe from the perspective of European farmland scientists and policy makers, that map would be similar to that one very popular on the internet about how America see the world (see google). In this map, WE would be a big, proude area while EE something small, marginal, insignificant. It is just a matter of ~1 week field trip here to realize, how complex these systems are (e.g. for these 7% etc. games)

  3. In its impact assessment the Commission has calculated the environmental benefits and opportunity costs of 5% “ecological set aside” and 10% and they came to the conclusion that 7% would be the best in terms of costs and benefits. You can find this in the CAP impact assessment.
    I will try to find the relevant text for you.

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