Time to break free from the ‘yield gap trap’

19 May, 2014 by (comments)

When we see a gap, be it physically in front of us or figuratively speaking, we are compelled to find a way to mind it, to fill it, to close it.

When we talk about the yield gap – the difference between actual crop yields and those potentially attainable in a given region – in the agricultural research and development world the same knee-jerk reaction compels us – “must close the gap!”

CIATs new strategic initiative to reduce yield gaps for sustainable intensification of agriculture is kicking-off by stepping back and asking some vital questions to help us rethink yield gaps and consider socio-economic constraints and whole system productivity. Who wants to close the gap and why? Specifically whose yield gap do we want to address? Are we asking the right questions to the right people? Do we have the idea of “closing” the gap and limiting the discussion to a “yield” gap all wrong?

Yield gap blog

Rethinking the yield gap is the only way to avoid falling into the “yield gap trap”. Photo by Neil Palmer/CIAT

Rethinking an old concept
Closing the yield gap is not a new concept. The idea of increasing yields and improving the genetic potential of crops and livestock has been around since the beginnings of agronomy and breeding. The yield gap term itself was coined some 30 years ago. But despite decades of work, we are still trying to close the yield gap for staple crops (maize, rice, wheat, cassava, beans) all over the world.

Global food security is calculated based on how many million tons of (staple) food is produced. Therefore, the current yield gap debate is perpetuated by development agencies, governments, and NGOs revolving around national and global food security discussions and the need to feed our rapidly growing population projected to reach 9 billion by 2050.  But are smallholder farmers really concerned about commodity yield gaps? Are we all speaking the same language?

We should not get trapped in the mindset that the food security of a smallholder means a large, beautiful maize field that provides enough food for the whole family, while excluding alternative income options, diversification or specialization. Not to be misunderstood, individual farmers certainly would be delighted to achieve high(er) yields of the commodities they grow – maize and beans in sub-Saharan Africa for example. But, at what cost and risk?

Weighing pros and cons and considering a multitude of constraining factors simultaneously, farmers might be more concerned about the crops or livestock that bring in the most cash, i.e. those crops that we might be promoting for crop diversification or linking farmers to markets. A clear illustration is the smallholders in Lushoto, Tanzania, who reserve the fertile valley bottom land for producing cash-crops like tomato and cabbages, while getting low yields from maize planted on steep and degraded hill slopes. In other words, smallholders are more concerned with improving the performance and productivity of their whole farm and their livelihoods, including off-farm activities and income. This is what we like to call the “farm gap.”

Lushoto Tanzania, Johnathan Stonehouse

Smallholders in Lushoto, Tanzania, reserve the fertile valley bottom land for producing cash-crops. Photo by Johnathan Stonehouse (Flickr)

Exploring the farm gap holistically

So where does this leave the yield gap debate and related research? Let’s not get trapped in a narrow-minded, single commodity yield gap debate and move forward to explore what a bottom-up, holistic approach looks like!

We aren’t suggesting abandoning past work on traditional agronomy and breeding; traditional approaches to “closing” the gap including sound agronomy, natural resource management and improved varieties are pieces of the puzzle. But, taken forward in isolation – without a clear understanding of smallholder realities – they often don’t achieve the profound and lasting impact that researchers were hoping for.

The farm gap approach forces us to put farmer decision-making at the center. At the same time, being concerned with the sustainability of smallholder production systems, there is no way we can ignore adding eco-efficiency into the equation. Such a holistic approach embraces the complexity and diversity of on and off-farm links with income, labor and resources. We strive to address farmer risk and vulnerability and farmer perceptions of production. We move beyond the field scale of the yield gap to a multi-scale approach across a landscape. Instead of being driven by the national and global agenda of general food security, the farm gap addresses multiple levels from the household up. This all lies within a context of ecosystem services and sustainability that must be addressed.

We will embrace this complexity and tackle our research questions from the farmers’ perspectives, to integrate their desires and perceptions. We want to know how taking this holistic, multi-scale, interdisciplinary, eco-efficient farm gap approach helps sustainably and better address food security and livelihoods. At the same time, we believe that these insights will be crucial for governments and global players to identify entry-points for shaping policies or targeting interventions with the aim to increase the production of staple crops, if this is what these stakeholders want to pursue.

The way forward
Now the big question is: how to put this new approach into action?

We have already laid the foundations with our work in breeding, agronomy, modeling, integrated pest and disease management, assessment mapping and management of soil fertility. Now it’s time to integrate these with our socio-economic, governance, landscape health, ecosystem services and “big data” expertise.

Rethinking the yield gap is the only way to avoid falling into the “yield gap trap”.

There are some immediate, no-regret options to increase farm productivity, such as adopting improved varieties or using available farm resources more efficiently, and we can start there testing out our new approach.


For more information about CIAT’s new approach to the yield gap, see Rethinking yield gaps in Africa on page 30 of the CIAT 2013/4 Annual Report and CIAT’s new Strategy 2014-2020.

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  • http://www.cgiar.org Alain Vidal

    Thanks Stephanie for reopening the debate on the yield gap. You are absolutely right to suggest shifting to a more holistic “farm gap”, which I called “income gap” in a former post under my CPWF Director’s blog two years ago. Hope your call for a discussion on this helps change mindsets !

  • Peter Ninnes

    Very good article

    • Juliet Braslow

      Thank you, Peter! I hope you were also able to browse some of the other articles and information on our site.

  • Judy

    Terrific insights! Over 70 years ago, my grandfather and father faced all small farmers’ obstacles in rural SD with no irrigation options. I’m delighted to learn your focus is on the
    realities…it was imperative to sustain livelihood as well as preserve the quality of the soil. Rotation of crops was a way of life as well as investing in options of more drought-resistant crops. Sustainablity may be hard for those facing severe economic situations…but, more power to you for addressing the issues at their source!!!!
    Thank you for sharing!

    • Juliet Braslow

      Thank you for your comments, Judy. It’s great to
      hear that the issues we are working to address in the tropics are relevant
      globally and across time (even in rural South Dakota, USA decades ago). Of
      course each context has its own separate set of variables (environmental, cultural,
      economic, etc.), and farmers are all unique with their own individual goals and
      management approaches. I think of sustainablilty as including economic
      sustainability, therefore the information, approaches and technologies we produce
      and share should be sustainable environmentally (eco-efficient) and
      economically, and of course feasible and suitable for the land managers who
      might adopt them.

  • Ed Garrett

    When I look at fields and the subject of yield gap comes up, one of the primary things I notice is the variation of stand within a field where yields are significantly below optimum. This takes into account the combination of seed placement (skips and misses as well as variable distance between seeds), germination failure, and differential timing of germination and emergence.

    These are informal observations but it appears that seed and seedling performance is negatively impacted by soil quality issues leading to poor seed soil contact and non-uniform seed placement (depth, distance, etc.). I noticed this in Hungary as well as other countries using standard agricultural equipment as well as in hand sown plots but the phenomena does not appear to be isolated to any single country.

    If anyone really does want to unravel the productivity gap, I suggest looking at ways to improve the seed zone as a place to start. Here in California, I’ve worked on systems that use compost as a planting medium to enhance seed performance. This can be done in a number of ways to create a seed zone that holds moisture and provides more ideal rooting and nutrient conditions for seedlings even if field conditions are poor.