An interview with Professor Sylvester-Bradley on how he sees the yield improvement challenges and opportunities.
March 18, 2015
Professor Roger Sylvester-Bradley is Head of Crop Performance with ADAS (UK) and honorary professor of temperate crop physiology with the University of Nottingham. Even with a 40-year career, Prof Sylvester-Bradley says that there has never been a more exciting time to be a crop scientist and refuses to retire! He currently leads the new Yield Enhancement Network (YEN) and a range of other research projects on yield improvement, nutritional efficiency and greenhouse gas emissions. We talked with Professor Sylvester-Bradley about how he sees the yield improvement challenges and opportunities.
Why is root health increasingly important for sustainable crop productivity?
With the planet’s growing population, it is obvious that we need to increase yields. In order to do so, we need to capture more resources. By resources, I mean more light energy and more water. Sometimes crops need more water and sometimes they need more light energy to increase yield, but most importantly we need to know which of these to target. Essentially the more light we can capture – say by keeping crop canopies green for longer – the more water we have to capture. And since we are not going to get more rain, we have to do this through better, and particularly deeper, root systems.
What were the trends in breeding over the last 50 years and what is the consequence?
This is quite interesting: plant breeders measure yield when they are breeding, but they don`t necessarily know exactly how this yield has been realized. During the green revolution, everybody understands that breeders increased the harvest index – the ratio of what you can harvest to the total crop biomass. By working with the breeders more recently, we have come to realize that in the phase after 1990, they have increased yields through a general increase in biomass. Higher biomass also requires more water and other soil resources to be captured. Essentially, the grower now faces the challenge of providing increased resources in order to realize these higher potential levels of biomass and yield.
Where do you see potential for further yield enhancement and how can we realize it?
Well, our estimates of the bio-physical yield potentials of European cereal crops are actually quite optimistic. We think there is plenty of potential for yields to increase. When we just look at the resources we have (i.e. the light and the water available) and the way these could be converted into harvestable biomass, potential yields are way beyond what we are achieving at the moment. If our theories work out, there is still a lot of room for improvement. But we have to use the science of resource capture, and be innovative, to get to that next level of yield. For example, there is no point in having a crop with a lot of leaf if the resources required such as water are not available to keep them alive. In this case, the more effective strategy would be to increase the water supply and that usually means better roots. You know the saying “you can’t manage it, if you can’t measure it”? Well we have concluded that realization of feasible yield potentials will depend on creating the tools and support systems that allow leading farmers to measure their success in capturing resources for crop growth. Their attention will then focus on ways of enhancing the capture of light energy and water, and their conversion, rather than just on making simple yield comparisons between varieties and chemicals.
With that in mind you have established the Yield Enhancement Network (YEN) in the UK – what is the YEN and what is your hope for it?
YEN is an open network sponsored by Syngenta and other organizations. It aims to find the innovators in farming and in the research community who are striving to close the gap between current yields and potential yields. YEN members compete for the highest yield and the greatest proportion of potential yield by comparing verified measurements of yield. The YEN also supports its competitors by estimating the light and water captured by their crops.
Importantly, YEN makes sure that successful innovators are recognized and aims to help them. Very often farmers are just as much innovators as scientists in laboratories, but they are not recognized for this and may lack the resources to make the most of their ideas. With this network, we can establish a really effective development chain between the farmer who is doing something that increases his yield and the researchers who can work out why. For farmers and researchers to work together effectively, they have to use the same terms and measure things in the same way; then everyone can analyse their yields and explain them to each other.
We set up this network not long ago in the United Kingdom. It is becoming increasingly popular with the leading farmers and the competitive farmers! So we are now inviting entrants and sponsors from across Europe to join the YEN, thereby aiming to generate a European network of on-farm innovators focused on enhancing crop growth and productivity and supported by comprehensive crop analysis and shared understanding of yield. Eventually we hope to have European champions regularly setting new record yields, and leading the way in helping to feed the world.
This year we received our first competition entries from Denmark, France and the Netherlands and hope that this participation will spread to other regions and organisations that are excited to work on the challenge of increasing yields.
Professor Roger Sylvester-Bradley was interviewed by Dr. Melanie Goll, Technical Innovation Manager, Syngenta. Melanie holds a Ph.D. in plant pathology and focuses on seed treatment development, especially fungicides and nematicides.