RE SEARCH Potato innovation continues to be necessary to feed a growing world population. ‘The yield gap of the potato is spectacular. For starch potatoes we know that the difference between very successful yields in trial fields and the yield averages in some cultivation areas can run up to 40 tons per hectare,’ Professor Martin van Ittersum points out. Fastest growth in Africa What’s tomorrow’s world like as far as food demand and food supply are concerned? These aren’t easy matters to predict, but Professor Martin van Ittersum of Wageningen University has a whole list of figures ready. On a basis of counts and figures from the past, he’s able to Nigeria and this number is expected to have risen to 440 million in 2050. More production, but also more sensible consumption To feed all those mouths, more food will be necessary. An important question is, does this mean that we’ll also have to ‘Innovation continues to be necessary to keep ahead of the competition.’ (Ruud Huirne) offer the potato sector an interesting look into his crystal ball. From the series of figures he conjures up on his screen, it transpires, for example, that in the year 2050, 60 percent more food will be necessary than we produced in 2010. The reason is the growing world population. ‘The total figure is now around 7 billion and will have increased to 1.5 billion in 35 years’, Van Ittersum shows his Audience. The fastest growth will take place in Africa. There are countries there where the population will triple. An example of a country where a gigantic increase will take place is Nigeria. There are currently 140 million people in produce 60 percent more food? Van Ittersum doesn’t think so because you can also do something about the demand side, for example by consuming more sensibly. ‘Less meat consumption, less food waste, for example, and adjusting Location Kenya (Tittonell et al., 2008) SE Asia (Laborte et al. 2012) The Netherlands (www.yieldgap.org) the human diet, with no food crops for green energy. Nobody knows to what extent these measures will work, but if they work, only 40 percent of extra production will be needed. That’s still a lot, of course. It will then be up to the farming world to take matters into their own hand, but how? Every one of you is familiar with the term “the green revolution”. In the years after the Second World War, we accomplished enormous yield increases thanks to the rise of mechanisation, artificial fertiliser, crop protection chemicals, breeding, and all the factors you are familiar with. This has made it possible to reduce the number of starving people from 23 percent in 1990 to 13 percent in 2015. Figures and graphs of yield measurements indicate that the yields are increasing much less than twenty to thirty years ago.’ And yet, we’ve not yet reached the end of our capacity, according to the Professor. ‘What farmers are achieving now, the average tons of potatoes per hectare, for example, is what we call the actual yield. If all farmers were to optimise their crop yields, the yields would be quite a lot higher, which we call the potential yield. You reach a potential yield when crops have received the maximum water and nutrients, didn’t contract any pests or diseases, etc.’ Closing of yield gaps The difference, or gap, between the actual and the potential yield in science is called a yield gap, Van Ittersum clarifies. ‘The gap in yield can vary by country, region, grower, but also by crop. When you look at different countries, for example, you immediately see big differences. So, in Kenya the yield gap of a crop such as maize is between 67 to 83 percent, in Southeast Asia for rice it’s between 29 Crops Maize Rice Various Yield gap (%) 67-83 29-56 10-20 In the Netherlands, the yield gap for an average of various different crops lies between 10 and 20 percent. (Martin van Ittersum) 18 Potato World 2016 • number 3 Pagina 17
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