Playing with food
How do you optimize the food supply in a field, in a town or even in an entire country? Three Tilburg students built their own games to tackle these questions.
In 1798, economist Thomas Malthus published an essay contrasting population growth with the growth of agricultural capacity. Because population grows exponentially and agricultural capacity grows linearly, an intersection would inevitably be reached after which population would be greater than food production could handle. Here, “intersection” is a mathematical euphemism for the start of a horrific famine. However, due to technological developments that Malthus had not taken into account, the disaster was ultimately avoided.
Yet this issue is still relevant today. The United Nations estimates that the world’s population will reach approximately 10 billion by 2050. Meanwhile, due to climate change, the amount of available agricultural land is more likely to decrease than increase. So, Malthus could be proven right after all.
To prevent his intersection in the 21st century as well, three econometrics and operations research students at Tilburg University are each developing a game for their bachelor thesis that focuses on an optimization problem in food supply. Under the guidance of Hein Fleuren, Mas van Gageldonk, Juliëtte Tillie, and Mark Smolenaers are each trying to find a mathematical optimum to feed as many people as possible with as few resources as possible. All three came across the Zero Hunger Lab through a guest lecture. Gageldonk: “I thought it was really cool that econometrics could also serve social purposes. The field is often fairly theoretical, with the goal of making as much money as possible. So, I thought it would be great fun to collaborate on an application that could really benefit people.”
Tricky trade-off
Tillie is trying to make the imaginary African village of Agriville completely self-sufficient in its food production. Here, the focus is also on the effects that a particular crop has on the rest of the ecosystem. For example, there must be bees to pollinate the crops. These insects have another benefit, which is that they scare away elephants.
“The first step is to increase food production to ensure that Agriville residents simply get enough nutrients,” says Tillie. “Then we look at how to attract as many bees as possible without sacrificing the nutrients needed for the population. To attract bees, though, flowers must grow on about 25 percent of farmland. With a mathematical model, I am trying to find an optimal balance in this.”
Van Gageldonk is looking at a higher level in terms of scale. His game focuses on food production across Nigeria. To do this, he has created a map of the African country, entering the soil type for each region. “The overarching goal of my game is to have as large a percentage of the population as possible get enough of all nutrients. You do this by growing different food types on each parcel of land. All parcels have their own soil type, so not every food type can be produced everywhere. Also, yield per hectare varies for each food type. In addition, all these food types contain their own nutrients, so there is not an equal need for each type. That ultimately creates a tricky trade-off of what to grow where to feed as many people as possible.”
The game includes 29 food types, 18 soil types, and 19 nutrients. There is a recommended daily intake for each of the nutrients. The score in the game is determined by how many people can get the recommended intake of each nutrient. So, if eighteen of the nineteen nutrients are produced in sufficient amounts, but one isn’t, you still have a poor score.
The goal of the games is to make it clear to players how complex the trade-offs involved in food production are
Juliëtte Tillie
Inspiring project
If you grow the same crop in a field every year, the soil will become depleted. The solution to this is to spread fertilizer, but that introduces new problems. For example, it poses significant environmental problems, known in the Netherlands as the nitrogen crisis. Also, the global supply of phosphate, a crucial ingredient of fertilizer, is in danger of running out during this century. In addition, this stock is highly concentrated in China and Morocco, which can create an uneasy dependency.
Smolenaers is trying a different approach and is looking at how rotating different crops can prevent soil depletion. “By alternating between different types of crops, the soil remains healthy for longer,” he says. “Each crop type has a specific sowing date and a specific harvest date. If you optimize them, you can, for example, harvest one crop in May and sow another in June. Sticking to one crop type means waiting a year before you can sow again. In the game I’m creating, players have to maximize yields over a five-year period by growing crops in the right order.”
It is not the intention to base policy on the games. “The goal of the games is to make it clear to players how complex the trade-offs involved in food production are,” Tillie says. Also, before the games can really be used as games, there is some work to be done on the graphics.
Yet the project turns out to be very inspiring. Smolenaers: “When we had the interim presentation in October, a student from another group came over afterwards to ask if she might be able to do an internship at the Zero Hunger Lab. That just goes to show how excited people get about this.”
Text: Wouter Schreuder
Date of publication: 1 April 2022