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Food & Water | nexus

How games can help science: Introducing Cropland Capture

By Linda See, Research Scholar, IIASA Ecosystems Services and Management Program

Researchers estimate we spend 3 billion hours a week on game playing. CC Image courtesy TheErin on Flickr

Researchers estimate we spend 3 billion hours a week on game playing. CC Image courtesy TheErin on Flickr

On a recent rush hour train ride in London I looked around to see just about everybody absorbed in their mobile phone or tablet. This in itself is not that unusual. But when I snooped over a few shoulders, what really surprised me was that most of those people were playing games. I hope this bodes well for our new game, Cropland Capture, introduced last week.

Cropland Capture is a game version of our citizen science project Geo-Wiki, which has a growing network of interested experts and volunteers who regularly help us in validating land cover through our competitions. By turning the idea into a game, we hope to reach a much wider audience.

Playing Cropland Capture is simple: look at a satellite image and tell us if you see any evidence of cropland. This will help us build a better map of where cropland is globally, something that is surprisingly uncertain at the moment. This sort of data is crucial for global food security, identifying where the big gaps in crop yields are, and monitoring crops affected by droughts, amongst many other applications.

Gamification and citizen science
The idea of Cropland Capture is not entirely unique. There are an astonishingly large number of games available for high tech gaming consoles, PCs and increasingly, mobile devices. While the majority of these games are pure entertainment, some are part of an emerging genre known as ”serious games” or ”games with a purpose.” These are games that either have an educational element or through the process of playing them, you can help scientists in doing their research. One of the most successful examples is the game FoldIt, where teams of players work together to decode protein structures. This is not an easy task for a computer to do, but some people are exceptionally talented at seeing these patterns. The result has even led to new scientific discoveries that have been published in high level journals such as Nature.

Jane McGonigal, in her book Reality is Broken (Why Games Make us Better and How They Can Change the World), estimates that we spend 3 billion hours a week alone on game playing, and that the average young person spends more time gaming by the end of their school career than they have actually spent in school. Although these figures may seem alarming, McGonigal argues that there are many positive benefits associated with gaming, including the development of problem-solving skills, the ability to cope better with problems such as depression or chronic pain, and even the possibility that we might live ten years longer if we played games. If people spent just a fraction of this time on “serious games” like FoldIt and Cropland Capture, imagine how much could be achieved.

Since the game started last Friday, 185 players have validated 119,777 square kilometers of land (more than twice the land area of Denmark).


Cropland Capture is easy to play – simply swipe the picture left or right to say whether there is cropland or not.

Get in the game
You can play Cropland Capture on a tablet (iPad or Android) or mobile phone (iPhone or Android). Download the game from the Apple’s App Store or the Google Play Store. For those who prefer an online version, you can also play the game at: For more information about the game, check out our videos at: During the next six months, we will be providing regular updates on Twitter (@CropCapture) and Facebook.

The game is being played for  six months, where the top scorer each week will be crowned the weekly winner. The 25 weekly winners will then be entered into a draw at the end of the competition to win three big prizes: an Amazon Kindle, a smartphone, and a tablet. The game was launched only last week so there is plenty of time to get involved and help scientific research.

Interview: The problems with phosphorus

In a new commentary (subscription required) in Nature Geoscience, IIASA researchers Michael Obersteiner, Marijn van der Velde,  and colleagues write about the problems facing the world’s food supply as we exhaust our supplies of phosphorus. Projections show that phosphorus supplies could run out in the next 40 to 400 years.  In this interview, Obersteiner and van der Velde give more background on the “phosphorus trilemma.”

field of wheat

Fertilizers containing phosphorus are vital for crop production – but phosphorus is limited in availability and growing scarcer.

Why is phosphorus so important?

MV:  Phosphorus is essential for life on Earth. It is a key component of DNA and cell membranes, and vital for cellular energy processes. Crops need phosphorus to grow. And to maintain crop production, and to make sure that soils remain productive, we have to add extra nitrogen and phosphorus as fertilizer. This is one of the food security issues in Africa where soils are suffering from nutrient depletion without replenishment.

Where do we get phosphorus and why is that supply in danger?

MO: Phosphorus is ubiquitous in the Earth’s crust. However, most of it is strongly bound in the soil , where plants cannot access it. Modern agriculture (which made human population explode) essentially began when we found ways to extract nitrogen from the air and phosphorus from minerals to make fertilizers for agricultural purposes.

The problem is that minable phosphorus is geographically concentrated in very few places. For example 75% of known reserves are located in Morocco and these reserves are limited. If, for example, political turmoil restricted access to the mines of Morocco, we would be in danger of short-term shortages that could lead to rising food prices or food insecurity in poor countries.

What problems do you expect as phosphorus becomes even more limited?

MO: The biggest problem we face is limited or no access to phosphorus fertilizers by the poor and food insecure.

MV: At the same time, rich countries apply excess fertilizers causing eutrophication to their lakes and rivers, while the poor cannot afford fertilizers.

What can be done about these problems?

MV: More efficient fertilizer application would make fertilizers cheaper to poor farmers, and at the same time help address the environmental problems. But in the long run we need to figure out how to produce food in a way that recycles nutrients at minimum loss rates.  (This also includes losses from human excrement!)

To better solve the issues around long-term phosphorus availability and equitable use we also need better data on how much phosphate rock is remaining in the world and where it is located. Countries will need to be persuaded to collaborate on both these issues to ensure equity.

How does IIASA research inform this debate?

MV:  In a paper we published earlier this year in PLOS ONE we showed the importance of soil phosphorus and the significant increases in yields that could be achieved in Africa with balanced micro-dosed applications of nitrogen and phosphorus. Available phosphorus in soils is generally low, especially in older weathered soils in the tropics where a lot of the phosphorus can be locked up in iron and aluminum complexes. We are currently investigating what application rates of nitrogen and phosphorus would be optimal for a range of soils and climates. This can then lead to better soil and nutrient management.

MO: In addition researchers in the Mitigation of Air Pollution and Greenhouse Gases program have been very active in finding solutions to the problem. For example:—Wilfried-Winiwarter-on-Reality-.en.html

What should people to know about this issue?

MO: Many things in nature that we like or depend on for our livelihood are substitutable. But phosphorus is in everything we eat and cannot be substituted by any element. If we continue business as usual we will squander this resource and thereby potentially compromising the wellbeing of our daughters and sons.

Further Reading

M. Obersteiner, J. Peñuelas, P. Ciais, M. van der Velde, and I.A. Janssens, 2013The phosphorus trilemma. Nature Geoscience, 6, 897-898, doi:10.1038/ngeo1990 [COMMENTARY].

M. van der Velde, L. See, L. You, J. Balkovič, S. Fritz, N. Khabarov, M. Obersteiner and S. Wood, 2013.Affordable nutrient solutions for improved food security as evidenced by crop trials. PLoS ONE 8(4): e60075. doi:10.1371/journal.pone.0060075 [OPEN ACCESS].


Marijn van der Velde is a Research Scholar with IIASA’s Ecosystems Services and Management (ESM) Program

Michael Obersteiner at IIASA conference 2012

Michael Obersteiner is the leader of IIASA’s Ecosystems Services and Management (ESM) Program.