Wheat is the world’s most important grain – and has high environmental costs. The reason for this is the required fertilization with nitrogen. Researchers at the Technical University of Munich (TUM) and the French Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE) have now calculated that new wheat varieties produce better harvests with consistent fertilization.
Finding the right level of wheat fertilization is not always easy. If you fertilize the wheat with little nitrogen, it uses it up, but does not produce the full harvest performance. If you fertilize it with a lot of nitrogen, the harvest is good, but the grain does not use up all of the fertilizer. The excess nitrogen enters the environment and puts a strain on ecosystems and the climate. At the same time, wheat is essential to satisfy growing world hunger.
In order to overcome these challenges, Senthold Asseng, Professor of Digital Agriculture at TUM, Pierre Martre (INRAE) and other researchers have examined new wheat varieties that are still in the experimental stage. To do this, the team used data from five test fields that are representative of global growing regions with particularly high yields. These were fed into a simulation model and calculated according to various climate scenarios. For this purpose, the researchers chose current climatic conditions, global warming of 1 K and 4.8 K. The results show what crop yield the tested varieties can achieve with different amounts of nitrogen added.
Make better use of nitrogen
The researchers were able to find out that under current climatic conditions, the new wheat varieties achieve 16% more crop yield than those previously used when they are fertilized in the same amount. The fact that they make better use of the applied nitrogen, i.e. have improved nitrogen efficiency, reduces their ecological footprint. At the same time, the team was able to show that nitrogen requirements will generally increase as a result of global warming if the plants’ harvest potential is to be fully exploited. But even then, the new varieties use nitrogen more efficiently than those previously used.
New wheat varieties are superior to the current ones in important aspects and can be a building block for food security. Nevertheless, the struggle for responsible use of nitrogen will remain an issue, and not just in the sense of climate and environmental protection. The researchers point out that nitrogen is a sometimes costly resource. Increased fertilization may be best for the harvest, but it is not possible for all producers globally and has an impact on the wallets of agricultural businesses and customers.
Thinking about food security systemically
The scientists still recommend continuing to use the wheat varieties tested in the model in breeding programs: “With improved breeding, we can manage to close the food gap for the next 20 to 30 years. However, we will not be able to achieve the balancing act between global food security, environmental protection and economic efficiency with new varieties alone,” says Senthold Asseng. “What we need is a systemic approach that, in addition to agricultural scientific methods such as modern breeding, also considers environmental aspects, socio-economic factors and the role of politics.”
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