Ensuring global food security is a key challenge, especially because of the challenges of climate change and increasing demand from a population expected to reach almost ten billion. A high diversity of crops can help ensure food security in agriculture. But this diversity alone is not enough. It also depends on ‘asynchrony’ or how the timing to sow or harvest crops differs in its distribution across the seasons, writes a research team with the participation of the University of Göttingen in the journal Nature.
Crop diversity is an important factor in maintaining agricultural production. A greater number of different crops reduces the risk of a complete crop failure, for instance if individual crops are affected by plant diseases, pest infestations or extreme weather such as drought. "However, the critical factor in securing production is actually asynchrony," says Lukas Egli, UFZ agroecologist and first author of the study. Greater asynchrony results from differences in the timing when crops are sown and harvested on arable land, as well as environmental change affecting plant growth and development – such as variations in the climate, habitat, elevation and season.
"The more that we can ensure regular spacing between crops over time, the lower the negative impact of extreme events, natural disasters and economic crises – so that a country's entire agricultural production is more secure," says Egli. For example, if different types of crops are harvested at the same time, the risk of the entire harvest being destroyed by a storm or flood increases. Such a total devastating loss can be avoided with asynchrony, specifically by using different sowing and harvesting times, by growing crops with different climate and management requirements or by using mixed crops.
The analysis of data from the Food and Agriculture Organization of the United Nations (FAO) showed that India, Mexico and China, for example, are among the countries with high production stability and high asynchrony. In contract, Russia, Australia and Argentina demonstrate low stability and low asynchrony. At present, however, the global trend in agriculture is towards a decrease in asynchrony. "In order to protect food supply and production from the unknown risks of the world market and fluctuations in the environment, countries will need to focus more strongly than ever before on a high degree of diversity and asynchrony of crops," comments Professor Teja Tscharntke, Agroecology Group at the University of Göttingen and co-author of the study.
Original publication:Egli, L., Schröter, M., Scherber, C., Tscharntke, T., Seppelt, R.: Crop asynchrony stabilizes food production. Nature (2020) DOI: 10.1038/s41586-020-2965-6
Professor Teja Tscharntke
University of Göttingen
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