High-Resolution Maps Reveal Hidden Losses in China’s Winter Wheat Harvest

Researchers from the Aerospace Information Research Institute (AIR) under the Chinese Academy of Sciences have developed the first-ever 10-meter resolution maps of harvested winter wheat areas across China’s top-producing regions from 2018 to 2022. The study published in the Scientific Data on September 27, used satellite remote sensing and advanced machine learning algorithms to highlight a significant discrepancy between planted and harvested areas. The research revealed that about 13% of planted winter wheat is lost before harvest due to meteorological factors such as dry-hot winds and waterlogging.

Winter wheat accounts for 95% of China’s total wheat production, making it a cornerstone of the country’s food security. Previous estimates, based solely on planted areas, often overestimated production by failing to account for crop losses. This study is the first of its kind to distinguish between the planted and harvested areas using high-resolution satellite data, with an accuracy rate of over 95%.

This research has practical implications for both policymakers and farmers. For the public, it provides a clearer understanding of how weather and other factors impact crop yields. For policymakers, these findings can help optimize resource allocation in times of food shortages or adverse weather conditions. "We now have a reliable tool to predict wheat losses due to meteorological conditions like waterlogging and dry-hot winds, allowing for better planning and response strategies," said HU Jinkang, lead author of the study.

The research team leveraged cutting-edge satellite technology, including Sentinel-2’s high spatial resolution imagery, to generate pixel-level maps of harvested areas. This approach not only improves accuracy but also enables large-scale monitoring of crop conditions over time. “With this data, we’re helping bridge the gap between research and practical agricultural solutions,” Hu added. By using these techniques, the study offers a blueprint for better agricultural management in a changing climate.

Beyond its technical advantages, the study highlights the pressing need to adapt agriculture to climate change. The researchers found that natural disasters, including severe dry-hot winds and waterlogging, were the primary causes of the 13% reduction in harvested areas. These results emphasize the importance of improving crop resilience and farming practices to mitigate losses in future harvests.

“This study marks a major step forward in agricultural monitoring. By accurately mapping the areas that are actually harvested, we can give a more realistic picture of wheat production in China,” said Prof. PENG Dailiang.

The study offers a vital tool for predicting and mitigating crop losses, especially in the face of increasingly unpredictable weather patterns. For China and other wheat-producing nations, this new method could improve food security and ensure better planning for future challenges in agriculture.