CropMapper-NCP

The CropMapper-NCP application is a tool for mapping crop and fallow area in the North China Plain. Groundwater tables have been dropping in the region. Because irrigated agriculture is the main consumer of groundwater resources, authorities are encouraging farmers through subsidies to fallow winter wheat. With the CropMapper-NCP web application it is now easy to verify subsidized fallowing using satellite remote sensing images. The app can also be used to monitor changes in the agricultural landscape related to urbanization, the development of greenhouses or changes in crop types. It generates 10-meter resolution maps and detailed agricultural statistics for any year since 2016.

The tool has been specifically developed for the often cloudy or hazy conditions of the North China Plain. In contrast to our other web apps of the CropMapper family (LINK), the CropMapper-NCP therefore uses radar remote sensing data to identify the most important crop types (wheat and maize, respectively, for each winter and summer season). The land use classification algorithms are based on unsupervised machine learning routines like in all the apps of the CropMapper family. No sort of hand-labeled field data or any other type of empirical data have been used to train the algorithms. The methodology therefore enjoys a high transferability in space and in time within the North China Plain and will generate reliable outputs also for future years to come.

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The application has been developed within the project Rehabilitation and Management Strategies of Overpumped Aquifers in a Changing Climate. This project offers a management system combining real-time monitoring, modelling and control to ensure sustainable use of a groundwater resource. The system was implemented in Guantao County in the North China Plain. Consequently, Guantao County appears on the starting screen of the app. The agricultural landscape of 260 more counties in three Chinese provinces can also be monitored through the app. Because the application is implemented using Google Earth Engine and Google services are not available in China, the algorithm behind the app has also been implemented as a cron job in Python. This means that the different maps are generated automatically in regular intervals and made available in China through an online integrated decision support system for groundwater management.

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