Mapping ground reality
Substrate survey team digs deep across 83 key black soil counties to unearth secrets of the earth and learn how to improve farming
He added that the survey is distinct from routine agricultural soil testing. Agricultural departments focus on the topsoil — how to plow it, how to manage it day to day. The substrate survey goes deeper, through the plow layer and into the material that controls whether water is retained, whether nutrients stay and whether the land can keep producing.
"One looks at how to farm the land. The other looks at whether the land can continue to support farming," Chen said.
He explained that in addition to conventional physical and chemical measurements, ground substrate surveys pay more attention to soil formation age and mineral composition.
"Since the current soil's formation typically takes several thousand to about 10,000 years, we focus on that longer time scale to understand how soils have been formed and evolved. In our surveys, we classified regions into similar environmental categories. Under these comparable conditions, if the soil in one region has been completely eroded away, we explore whether soil from another region could be relocated to make up for the loss."
Over the roughly 40 years from the 1980s to the 2020s, the black soil layer in Northeast China experienced an overall decline in thickness, showing a clear thinning trend, with reductions ranging from 2 to 19 centimeters, according to 2025 research findings by the Northeast Institute of Geography and Agroecology of the Chinese Academy of Sciences.
Chen's team does not carry out protection work itself. It submits recommendations to local authorities. In areas where black soil faces easy erosion, it suggests topsoil stripping — removing and storing the precious layer before it is lost. In other places, it advises where protection should be prioritized, and where farming methods need to change.
Over two years of fieldwork in Northeast China's black soil region since 2022, the team amassed nearly 185,000 samples. For the first time, the team quantitatively mapped the boundaries of black soil resources, pinpointing a total area of 387,500 square kilometers.
The survey, involving 145 core technical members from the center, was completed in two years in collaboration with institutions like the Chinese Academy of Sciences, China Agricultural University and local natural resources authorities.
