Abstract:Black soil region in Northeast is one of important commercial food production bases in China, and is irreplaceable for the national food security. However, the sustainable development of agriculture in Northeast has been severely constrained by soil degradation caused by long-term intensive and unbalanced use of arable land without protection of it. To solve this problem, original Heilongjiang Institute of Agricultural Modernization, Chinese Academy of Sciences (CAS) established Hailun Agro-ecosystem Experimental Station (Hailun Station), CAS in the central black soil region in Northeast in 1978. Since then, a series of long-term experiments have been set up based on the structure and function of the region. The evolution of soil fertility has been divided into three periods in light of the long-term monitoring and research for key elements in agro-ecosystem. The thresholds of soil organic matter on regional scale were proposed, and the evolution of soil fertility under different management patterns of soil nutrients was expounded, which verified that appropriate arrangement of field crops could regulate and control the impact of pests on crops. 10 high-yield soybean varieties were bred with pedigree method and were applied in Heilongjiang Province. Through the research and development of critical technologies for constructing fertile cultivated soil layer, the protection and utilization patterns of black soil were established, which were demonstrated and extended in more than 10 major grain-producing counties in Heilongjiang Province. Long-term research provides scientific and technological support for the protection of black soil and regional agricultural development through the combination of basic research, critical techniques development and large-scale demonstration.