Key Principles and Techniques for Controlling Black Soil Degradation and Enhancing Fertility in Northeast China

Northeast China hosts one of the world’s four major black soil regions, accounting for approximately 36 million hectares of cultivated land. Producing one-quarter of China’s total grain output and one-third of its commercial grain transfers, this region serves as a vital cornerstone for national food security. However, unsustainable land use and climate change have driven severe soil degradation, manifesting as thinning topsoil, declining organic matter, and increased bulk density—collectively threatening sustainable production. To address these challenges, we conducted a five-year intensive study, and proposed an innovative degradation control theory centered on “enhancing inherent stable soil fertility”. A targeted technological system was developed, with emphasis on the incorporation of multi-source organic materials and optimized tillage practices, to overcome key technical barriers to soil restoration under intensive farming. Furthermore, in light of regional variations in environmental conditions and soil constraints, locally adapted models for black soil conservation—such as the “Longjiang Model”, “Lishu Model 2.0”, and “Da’an Model”, have been established. In core demonstration areas, these approaches achieved notable outcomes: Soil organic matter increased by 13–17%, soil erosion intensity decreased by more than 80%, and crop yields improved by 5.4–14.2%. This study provides robust scientific support for national strategies aimed at conserving and sustainably utilizing black soil resources.