Soil degradation: a problem threatening the sustainable development of agriculture in Northeast China

TLDR

Soil degradation—driven by erosion, loss of organic matter, and compaction—poses a global threat, and in Northeast China protecting its Mollisol soils is essential for agricultural sustainability. The study aims to highlight Northeast China’s critical grain production role, track changes in sown acreage and yield, and propose erosion‑control strategies to sustain Mollisol productivity. The authors assess water‑erosion patterns, gully dynamics, soil physical and chemical properties, and microbial enzyme activities across the region. Water erosion has reduced 39.3 % of farmland, with erosion rates of 1.24–2.41 mm yr⁻¹ and soil loss up to 220.5 t ha⁻¹ yr⁻¹, while SOC has declined 0.5 % yr⁻¹, yet crop rotation can preserve soil organic matter and improve soil properties.

Abstract

Soil degradation that results from erosion, losses of organic matter and nutrients, or soil compaction are of great concern in every agricultural region of the world. The control of soil erosion and loss of organic matter has been proposed as critical to agricultural and environmental sustainability of Northeast China. This region is bread basket of China where the fertile and productive soils, Mollisols (also called Black soils), are primarily distributed. In this paper, we introduce the importance of Northeast China's grain production to China, and describe the changes of sown acreage and grain production in past decades. This paper also summarizes the distribution, area and intensity of water erosion, changes in the number of gullies and gully density, thickness of top soil layer, soil organic matter content, bulk density, field water holding capacity, and infiltration rates; the number of soil microorganism and main enzyme activities from soil erosion in the region are also summarized. The moderately and severely water-eroded area accounted for 31.4% and 7.9% of the total, and annual declining rate is 1.8%. Erosion rate is 1.24-2.41 mm/year, and soil loss in 1°, 5° and 15° sloping farmlands is 3 t/ha/year, 78 t/ha/year and 220.5 t/ha/year, respectively. SOC content of uncultivated soil was nearly twice that of soil with a 50-year cultivation history, and the average annual declining rate of soil organic matter was 0.5%. Proper adoption of crop rotation can increase or maintain the quantity and quality of soil organic matter, and improve soil chemical and physical properties. Proposed strategies for erosion control, in particular how tillage management, terraces and strip cultivation, or soil amendments contribute to maintain or restore the productivity of severely eroded farmland, are discussed in the context of agricultural sustainability with an emphasis on the Chinese Mollisols.