Creation and Application of a Full Soil Layer Fertilization Technology Model for Continuous Maize Cultivation with Straw Return in Black Soil of Northeast China

Black soils are critical resources for global food security, particularly for high-yield maize production. However, continuous planting practices have led to significant challenges, including inadequate organic material inputs, shallow fertile layers, and uneven nutrient distribution. These factors contribute to soil fertility degradation, reduced nutrient storage capacity, and difficulties in supporting root expansion and water/nutrient uptake, thereby complicating the maintenance of sustained high yields. In northeast China, the annual maize straw production exceeds 100 million tons. Implementing effective straw return strategies is essential for optimizing soil layers and enhancing carbon content. This paper advocates for a scientific and systematic approach to maize straw management, aimed at improving both soil fertility and maize yields under intensive agricultural practices. We outline the background and objectives of the full-layer fertilization technique, highlighting the significance of the 20–40 cm soil layer for achieving optimal maize yields. Long-term trials have demonstrated that over 90% of maize roots are located within this depth, and increased planting density can enhance root length density by 15.8 to 38.4%. Furthermore, practices such as deep tillage and the incorporation of carbon inputs from maize straw have been shown to improve soil structure and moisture retention. Developed by the Jilin Academy of Agricultural Sciences, this method includes machine harvesting, shredding, and deep plowing, achieving over 90% straw decomposition. These practices not only enhance soil quality and nitrogen content but also promote sustainable agricultural methods while reducing reliance on chemical fertilizers. Our findings provide valuable insights for soil protection and land quality improvement in black soil regions globally.