Evaluation on soil fertility quality under biochar combined with nitrogen reduction

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Science

Background:

• Purple soils in southwest China face challenges with soil fertility and crop productivity.
• Optimizing fertilization strategies is crucial for sustainable agriculture and environmental protection.

Purpose of the Study:

• To investigate the combined effects of biochar and nitrogen reduction on soil fertility and rapeseed yield.
• To identify key soil factors influencing rapeseed yield under these treatments.
• To determine the optimal biochar and nitrogen combination for sustainable crop production.

Main Methods:

• A two-year field experiment was conducted using varying rates of biochar (0-40 t ha⁻¹) and nitrogen reduction (100%-60%).
• Soil chemical, physical, and biological properties were assessed using gray correlation, principal component, and cluster analyses.
• Rapeseed yield and soil quality were evaluated to identify optimal treatment combinations.

Main Results:

• Available phosphorus, water-stable aggregate size, fungal populations, and microbial utilization of organic compounds were key factors for rapeseed yield.
• The N100B10 (100% nitrogen, 10 t ha⁻¹ biochar) treatment showed the highest soil quality score, followed by N80B10 and N100B20.
• Optimal results for soil quality and yield were achieved with 10 t ha⁻¹ biochar and 144 kg ha⁻¹ nitrogen, indicating reduced nitrogen input and increased benefits.

Conclusions:

• Combining biochar with nitrogen reduction is an effective strategy for enhancing soil fertility and crop productivity in purple soils.
• Specific soil properties like available phosphorus and microbial activity are critical indicators of soil health and yield potential.
• The findings provide a scientific basis for sustainable fertilization management in biochar-amended nitrogen-reduced systems in southwest China.