free digging rate

例句：

1. 1. The free digging rate of the soil is crucial for plant growth.
   土壤的自由挖掘率对植物生长至关重要。
2. 2. The company's free digging rate has increased significantly in recent years.
   该公司近年来的自由挖掘率显著提高。
3. 3. The free digging rate is influenced by many factors, including climate and soil quality.
   自由挖掘率受到许多因素的影响，包括气候和土壤质量。