yield of ground water

例句：

1. 3.
   土壤
2. 1. The yield of the crop was disappointingly low.
   作物的产量令人失望地低。
3. 2. The company's yield has increased significantly since the reform.
   自改革以来，公司的产量显著增加。
4. 3. The yield of the soil is directly related to its quality.
   土壤的产量与其质量直接相关。