Concept:Soil water conservation means using farming practices that reduce moisture loss from the soil, especially losses caused by evaporation and excessive transpiration.
Explanation:I. Adequate spacing: This gives each crop plant enough room to grow, so plant roots do not overcrowd or compete too heavily for the limited water available in the soil.
When crops are properly spaced, soil moisture is used at a slower and more balanced rate.
II. Disease control: Controlling crop diseases helps protect the health of the plant and improve its yield.
However, disease control does not directly reduce evaporation from the soil surface or help the soil hold more water.
Therefore, it is not considered a direct method of conserving soil water.
III. Cover cropping: Planting low-growing crops to cover bare soil blocks direct sunlight from reaching the ground.
This greatly reduces evaporation, keeps the soil cooler, and allows moisture to remain trapped in the soil for a longer time.
From the methods listed, adequate spacing and cover cropping are the practices that conserve soil water on a farm.
Answer:B. I and III only