(a) With the aid of an annotated diagram only, illustrate the water cycle. (b) State three forms in which water exists in the soil (c) List five importance ...

Answer Details

(a) Here is an annotated diagram of the water cycle:

The water cycle, also known as the hydrologic cycle, is the continuous movement of water between the Earth's surface and atmosphere. The process begins with the sun's heat causing water to evaporate from bodies of water and transpire from plants. This water vapor then rises into the atmosphere, where it cools and condenses into clouds. The clouds then release precipitation in the form of rain or snow, which replenishes bodies of water or infiltrates into the ground. The cycle then repeats itself.

(b) Three forms in which water exists in the soil are:

• Gravitational water: This is the water that moves downward through the soil due to gravity after a rain or irrigation event. It is not held by the soil particles and can be lost through drainage.
• Capillary water: This is the water that is held by the soil particles and is available for plant uptake. It is held in small pores and can move upward against gravity due to capillary action.
• Hygroscopic water: This is the water that is held tightly to the soil particles and is not available for plant uptake. It is held too tightly for roots to extract it.

(c) Five importance of water to crops are:

1. Photosynthesis: Water is a key component in the photosynthesis process, which is how plants produce their food. Without water, photosynthesis cannot occur, and the plant will not be able to grow and produce.
2. Nutrient uptake: Water is necessary for the uptake of nutrients by plants. Nutrients dissolve in water and are transported to the plant roots for uptake. Without water, nutrients cannot be taken up by the plant.
3. Turgor pressure: Water helps to maintain turgor pressure in plant cells, which gives the plant its structure and support. Without water, plants can wilt and become damaged.
4. Temperature regulation: Water helps to regulate the temperature of plant leaves through transpiration. When water evaporates from the leaves, it cools the plant and prevents it from overheating.
5. Yield and quality: Adequate water supply is necessary for plants to produce high yields and quality crops. Water stress can lead to reduced yields and poor crop quality.

Overall, water is essential for plant growth and development, and its availability is a critical factor in crop production.