Question

Give a brief description of the factors that affect primary productivity.

Answer 1

1. It depends on the plant species inhabiting a particular area.
2. It depends on environmental factors such as light, temperature, water, and precipitation.
3. It depends upon the availability of nutrients.
4. It also depends upon the photosynthetic capacity of plants. The greater the photosynthetic activity, the higher the primary productivity.

Answer 2

1. Solar radiation: The tropics receive the most sunlight. Poles receive little light. As a result, photosynthesis is at its peak, and net primary production (NPP) in the tropics exceeds 20 t ha⁻¹ year⁻¹, compared to 8 t ha⁻¹ year⁻¹ in temperate forests.
2. Temperature: Because of the cold environment, temperate forests produce less (8 t ha⁻¹ year⁻¹) than tropical rainforests (20 t ha⁻¹ year⁻¹).
3. Moisture: Rainfall and humidity improve ecological production.
4. Nutrients: Nutrients are necessary for producer growth. Desert soils are lacking in nutrients and, thus, are less productive.
5. Photosynthetic efficiency of producers: C₄ plants are more productive than C₃ plants.