Soil fertility: แบบฝึกหัด

Which plant nutrient is primarily responsible for promoting vegetative growth and the development of healthy, green leaves?

A soil test reveals a very low pH level. Why might this lead to poor crop growth even if fertilisers are applied?

In the nitrogen cycle, which process involves the conversion of nitrates \( (NO_3^-) \) into atmospheric nitrogen gas \( (N_2) \) by bacteria in anaerobic conditions, such as waterlogged soil?

What is a visible sign of phosphorus deficiency in a growing crop?

In the nitrogen cycle, what is the name of the process where bacteria convert nitrates \( (NO_3^-) \) back into nitrogen gas \( (N_2) \), often occurring in waterlogged soils?

State two benefits of incorporating compost into the soil to maintain fertility.

Explain how the inclusion of legumes in a crop rotation system helps to maintain soil fertility without the immediate addition of synthetic fertilisers.

Describe the specific role of denitrifying bacteria within the nitrogen cycle and state the specific soil conditions that promote their activity.

Organic matter is vital for maintaining soil health.
(a) Name one specific example of an organic fertiliser used on a farm.
(b) State one way organic matter improves the physical structure of sandy soil.

Legumes are often included in crop rotations to improve soil fertility.
(a) Explain the biological mechanism by which legumes increase soil nitrogen levels.
(b) Identify one inorganic fertiliser that is considered a compound fertiliser, providing more than one major nutrient.