Q.2.a. Define the term ‘field capacity’ in relation to soil water content. (3)
b.decribe how the water content in the growing media of a container plant can be controlled to ensure optimum growth. (4)
c.List THREE of the major nutrients used when growing plants in containers. (3)
Sample Answer
a. Field capacity is the amount of water remaining in the soil a few days after having been wetted and after free drainage has ceased. At field capacity, water fills the micropores and mesopores, while air fills the macropores. At field capacity, the water and air balance of the soil is considered to be ideal for crop growth.
b. Gardeners can use a number of strategies to maintain an optimum balance of water and air in the growing media of containers. A key first step is to select a growing media that suits the requirements of the plant, for instance, a sandy mix for cacti. Other steps may include incorporating organic matter to improve drainage and water retention, adding water-retaining gels to the growing media when preparing the container, or adding sand or perlite to the growing media to increase pore space. Adding mulch to the surface of the container also helps to ensure the growing media does not dry out quickly.
c.Three of: nitrogen, phosphorus, potassium, calcium and magnesium.
