Another commentary on an exam question, this time from Plant Nutrition and the Root Environment in February 2018:
Q4a) State what is meant by the term ‘mulch’. (2 marks)
b) State TWO distinct NAMED garden situations for EACH of the following types of mulch:
i) organic (2 marks)
ii) inorganic (2 marks)
c) Describe TWO
reasons why organic mulches are more beneficial than inorganic mulches. (4 marks)
This question relates to the following parts of the syllabus:
2.2 Describe the characteristics and uses of different types of organic matter added to the soil.
Describe the characteristics of the following materials: farmyard manure, garden compost, mushroom compost, composted green waste, leaf mould, chipped bark, composted straw, green manure and crop debris.
Describe the appropriate uses for the above materials, to include: mulching, soil improvement, nutrient supply.
Describe the benefits and limitations of using the above materials.
State the purpose of mulching and compare organic mulching materials with inorganic alternatives (eg polythene, woven fibres, gravel, glass).
State the environmental implications of mulching and mulching materials, the effect on the soil of green manures.
2.3 Describe methods of composting and their use/application in horticultural practices.
Describe the use of composted plant material as a soil improver, mulch, supplier of nutrients.
For part a) the examiners’ comments suggest the answer of ‘an organic or inorganic material that is placed on the surface of the soil’.
Part b) is an example of a question where it is important to give the correct number of answers for each of the separate parts – i.e. two for organic and two for inorganic. The numbers required are in bold to make this clearer.
Although specific examples of mulches aren’t asked for in the question, they are suggested in the examiners’ comments, and do help to show distinct situations. For part i) the following is suggested:
‘Organic mulch, e.g. composted bark or leaf mould, can be placed around the base of established plants in borders. Straw type mulch can be placed around crops, e.g. strawberries to prevent water splash’.
For part ii) the following is suggested:
‘Inorganic mulches, e.g. glass or slate chippings, can be placed on container plants as a decorative mulch. Gravel can be placed on the top of a woven fibre, e.g. mypex, on a garden path’.
These answers have the distinct situations of established plants in borders; a strawberry crop; container plants; and a garden path. It is a good idea to use bullet points or number your answers for each part.
Part c) needs more detail for each of the two reasons as it asks you to ‘describe’ .
Again, bullet points or numbers are useful as it gives you a reminder that you have given the correct number of reasons and makes it clear.
Two of the suggested reasons are:
‘Organic mulches are incorporated into the soil by soil organisms and are broken down to provide nutrients for plants’.
‘Organic mulches will encourage soil organisms which have a positive effect on soil structure’.