INCLUDING EXAMINERS COMMENTS

R3102

THE ROOT ENVIRONMENT, PLANT NUTRITION & GROWING SYSTEMS

Level 3

Wednesday 8 February 2017

13:40 – 15:20

Written Examination

Candidate Number:……………………………………………………………… Candidate Name:………………………………………………………………… Centre Number/Name:…………………………………………………………...

IMPORTANT – Please read carefully before commencing:

i) The duration of this paper is 100 minutes;

ii) ALL questions should be attempted;

iii) EACH question carries 10 marks;

iv) Write your answers legibly in the spaces provided. It is NOT necessary that all lined space is used in answering the questions;

v) Use METRIC measurements only;

vi) Use black or blue ink only. Pencil may be used for drawing purposes only;

vii) Where plant names are required, they should include genus, species and

where appropriate, cultivar;

viii) Where a question requires a specific number of answers; only the first answers given that meet the question requirement will be accepted, regardless of the number of answers offered;

ix) Please note, when the word ‘distinct’ is used within a question, it means

that the items have different characteristics or features.

Ofqual Unit Code M/505/2839 Please turn over/…..

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ANSWER ALL QUESTIONS

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Q1 a)

b)

Name ONE sedimentary rock found in the UK.

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Describe TWO processes involving water which weather parent rock.

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Brown earth is one soil type found in the UK. Name THREE other soil types found in the UK.

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Q2

Describe FIVE properties of humus that make it beneficial for plant growth. ………………………………………………………………………………………...

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Q3 a)

State FOUR reasons for selecting EACH of the following as constituents of growing media:

i) polystyrene granules; ii) coir.

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State TWO limitations of ONE of the constituents named in a).

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Q4

Describe how EACH of the following forms of nitrogen is involved in the nitrogen cycle:

i) nitrogen gas (N2); ii) ammonium ion (NH4

+); iii) nitrite ion (NO2

-); iv) nitrate ion (NO3

-).

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Q5

Describe how the characteristics of EACH of the following soil textures affect the amount of water held in that soil at field capacity:

i) clay; ii) sand.

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Q6 a)

b)

Describe the role of earthworms in the breakdown of organic matter.

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Explain how the carbon:nitrogen ratio of added organic matter affects soil fertility. ………………………………………………………………………………………...

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Q7

Describe EACH of the following drainage systems for improving soil aeration, by completing the table below.

Pipe Drainage Swales

Characteristics

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Advantages

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Q8 a)

b)

State what is meant by EACH of the following terms:

i) fertigation; ii) foliar feeding.

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Describe fertigation under EACH of the following headings: i) named crop; ii) horticultural situation; iii) method. ………………………………………………………………………………………...

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Q9

Describe disease management techniques available to organic growers under EACH of the following headings:

i) hygiene; ii) cultural control; iii) chemical control.

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Q10

State THREE benefits and TWO limitations of EACH of the following soil management techniques, used in organic growing, using the table below. Green manuring Minimum cultivation

Benefits 1

2

3

Limitations 1

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©These questions are the property of the Royal Horticultural Society.

They must not be reproduced or sold.

The Royal Horticultural Society, Wisley, Woking, Surrey GU23 6QB. Charity Registration Number: 222879/SC038262

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R3102

THE ROOT ENVIRONMENT, PLANT NUTRITION & GROWING SYSTEMS

Level 3

Wednesday 8 February 2017

Candidates Registered 81 Total Candidates Passed 77% Candidates Entered 71 Passed with Commendation 20% Candidates Absent/Withdrawn 8 Passed 57% Candidates Deferred 2 Failed 23%

Senior Examiner’s Comments On the whole this paper was well answered with the majority of candidates attempting and completing all the questions. The following guidelines should be of help to future candidates.

1. Where named plant examples are asked for, full botanical names (genus and species) are

required to achieve full marks. Common names will not be given a mark.

2. Use the command statements e.g. list or name (single words only), state (a few sentences),

describe or explain (a fuller answer) together with the mark allocation, to judge the depth of the

answer. Half marks are often allocated where the basic information given is correct but needs

further qualification to gain the full mark.

3. Where a number of answers are specified in the question, the examiner will not select correct

answers from a list e.g. if the question states ‘State’ TWO plant names’, only the first two names

given will be marked.

4. Labels on diagrams should be correctly positioned to avoid ambiguity and diagrams should be

clearly drawn and annotated. No marks will be awarded for artistic merit.

5. Candidates should use unambiguous plant examples as reference sources from, for example, the

RHS Find a Plant Service available on the RHS Website.

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Q1 a) Name ONE sedimentary rock found in the UK. 1 a) Candidates were asked to name one sedimentary rock found in the UK. A mark was awarded

where candidates clearly stated sandstone, clay, silt stone or limestone.

b) Describe TWO processes involving water which weather parent rock. 6 b) Candidates were expected to describe two processes involving water which weather parent rock.

Good marks were gained by candidates who described the effect of processes including glaciers, freeze/thaw (ice), rivers and rain including acid rain. Examples included rivers as the weathering agent and then described how water abraded the rock as it flowed over it, removal of rock particles, exposure of lower layers and continual abrasion. Another example was the process of water freezing and thawing in rock fissures; expanding on freezing and pushing rock apart, then thawing, and this continuous process eventually breaks rocks apart and exposes lower layers to water infiltration. Other weathering agents included wetting and drying and acid rain. No marks were given for weathering agents such as waves crashing on a beach and eroding cliffs.

c) Brown earth is one soil type found in the UK. Name THREE other soil

types found in the UK. 3

c) Candidates were expected to name three types of soil found in the UK other than brown earth and the most commonly named were gley, podzol, and rendzina. This question was generally well answered. Q2 Describe FIVE properties of humus that make it beneficial for plant growth. 10

High marks were awarded to those candidates who clearly stated five properties of humus and explained the benefits to plant growth including high Cation Exchange Capacity (CEC) which allows cations to be held against leaching/gravity and so are available to plants. Humus has colloidal properties that increase the water holding capacity of the soil which makes it more resistant to drought/drying. Other properties of humus include long term storage of nutrients, it is stable, it enables particle aggregation and so good crumb formation, which in turn aids structure of the soil, it darkens the soil to help heat absorption and any other valid points. This question was generally well answered.

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MARKS Q3 a) State FOUR reasons for selecting EACH of the following as constituents of

growing media:

i) polystyrene granules; 4 ii) coir. 4

a) i) High marks were awarded where candidates stated four of the following: polystyrene was inert, stable, light, increased Air Filled Porosity (AFP), aided drainage

ii) High marks were gained when candidates stated four of the following: coir has high Cation Exchange Capacity, high water holding capacity, good buffering capacity, it is horticulturally sterile and contains few nutrients but holds added nutrients well giving growers control over its nutrient content.

b) State TWO limitations of ONE of the constituents named in a). 2

b) Candidates were asked to state two limitations for one of the constituents named in a). Marks were given for stating that polystyrene is environmentally unsustainable, does not biodegrade, has no buffering capacity, no CEC, no nutrient content, no nutrient holding. For coir, appropriate limitations included it may be contaminated, it is transported from abroad so not environmentally sustainable, it may degrade/slump, and is not suitable for all plants due to its limited pH range.This question was generally well answered.

Q4 Describe how EACH of the following forms of nitrogen is involved in the nitrogen cycle:

i) nitrogen gas (N2); 3 ii) ammonium ion (NH4

+); 2 iii) nitrite ion (NO2

-); 2 iv) nitrate ion (NO3

-). 3

i) Marks were awarded to candidates who stated that nitrogen gas was present in the atmosphere or soil air, it was a substrate for nitrogen fixing bacteria, and that it was produced by denitrifying bacteria.

ii) Marks were awarded where candidates stated that the ammonium ion occurred after mineralisation of organic matter, was produced by ammonifying bacteria and was present in soil water and fertiliser.

iii) Marks were awarded where candidates stated that the nitrite ion was present as an intermediate product in the conversion of ammonium ion to nitrate ion, by nitrifying bacteria. The nitrite ion is also produced when nitrate ions are denitrified under wet/cold soil conditions. A mark was also awarded for stating that it is toxic to plants.

iv) The nitrate ion is found in soil water, as a result of nitrification by Nitrobacter, it is a substrate for denitrifying bacteria and also could be obtained from fertilisers. A mark was awarded for stating it was taken up by plants.

Parts i) and iv) were generally very well answered but in ii) and iii) there was confusion as to whether ammonium ions were taken up by plants and the same applied to the nitrite ion. For iii) there was more confusion about where it occurred in the nitrogen cycle.

28

MARKS

Q5 Describe how the characteristics of EACH of the following soil textures affect

the amount of water held in that soil at field capacity:

i) clay; 5 ii) sand. 5

i) Marks were awarded to those who stated a clay soil

was formed of many minute particles,

contained a high proportion of micropores,

held water against gravity,

had a high surface area to volume ratio and

held onto water molecules strongly due to the surface charges on the particles.

To gain full marks, candidates must link the above characteristics to field capacity and state that a clay soil at field capacity holds large volumes of water. ii) Marks were given where candidates stated that sand

contained larger particles,

had more macropores, which did not hold water against gravity and so drained freely,

the larger particles were inert so had no surface charges,

they had a low surface area to volume ratio and were not porous so water was not held within

them and other factors.

To gain full marks, candidates must link the above facts to field capacity and state sand at field capacity holds low volumes of water.

This question was generally answered well overall although some candidates were confused about field capacity and potential structural characteristics of a clay soil such as capping and pans affecting water movement. Several candidates discussed improvements to each soil which gained no marks.

29

MARKS

Q6 a) Describe the role of earthworms in the breakdown of organic matter. 4

a) High marks were awarded where candidates described how earthworms

break up softer plant material,

increase the surface area of organic matter for action by micro-organisms,

drag the litter layer further into soil profile,

increase aeration allowing aerobic breakdown of organic matter,

aid drainage and other factors.

No marks were gained where candidates discussed optimum conditions for earthworms as this was not the question. b) Explain how the carbon:nitrogen ratio of added organic matter affects

soil fertility. 6

b) High marks were awarded where candidates stated that micro-organisms needed both carbon and nitrogen to survive, that once the nitrogen in added organic matter was depleted, they may take it from the soil, thereby locking it up and making it unavailable to plants, that a high C:N ratio means soil fertility is reduced as nitrogen is depleted, and that a low C:N ratio with high N led to rapid mineralisation. Any of these gained a mark. This question was generally well answered. In part a) many candidates discussed suitable conditions for earthworms, the species found in the UK and how they are a pest on lawns, none of which was relevant. For b) several candidates discussed carbon and nitrogen fertilisers/additives rather than organic matter and one or two concentrated on compost making.

30

MARKS Q7 Describe EACH of the following drainage systems for improving soil aeration,

by completing the table below. 10

Candidates were expected to describe pipe drainage and swale drainage in terms of their main characteristics, the advantages of choosing the system and an appropriate situation for their use. Good marks were awarded where candidates stated that pipe drainage characteristics included clay or plastic pipes, interlinked, draining to an outlet, and may be herringbone pattern lay out. Swales are shallow channels with gentle slopes, allowing water to collect and soak away from a site, they are often vegetated and may include check dams. For the advantages of selecting each system high marks were awarded where candidates stated pipe drains could be used for large areas, were effective in that they could drain large volumes of water, and were long lasting or other valid points, and for swales that they were effective at storing run-off, easily incorporated into the landscape, blockages were easily dealt with and other valid points. For appropriate situations marks were given for pipe drainage for use in field/agricultural situations and for swales at road sides or at edge of public amenity areas (golf course, parks etc.). This was generally well answered. A few candidates did not know what swales were and several were confused about an appropriate situation for the drainage methods.

Pipe Drainage Swales

Characteristics

4 MARKS

1

2

Advantages

4 MARKS

1

2

Appropriate situation

2 MARKS

31

MARKS

Q8 a) State what is meant by EACH of the following terms:

i) fertigation; 1 ii) foliar feeding. 1

a) High marks were awarded where candidates clearly stated fertigation was the addition of nutrients into the irrigation water and foliar feeding was the application of fertiliser solution directly to the leaves of plants.

b) Describe fertigation under EACH of the following headings: i) named crop; 1 ii) horticultural situation; 1 iii) method. 6 b) i) A mark was awarded where candidates stated Solanum lycopersicum, Lactuca sativa or other suitable crop - half marks were awarded for the common name or genus name only. ii) A mark was given where candidates described a horticultural situation such as in a greenhouse, hydroponics or other suitable situation. iii) High marks were awarded where candidates described the following points: the fertilisers must be soluble, the named fertiliser or nutrient, they are applied in a measured dose to the irrigation water, the solution is monitored for conductivity, it is monitored for pH, how it is tested, the method of application, the growing medium, growers must ensure drip lines flowing for even application, and maintenance such as washing of growing medium, clearing pipes to remove salt build up and any other valid point. Generally, this question was answered well although a few candidates did not understand what fertigation was.

32

MARKS

Q9 Describe disease management techniques available to organic growers under EACH of the following headings:

i) hygiene; 3 ii) cultural control; 5 iii) chemical control. 2

i) High marks were awarded where candidates described the methods available to include clean

tools, surfaces and hands and all materials used, quarantine of new plants/suspected

diseased plants, storage in appropriate conditions, provenance of any introduced plants, and

disposal of waste or infected material properly, application of clean water and appropriate

drainage.

ii) High marks were awarded to candidates who stated cultural controls to include spacing

correctly, use of companion plants to attract predators to eat aphids (to avoid viral infection),

weed control to remove hosts for diseases, crop rotation, timing of planting dates, cropping

timing, and use of resistant varieties or other valid control.

iii) High marks were given where candidates named approved chemicals. Copper fungicides were awarded no marks because they were banned for use from December 2016. However if candidates stated that a copper fungicide could be used up until that date, they gained a mark.

33

MARKS Q10 State THREE benefits and TWO limitations of EACH of the following soil management techniques, used in organic growing, using the table below.

Candidates were asked to state three benefits and two limitations of green manuring and minimum cultivation. The benefits of green manuring are that it protects the soil from erosion, adds organic matter which improves soil structure when dug in and also adds some nutrients as it decomposes, and if legumes are used as the green manure they also increase nitrogen levels. The green manure when growing provides habitats and increases biodiversity. The benefits of minimum cultivation are that it prevents soil compaction, does not break down soil structure, does not disturb the soil ecosystem and does not mix top and sub soil. The limitations of green manuring are there is a loss of the area for crop production, labour demand is increased, time is lost between sowing and digging in and use for the next crop, it may increase some diseases, and green manure may become a weed if allowed to set seed. The limitations of minimum cultivation are that it is labour intensive, it can be expensive, and the grower needs to source a regular supply of organic matter in large quantities.

This question was generally well answered. Many candidates forgot that green manure only improves the nitrogen content of the soil if it is a leguminous crop. No marks were awarded for stating minimum tillage keeps carbon in the soil.

Green manuring Minimum cultivation

Benefits

5 MARKS

1

2

3

Limitatons

5 MARKS

1

2