NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 1 of 10
Assessment Schedule – 2007
Agricultural and Horticultural Science: Analyse a primary production environmental
issue (90653)
Evidence Statement
Q
One
(a)
Evidence
Key sources / conditions are
underlined.
Achievement
Achievement with
Merit
Explains the
source of the
greenhouse gas
Explains, in depth,
the source of the
greenhouse gas
AND
AND
 The use of tractors and other
agricultural machinery in modern
farming systems. The combustion
of diesel / petrol produces carbon
dioxide.
States a specific
example or context.
States a specific
example or context.
eg carbon dioxide
eg carbon dioxide
 Oxidation of soil organic matter as
a result of increased levels of
mechanical cultivation.
The increased use
of tractors and other
agricultural
machinery in
modern farming
systems. The
engines of these
vehicles produce
carbon dioxide.
The increased use of
tractors and other
agricultural
machinery in modern
farming systems. The
combustion of diesel /
petrol / fuels produces
carbon dioxide.
(i) Carbon dioxide
 Heating greenhouses using gas or
oil burners. The combustion of the
gas / fuel produces carbon dioxide.
 Clearing / felling forests and
replacing them with pasture.
Approximately 50% of the carbon
in this situation is released as
carbon dioxide.
 Burning crop stubble in order to
clear it results in the combustion
of the organic material into carbon
dioxide.
(ii) Methane
 Methane is a by-product / waste
product of the digestive processes
in the rumen of ruminant livestock
(cattle, sheep, deer, etc). As
numbers (particularly of cattle)
increase, so too does the
emission of methane. From 1990
to 2002, methane emissions from
the dairy sector increased 65%.
eg methane
On the basis of the
energy requirement
of the “standard
breeding ewe”,
Lassey et al (1992)
deduce a methane
emission under NZ
animal husbandry
conditions of 11.5 kg
of CH4 per stock unit
per year (for cattle,
around 80 kg CH4 /
cow / year).
Achievement
with Excellence
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 2 of 10
(iii) Nitrous oxide
 Nitrous oxide emissions produced
by soil bacteria. The main sources
of nitrogen for these processes
are animal urine and directly from
nitrogenous fertilisers. (Note:
'Fertiliser' is too broad). As the
use of nitrogen fertilisers has
increased, so too have stocking
rates (particularly dairy and
intensive beef farming) and hence
the emissions of nitrous oxide.
 Poorly drained / pugged soils that
are high in nitrogen are susceptible
to increased production / release of
nitrous oxide.
CODE
up to 3  A1
up to 3  M1
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 3 of 10
Q
One
(b)
(i), (ii)
Evidence
Achievement
Possible environmental
implications
 Increased air temperatures
due to greater retention of
solar radiation (ie the
‘greenhouse effect’).
 Increased plant growth due to
higher temperatures and
greater carbon dioxide
concentrations in the
atmosphere.
 Rising sea levels due to the
melting of the polar ice caps
caused by the warmer
temperatures.
 More coastal erosion due to
the higher sea levels and more
dynamic weather patterns.
Describes an
implication and
explains why it
occurs.
Achievement with
Merit
Describes an
implication and
explains, in depth,
why it occurs.
eg carbon dioxide
Increased plant
growth due to higher
temperatures and
greater carbon
dioxide
concentrations in the
atmosphere,
resulting in an
increase in the
photosynthetic rate
of many plants.
 More extreme weather events
like droughts and floods due to
changing weather systems and
the ability of air to carry more
water as it becomes warmer,
and the interactions between
warm and cold air masses
become more dynamic.
 Changes to current
ecosystems (both native and
farmed) due to the change in
temperatures and weather
patterns.
CODE
up to 2  A1
up to 2  M1
Achievement with
Excellence
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 4 of 10
(b)
Possible economic implications
(iii)
 Increased costs associated
with the control of erosion of
both coastlines and rivers.
Describes an
implication and
explains why it
occurs.
Describes an
implication and
explains, in depth,
why it occurs.
 Loss of production in droughtaffected areas and due to
increased flooding / storm
events.
 Producers of greenhouse
gases may be required to pay
a carbon 'tax' to help pay for
the costs associated with
global warming.
 Increases in production /
grower returns may result from
warmer temperatures and
growers being able to change
to more profitable options that
were not an option with the
cooler climate that was
previously experienced in a
particular area.
CODE
1  A1
1  M1
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 5 of 10
Q
Two
Evidence
Achievement
See example answers below.
(a) (b)
(c)
Describes a valid
strength AND
weakness for the
selected course of
action.
Achievement with
Merit
Describes a valid
strength AND
weakness for the
selected course of
action.
Achievement with
Excellence
Describes a valid
strength AND
weakness for the
selected course of
action
AND
Evidence for the
requirement for a
recommendation
comes from answers
given for the first part
of Question Three.
CODE
up to 3  A2
Evidence for the
requirement for a
justified
recommendation
comes from
answers given for
the first part of
Question Three.
up to 3  M2
assesses the relative
strengths and
weaknesses of the
course of action.
Notes:
 Material from
Question Three
(the justified
recommendation)
can be considered
when deciding
whether a
comprehensive
evaluation of the
courses of action
has been carried
out.
E
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 6 of 10
Question Two continued
(a)
Carbon dioxide
Courses of action:
(1) Create ‘carbon sinks’ by planting forests / woodlots
(i)
Strengths
 An easily achievable option.
 Provides a long-term income from the land in the form of wood / logs.
 Growing forests are an effective sink for atmospheric carbon – estimated to be absorbing
around 20 million tones of atmospheric carbon each year. (We produce about 70 million
tonnes of CO2-equivalent greenhouse gas per year.)
 New Zealand expects to absorb up to 105 million tonnes of CO 2 in the 4-year period 2008–
2012 in forests planted after 1990.
(ii) Weaknesses
 Carbon dioxide emissions contribute only a very small part of the total effect of greenhouse
gas emissions from agriculture in New Zealand.
 If the trees are eventually harvested, this would result in the release of some of the stored
carbon from the decay of the slash and debris.
(2) Retire unproductive hill country to allow regeneration
(i)
Strengths
 Reduction in hill country erosion associated with this action.
 Minimal loss in production and income.
(i)
Weaknesses
 Once established / mature, the net effect of these regenerated areas on the atmospheric CO2
levels would be minimal, as the release of CO2 from the decay of the leaf litter / dead plant
material increases.
(3) Reduce / limit the burning of fossil fuels used to heat greenhouses
(i)
Strengths
 Reduction in the overall production of CO2 in NZ.
(ii) Weaknesses
 Loss in productivity due to the inability to heat greenhouses to the optimum level.
 Lack of (and cost of) suitable alternative heating options.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 7 of 10
Question Two continued
(b)
Methane
Courses of action:
(1) Reduce the number / density of ruminant animals on New Zealand farms
(i)
Strengths
 Reducing ruminant numbers not only decreases CH4 emissions (a potent greenhouse gas –
21 times more potent than CO2) but would result in a decrease in N2O emissions due to the
reduced need to apply large quantities of urea and other nitrogenous fertilisers, and fewer
urine patches and other high-risk emission situations.
 The effect on the level of emissions is apparent very quickly.
(ii) Weaknesses
 There would be huge opposition from the farming sector as it would cause a total change in
land use, farming systems and livelihood for thousands of farmers.
 The economic effect on communities and the country would be significant.
(2) Shift to a grain or meal feeding system
(i)
Strengths
 A high-energy diet would promote rapid liveweight gains and marbling of meat.
(ii) Weaknesses
 Because this is a high-cost system – due to the requirement for mechanisation and labour
inputs – it does not have the competitive advantage of feeding stock on pasture.
 Moves towards biofuel production mean that grain producers will increasingly target this
market, thereby leading to a significant increase in the cost of grain for livestock production.
 Availability of grain to all livestock growers is limited, especially to those on hill- and highcountry properties that have a high number of ruminant animals.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 8 of 10
Question Two continued
(c)
Nitrous oxide
Courses of action:
(1) Reduce / limit the application of nitrogenous fertilisers by farmers
(i)
Strengths
 Less money spent on the purchasing of fertiliser.
 Less nitrogen available for oxidation into N 2O from both fertiliser sources and from urine
patches. (N2O is a very potent greenhouse gas – 210 times more potent than CO2.)
(ii) Weaknesses
 Pasture growth on farms that traditionally use lots of nitrogenous fertiliser would be reduced.
 Stocking rates and farm productivity would decrease.
(2) Increase the use of nitrification inhibitors such as Eco-N
(i)
Strengths
 Increase in the effective use of soil nitrogen for plant growth.
 Decrease in not only N2O emissions but also the leaching of nitrates into waterways.
(ii) Weaknesses
 Cost involved in the purchase and application of the nitrification inhibitors.
 The actual effectiveness is still a matter of some debate amongst soil scientists and fertiliser
companies.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 9 of 10
Q
Evidence
Achievement
Three
Explains in detail the strengths
of the selected course of action
and highlights significant
disadvantages that exist for the
other two courses of action
considered.
Achievement with
Merit
ONE course of action ONE course of action is
is selected / chosen as selected / chosen as a
a recommendation.
recommendation
Evidence will include that given
for Question Two (a), (b), and
(c).
AND
its choice is justified.
the reasons for
opting for it are
explained
In justifying their chosen
course of action,
candidates must clearly:
AND
 explain the reasons
for opting for it
 explain why the other
TWO courses of
action described in
Question Two are
not preferred.
CODE
A3
ONE course of
action is selected
AND
 select ONE course of
action
See example answer below.
Achievement with
Excellence
M3
an explanation with
detail and depth is
given for why the
TWO other
courses of action
described in
Question Two are
not preferred.
(The depth and
detail can be
demonstrated in
responses to
Question Two)
E
eg Create ‘carbon sinks’ by planting forests / woodlots
This option is the most easily implemented across a range of regions and land-uses. It does not
significantly reduce the productive capability of the farmland, as the less-productive parts of the farm
would be those planted in trees. Additionally, it would provide a long-term income from the land in the
form of wood / logs.
Growing forests are an effective sink for atmospheric carbon – they are estimated to be absorbing
around 20 million tones of atmospheric carbon in New Zealand each year. New Zealand produces about
70 million tonnes of CO2 -equivalent greenhouse gas per year. In the 4-year period 2008–2012, New
Zealand expects to absorb up to 105 million tonnes of CO2 in forests planted after 1990.
While methane production from ruminants is the single largest source of emissions from New Zealand
agriculture, at present we do not have an effective course of action that does not involve the reduction of
stock (sheep and cattle) numbers, and consequent huge economic and social implications. Future
research may provide an effective solution to this source of methane, but at present it would seem that
the costs greatly outweigh the benefits.
The use of nitrification inhibitors that reduce the emissions of nitrous oxide from farmland (especially
intensively farmed land) has increased in the past few years. While they do reduce the emissions of N 2O
– a very potent greenhouse gas (210 times more so than CO2) and increase farm crop / pasture growth,
there is a cost associated with application, and it is difficult and more costly to apply to rolling or hill
country that is being stocked at increased stocking rates.
At present, N2O is only the third-most-significant greenhouse gas after methane and carbon dioxide.
Therefore, the planting of forests / woodlots to act as ‘carbon sinks’ is the most effective and socially
acceptable course of action, and has the most positive economic outcomes compared with the other
options available to New Zealand producers.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2007 — page 10 of 10
Judgement Statement
Achievement
Achievement with Merit
Achievement with
Excellence
2 x A1 from 1(a)
2 x M1 from 1(a)
Merit plus
1 x A1 from 1(b) (i) OR (ii)
OR
1xE
1 x A1 from 1(b) (iii)
1 x M1 from 1(b) (i) OR (ii)
AND
1 x M1 from 1(b) (iii)
2 x A2
OR
AND
3 x A1 from 1(a)
1 x A3
3 x A1 from 1(b)
AND
2 x M2 (OR 3 x A2)
AND
1 x M3
ie 4 A1 + 2 A2 + 1 A3
ie 4 M1 (OR 6 A1) + 2 x M2
(OR 3 x A3) + 1 x M3
ie M + 1x E