NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 1 of 9
Assessment Schedule – 2009
Agricultural and Horticultural Science: Analyse a primary production environmental issue
(90653)
Evidence Statement
Issue 1: The breakdown of soil stability in intensive agricultural / horticultural systems
Q
ONE
Evidence
Negative environmental
implications:
 Increase in soil surface erosion / loss
of topsoil during heavy rain, as the
finer particles are more easily
‘washed’ away.
 Increased loss of topsoil / wind
erosion of soil, due to the loss of a
crumb structure; increase in fine
particles that are more susceptible to
wind erosion.
 Increased volumes of sediments in
rivers and streams due to more soil
being carried in surface run-off.
 Greater production of greenhouse
gases (N2O) due to anaerobic
conditions in over cultivated or
pugged soil favouring their release –
especially in high-fertility, intensively
farmed soils.
 Decreased plant growth / pasture
production due to the decrease in
aeration / macropores in the soil.
(Winter pugging has been shown to
reduce annual pasture production
35% in a single year, or 53% after
two years of the soil sustaining
pugging damage).
Economic implications
Loss of yield and hence income, due to
the breakdown of soil structure /
stability. Trials in Canterbury show
yield/income losses of 18% – 62%
associated with the combined effects of
topsoil loss and structural breakdown.
Increased costs associated with
increased fertiliser and cultivation
required by degraded soils when
cropping them.
Negative social implications:
 Increased sediment in run-off causes
silting-up of streams / rivers
downstream, affecting both
recreational activities (eg fishing), as
well as others who may use the
water for a variety of purposes (eg
drinking water).
Achievement
The
environmental,
economic, or
social implication
is explained in
general terms, but
lacks specific
detail or data.
Eg Winter pugging
reduces pasture
growth, due to the
damage done to
the pasture plants
and the reduced
ability of the soil to
drain.
Merit
The
environmental,
economic, or
social implication
is explained in
detail.
Detailed
explanations
involve the use of
accurate, relevant
data and / or a
thorough
explanation of why
the implication
occurs.
Example of depth:
Winter pugging
has been shown to
reduce annual
pasture production
by 35% in a single
year, or 53% after
two years of the
soil sustaining
pugging damage.
Trials in
Canterbury show
yield losses of
18% – 62%
associated with
the combined
effects of topsoil
loss and structural
breakdown.
Excellence
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 2 of 9
Q
TWO
Evidence
Intensive agricultural (livestock)
production systems
Courses of action:
1. Remove stock from pasture and put
on a stand-off pad or feed pad.
Strengths:
 Further damage to the pasture is
prevented, allowing for greater future
growth / production than if pugging
had occurred.
 Stock remain on the farm allowing
for ease of management.
 Risk of topsoil erosion / run-off into
streams is minimised.
 Soil structure is not damaged.
Weaknesses:
 High capital costs involved in
building a pad.
 Need to transport feed / silage to the
stock while they are on the pad or
allow stock back onto pasture for a
period of time daily to feed –
minimising damage to the pasture.
 Need to deal with the effluent of the
stock while they are on the pad.
 Animal health issues if on a pad for a
long period of time.
2. Spread stock over a larger area.
Strengths:
 Damage to pasture / soil is reduced,
as treading density / intensity is less.
 No need to remove stock from
pasture / farm, thus no extra
management is required.
Weaknesses:
 ‘Saved’ pasture will be eaten at a
greater rate, possibly causing feed
supply problems later in the season
(especially with prolonged periods of
hot weather).
 Some damage to soils / pasture is
still likely to occur, affecting soil
structure / pasture growth.
 An increased area of the farm is
affected.
 Extra management required where
animals are spread over a larger
area and / or an increased number
of paddocks – especially milking
dairy farms.
Achievement
Valid strengths
and weaknesses
are assessed
(described) in
general terms.
Merit
Excellence
A comprehensive
evaluation requires
depth in the
information being
presented, which
can be quantitative
and / or qualitative.
This generally
involves the use of
data when
assessing the
respective
strengths and
weaknesses.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 3 of 9
3. Purchase a run-off block on a lighter
soil type.
Strengths:
 No damage done to ‘home’ farm
pastures / soils, allowing for
increased growth / pasture
production.
 Feed conserved and utilised at times
of peak need, eg calving.
 The lighter soils of the run-off are
less likely to sustain major long-term
damage and will generally recover
faster.
Weaknesses:
 Capital costs of purchasing the runoff.
 Costs / time involved with moving
stock to farm from the run-off and
managing them there.
 Not an option for an ‘in-milk’ dairy
herd.
 Many regions of New Zealand will
not have an area with “lighter” soil
types.
 Increased supervision of stock
required.
Intensive plant production systems
Courses of action:
1. Use minimum tillage techniques /
technologies (eg direct drilling in
combination with the application of
herbicides to plant crops, to remove
competing vegetation.
Strengths:
 Less physical disturbance to soil,
reducing the potential for soil
structural damage.
 Less risk of soil erosion (water and
wind), as soil particles are less
exposed.
 Decreased costs of fuel, etc, as
fewer ‘passes’ are done by tractors
during seed bed establishments /
sowing.
 Soil biota (worms, etc) allowed to
exist without getting “chopped up”.
Weaknesses:
 Some crops / stubbles are difficult to
sow into. Some crops require a fine
seed bed for optimum germination.
 Use of herbicides may involve
chemicals that build up in the soil /
environment.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 4 of 9
2. Plant a ‘cover’ or ‘green manure’
crops following the harvest of each
‘main’ crop.
Strengths:
 Provides time and organic matter to
encourage soil organisms to begin to
improve / repair soil structure.
 Organic matter addition to the soil
helps ‘condition’ the soil, making it a
better medium for plant growth.
Weaknesses:
 Extra costs involved with planting a
‘cover’ crop.
 No income being generated from the
land at this time.
3. Continue to use conventional
cultivation techniques (ie using
ploughs, rotary hoes, etc) when
cultivating soil prior to planting.
Strengths:
 Ability to establish the fine seed
beds some crops prefer.
 Farmers and contractors have
existing skills, machinery and
experience in this form of preplanting management.
Weaknesses:
 Continued breakdown of soil stability
– especially if cultivating soils
outside optimum moisture content or
if using rotary hoes and similar ‘high
impact’ machinery.
 Higher fuel / energy costs
associated with most conventional
cultivation programmes.
 More limited by wet soils / wet
weather – unable to cultivate.
THREE
Selects ONE course of action
recommended as the best for New
Zealand growers to implement, in order
to prevent or minimise the negative
environmental impacts of the chosen
issue.
A course of action
is recommended.
In justifying their
chosen course of
action, candidates
must clearly select
ONE course of
action, and:
Explain the
reasons for opting
for it in relation to
its ability to reduce
/ minimise the
negative
environmental
impacts, and with
consideration to
the social and
economic
implications, in
comparison to the
other course of
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 5 of 9
action.
Issue 2: The use of water for irrigation in intensive agricultural / horticultural systems
Q
ONE
Evidence
Negative environmental
implications:
Decreased river and stream levels
As water is extracted from streams and
rivers for irrigation purposes, the
volume of water remaining in the
watercourse is reduced. The water
applied to the land
does not re-enter the rivers and
streams, as it is used for tissue growth,
evapo-transpiration, etc.
Increased water temperatures
Lower river volumes result in the water
heating up faster. Warmer water
contains less dissolved oxygen, and so
aquatic life is adversely affected.
Growth of weeds is also enhanced with
warmer water temperatures.
Less dilution of contaminants, eg
effluent
As the volume of contaminants does
not generally diminish as river levels
drop, the dilution of any contaminants
entering the river is decreased,
potentially pushing the level from
previously acceptable to unsafe /
unacceptable levels.
Greater potential for leaching of soil
nutrients
The introduction of irrigation to the
farming system is matched by an
intensification of land use, fertiliser
application, etc, carrying with it a
greater potential for nutrient leaching.
If the land users over-irrigate (apply
water to excess of field capacity), the
excess water drains away via leaching
or surface run-off. Run-off carries with
it dissolved nutrients and possibly
effluent.
Lowering of water tables and aquifers
As water is extracted from
underground aquifers, the extraction
may exceed the rate at which water
enters the aquifer. This results in the
level of the aquifer dropping, which in
turn can reduce instream flow rates
and dilution rates, and has potentially
been linked to land instability /
subsidence.
Positive economic implications
Achievement
Merit
The environmental,
economic, or social
implication is
explained in
general terms, but
lacks specific detail
or data.
The
environmental,
economic, or
social implication
is explained in
detail.
Detailed
explanations
involve the use of
accurate, relevant
data and / or a
through
explanation of
why the
implication
occurs.
Eg recent figures
put the value of
irrigation in terms
of increased
primary
production at
$800 – 1,000
million.
Excellence
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 6 of 9
 Increased farm productivity and profit
through greater pasture growth,
higher yields, improved quality.
 Eg the move from sheep farming for
wool and meat in Canterbury into
dairy farming has resulted in an
estimated drop of $22 million in
sheep / beef production, but an
increase of $242 million in dairy
production.
 Recent figures put the value of
irrigation in terms of increased
production at $800–1,000 million.
 The spin-off effects of increased farm
income on service industries and
rural businesses. Suggested ratio: $1
of extra farm produce generates up
to $8 of off-farm economic activity.
Negative social implications
 Loss of recreational fisheries due to
low flows or rivers even drying up.
 The spin-off effects of increased farm
income on service industries and
rural businesses – it is estimated that
for every $1 earned on the farm,
another $8-10 are earned in service
and support industries.
 Changes in community
demographics – intensification and
higher populations impact school
numbers. Changing land use brings
changes to communities, eg dairy
farming brings a larger group of
families that move on to new farms
on a frequent basis.
Q
TWO
Evidence
Potential courses of action:
1. Allow continued and unrestricted
water for all farming practices.
Strengths:
 Maximises income / revenue from
farming across NZ.
 Existing water users can continue to
use water and continue their current
farming operation unchanged.
 New users can get water, thereby
allowing for developing of
‘agriculture’ in areas previously
restricted by lack of rainfall.
 The intensification that may result
from irrigation, new crops, etc may
have positive impacts in rural areas
that were previously struggling in
terms of depopulation, dropping
school numbers, etc.
Weaknesses:
Achievement
Valid strengths and
weaknesses are
assessed
(described) in
general terms.
Merit
Excellence
A comprehensive
evaluation requires
depth in the
information being
presented, which
can be quantitative
and / or qualitative.
This generally
involves the use of
data when
assessing the
respective
strengths and
weaknesses.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 7 of 9
 River and stream ecosystems can be
devastated due to the impacts of
removing large quantities of water,
reducing flows and causing loss of
habitat for macro and micro fauna,
increased water temperatures, less
dilution of contaminants, etc.
 Negative social impacts include loss
of fisheries, swimming holes, and
existing water bores running dry, due
to the lowering of water tables and
aquifers.
 Less water is available for other
water uses, eg hydro-electric power
generation.
2. Restrict water usage to a level
where minimum flow levels (that
have been established according to
acceptable environmental impact by
regional councils) are not reached.
Allocation is on the basis of
consents and a “first come, first
served” basis.
Strengths:
 Current usage, practices and
economic benefits are essentially
allowed to continue.
 The environmental impacts are kept
to a minimum – river habitats are
essentially sustainable.
Weaknesses:
 Potential production and income is
not realised, due to the inability to
further develop / irrigate areas that
are already fully allocated in terms
of their allowable water usage.
 Times when the water is needed the
most, ie during droughts, are when
river and stream flows are at their
lowest, and there is little or no water
available.
 Debate exists as to what the
minimum flows should be; the
maximum extraction rates that
aquifers can cope with are still
being established.
3. Develop strategies to better utilise
the water currently available, eg
store the excess water in times of
plenty, using irrigation storage
dams.
Strengths:
 Production and revenue are further
increased by being able to access
water at times when the minimum
flow restrictions previously
prevented it.
 Environmental impacts on river
ecosystems and aquifer levels are
kept at current levels.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 8 of 9
Weaknesses:
 Storage dams have their own
environmental impacts.
 The cost of building these are high,
often require local or central
government assistance, and have to
cope / comply with the Resource
Management Act and other “red
tape”.
4. Restrict the “take” of water for
irrigation to a point where the
impact on river and stream
levels/ecosystems are negligible
and water tables are unaffected.
Strengths:
 River ecosystems can be allowed to
return to previous states.
 Other social and recreational users
can fully utilise the resource.
 Our “clean, green” image with
overseas markets and tourists is
enhanced.
 Water for stock, household, and
other purposes remains available.
Weaknesses:
 Collectively, farmers have invested
hundreds of millions of dollars in
irrigation systems, and rely on them
for the economic viability of their
farms. They will be severely
affected, and in many cases their
farms will be rendered uneconomic.
 The social impacts in many
intensive farming regions, eg
Canterbury, where irrigation has
resulted in huge changes in farming
focus, would be profound.
 There would be substantial impacts
on national production, including
export volumes for some products.
In some industries, there would be
flow-on effects to producers in
other, less intensively irrigated
regions, due to reduced ‘economies
of scale’ and other factors, eg
Fonterra shareholders.
 Some dry regions would risk
reverting to wind erosion-prone,
weed infestation prone landscapes
and land uses.
 Irrigation is a large contributor to the
“green” appearance that New
Zealand is famous for. Less of it
means more dry, arid images for
both local and overseas observers.
NCEA Level 3 Agricultural and Horticultural Science (90653) 2009 — page 9 of 9
Q
Evidence
THREE
Selects ONE course of action
recommended as the best for New
Zealand growers to implement, in
order to prevent or minimise the
negative environmental impacts of the
chosen issue.
Achievement
A course of action
is recommended.
Merit
Excellence
In justifying their
chosen course of
action, candidates
must clearly
select ONE
course of action
and explain the
reasons for opting
for it in relation to
its ability to
reduce / minimise
the negative
environmental
impacts, and with
consideration to
the social and
economic
implications, in
comparison to the
other course of
action.
Judgement Statement
Question
Achievement
Merit
Excellence
1.
A or M
2 environmental +1 economic
or social aspects explained.
2 environmental +1 economic
or social aspects explained in
detail
OR
3 environmental +1 economic
+1 social aspects explained.
2 environmental +1 economic
or social aspects explained in
detail
OR
3 environmental +1 economic
+1 social aspects explained.
2.
A or E
4 strengths / weaknesses
explained.
4 strengths / weaknesses
explained.
4 strengths / weaknesses
explained in detail.
3.
A or M
A recommendation is made.
A course of action is justified.
A course of action is justified.
Final
judgement
3A
2M
1A
2M
1E
Note: Grades in brackets indicate that evidence for another question in the paper has been recognised.