Land management on Bay of Plenty dairy farms - Managing land to reduce sediment and phosphorus loss
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Land management on Bay of Plenty dairy farms Managing land to reduce sediment and phosphorus loss
Land management on Bay of Plenty
dairy farms
The land is one of dairy farmers’ greatest assets and managing land productively and sustainably will add further value
to the farm. It’s part of future proofing New Zealand’s unique farming landscape and waterways to ensure we continue
to have productive land to farm and a beautiful environment to enjoy.
Bay of Plenty dairy farmers have learnt to farm with a wide range of soil and land types. The addition of adverse
weather events has meant Bay of Plenty dairying has some of the most diverse landscapes in the country.
This guide covers six areas which have the greatest impact on the land in the Bay of Plenty, with advice on how to
manage these areas for the best outcome for your land and the environment. These include:
Erosion | Crops | Pugging | Races | Waterways | Wetlands
Many actions to land improvement will have multiple on-farm benefits, indicated by the following icons:
On-farm benefits:
Environmental Animal health Farm profit
The effect of soil loss
Soil loss can significantly decrease productivity and profitability on a dairy farm by decreasing the amount of available
nutrient-rich topsoil for grass growth. Most erosion and land damage occurs during times of high rainfall, particularly in
areas with already exposed or disturbed soil.
Runoff from a farm can contain phosphorus, nitrogen, bacteria and sediment which affects water quality. Lakes,
estuaries and harbours are particularly sensitive as contaminants don’t flush through, accumulating in these water
bodies. The cumulative effect of farmers reducing runoff will improve the health of waterways.
Trees such as poplar or hybrid/sterile willows can be planted to stabilise steep or unstable land.
Erosion control
Sloping land is more susceptible to erosion and can occur relatively unseen. Erosion leads to the loss of valuable topsoil
on all land types.
Main types of erosion in the Bay of Plenty
Actions to prevent and reduce erosion
Sheet erosion
• Rest the paddock as soon as open patches
of soil appear to allow pasture to recover.
Consider over-sowing when soil conditions
suit.
• Achieve residuals of around 1500kg/DM with
effective grazing management.
• Where erosion is occurring, plant trees such
as hybrid willows and poplars which help
stabilise soil.
• Where gully erosion has occurred, Gully erosion
re-contouring can help to spread the flow of
water more evenly, which would otherwise
form channels in paddocks.
• Graze steep areas with young stock (lighter
animals will have less impact on the land).
• Highly eroded areas may benefit from
retirement to native forest or plantation
forestry.
Slip/slump erosion
Benefits of reducing erosion
Water quality is improved by reducing
the amount of sediments entering
waterways.
Ensuring topsoil is kept in paddocks is
beneficial for grass growth and milk
production.
Erosion-control trees such as hybrid willows
Streambank erosion
and poplars provide shade and shelter for
stock.
FARMER’S TIP
“Talk with forest harvest and establishment crews
before planting trees. In areas that were going to
be too tricky to harvest we retired them to natives.”
Hank Hodge, Kaimai
Cropping area establishment
Cropping can cause soil to be exposed for long periods of time, during which rain and overland flow paths wash
soil into waterways. The Bay of Plenty has light crumbly soils that erode easily, even on gentle slopes. Exposing them
during cultivation leaves them prone to rill and gully erosion.
Figure 1. Cultivate across slopes where possible to reduce
soil loss by redirecting water flows.
Actions for improving cropping areas
• Where possible, use cultivation technology
such as direct drilling and broadcasting, which
will decrease soil disturbance. Water
• Grazing in cropped paddocks should start
furtherest away from waterways and graze
back towards them, leaving a buffer strip
available to filter and trap sediment.
• Where health and safety allows, it is good
practice to cultivate across slopes rather than
up and down slopes which can speed up the
movement of soils. (Figure 1) Figure 2. Leaving grass strips undisturbed in gully areas
helps to trap sediment.
• Leave grass strips across slopes of cultivated
paddocks to act as filters to trap sediment
running off cultivated areas. (Figure 2)
• Have an understanding of where water flows
or moves in a paddock during wet periods.
Avoid cultivation in areas of intermittent
water-flows such as seeps and dry streambeds
to minimise soil loss. Water
• Time your cultivation for when soil moisture is
Grass strips to filter
low. This will reduce compaction of the soil. sediment
Benefits of improving cropping areas
Reducing soil disturbance and minimising Reducing erosion of cropping areas will
runoff will mean less sediment and nutrients reduce the risk of seed or crop loss at
entering waterways. establishment and help retain the amount of
valuable topsoil.
Pugging prevention
Many soils in the Bay of Plenty are prone to pugging in wet weather. The management of pasture has a big impact on
how susceptible paddocks are to pugging. Pugging causes runoff of fine sediment; a major pollutant of Bay of Plenty
waterways.
Benefits of reducing pugging
Actions to minimise pugging
Avoiding damage from pugging is beneficial
• Select paddocks better suited to wet weather to waterways, as pugged areas increase
grazing, such as paddocks that dry out faster surface runoff.
and use these during winter rounds.
An area of seriously pugged pasture in
• Minimise movement of animals around
spring will produce about 40% less dry
paddocks.
matter than undamaged pasture through
• Resting and re-grassing of paddocks that the following season. Reducing pugging will
have been severely pugged or compacted also reduce the need for re-grassing.
will help reduce the impact on future pasture
production.
Reducing pugging and mud will help
• On-off grazing can be an effective tool to maintain foot and teat health, reducing
reduce pugging damage. environmental mastitis.
Sacrifice paddocks should be used as a last
TIP resort and should only occur when all other
options have been exhausted. If a sacrifice
Carry out a cost-benefit analysis before
paddock has to be used, there are management
construction of off-paddock infrastructure. For
more information visit dairynz.co.nz/standoff.
considerations that will reduce environmental
and animal health risks. For further advice vist
dairynz.co.nz/wintermanagement.
Race construction
Races can create channels that transport sediment, bacteria and nutrients into waterways.
Benefits of improving races
Actions to improve races
Well-constructed races with cut-off drains
• A ’speed bump’ can be used to direct water that shed water to paddocks and a suitable
off the track on a steep slope. camber will be less likely to send sediment
into waterways.
• Minimise shaded areas to ensure races dry
quicker.
Correctly designed and constructed races
• A gradual camber between 3-8% will allow
will help to improve cow flow and reduce
cows to use the entire width of the race. If
lameness.
the incline is too steep, the cows will walk on
flatter areas in the centre or edges of the race.
A well maintaned race can reduce lameness
• If you have a race next to a waterway, ensure in the herd and increase milk production
it slopes away from the water towards a with improved cow health and cow flow.
paddock or sediment trap.
p
Speed bum
• A speed bump forces water off/away from • A gradual incline of 3-8% will ensure cows use
the race surface and prevents the loss of race the entire width of the race and allows water
material. to drain.
• Avoid large shady areas which prevent races • Large wet patches along race edges indicate a
from drying out. lack of ability to drain water.
• Avoid completely flat races which cause • Cows walking single file may indicate the race
water to sit/pool on the surface. needs maintenance or is not suitable for stock.Waterway management
Stream bank erosion
The erosion of stream banks is an ongoing issue in the Bay of Plenty due to the mixture of heavy and light soils. Stream
erosion causes large amounts of sediment and phosphorus to enter waterways.
Actions to reduce bank erosion FARMER’S TIP
• Drain banks should be gradually sloped, with “Use good quality plants. They will require less
a shallow ‘V’ formation rather than a more maintenance and will reach canopy closure
unstable ‘U’ shaped bank. quicker.”
Hank Hodge, Kaimai
• Eroding streambanks can be planted to help
stabilise them.
• Size culverts to cope with high flows as well
Crossings
as allowing for fish passage.
Well-constructed crossings will reduce bank erosion and
• Nib walls and diversion channels prior to
the amount of faecal matter that enters waterways. The
crossings help to avoid the movement of run-
type of crossing and the location is important so that it
off into waterways.
can adequately cope with high volumes of water during
• Locate bridges and culverts where there are floods.
regular stock crossing points to prevent stock
accessing water and maximise cow flow. Benefits of having well designed and
• Exclude stock from wetlands to avoid them
constructed crossings
getting stuck or eating poisonous swamp
Well constructed crossings minimise direct
plants such as sweet reed grass.
effluent and sediment entering waterways
and improve the habitat for fish and other
in-stream species.
Keeping stock out of waterways will ensure
Benefits of stopping stream bank erosion
they aren’t used as a drinking source,
Stable stream banks means less sediment minimising the risk of waterborne diseases
enters waterways, creating a healthier such as Liver Fluke. It also ensures cows can
habitat for wildlife. receive minerals added to stock water.
Preventing stream bank erosion can help Culverts and bridges will help speed up safe
protect productive farming land. crossing and allow for movement of stock
and vehicles during higher river flows.
Successful riparia
n planting in the
Bay of Plenty
FAST 5 PLANT
S FOR BAY OF
1 PLENTY
2
3
4
5 A valuable asset for
your farm
Cabbage tree
Getting riparian plan
Pukio When fenced and
Karamū planted, riparian
Manuka filter out sediment zones are a valuable
These five go-to Mānuka asset for dairy farms.
ting right
plants are ideal to Mountain flax and nutrients that They function like
start your planting valuable habitat leave farmland a sieve, helping
pasture and don’t with – they are hardy, for animals, birds, in runoff before to
require shelter. Ask fast-growing, can insects and fish. they enter waterways
. They also provide
in the Bay of Plenty
are best adapted your nursery for be planted straight
to your climate and eco-sourced plants into a
as they are grown
soils. from local wild seed
and
How do healthy riparian
zones improve water
quality?
Table of Riparian • Riparian zones help
Plants to reduce sediment
into waterways,
Tolerates key: sediment means improving water
less cost for drain clarity and the habitat
Full sun
Wind Salt wind
clearing and less
risk of flooding. for insects and fish. Your step-by-step
Benefits key: Frost hardy
Poorly drained soil • Riparian zones reduce
Less
guide for successful
Karl and Maggy
Buhler milk 250
Attracts birds
Attracts bees
Slope stabilisation
(boggy) Dry soil conditions
providing a better
nutrients into waterways,
decreasing weed
riparian planting
cows on 100 hectares Filters runoff environment for growth, improving
of the Pongakawa in the Pongakawa Plant name Shade Fish habitat swimming and fishing biodiversity and
Stream and contains Valley. Their farm for you and your water quality, and
many small spring-fed is bisected by a Type On your farm, well community.
and native plants tributary Tolerates managed riparian
and are involved wetlands. They Benefits zones will improve
in several planting are passionate in waterways. Taller
projects in the about riparian Size (height x width) stock managemen
area. planting Lower bank zone trees will provide t and protect them
shelter from wind,
PLANTING IN BAY OF PLENTY
Karl and Maggy Space 1-1.5 m between increase shade and from getting stuck
started their riparian Cabbage tree (tī
kōuka) plants reduce heat and or drowning
planting over a decade Riparian plants stabilise wind
they fenced and ago when
Cordyline australis Tree banks with their stress.
planted a boggy roots, limiting the
area on the farm Pukio loss of your land
cows getting stuck. to help prevent 10x3
10 x 3mm through erosion.
They received advice,
TOP TIPS
Carex secta Sedge
management plan funding and a riparian
from Bay of Plenty Cutty grass (rautahi) The Sustainable Dairying:
them with clear goals Regional Council 0.75x1
0.75 x 1mm Water Accord (Water
which provided
in an achievable
timeframe. Karl and Maggy
Carex geminata Sedge
to manage the land
in a way that contributes
Accord) was developed
in 2013 by the dairy
Karl and Maggy
find that by doing
Buhler Giant umbrella sedge
Cyperus ustulatus
(upokotangata)
Sedge
0.75
0 75 x 1 m management is a
requirement of the
to achieving water
quality desired by
industry and is a
commitment
the bulk of planting Water Accord. New Zealanders.
plants have a good in autumn, Good riparian
chance to get their “Get rid of weeds Swamp sedge (p
ūrei)
The Water Accord
roots down, increasing first” 1x1m requires dairy farmers
their survival over Carex virgata Sedge to ensure:
summer. Frost-tender Before you plant, • Stock exclusion from
September to avoid plants are planted control weeds through Summer-flowering 90% of farm waterways*
the coldest weather. around toetoe (toetoe) 0.75 x 1 m
Sustainable Dairying:
spraying or manual Austroderia fulvida Grass deeper than 30 cm and drains** greater Water Accord
removal. In very and significant wetlands than 1 m in width A Commitment to
and
New Zealand
Karl says that controlling areas this may take weedy by 31 May 2014
by the Dairy Sector
• 50% of dairy and 100% by 31
For information about suitable planting types, download or order “Getting riparian
the invasive glyceria two to three years, 1.5 x 1.5 m farms with waterways* May 2017.
component of their weed is a major but it is much easier Upper bank zone have a riparian planting
riparian managemen than trying to control by 31 May 2020. plan by 31 May 2016
t. “Planting natives Black matipo
Karam ū Space 1.5-2 m between and all
different to glyceria that look weeds once plants (kōhūhū) plants
makes it easier to have gone in. Pittosporum
Coprosma Small tree/tree
Shrub/small • Of these farms
when spraying,” avoid killing desired robusta
tenuifolium tree half of their riparian
he says. “Glyceria plants Mānuka plan committmen
can smother plants “Select native plants 8 x 31.5
4 mm
with full implementa ts have been met
perseverance it can but with sheer tion by 2030. by 31 May 2020,
be removed.” that are resistant Leptospermum scoparium Small tree
to broadleaf spray” Mānuka flax
Mountain *A water accord
4 x 1.5m waterway is a “lake,
Karl and Maggy Flax drains) that permanently spring, river or stream
have planted around Planting grass-like
Leptospermum
Phormium cookianum
scoparium
contains water and (including streams
years, creating a 15,000 plants over species (monocots) that have been artificially
planting right in the Bay of Plenty” from dairynz.co.nz/waterways.
the last 12 immediately following any significant wetland. straightened but
visually stunning cabbage tree, flax, like Akeake
1x1m extreme weather This does not include excluding
property and greatly toetoe, carex species Small tree events”. temporary watercourses
birdlife which was improving the Dodonaea viscosa
**A water accord that flow during
absent when they and other native drain is an artificially or
bought the farm. sedges is a great Black matipo (kō permanently flowing created channel
idea hūhū) 6x3m water but does not designed to lower
where broadleaf Pittosporum tenuifolium Small tree/tree include any modified the water table and/or
weeds occur, as (e.g. straightened) reduce surface flood
these natural watercourse. risk and which has
plants are resistant Kahikatea*
to broadleaf sprays, 8x3m
Dacrycarpus dacrydiodes Tree
making it much
easier to control
weeds Kānuka
without the risk 40-60 x 4 m
of damaging plants. Kunzea ericoides Tree
Koromiko
“Don’t plant flax too 8x3m
close to the edge Hebe stricta Shrub
of the stream” Lemonwood (tarata) Protecting our
1.8 x 1 m valuable water
Flax is a good riparian Pittosporum eugenoides Tree resource is important
who use water for dairying in
plant, but it's large for drinking and New Zealand. It
economic, recreationa
2014
Mahoe also benefits the
when fully grown 9x4m l, aesthetic, ecological community
and may fall into Melicytus ramiflorus Tree
the Riparian zones can and cultural activities.
stream, taking a chunk be used to maintain
Version 1 – December
of the bank with Mingimingi
and bacteria that and improve water
It’s best to move it. 10 x 3 m
leave the land as quality. Once fenced
flax further away Coprosma propinqua Shrub and planted, they
from the runoff. Healthy riparian filter nutrients, sediment
stream edge to avoid Swamp flax (harakeke) zones will improve
this happening. 4 x 1.5 m This practical ‘how the health of your
Phormium tenax Flax to’ guide for riparian waterway.
profitable dairy farm. management covers
Tōtara* It includes advice planting and maintaining
2x2m from industry and riparian zones for
Podocarpus totara Tree regional council a sustainable and
experts.
Wineberry (makomako) What are riparian
Aristotelia serrata Shrub/tree
20 x 4 m
zones?
DNZ40-065
Riparian zones are
*Plant these species 8x3m the strips of land
into existing vegetation wettest, such as beside drains, streams,
or two to three years wetlands, springs, rivers and lakes.
after initial plantings seeps and gullies. They include areas
so they have shelter on-farm where the
to grow. soils are
DairyNZ farmer informat
ion service 0800
4 DairyNZ (0800
4 324 7969)
dairynz.co.nzProtecting wetlands
New Zealand has lost 90 percent of its wetland areas due to drainage. It is important to maintain wetlands as they
protect land from flood damage, due to their ability to slow or hold surface water and release this slowly over time.
They also reduce the amount of sediment entering waterways and provide a valuable habitat for native wildlife.
Benefits of protecting wetlands
Wetlands retain and filter nutrients before
they enter waterways, are a valuable habitat
for native species and reduce flood flows.
Fencing wetlands will reduce the likelihood
of stock getting stuck. Reducing the amount
of muddy areas you have is important for
maintaining teat health and reducing the
incidence of mastitis.
Wetlands can protect land from flood
damage due to their ability to slow or even
hold surface water and release it slowly over Wetlands include anything from small on-farm seeps to large,
time. regionally recognised wetland areas. All wetlands, regardless of
size, hold significant importance for native flora and fauna and
will help filter contaminants leaving the farm in runoff.
Version 1 – May 2015
DNZ40-021
DairyNZ farmer information service 0800 4 DairyNZ (0800 4 324 7969) dairynz.co.nzYou can also read
