Scott Farm


4 min read

Past and present projects Fluent in effluent management

Scott Farm focuses on research for effective dairy farming systems, especially for pasture-based Waikato farming. The farm covers 115ha with a herd size of 330 and a variety of soil types. They've undertaken several research projects, looking into issues like ryegrass recovery, nitrate leaching, and milk production. A highlight at Scott Farm is their Effluent Irrigation System (EIS). This system treats dairy wastewater from Lye and Scott Farms. The EIS separates solids and liquids; solids fertilise crops, and liquids irrigate 112 ha. The system reduces fertiliser costs, improves effluent management, and meets compliance requirements.

Welcome to DairyNZ's Scott Farm, home to research on effective farming systems for dairy farmers, with particular relevance for pasture-based Waikato farming.

Farm profile

Farm area: 115ha effective milking platform
Research focus: Larger-scale farm systems trials
Herd size: 330 (subject to scientific requirements)
Pasture production: averages 17t DM/ha annually (150kgN/ha/year)
Soil type and fertility: Peaty loams, sandy loams, silt loams
Dairy Infrastructure: 44 bail turn-style; GEA Westfalia milking system


Past and present projects

DairyNZ's larger scale farming systems research trials are based at Scott Farm.

Forage Value Index validation (2017-2021)


Compare newly established pastures representing high and low ratings on the Forage value Index.

What we learned

Trial still in progress.

Ryegrass persistence and recovery trial (2018-2021) Part 2


Three management interventions for recovering ryegrass populations in run-out pasture from part 1 (see below) were assessed.

What we learned

Pasture deferral shows promise as an intervention for recovering failing ryegrass pastures through natural reseeding.

Ryegrass persistence and recovery trial (2011-2016) Part 1


Investigating the effect of plant density (created by differences in seeding rate) on plant morphology and survival.

What we learned

In autumn 4 years after sowing, ryegrass had fallen to 20% of HM.

This pattern was not prevented by any combination of ryegrass functional type, endophyte, seeding rate, or best-practice dairy cattle grazing and soil nutrient management.

Pastoral 21 (2011-2016)


Aimed to determine if existing technologies could reduce nitrate leaching by 50% while maintaining high levels of milk production and profitability.

  • Two farmlets
  • One stocked at 3.2 cows/ha (current) and
  • Compared with farmlet stocked at 2.6 cows/ha focusing on higher cow production through higher genetic merit cows, lower N fertiliser usage and removing cows from pasture during critical N leaching periods (future).

What we learned

The methods employed by the future farmlet reduced N leaching by 43%, and while each cow produced 68 kg more MS/cow, MS per ha was 50 kg lower.

  • The future farmlet yielded $279/ha/yr less profit than the current farmlet.

25t DM/ha (2010-2012)


  • Six farmlets compared perennial ryegrass and tall fescue swards
  • Four of the farmlets included either chicory-red clover or lucerne crops planted on 20-25% of the area.

What we learned

  • Using tall fescue improved total annual herbage yield compared with perennial ryegrass.
  • Milksolids production and operating profit were lower.

Stand-off trial (2010)


Investigated the effect of 16 hours/day removal from pasture on:

  • capture of urination events
  • milk production
  • pasture intake and
  • animal welfare

from cows grazing pasture in early and late lactation.

What we learned

Restricting grazing and reducing urinations on pasture could be a mitigation strategy for decreasing N loss to the environment at high-risk times while maintaining production and welfare.

Achieving annual yields of 45t DM/ha (2007-2009)


Explored the feasibility in ungrazed plots of achieving a target of growing 45t M/ha/yr of forage with an average metabolizable energy (ME) value of 11 MJ ME/kg DM.

What we learned

The target was exceeded using a sequence of maize followed by a winter oat crop.

Farming without nitrogen comparison trial (2001-2010)


Two farmlets:

  • One with 0 N/ha and 2.4 cows/ha
  • The other with 180kg N/ha and 3.1 cows/ha

What we learned

  • On average 1 kg N/ha added 1.1kg MS/ha.
  • Over 10 years N increased profit but below milk price of $5.10/kg 0 N was more profitable.

Prototype farm trial (2006-2009)


Farmlet 1: Aim to produce 1750kg MS/ha all from home-grown feed.

Farmlet 2: Test technologies aimed at reduced N leaching, such as strategic stand-off and nitrification inhibitors.

What we learned

Farmlet 1:

  • 1480 kg MS/ha achieved.
  • Increased DM/ha grown by 2.1 t DM/ha with 0.8 t DM/ha coming from maize.
  • Cost of extra DM was 38 cents/kg DM

Farmlet 2:

  • Established that autumn urine patches added a greater amount to N leaching than winter urine.
  • Standing cows off in autumn had a larger effect on leaching than winter stand-off.

RED Trial (2001-2006)


  • 7 farmlets of varying intensity.
  • Stocking rate from 2.4 cows/ha to 7 cows/ha.
  • Inputs varying from pasture only and 0 nitrogen to 50% of annual feed being imported as maize silage

What we learned

  • MS per effective ha ranged from 1000 to 2900kg MS/ha
  • N leaching was measured and modelled

Fluent in effluent management

A main feature of Scott Farm is an Effluent Irrigation System (EIS) for treating dairy wastewater from both Lye and Scott Farms, with research trials conducted on both farms able to utilise the nutrients from this system.

Until 2012, Scott Farm used an 'environmentally friendly' Advanced Pond System (APS) for effluent storage and treatment. Like many older effluent systems, the APS became difficult to operate within compliance limits over time and spurred DairyNZ to install a new system, the EIS, while still retaining some of the APS infrastructure to minimise the cost of the upgrade. The EIS was designed and developed to cope with around 12,000 m3 of effluent, 72,000 m3 of wash water and 7,000 m3 of rainwater annually. Given the cost of upgrading, meeting effluent compliance requirements for years to come was also a key priority.

So how does the EIS work? Effluent from both Lye and Scott Farm is piped to the EIS located on Scott Farm. It is collected in a large sump and then pumped over a 1.2 m static “wedge wire” screen separator, which separates fibres down to 1mm. The screened liquid flows through a 150 mm gravity discharge pipe and is then pumped to a storage pond. T solids slide into a concrete bunker and are periodically moved to a composting area. The solids are used to fertilise and condition cropping areas on both farms. The bunker is large enough to store solids for a longer period, giving plenty of flexibility for emptying. With the solids sorted, that just leaves the liquid.

From the storage pond, the liquid is pumped over a total area of 112 ha, with about 50% of the land being on each farm. The area is split into seven irrigation zones, requiring 168 K-line pods. Application depths can be adjusted from 5-25 mm either manually or by phone text, so the Farm Manager can keep control of effluent application remotely.

Soil moisture content is regularly monitored to ensure saturated soils are not irrigated, mitigating the risk of run-off. However, storage of liquid manure for long periods can then become a risk in itself. To counteract this, there are actually two ponds that store liquid. The first pond has a working capacity of 4,552 m3 while an overflow pond can take an additional 1,686 m3, in total equating to around 28 days storage. And this is where the old infrastructure was put to use; converting the old APS ponds into the new EIS ponds to keep costs down.

The EIS has other financial advantages; being able to apply the liquid manure whenever soil conditions are optimal means that the overall fertiliser bill can be cut by around $27,000 per annum. More muck than buck!

Last updated: Aug 2023

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