4.1
Farm selection
As outlined in research methods above, four case study farms were identified and contacted to collect data for kale and fodder beet crops, which was used to create a representative model of a dairy support unit. This model was then run through Overseer 6.2.2 with different management options.
Four case study farms were identified with the help of Guy Trafford and Marv Pangborn. To be suitable for the research the farms had to meet certain specifications.
Farms were to all be located within the Selwyn Te Waihora catchment zone in Canterbury. The research focus is on Variation 1 in the Land and Water Regional Plan, which outlines policies and rules regarding management practices and nutrient loss to water restrictions specific to this zone.
The farms were all to have dairy support as a component of the whole farm system. This research focuses on the environmental issues of dairy wintering systems and the
management options available to reduce nitrogen losses to water.
An equal number of kale and fodder beet crops between all the selected case study farms was necessary to ensure enough data was available to conduct a fair analysis.
The farmers were required to be open to participating in the research and have good historical farm records to ensure any data collected is both reliable and relevant.
Data collection occurred on farm after initial contact by phone and email. Data relevant to farm system, current management practices, farm physical attributes and financials for the kale and fodder beet crops were all recorded. Sufficient information on the current farm system had to be available to ensure an accurate Overseer nutrient report could be completed. Data gathered is outlined in table 1 below. More detailed information is recorded in appendices 10.1 to 10.4.
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4.2
Case study farm quantitative information
Table 1 Overview of case study farms
Farm A Farm B Farm C Farm D
Area (total) 523, 483 ha effective 455ha 330ha 550ha
Location North Rakaia River vicinity Hororata North Rakaia River vicinity Hororata
Climate Annual rainfall - 712 mm, average temperature - 11.3, PET- 880mm Annual rainfall - 794mm, average temperature - 11.3, PET- 882mm Annual rainfall - 735 mm, average temperature - 11.1, PET- 1020mm Annual rainfall - 872 mm, average temperature - 11.1, PET- 860mm
N Baseline 61kgN/ha/year 36kgN/ha/year 32kgN/ha/yr NA
N current system 61kgN/ha/year 78kgN/ha/year 32kgN/ha/year
CPW yes yes yes yes
Kale 45ha 70ha 0ha 42ha
Fodderbeet 45ha 30ha 27ha 0ha
Farm system
Dairy support Arable + Dairy support Arable + Dairy support Sheep, beef, arable, dairy support
Stock classes
290 MA Carry-over cull dairy cows, 5400 wintered dairy cows (all friesian)
800 Dairy calves, 90 Coopworth sheep, 50 Trading steers, 1800 MA dairy cows wintered.
50 trading steers, 300 dairy heifers, 1000 MA dairy cows for wintering
2200 MA Coopworth ewes, 310 MA Angus cows, 70 trading cull cows, 650 Friesian calves, 320 MA dairy cows
Dominant soil type Eyre silty loam Lismore silt loam Lismore silt loam Claremont silt loam
Soil Features Well drained, gravelly loam, moderate to high PAW (70- 104mm in top 60cm)
Well drained, moderate PAW (86mm in top 60cm)
Well drained, moderate PAW (86mm in top 60cm)
Poorly drained, moderate to deep soil with high PAW (90mm)
Other soil types
Numerous well drained loam soils. 100ha stony fluvial loam, with low PAW (46-55mm). 109 ha of Waimakariri silty loam with very high PAW (109- 141mm), 109ha of Lismore shallow silty loam with moderate PAW (86mm)
Darnley silt loam, stony, moderately well drained with low PAW (54mm in top 60cm)
Numerous silt loam soils ranging from Waimakariri (PAW of 141mm) to Eyre soil (PAW of 70mm)
Two shallow silty loams (Ruapuna and Darnley soils), well drained with a high PAW (94mm) aand low PAW (54mm) respectively. A deep silty loam Mayfield soil with moderate PAW (81mm) and a riverbed soil- basically stones.
Irrigation
473 ha irrigated, 59 ha dryland Fully irrigated 242ha Irrigated 210ha irrigated
Type Centre pivot and lateral
irrigators Centre Pivot
Centre Pivot and Travelling
irrigators Centre pivots
Water supply 170ha of CPW irrigation,
303ha Rakaia Gallery CPW CPW CPW
Irrigation Management Some precision Irrigation, neutron probes and irrigation scheduling
Irrigation scheduling, soil moisture content readings from 3 neutron probes
Irrigation scheduling and visual assessment of soil to determine moisture
Some VRI irrigation, visually asses soil moisture for irrigation scheduling
Supplement feeds 4000T/ DM 250T DM 360T DM 256 T DM
Source On farm On Farm and purchased On farm On farm and purchased
Type
Cereal and Grass Silage
Barley Straw and Pea Vine harvested, RG straw purchased
Barley straw and grass silage
Barley grain and straw, pasture and cereal silage all harvested on farm, RG straw purchased
Destination
Wintering dairy cows (6kgDM/d for 55 days) and sold off farm
Barley straw to wintering MA dairy cows, pea vine to replacement heifers on pasture
80% silage/ straw fed out on winter crops, remainder fed to replacement heifers
Barley- MA ewes, P and C silages- farm stock, barley straw- wintering dairy cows. RG straw- calves on crop
Winter crop mgmt Sold standing at $0.23/kgDM (current prices) Sold standing at $0.21/kgDM (current prices) Sold standing at $0.21/kgDM (current prices) Sold standing at $0.21/kgDM (current prices)
Grazing revenue Kale
Yield Average 16tDM/ha Average 14tDM/ha - Average 12.5tDM/ha
Cost $1299/ha $1690/ha - $1732/ha
Income $3680/ha $2940/ha - $2625/ha
Gross Margin $2380/ha $1250/ha - $893/ha
Grazing revenue Fodder beet
Yield 26tDM 23tDM 26.5tDM -
Cost $2535/ha $2331/ha 2815/ha -
Income $5980/ha $4830/ha $5565/ha -
Gross Margin $3444/ha $2499/ha $2749/ha -
Yield test methods Commercially tested Tested on farm Commercially tested Tested on farm
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4.3
Case study qualitative information
Table 2 Case study farms qualitative information