Organic-Conventional Dairy Systems Trial in New Zealand: Four Years Results

Organic-Conventional Dairy Systems Trial in New Zealand: Four Years Results Terry Kelly, Natalie Butcher, Kerry Harrington, Colin Holmes Dave Horne, Peter Kemp, Alan Palmer, Alison Quinn Nicola Shadbolt, Alan Thatcher http://agservices.massey.ac.nz

Welcome to Massey University s Dairy Cattle Research Unit

and to the Organic- Conventional Dairy Systems Trial Organic: 20.4 ha Conventional: 21.3 ha

Old style 10 bale walk-through dairy shed

Genesis of the Organic-Conventional Dairy Systems Trial 2000: the dairy industry approached Massey to set up a comparative systems trial 1 August 2001: the trial began the farm was split into two as evenly as possible, both in terms of land and herds Organic farmlet began its conversion 1 August 2003: organic farmlet achieved full organic certification

The long-term aim of this research: To better understand organic dairy farming systems by investigating component interactions in these systems, and by determining how impacts and interactions change over time as organic systems mature, and compare these changes to those on a conventionally managed system with nearly identical resources.

Key long-term objectives are: 1. Develop farm and herd management systems that optimise performance over time; 2. Compare the impacts of organically and conventionally managed dairy systems on soil health & water quality, pasture and forage crop productivity, and animal production and health; 3. Identify management practices that improve the biological activity of soils, optimize clover content and best maintain biological N fixation, and best control mastitis and other health issues in organic milk production systems; and 4. Determine the stability and sustainability of high biodiversity organic dairy pastures, including the control of weeds.

Farming systems management Each farmlet is managed individually according to best Practice Thus, no attempt is made to do the same thing on one farm as is done on the other farm Conventional farmlet: best practice as for the other Massey dairy farms Organic farmlet: best practice guided by the certifying agency and an organic farmer advisory group

Monitoring and data collection Full production data for both cows and pastures on both farmlets Animal growth and health status for both herds are carefully and comprehensively monitored Pasture composition and weeds on both farmlets are surveyed twice yearly A range of soil properties and processes are measured on both farmlets Soil physical, chemical and biological characteristics Soil nitrogen dynamics are being studied in detail

Results: Some Considerations The Tokomaru silt loams are far from ideal for Dairying No long-term funding annual funding only Limited funding the first two years

ProfitWatch 5yr mean 99/00-02/03 01/02 Organic/Conventional Comparison Trial Yr 1 Yr 2 Yr 3 Yr 4 01/02 02/03 02/03 03/04 03/04 04/05 Max. Cows Milked 120 44 44 49 48 51 46 48 43 Effective Dairy Ha 48 20 20 21.3 20.4 21.3 20.4 21.3 20.4 Stocking Rate 2.5 2.2 2.2 2.3 2.4 2.4 2.3 2.3 2.1 Pasture Grown tdm/ha 8.9 7.7 13.5 11 12.2 9.8 kgms/cow 290 451 436 318 317 457 410 401 345 kgms/ha 726 993 959 722 742 1094 925 902 721 Gross Farm Income $/ha 3484 5247 5173 2860 2858 4872 4529 4212 3776 Operating Expenses $/ha 2553 2875 3102 3178 4061 3069 3038 3629 3793 Operating Profit $/ha 931 2373 2070-318 -1203 1803 1490 583-17 04/05 Return on Assets % 3.7% 9.5% 8.3% -1.3% -4.8% 7.2% 6.0% 2.3% -0.1% Cost of Capital $/ha 1250 1250 1250 1250 1250 1250 1250 1285 1285 Cost of Milk $/ha 3449 3650 3841 4428 5311 4319 4288 4509 4648 Cost of Milk $/kgms 4.76 3.68 4.00 5.77 6.90 3.49 4.06 5.00 6.45 Difference % 9% 20% 16% 29%

Animal Health No apparent significant differences between the two herds both were relatively healthy Live weights, body condition scores and SCCs for both herds were similar Slightly higher incidence of mastitis in the organic herd, but so far has been manageable Organically reared calves have grown exceptionally well and tended to be slightly heavier and in better condition than their conventional counterparts

Pasture Management Though species composition of the pastures on the two farms has remained similar, white clover is higher on the organic side but is still sub-optimal. Weeds have not been a particular problem on either farmlet. Mineral analyses are being done on various weed/herb species to determine their nutritative value for the cows.

Earthworm numbers & mass measured winter of 2004 Conventional paddocks Organic paddocks Earthworm numbers 15 20.3 Earthworm mass (g) 3.56 4.40 Mass per earthworm (g) 0.24 0.22

Soil and Water The same soil type covers the entire farm, and initial soil quality of the two farms was very similar No major differences between the conventional and organically managed paddocks for ammonium-n or nitrate-n Although there was some indication that earthworm populations and mass might be greater on the organic paddocks, the difference was not significant There is less leaching of nitrate-n from the organic farm than there is from conventional farm

Mean nitrate-n concentrations during winter-spring 2004 Conventional paddocks Organic paddocks in mole-pipe drainage: in suction cup samples: Nitrate-N (mg l -3 ) Nitrate-N at 150 mm (mg l -3 ) Nitrate-N at 300 mm (mg l -3 ) 8.8 5.3 4.8 0.3 7.4 0.6

P nutrient status measured in the autumn of 2005 Olsen P (μg P ml -1 soil) Resin P (%w/w) sulphate-s (μg S g -1 soil) Potassium (MAF units) Conventional paddocks Organic paddocks 45 37 (41*) 106 117* 22 12 8.3 6.7 * Excludes two substantially inferior paddocks

Preliminary Conclusions Pasture production, and hence milk production, is less on the organic farmlet, most likely due to the inability to cost-effectively apply nitrogen fertilisers at critical periods in the spring. Mastitis, though more of a challenge on the organic farm, is manageable and has remained below tolerance levels; other animal health issues have not been a problem under organic management. Organically rearing young stock is feasible, and in fact may be a very viable option for dairy farmers. Impacts on the environment in the form of nitrate-n contamination to ground and surface water appear to be less under organic management. with a price premium for organic milk, the organic dairy system seems to be an economically viable option for dairy farmers.

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