Rootzone reality: A network of fluxmeters measuring nutrient losses under cropping rotations Presented by Matt Norris

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1 Rootzone reality: A network of fluxmeters measuring nutrient losses under cropping rotations Presented by Matt Norris

2 utrient losses in New Zealand me key changes over the past few years: Regulatory policies Access to markets eater requirement for growers to demonstrate: That their production systems are sustainable That they are taking proactive steps to mitigate nutrient losses from their systems se of tools: Predict whole farm outcomes Set associated policies?? Measured Data??

3 ootzone Reality: Objectives Provide growers and regional authorities with robust measurements of N and P leaching losses from cropping farms across sites and seasons We need data!» As a platform for discussion» To determine whether GMP s are having the desired impact» To inform models and policy verview:» Trial design and experimental sites» Measurements» Results from Year 1: Focus on N losses

4 easuring N losses: the tension fluxmeter What is a tension fluxmeter?»»»» 200 mm PVC pipe that intercepts drainage (stores ~14 L) Filter zone to reduce sediment transfer Passive wick Drainage pumped to surface through plastic tubes 150 mm 50 mm Top of fluxmeter is at a depth of 1.0 m Drainage validated against a soil water balance 1000 mm 150 mm

5 Canterbury Canterbury Waikato/Auckland Waikato/Auckland Hawke s Bay Auckland/ Waikato Manawatu Hawke s Bay Hawke's Hawke's BayBay Manawatu Manawatu Manawatu Waikato/Auckland Canterbury Canterbury The fluxmeter network seed seed Site 1 Site 1 Site 2 Site 2 Barley Barley Site 4 Site 4 Site 5 Site 5 Site 7 Site 7 Carrots Carrots Site 8 Site 8 Peas Peas Spinach Spinach grazed grazed grazed grazed Beans Beans Oats Oats Wheat Wheat Sweetcorn Sweetcorn Site 10 Site 10 grazed grazed Lettuce Lettuce Spinach Spinach Maize Maize Site 6 Site 6 Wheat Wheat White clover White clover seed seed Site 3 Site 3 Site 9 Site 9 grazed grazed Site 11 Site 11 Onions Onions Site 12 Site 12 Onions Onions Barley Barley SepSep AugAug Jul Jul JunJun MayMay AprApr MarMar FebFeb JanJan DecDec NovNov OctOct SepSep AugAug 2015 Limited 2014The New Zealand Institute for Plant & Food Research

6 ey measurements Drainage» Volumes» Inorganic N (NO3, NH4)» Phosphorus (DRP, total P) Crop biomass» Dry matter» N and P export Soil fertility» Range of N, P and C measures

7 Measured drainage from Aug 14 Sept 15

8 Measured N losses from Aug 14 Sept 15

9 Measured N losses from Site 5 ~ 25% of drainage ~75% of drainage 72 kg/ha 60 kg/ha 24 kg/ha 11 kg/ha 42 kg/ha 9 kg/ha 3 kg/ha

10 Measured N losses from Site 5 250% wetter than long term average

11 Measured N losses from Site 5

12 Measured N losses from Site kg N/ha

13 Measured N losses from Site kg N/ha 450 mm irrigation

14 Overall synthesis from network to date In Year 1:» Captured drainage ranged from 0 to 611 mm» N losses ranged from 0 to 226 kg N/ha Winter and spring losses dominate» Rainfall is a key driver» In general irrigation is not resulting in significant drainage Need to consider the long term patterns

15 Acknowledgements Grower collaborators Project managers: Diana Mathers (FAR) and Angela Halliday (Horticulture NZ) PFR team: Paul Johnstone, Gina Clemens, Glenn Clark, Peter Wright, Carlo van den Dijssel, Steve Green, Steve Thomas, Sarah Bromley, Nathan Arnold, Paulo Zuccarini, Adrian Hunt, Christina Finlayson, Shane Maley, Mike George.