Nitrate Loss Under Vineyard Soils on the Wairau Plains

Nitrate Loss Under Vineyard Soils on the Wairau Plains

Steve Green, Rob Agnew & Marc Greven Peter Davidson & Rachel Rait

Plant & Food, Palmerston North Plant & Food, Viticulture & Oenology, Blenheim Marlborough District Council, Blenheim

Our Fertilized World If we’re not careful, agriculture could destroy our planet. Here’s how to grow all the food we need with fewer chemicals.

May, 2013

Fertilizer runoff causes toxic algal blooms. This one covered a third of Lake Erie in 2011 The New Zealand Institute for Plant & Food Research Limited

National “Bottom Lines” for Water Quality A National Objectives Framework

The New Zealand Institute for Plant & Food Research Limited

Community engagement to set targets


Plan Change 6 (PC6) for the Tukituki catchment

If the Gimblett Gravels were in this regime, as LUC VII, the leaching limit would be 11.6 kg NO3-N ha-1 y-1

The Land Use Capability (LUC) system for linking land management practices to receiving water quality “... has an inherent logic because it is based on the actual natural capital of the soils which reflects the uses that are likely to be made of the relevant land in the future.” The New Zealand Institute for Plant & Food Research Limited

The Impact of Land Management on Water Resources is via Leaching This is a challenge for Regional Councils! ET

RF

Land management DR

Surface-Groundwater-Surface Connections TRC

Leaching & drainage connects the land management impacts to receiving water bodies. What is the dilution & attenuation? Receiving Water Bodies


Location of site to measure nutrient loss

Wairau River

Wratts Road

Spring Creek

1.2

Nitrate-N (mg/L)

1.0 0.8

0.6 0.4

0.2 0.0 Oct06 Oct07 Oct08 Oct09 Oct10 Oct11 Oct12 Oct13 The New Zealand Institute for Plant & Food Research Limited

Sensors installed to measure drainage

• Sensors were installed in the Motukawa vineyard at Giffords Road • Our presentation provides an update of trial results where we are measuring nitrate loss under vineyard soils on the Wairau Plains. The New Zealand Institute for Plant & Food Research Limited

Drainage flux meters under the vineyard (1.2m) 200 mm

Convergence ring

150 mm

Wick material

50 mm

The drainage flux of water (DW, mm/d) over the time interval (Δt, day), is calculated as:

Air inlet tube

1000 mm

The leaching flux of nutrients (LN, kg/ha/d) is calculated as:

Tipping spoon

Water outlet tube

150 mm


TDR sensors to measure soil water content Rainfall

0.40

80

0.30

60

0.20

40

0.10

20

0.00

0

May Aug

Nov

Feb

May Aug

Soil water content [V/V]

60-90

• Time Domain Reflectometry (TDR) sensors installed from the soil surface to a depth of 1.8 m • Changes in soil water content are measured daily to track the soil water balance

Rainfall [mm/day]

30-60

Nov

Feb

90-120

May Aug

Nov

Feb

May Aug

Rainfall

0.40

80

0.30

60

0.20

40

0.10

20

0.00

0 The New Zealand Institute for Plant & Food Research Limited May Aug Nov Feb May Aug Nov Feb May Aug

Nov

Feb

May Aug

Rainfall [mm/day]

Soil water content [V/V]

0-30

A Soil-Plant-Atmosphere System Model of Water and Nutrient Fate crop (pasture, tree, field crop) FAO-56 approach

Bare soil Grass inter-row

Fine sandy loam Fine sand Coarse gravel The New Zealand Institute for Plant & Food Research Limited

3

Vine water use [mm/d] is scaled to potential ET

Vine water use measured with sap flow sensors (markers)  scaled to potential ET using a ‘crop factor’ approach The New Zealand Institute for Plant & Food Research Limited

Soil water balance for the vineyard 90-120 SWC data

150-180 DR Model Rainfall DR data

500

1000

0.4 400

80 800

0.3 300

60 600

0.2 200

40 400

0.1 100

20 200

0 0.0

00

[mm/day] Rainfall [mm] Drainage

Soil [V/V] content[mm] watercontent Soilwater

0-30 SWC model

Apr Jul Oct Jan Apr Jul Jul Oct Oct Jan Jan Apr Apr Jul Jul Oct Oct Jan Jan Apr Apr Jul Jul

• A simple water balance model to estimate changes in soil water content & drainage losses from the vineyard • This data will be useful in estimating recharge rates and testing models of the land surface & groundwater interactions The New Zealand Institute for Plant & Food Research Limited

Crop growth and nutrient uptake  grapevines leaf DM

shoot DM

bunch DM

1200

Trimming (LAI ~ 1.0)

plant DM [kg/ha]

1000

Leaf fall

800 600

Winter pruning

400

• phenology  GDD • growth  f(Rg, Ta, W, N) • uptake  f(supply & demand)

200

0 Sep Oct Nov Dec Jan

Jul

120.0

120.0

25.0

flowering 100.0

80.0

80.0

Flowering [%]

100.0

60.0 40.0

harvest 20.0

Brix [%]

budburst Bub break [%]

Feb Mar Apr May Jun

60.0

0.0 0

100

200

300

400

500

GDD sum (degree-day)

600

700

10.0

40.0 5.0

20.0

20.0

15.0

0.0 1100

800

1200

1300

1400

1500

1600

0.0 2000

2200

2400



2600

2800

3000


3200

3400

Seasonal pattern of bunch nitrogen 2003/04

2004/05

2005/06

4.0

Bunch nitrogen [%]

F

FS

V

H

3.0

2.0

1.0

0.0 20/Oct

20/Nov

20/Dec

20/Jan

19/Feb

21/Mar

20/Apr

• Bunch nitrogen declines over the season • The nitrogen content plateaus between veraison and harvest The New Zealand Institute for Plant & Food Research Limited

Mineralization of Soil OM Fresh OM CO2

(1-fe)

KL CL NL

Litter

 3 pools - litter, humus, manure  1st order rate constants (K’s) and

fe

KL (1-fh)

fh

fe/ρo (1-fe/ρo)

efficiency factors (fe, fh) and soil C:N  modified by temperature & moisture

Ch Kh

Nh

NH4+

Humus

Mineral-nitrogen is generated by natural soil processes

Mineral N [mg/kg]

150

100

parameterized using lab incubations

50

 sensitive to fraction of CL and the KL

0 0

20

40

60

80

Time [d] The New Zealand Institute for Plant & Food Research Limited

Seasonal pattern of nitrate concentrations selected DFMs

All DFMs

6.0

nitrate-N [mg/L]

200 mm

4.0

Convergence ring

150 mm

Wick material

50 mm

Air inlet tube

2.0

1000 mm Tipping spoon

Water outlet tube

150 mm

0.0 Apr

• •

Jul

Nov Mar

Jul

Nov Mar

Jul

Nov Mar

Jul

DFM devices are capturing water that drains from the vineyard Elevated levels of nitrate are seen at a depth of 1.2 m The New Zealand Institute for Plant & Food Research Limited

Leaching of nitrogen is occurring from vineyards Wratts Road

DFM-data

7.0

Nitrate-N (mg/L)

6.0

Rootzone @ 1.2 m depth

200 mm

5.0 4.0

3.0

Convergence ring

150 mm

Wick material

50 mm

Air inlet tube

Groundwater 2.4 km away

2.0


1.0

Water outlet tube

0.0 Oct06 Oct07 Oct08 Oct09 Oct10 Oct11 Oct12 Oct13

150 mm

• Levels of nitrate in drainage water are greater than in groundwater • Ongoing monitoring will capture different climatic conditions. • Use DFM data to explore the linkage (attenuation and time delay) The New Zealand Institute for Plant & Food Research Limited

Attenuation and delay of nutrients in GW Wratts Road

Model

1.2 200 mm

Nitrate-N (mg/L)

1.0 Convergence ring

150 mm

Wick material

50 mm

0.8 Air inlet tube

0.6 ANZECC Surface Water Guideline

0.4


0.2

Water outlet tube

0.0 Oct06 Oct07 Oct08 Oct09 Oct10 Oct11 Oct12 Oct13

150 mm

• a time delay and attenuation model can be used to estimate the groundwater (GW) concentrations as: • The groundwater lags leaching by 185 days. • And the good news ... the GW concentration is just 10% of that leaching. The New Zealand Institute for Plant & Food Research Limited

Cumulative losses of Nitrate-N 8.0 200 mm

nitrate-N loss [kg/ha]

Wairau aquifer at very low levels 6.0

Convergence ring

150 mm

Wick material

50 mm

Air inlet tube

4.0 1000 mm Tipping spoon

Water outlet tube

2.0

150 mm

0.0 Apr

• • •

Jul

Nov

Mar

Jul

Nov

Mar

Jul

Nov

Mar

Jul

The NO3-N leaching is less than 4 kg/ha/yr. The NH4-N leaching rate is quite small (< 0.5 kg/ha/yr) Negligible loss during past 18 months – GW in decline The New Zealand Institute for Plant & Food Research Limited

Annual leaching is low under viticulture 100.0

6.0

4.0

2.0

0.0 Apr12 Jul12 Oct12 Dec12 Apr13 Jul13 Oct13 Jan14 Apr14

Nitrate-N loss [kg/ha/yr]

nitrate-N loss [kg/ha]

8.0

80.0 60.0 40.0 20.0 0.0

• •

Nitrate loss is very low (3-4 kg/ha/yr ) compared with other land uses Other land uses could be monitored (or modelled) across the Plains


Ground water quality under the plains Well 1156

Well 2651

Well 0015

Nitrate nitrogen [mg/L]

14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0 90

92

93

95

97

99

01

03

05

07

09

11

13

• Current water quality (for nitrate) is very good under the plains • Some ‘hot spots’ in the southern valleys (previous land use and/or dilution/dispersion effects in the aquifer) • More detailed modelling required The New Zealand Institute for Plant & Food Research Limited

Detailed modelling of nitrate losses SPASMO

Wratts Road

Nitrate-N (mg/L)

3.0

1.0 0.8

2.0 0.6 0.4

1.0

0.2 0.0

Nitrate loss [kg/ha/month]

1.2

0.0 02

03

04

05

06

07

08

09

10

11

12

13

14

• A dynamic model (e.g. SPASMO) is being used to explain historical loading of nutrients (1-d at the base of the root-zone) • Scott Wilson (Aqualinc) is coupling our leachate/SPASMO data with MODFLOW/MT3D to explain dilution and dispersion in the groundwater and potential impacts on springs The New Zealand Institute for Plant & Food Research Limited

Summary of the trial •

Trials have been successful at determining nitrate losses and provide a baseline (for viticulture) which covers most of the Wairau Plains

•

Monitoring will continue to capture more diverse range of rainfall.

•

Council has long-term (>20 yr) records from some wells  changes in water quality over time and some hot spots for nitrate..

•

Can explain changes in water quality at Wratts Rd using a simple model

•

Next stage of this project is to develop a dynamic model of land use interactions with groundwater.


Acknowledgement the support of Marlborough District Council  Rachel Rait & Peter Davidson

Further contact: Dr Steve Green, Plant & Food Research, Tennent Drive, Palmerston North, NZ