SPot Farm East Results Irrigation and nitrogen

Mark Stalham & Marc Allison

Trials conducted by NIAB CUF • N * Irrigation (sandy loam, 80 % S, 13 % C)

• N (260 kg) • Standard Split N • All N in seedbed

• Irrigation • Standard (15 mm @ 15 mm SMD) • Frequent (2 x 8 mm rather than 15 mm dose) • Over-water (25 mm @ 15 mm SMD)

• Irrigation start date for processing crops • Standard 15 mm @ 15 mm SMD from TI • Delayed start (1 week after TI)

• Scab control for packing crops (sand, 14 varieties) • Standard 10 mm SMD in bed from TI for 4 weeks, 15 mm

application • Half-frequency 20 mm SMD in bed, 25 mm application

• Sulphur (sponsored by CUPGRA)

N * Irrig: soil moisture deficits

0

1

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10

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50

60

13-May 03-Jun 24-Jun 15-Jul 05-Aug 26-Aug

Dai

ly w

ater

use

(m

m)

SMD

/Irr

igat

ion

/Dra

inag

e (m

m)

Standard Irrigation

SMD

Limiting

Scab

Irrig

Drain

PotETp

ActETp

N * Irrig: soil moisture deficits

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13-May 03-Jun 24-Jun 15-Jul 05-Aug 26-Aug

Dai

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use

(m

m)

SMD

/Irr

igat

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/Dra

inag

e (m

m)

Frequent Irrigation

SMD

Limiting

Scab

Irrig

Drain

PotETp

ActETp

N * Irrig: soil moisture deficits

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13-May 03-Jun 24-Jun 15-Jul 05-Aug 26-Aug

Dai

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use

(m

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SMD

/Irr

igat

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/Dra

inag

e (m

m)

Over Water

SMD

Limiting

Scab

Irrig

Drain

PotETp

ActETp

Irrig timing: soil moisture deficits

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13-May 03-Jun 24-Jun 15-Jul 05-Aug

Dai

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(m

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SMD

/Irr

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/Dra

inag

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Delayed Start

SMD

Limiting

Scab

Irrig

Drain

PotETp

ActETp

Best practice schedule: Rules: 1. Have to irrigate 3 days ahead of limiting SMD trigger to complete field 2. No knowledge of future rainfall 3. Have long-term ET as prediction

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aily

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SMD

/Irr

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SPot East Best Practice Irrigation

SMD

Limiting

Scab

Irrig

Drain

PotETp

ActETp

Comparisons: Standard, Best Practice, Optimised

Irrigation (mm)

Drainage (mm)

Water use (mm)

Efficiency† (%)

Modelled yield (t/ha)

Standard 160 96 258 97.8 65.4

Best Practice 105 41 251 95.3 63.7

Optimised 165 79 259 98.3 65.7

†Efficiency in meeting water requirement of canopy and ET demand

www.niab.com/NIAB_CUF_Irrigation_Scheduling

Agrii Soil Water Sensor Data Standard Over water

Aquaspy Soil Water Sensor Data

30

40

50

60

70

01-Jun 29-Jun 27-Jul 24-Aug 21-Sep

Re

lati

ve w

ate

r co

nte

nt

(%)

Standard

Moisture 10

Moisture 20

Moisture 30

Moisture 40

Moisture 50

Moisture 60

30

40

50

60

70

01-Jun 29-Jun 27-Jul 24-Aug 21-Sep

Re

lati

ve w

ate

r co

nte

nt

(%)

Over-water

Moisture 10

Moisture 20

Moisture 30

Moisture 40

Moisture 50

Moisture 60

Standard irrigation

Standard irrigation practice finished with the soil moisture mostly depleted

Depletion was at 20-60cm by the end of the season

Standard irrigation

Irrigation events only penetrating to ~20cm

Root activity at 60cm. Soil moisture at 30-60cm was depleted at the end of the season.

Rapid soil moisture depletion in top 60cm

Over irrigation

Over irrigation finished with greater soil moisture compared to the standard practice

Moderate depletion in 40-60cm by end of the season. Top 30cm still wet.

Over irrigation

Rapid soil moisture depletion in top 40cm

Irrigation events generally penetrating to 60cm

Drainage events recorded by Theta Probe Over Water recorded rapid wetting at every irrigation. Nothing in Standard except on 1 August but model also showed this.

Wetting across bed

Infiltration across bed after 2 hours: Standard irrigation, 18 mm, 26 July

Infiltration across bed after 2 hours: Over-water irrigation, 27 mm, 1 August

Infiltration: 17 mm 27 mm

N * Irrig: ground covers

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80

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12-May 02-Jun 23-Jun 14-Jul 04-Aug 25-Aug

Gro

un

d c

ove

r (%

)

Std Irrig, Split N Std Irrig, seedbed N

Freq Irrig, Split N Freq Irrig, seedbed N

O-water Irrig, Split N O-water Irrig, seedbed N

Irrig timing: ground covers

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12-May 02-Jun 23-Jun 14-Jul 04-Aug 25-Aug

Gro

un

d c

ove

r (%

)

Standard Delayed-start

N * Irrig: yield (irrigation means) Irrig

N

Stems

(000/ha)

Tubers >10 mm (000/ha)

Tubers <40 mm (000/ha)

Yield >40 mm

(t/ha)

>90 mm length

(%)

DM (%)

DM yield (t/ha)

Std 76 (± 7.0)

405 (± 34.5)

89 (± 19.9)

68.7 (± 4.62)

94 (± 1.4)

22.3 (± 0.41)

15.8 (± 1.29)

Freq 64 (± 5.5)

319 (± 41.6)

37 (± 11.9)

70.8 (± 5.57)

92 (± 3.1)

22.3 (± 0.41)

16.1 (± 1.42)

O-water 76 (± 15.6)

426 (± 102.0)

90 (± 51.5)

67.4 (± 5.52)

91 (± 6.4)

21.5 (± 0.81)

14.5 (± 1.87)

Irrig Timing: yield Irrig

Stems

(000/ha)

Tubers >10 mm (000/ha)

Tubers <40 mm (000/ha)

Yield >40 mm

(t/ha)

>90 mm length

(%)

DM (%)

DM yield (t/ha)

Std 82 (± 9.9)

385 (± 46.3)

67 (± 19.2)

70.9 (± 1.79)

93 (± 3.4)

22.3 (± 1.56)

16.2 (± 1.56)

Delayed start 86 (± 4.2)

397 (± 13.8)

67 (± 5.7)

75.5 (± 2.23)

89 (± 0.4)

22.8 (± 0.86)

17.2 (± 0.77)

N * Irrig: quality (irrigation means)

Irrig

Greens

(%)

Cracks

(%)

Dolls (%)

Brown centre

(%)

Hollow heart

(%)

Fry colour (USDA)

Std 0 (± 1.0)

5 (± 4.5)

3 (± 2.8)

15 (± 4.5)

8 (± 13.3)

n/a

Freq 2 (± 3.2)

3 (± 1.8)

3 (± 4.6)

15 (± 6.3)

5 (± 7.7)

n/a

O-water 0 (± 0.0)

5 (± 2.0)

5 (± 3.5)

18 (± 8.8)

9 (± 10.7)

n/a

Std 0 (± 0.0)

2 (± 1.2)

2 (± 1.2)

13 (± 5.8)

8 (± 14.4)

n/a

Delayed start 0 (± 0.6)

1 (± 0.7)

0 (± 0.0)

17 (± 15.3)

3 (± 5.8)

n/a

N * Irrig: quality: worst dolling/cracking in OW

N * Irrig: quality: worst BC/HH in frequent

Summary

• No effect of irrigation regime (rate or timing) on ground cover development or duration

• No effect of irrigation regime on yield or quality

• Twice frequency irrigation: no effect

• Delayed start: no effect

• Over watering did not advance canopy senescence or increase internal defects or misshapes but did decrease [DM]

Common scab

Maximum SMD (mm) for common scab control in different varietal scheduling groups (AHDB R448)

Group 1. Susceptible 2. Intermediate 3. Resistant

Soil texture

Varieties Maris Piper(1)

Maris Peer (5)

Charlotte (4)

Desiree (4)

Estima (6)

Exquisa

Flair

King Edward (7)

Marabel†

Melody (7)

Nectar (6)

Rooster (6)

Sylvana (7)

Safari† (4)

Venezia

Vivaldi (5)

Bute (4)

Electra (8)

Elfe

Jelly (6)

Lanorma (7)

Orchestra (8)

Perline

Regina

Vales Sovereign (7)

Volare (5)

Sand 9.8 14.6 18.8

Loamy Sand 12.0 17.9 23.1

Sandy Loam 13.4 20.0 25.8

Sandy Silt Loam 14.4 21.5 27.7

Silt Loam 16.3 24.3 31.4

Clay Loam/Clay‡ 14.4 21.5 27.7

Notes: SMD for top 25 cm of ridge and stone-free ridge profile. This can be calculated by water balance (‘model’), directly measured or converted from soil water tension. †Marabel and Safari: tentative. ‡Excessively cloddy soils may need to be maintained at a smaller SMD. Values in () are the rankings for common scab resistance in Potato Council Variety Database. 1 = most susceptible, 9 =fully resistant.

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21-May 11-Jun 02-Jul 23-Jul 13-AugD

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SMD

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Standard 15 mm

SMD

Limiting

Scab

Irrig

Drain

PotETp

ActETp

Packing scab: soil moisture deficits

Packing scab: soil moisture deficits

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SMD

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Half-frequency 25 mm

SMD

Limiting

Scab

Irrig

Drain

PotETp

ActETp

Tuber initiation (TI)

Pathogenic Streptomyces populations Maris Piper

0.0E+00

4.0E+04

8.0E+04

1.2E+05

1.6E+05

0 1 2 3 4 5

Weeks after tuber initiation

txtA

(co

pie

s/g

)

Rainfed

Scheduled

Over-irrigated

Vales Sovereign

0.0E+00

4.0E+04

8.0E+04

1.2E+05

1.6E+05

0 1 2 3 4 5

Weeks after tuber initiation

txtA

(co

pie

s/g

)

Rainfed

Scheduled

Over-irrigated

Packing scab: emergence / TI Emergence TI

(Days) 50 % First to 50 % First to 90 % 50 %

Estima 37 4 6 15

Jelly 38 3 5 19

Juliette 38 4 7 19

Lanorma 39 4 8 15

Leontine 36 5 7 12

Maris Peer 33 4 7 16

Maris Piper 38 3 7 17

Melody 38 2 6 18

Nectar 36 3 5 19

Red Fantasy 40 5 9 22

Rooster 38 3 7 18

Saxon 39 4 7 15

Soraya 38 2 5 18

Vales Sovereign 45 7 27 18

Mean 38 4 8 Most 17 ± 2

Packing demonstration: common and powdery scab

Common scab Greening Cracking Powdery scab

Variety SMD

Incidence

(%)

Packable

(%)

Severity

(% SA)

Incidence

(%)

Incidence

(%)

Incidence

(%)

Cankerous

(%)

Estima 10 100 100 0.55 4 9 64 32

20 100 100 0.62 5 23 4 7

Jelly 10 98 100 0.49 2 0 4 2

20 94 100 0.51 13 0 0 0

Juliette 10 95 100 0.47 16 2 5 2

20 100 100 0.57 7 2 2 0

Lanorma 10 100 100 0.52 5 0 13 4

20 100 100 0.57 13 11 2 0

Leontine 10 100 100 0.60 3 0 5 0

20 100 97 1.37 0 2 0 0

M Peer 10 96 98 0.83 4 0 16 7

20 100 98 1.24 2 4 0 0

M Piper 10 100 100 0.86 0 0 9 7

20 100 91 2.55 0 11 2 0

Melody 10 100 96 1.54 2 2 4 4

20 100 100 0.81 0 3 0 2

Nectar 10 100 100 0.55 4 2 27 13

20 100 98 1.00 2 22 7 0

Red Fantasy 10 100 100 0.54 5 0 21 4

20 100 96 1.31 4 9 4 4

Rooster 10 96 100 0.48 6 6 8 4

20 96 100 0.69 6 4 2 2

Saxon 10 100 100 0.80 2 6 6 4

20 100 100 0.96 11 2 0 9

Soraya 10 100 100 0.75 6 4 22 8

20 100 100 0.82 7 5 4 0

V Sovereign 10 91 100 0.62 2 4 20 4

20 95 100 0.60 0 9 2 2

Maris Piper 10 mm SMD 20 mm SMD

Summary • Maris Piper worse common scab with infrequent

irrigation, slightly worse in Leontine and Red Fantasy

• Melody slightly better common scab with infrequent irrigation

• Powdery scab increased with frequent irrigation

• Cracking increased with frequent irrigation

• Emergence period short except for Vales Sovereign

• Very short emergence-TI in Leontine, long in Red Fantasy

www.niab.com/NIAB_CUF_Irrigation_Scheduling

Nitrogen

Trials conducted by NIAB CUF • N * Irrigation (sandy loam, 80 % S, 13 % C)

• N (260 kg) • Standard Split N

• All N in seedbed

• Irrigation • Standard (15 mm @ 15 mm SMD)

• Frequent (2 x 8 mm rather than 15 mm dose)

• Over-water (25 mm @ 15 mm SMD)

• Sulphur (sponsored by CUPGRA)

N treatments (260 kg/ha total)

• Standard split N • 20 kg N as DAP 24 March

• 80 kg N as Chafer N30+S 24 March

• 80 kg N as Chafer N30+S 10 May

• 80 kg N as Extran 16 June

• 30 kg N considered as a top up due to rain, but not applied

• Seedbed N • 20 kg N as DAP 24 March

• 240 kg N as Chafer N30+S 24 March

N * Irrig: ground covers

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12-May 02-Jun 23-Jun 14-Jul 04-Aug 25-Aug

Gro

un

d c

ove

r (%

)

Std Irrig, Split N Std Irrig, seedbed N

Freq Irrig, Split N Freq Irrig, seedbed N

O-water Irrig, Split N O-water Irrig, seedbed N

N * Irrig: yield (all treatments) Irrig

N

Stems

(000/ha)

Tubers >10 mm (000/ha)

Tubers <40 mm (000/ha)

Yield >40 mm

(t/ha)

>90 mm length

(%)

DM (%)

DM yield (t/ha)

Std Split 76 (± 1.6)

414 (± 23.9)

99 (± 11.4)

66.8 (± 3.46)

93 (± 1.1)

21.8 (± 0.11)

15.0 (± 0.69)

Seedbed 76 (± 12.3)

396 (± 45.1)

79 (± 28.4)

70.6 (± 5.78)

94 (± 1.7)

22.8 (± 0.72)

16.6 (± 1.88)

Freq Split 67 (± 6.9)

352 (± 35.3)

42 (± 9.6)

73.2 (± 10.05)

89 (± 3.7)

22.7 (± 0.49)

16.9 (± 2.40)

Seedbed 61 (± 4.2)

287 (± 47.9)

33 (± 14.2)

68.4 (± 1.08)

95 (± 2.4)

21.9 (± 0.34)

15.2 (± 0.44)

O-water Split 77 (± 18.2)

512 (± 129.0)

136 (± 61.2)

64.7 (± 9.05)

89 (± 9.5)

21.4 (± 1.19)

14.6 (± 2.95)

Seedbed 75 (± 12.9)

340 (± 75.1)

45 (± 41.8)

65.9 (± 1.99)

93 (± 3.2)

21.7 (± 0.44)

14.5 (± 0.79)

N * Irrig: yield (N means) Irrig

N

Stems

(000/ha)

Tubers >10 mm (000/ha)

Tubers <40 mm (000/ha)

Yield >40 mm

(t/ha)

>90 mm length

(%)

DM (%)

DM yield (t/ha)

Split N 73 (± 8.9)

426 (± 62.7)

92 (± 27.4)

68.2 (± 7.52)

90 (± 4.8)

22.0 (± 0.59)

15.5 (± 2.01)

Seedbed 70 (± 9.8)

341 (± 56.0)

52 (± 28.1)

68.3 (± 2.95)

94 (± 2.4)

22.1 (± 0.50)

15.4 (± 1.04)

N * Irrig: quality (Irrig and N means)

Irrig

N

Greens

(%)

Cracks

(%)

Dolls (%)

Brown centre

(%)

Hollow heart

(%)

Fry colour (USDA)

Split N 0 (±0.9)

3 (± 1.6)

3 (± 4.1)

17 (± 4.3)

8 (± 10.3)

n/a

Seedbed 1 (± 2.6)

6 (± 3.3)

4 (± 3.0)

15 (± 8.3)

7 (± 10.9)

n/a

Soil mineral N from soil cores

Soil NO3 sensors (Tony Millar, JIC + Agrii)

50

Water input and drainage SPot Farm East Elveden Standard irrigation and standard N application

-200

-100

0

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300

400

500

600

1 Apr 1 May 31 May 30 Jun 30 Jul 29 Aug 28 Sep

Cu

mu

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ain

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igat

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an

d d

rain

age

(mm

)

Rain

Planting Emergence 55 DAE

273 mm

Rain + Irrigation 433 mm

Drainage below 60 cm

- 96 mm

51

Water input and drainage SPot Farm East Elveden Over-watered and all N in seedbed

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-100

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400

500

600

1 Apr 1 May 31 May 30 Jun 30 Jul 29 Aug 28 Sep

Cu

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age

(mm

)

Planting Emergence 55 DAE

Rain

273 mm

Rain + Irrigation

532 mm

Drainage below 60 cm

- 191 mm

52

0

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40

60

80

100

1 May 1 Jun 2 Jul 2 Aug 2 Sep 3 Oct

Gro

un

d c

ove

r (%

)

Standard Irrigation Standard Split N

Over-watered Irrigation All N in Seedbed

Standard Irrigation standard split N

Over-watered all N in seedbed

Total FW yield (t/ha) 68.9 ± 1.96 67.0 ± 1.38

Effect of N and water application strategy on yield. Russet Burbank, SPot Farm East Elveden 2016

NB Unreplicated strips

53

Effect of rainfall and irrigation strategy on estimates of N leaching at SPot Farm East

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0 20 40 60 80 100 120 140 160 180 200

Nit

roge

n le

ach

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elo

w 6

0m

cm

(kg

N/h

a)

Drainage below 60 cm (mm)

Over watered and 260 kg N/ha in seedbed

Up to 55 days after emergence and assuming no N uptake by the crop, potential leaching losses were c. 53 kg N/ha

Summary

• No effect of nitrogen placement or timing on ground cover development or duration

• No effect of nitrogen regime on yield or quality

• Less soil nitrogen at 50-60 cm at harvest in over watered than in standard irrigation

Sulphur CUPGRA

Sulphur: ground covers

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80

100

12-May 02-Jun 23-Jun 14-Jul 04-Aug 25-Aug

Gro

un

d c

ove

r (%

)

No S

AS

S + AN

Sulphur: petiole sap test 11 August (mg/l)

Treatment S NH4 NO3 P K Mg Mn Mo

No S 136 5.3 56.3 65.9 4868 453 14.7 0.45

AS 251 11.3 72.0 66.0 4879 511 17.8 0.16

AN + S 189 6.8 54.8 59.3 4760 489 17.2 0.20

S.E. (14 D.F.) 20.9 3.42 17.80 2.34 83.9 22.6 1.77 0.132

AS > No S

Sulphur: yield Treatment

Stems

(000/ha)

Tubers >10 mm (000/ha)

Yield >40 mm

(t/ha)

>90 mm length

(%)

DM (%)

DM yield (t/ha)

No S 70 278 68.5 94 21.8 15.0

AS 69 258 62.7 92 21.8 13.7

S + AN 71 269 63.1 94 22.2 14.1

S.E. (14 D.F.) 2.2 9.5 2.00 1.3 0.27 0.56

Sulphur: quality

Irrig

Greens

(%)

Cracks

(%)

Dolls (%)

Brown centre

(%)

Hollow heart

(%)

Fry colour (USDA)

No S 0.7 6.0 6.6 19 1.9 n/a

AS 0.8 5.5 8.9 18 6.9 n/a

S + AN 0.9 8.1 6.7 18 4.4 n/a

S.E. (14 D.F.) 0.41 1.19 1.98 3.5 1.89

Summary

• No effect of S!