DEVELOPING NITROGEN FERTILISER MANAGEMENT … · DEVELOPING NITROGEN FERTILISER MANAGEMENT...

PJ Neethling, E du Toit, J Labuschagne, P Swanepoel

Overberg Agri Voorplant Inligtingsdag, Rietpoel. 13 March 2018

DEVELOPING NITROGEN FERTILISER MANAGEMENT STRATEGIES FOR

WHEAT AND CANOLA UNDER CONSERVATION AGRICULTURE

PRACTICES IN THE WESTERN CAPE, SOUTH AFRICA

© Western Cape Government 2012 |

Outlay of presentation

Background

Materials and methods

Results and conclusion

General conclusions

Acknowledgements

2


Background

Nitrogen (N) is one of the most limiting plant nutrients (Provin and Hossner, 2001; Zhu et al., 2013)

Supplying enough N to growing crops is one of the most critical factors influencing wheat production

Conservation agriculture (CA) practices will influence the physical, chemical and biological properties of soils (Grahmann et al., 2014)

These changes will influence the amount of available N

It is therefor important to establish optimal and effective N management programmes under CA practices

3


Background

There has been a strong drive towards CA in South Africa,

especially within the Western Cape Province (Basson et

al., 2017).

N fertiliser management needs to be site-specific • Differences in climate and soil characteristics

• Six individual sites were identified within the larger Western Cape area

4

© Western Cape Government 2012 |5

1. Uitkyk, Riversdale

2. Tygerhoek Research Farm

3. Klipfontein, Caledon

4. Langgewens Research Farm

5. Nuhoop, Porterville

6. Klipklei, Darling

South Africa

5


Rainfall : Riversdale and Tygerhoek

6

0

20

40

60

80

100

120

Apr May Jun Jul Aug Sep

Ra

infa

ll (

mm

)

Month

Riversdale 2016

2016

Long-term

0

20

40

60

80

100

120

Apr May Jun Jul Aug Sep Oct

Ra

infa

ll (

mm

)

Month

Riversdale 2017

2017

Longterm

0

20

40

60

80

100

120

Apr May Jun Jul Aug Sep Okt

Ra

infa

ll (

mm

)

Month

Tygerhoek 2016

2016

Longterm

0

20

40

60

80

100

120

May Jun Jul Aug Sep Oct

Ra

infa

ll (

mm

)

Month

Tygerhoek 2017

2017

Longterm


Materials and MethodsStudy 1 (N rates + Foliar)

7

N input at plant

(kg N ha-1)

N topdress treatment

(Whole plot)Topdress N rate (kg N ha-1)

Foliar N application

(split plot)

Total N input

(kg N ha-1)

0 C (control) 0-Foliar 0

+Foliar 10 (yr 1) & 20 (yr 2)

25 T0 0-Foliar 25

35 (yr 1) & 45 (yr 2)+Foliar

25 T1 25-Foliar 50

60 (yr 1) & 70 (yr 2)+Foliar

25 T2 50-Foliar 75

85 (yr 1) & 95 (yr 2)+Foliar

25 T3 75-Foliar 100

110 (yr 1) & 120 (yr 2)+Foliar

25 T4 105-Foliar 130

140 (yr 1) & 150 (yr 2)+Foliar

25 T5 135-Foliar 160

170 (yr 1) & 180 (yr 2)+Foliar

25 T6 165-Foliar 190

200 (yr 1) & 210 (yr 2)+Foliar


Materials and Methods

8

Experimental design– Two separate studies;

First study: • a) Topdressed Nitrogen (N) rates’ effect on crop yield• b) Late-season foliar N applications’ (UAN) effect on grain protein content.

Second: • The effect of different N sources at topdress on crop yield and protein.

– The first study was laid out in a split-plot design:

-Seven N topdressing rate treatments plus a control (whole factor).

-Half of the whole plots received foliar UAN (sub-plot factor).

-Whole plot sizes were 12.6 x 2.1 m and sub-plot sizes 6.3 x 2.1 m.

-Replicated in four blocks.

– The second study was laid out in a randomized block design:

-Five N source treatments (Urea, Urea + I, AMS, LAN, LAN + S).

-Plot sizes were 9 x 2.1 m.

-Replicated in four blocks.

Kysan All N UREA+I All NB21B10 B15B9 UREA All N

B22B16Kysan All NB3 B4

Sp

uit

stro

ok

Sp

uit

stro

ok

AMS UREA+IB14

Sp

uit

stro

ok

UREA AMSB11B8 Kysan

B20B5 LAN

Sp

uit

stro

ok

B23B17AMS UREAB2

Sp

uit

stro

ok

Sp

uit

stro

ok

UREAB13B7

Sp

uit

stro

ok

LANKysanB12LAN AMSLAN

B19B6 UREA+IUREA+I

Sp

uit

stro

ok

B24B18B1

Sp

uit

stro

ok

21 28

Sp

uit

stro

ok

T3 + F1 C + F1 T2 + F1

T3 + F2

T3 + F1

Sp

uit

stro

ok

T4 + F2

C + F1

C + F2

T4 + F1T2 + F1

T2 + F2 T1 + F2C + F2

T1 + F1

T2 + F2T3 + F2

Sp

uit

stro

ok

13 204 5 12 29S

pu

itst

roo

k

22 27

Sp

uit

stro

ok

T6 + F1

T6 + F2T0 + F2

T0 + F1

T0 + F2 T4 + F2

Sp

uit

stro

ok

T5 + F1

T5 + F2 T1 + F2

T1 + F1T4 + F1

T4 + F2

T0 + F1 T4 + F1

T5 + F2

T5 + F1

Sp

uit

stro

ok

14 19113 6 30

Sp

uit

stro

ok

2310 26

T3 + F1

Sp

uit

stro

ok

T6 + F2

T6 + F1

Sp

uit

stro

ok

T1 + F2

15T3 + F2 T2 + F2

T2 + F1 T3 + F1

T3 + F2 T6 + F2

T6 + F1T5 + F1

T5 + F2 Sp

uit

stro

ok

18T0 + F2

T0 + F1T1 + F12 7 31

REP 1 REP 2 REP 3 REP 4

Sp

uit

stro

ok

249T2 + F1

T2 + F2

Sp

uit

stro

ok

Sp

uit

stro

ok

T1 + F2 T0 + F2

25C + F2T4 + F2

Sp

uit

stro

ok

32171 8

T6 + F2

T6 + F116

C + F1T1 + F1 T0 + F1T4 + F1

T5 + F2

T5 + F1

C + F2

C + F1


Materials and Methods

9

Cropping rotations

• Wheat after canola (All sites except Caledon)

• Wheat after lucerne (Caledon)

Planting method

– Discplanter

– Row spacing 175 mm

– Standard N rate of 25 kg N ha-1 at plant

– 5 kg N ha-1 with seed, 20 kg N ha-1 broadcasted

Fertiliser management

– Top-dress at 4-5 leaf stage at maximum N uptake (±40 days after planting)

– Foliar UAN application at beginning of ear emergence


Materials and MethodsStudy 2 (N sources)

Fertiliser sourceN and S elemental

composition

Limestone ammoinium nitrate (LAN) 28% N

Ammonium Sulphate (AMS) 21% N; 24% S

Kysan (LAN + S) 24% N; 3% S

Urea 46% N

Urea + urease inhibitor 46% N

SiteTopdress N rate (kg N ha-1)

Year 1 Year 2

Riversdale wheat after canola 30 30

Tygerhoek wheat after canola 55 55

Caledon wheat after lucerne 5 10

Langgewens wheat after medics 48 48

Langgewens wheat after canola 75 75

Porterville wheat after medics 35 35

Porterville wheat after canola 63 63

Darling wheat after medics 35 35

Darling wheat after canola 65 65


Results : Average yields for 2016 & 2017

11

4076 3950

3516

4759

33683545

2659

2039 1927

1341

33533085

2471

2005

1305

594

946734

0

1000

2000

3000

4000

5000

Yie

ld k

g h

a-1

Yield 2016

Yield 2017


Results

Study 1

Topdressed N rates


Results : Riversdale wheat after canola

13

1417 3639 4082 4359 4752 4624 4890 4849

d

c

bcabc

ab aa a

0

1000

2000

3000

4000

5000

6000

C 0 25 50 75 105 135 165

Yie

ld (

kg

ha

-1)

Topdress N rate (kg ha-1)

Yield 2016

LSD: 671.8

P < 0.05

CV: 8.1%

1175 1298 1517 1454 1561 1200 1262 1314

c

abc

ababc

a

cbc

abc

0

200

400

600

800

1000

1200

1400

1600

1800

2000

C 0 25 50 75 105 135 165

Yie

ld (

kg

ha

-1)


Yield 2017

LSD: 260.9

P < 0.05

CV %: 10.2


Results : Tygerhoek wheat after canola

14

2462 3729 3840 4211 4458 4243 4524 4132

b

a a

aa

a

a

a

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

C 0 25 50 75 105 135 165

Yie

ld (

kg

ha

-1)


Yield 2016

LSD: 877.0

P < 0.05

CV%: 15.1

3126 3382 3318 3324 3540 3111 3498 3527

aa a a

a

a

a a

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

C 0 25 50 75 105 135 165

Yie

ld (

kg

ha

-1)


Yield 2017

LSD: 458.4

P < 0.05

CV%: 9.0


Results : Caledon wheat after lucerne

15

3377 3778 3532 3819 3342 3206 3523 3555

a

aa

a

aa

a a

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

C 0 25 50 75 105 135 165

Yie

ld (

kg

ha

-1)


Yield 2016

LSD: 855.5

P < 0.05

CV %: 16.5

3005 3284 3092 3119 3245 2961 3046 2929

a

aa a

a

a aa

0

500

1000

1500

2000

2500

3000

3500

4000

4500

C 0 25 50 75 105 135 165

Yie

ld (

kg

ha

-1)


Yield 2017

LSD: 457.6

P < 0.05

CV %: 10.1


Results

16

Total N rates (kg N ha-1), where no further increase (P > 0.05) in yield was recorded

with increasing N rates, vs the recommended N rates (kg N ha-1) for wheat

production at each specific site.

Site

Year 1 Year 2

Total N appliedTotal N

recommendedTotal N applied

Total N

recommended

Riversdale wheat after

canola50 55 25 55

Tygerhoek wheat after

canola25 80 0 78

Caledon wheat after

lucerne0 30 0 35


Conclusion

17

Increasing topdress N rates had a less profound effect on crop yields than expected

Due to the potential influence of CA, fertiliser N recommendations might have to be adjusted


Results

Study 1

Late-season foliar UAN application


Results : Riversdale wheat after canola

hi i

fgh fg

ef

debcd

ab

i

ghi

fgef

cd

bcab

a

7

8

9

10

11

12

13

14

C 0 25 50 75 105 135 165

Pro

tien

co

nte

nt

(%)

Topdress N rate (kg ha⁻¹)

2016

Protein

Protein + foliar

LSD: 0.8

CV %: 3.7

g

ef

edc bcde

bcdabc abc

ab

f

cdef

def

bcde

abcab

a a

8

9

10

11

12

13

14

15

16

17

C 0 25 50 75 105 135 165

Pro

tein

co

nte

nt

(%)

Top-dress N rate (kg ha⁻¹)

2017

Protein

Protein + foliar

LSD: 1.4

CV %: 6.2



h h

fgef efg

decd deg

defde

aab ab bc

ab

7

8

9

10

11

12

13

14

C 0 25 50 75 105 135 165

Pro

tein

co

nte

nt

(%)


2016

Protein

Protein + foliar

LSD: 0.5

CV %: 3.0

f

e e

de

bcd

ab aba

de dee

de

bcdab ab

a

8

9

10

11

12

13

14

15

C 0 25 50 75 105 135 165

Yie

ld (

kg

ha⁻¹

)


2017

Protein

Protein + foliar

LSD: 1.0

CV %: 5.5


Results : Caledon wheat after lucerne

ghh

efg cde cde cde

aba

def

fgh

cdebc bcd bc ab

abc

10

11

11

12

12

13

13

14

14

15

15

C 0 25 50 75 105 135 165

Pro

tein

co

nte

nt

(%)


2016

Protein

Protein + foliar

LSD: 0.6

CV %: 3.3

cdefabcde

eff

cdef

abcd abcdebcdef

def

abcd abc

cdef

abcdab a

abcd

10

11

12

13

14

15

16

17

C 0 25 50 75 105 135 165

Pro

tein

co

nte

nt

(%)


2017

Protein

LSD: 1.2

CV %: 5.7


Conclusion Study 1

a) Topdressed N rates: • Increasing topdress N rates had a less profound effect on

crop yields than expected

• Due to the potential influence of CA, fertiliser N

recommendations might have to be adjusted

b) Late-season foliar UAN application• UAN consistenly increased protein content at two

(Tygerhoek, Langgewens M/W) of the nine sites during

Year 1.

• At the other seven sites in Year 1 and all of the sites in

Year 2, UAN failed to consistently increase protein

contents.

• These results indicate that the application of foliar UAN as

a tool to increase grain protein content of wheat might

not be feasible (not conclusive).


Results

Study 2

N sources



4002 4273 4202 4152 3919

aa a a

a

0

1000

2000

3000

4000

5000

Urea Urea + I AMS LAN Kysan

Yie

ld (

kg

ha

-1)

N source

2016

LSD: 521.5

CV %: 8.2

LAN + S

3240 3154 3303 3164 3147

a aa

a a

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Urea Urea + I AMS LAN LAN + S

Yie

ld (

kg

ha

-1)

N source

2017

LSD: 323.1

CV %: 6.6


4675 4808 4331 4663 4859

ab ab

aba

Urea Urea + I AMS LAN Kysan

Riversdale C/W

LAN + S

3949 3941 4175 3929 3695

a aa

aa


Caledon L/W

Other 2016 results

Study 2


1430 1251 1591 1539 1372

abc

c

a ab

bc


Riversdale C/W

3217 3206 3332 3126 3346

a a aa

a


Caledon L/W

Other 2017 results

Study 2


Conclusion Study 2

Different N sources had no profound effect on yield.

This might indicate that the optimal N source for wheat

production might be the cheapest and most accessible

one.


General conclusion wheat

Fertiliser N recommendations might have to be adjusted.

The recommended rates of N to produce wheat lead to over-fertilisation in some areas, which may, in turn, lead to environmental pollution and can lead to economic losses.

Foliar N application at post-anthesis had limited success in increasing grain protein content of wheat.

Determining the optimal N source might entail choosing the most cost-effective and accessible source.

E du Toit, J Labuschagne, P Swanepoel

African Combined Congress Cape Town 18 January 2018

Canola N trial

© Western Cape Government 2012 | 30

Results

Study 1

a) Soil mineral N content

b) Topdressed N rates yield

c) Foliar N application at stem elongation yield


Riversdale: Soil mineral N content 2016

31

a c ab

abc

abc

abc

bc

abc

a

aa

aa a

a

a

dcd

cdcd

bcd

bcab

a

bab ab

aab ab ab ab

0

20

40

60

80

100

120C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N

Pre-plant Pre-topdress Post-topdress Post-harvest

So

il m

inera

l N

co

nte

nt

(mg

kg

-1)

Sampling time

LSD = 1.72

CV = 4.51

LSD = 18.95

CV = 26.6

LSD = 33.43

CV = 30.28

LSD = 5.89

CV = 24.82


Riversdale: Soil mineral N content 2017

32

26 2

9

19

a

aa a

a

aa a

cd b

cd abcd

d

abcd a

b

a

abc

abcc c

ab

bc bcabc

a

0

20

40

60

80

100

120R

ep 1

Re

p 2

Re

p 3 C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N


So

il m

inera

l N

co

nte

nt

(mg

kg

-1)

Sampling time

LSD = 14.12

CV = 20.46

LSD = 18.56

CV = 30.84

LSD = 11.06

CV = 37.98


Tygerhoek: Soil mineral N content 2016

33

a a a a

a aa a b

a

ab

b

ab ab

ab

a

c

c

c

c c

bc

ab

a

a

a a a aa a a

0

20

40

60

80

100

120C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N


So

il im

era

l N

co

nte

nt

(mg

kg

-1)

Sampling time

LSD = 10.27

CV = 16.29

LSD = 15.93

CV = 19.25

LSD = 26.32

CV = 22.66

LSD = 10.2

CV = 40.65


Tygerhoek: Soil mineral N content 2017

34

34

32

24

29 a

a a a aa

aa

ab

c

abcbc

ab abc

a a

b b ab abb

aab

ab

0

20

40

60

80

100

120R

ep 1

Re

p 2

Re

p 3

Re

p 4 C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N C

0 N

25

N

50

N

75

N

10

5 N

13

5 N

16

5 N


So

il m

inera

l N

co

nte

nt

(mg

kg

-1)

Sampling time

LSD = 13.15

CV = 25.81

LSD = 14.17

CV = 34.45

LSD = 7.18

CV = 24.42


Riversdale yield 2016 and 2017

35

d d

abc

c

abbc

a ab

0

500

1000

1500

2000

2500

C 0 25 50 75 105 135 165

Yie

ld (

kg h

a-1)


Riversdale 2016

b

abab

a

ab ab ab

bA

A AA A A A A

0

500

1000

1500

2000

2500

C 0 25 50 75 105 135 165

Yie

ld (

kg h

a-1)


Riversdale 2017

yield

yield+f


Tygerhoek yield 2016 and 2017

36

c

b ab ab aba

bab

0

500

1000

1500

2000

2500

3000

C 0 25 50 75 105 135 165

Yie

ld k

g h

a-1)

Topdress N (kg ha-1)

Tygerhoek 2016

b ab abab ab

b

aab

A

AA A

AA

A A

0

500

1000

1500

2000

2500

3000

c 0 25 50 75 105 135 165

Yie

ld (

kg h

a-1)


Tygerhoek 2017

yield

yield+F


Riversdale: Relative Yield

37

0

10

20

30

40

50

60

70

80

90

100

110

C 0 25 50 75 105 135 165

Re

lativ y

ield

(%

)

Topdresed N rate (kg N ha-1)


Tygerhoek: Relative Yield

0

20

40

60

80

100

120

c 0 25 50 75 105 135 165

Re

lative

yie

ld (

%)

Top dress N rate (kg N ha-1)


ResultsStudy 2

a) N sources yield


N source yield: Tygerhoek and Riversdale 2017

40

a a

a

a

a

0

500

1000

1500

2000

2500

3000

UREA UREA+I AMS LAN KYSAN

Yie

ld (

kg

ha

-1)

N Source

Tygerhoek LSD = 539.02

CV = 14.28

ab ab ab b

a

0

500

1000

1500

2000

UREA UREA+I AMS LAN KYSAN

Yie

ld (

kg

ha

-1)

N source

Riversdale LSD = 477.37

CV = 18.33


Conclusion (Canola)

41

Low soil N response to N fertiliser in dry year (2017)

Low yield response to N fertiliser in dry year (2017)

Adapt N fertilser rate to climate (dry season)

Final topdress N rate recommendations will be formulated after 4 years of data capturing

No significant increase in yield for additional Foliar N topdressing

Similar yield results between N sources at optimal rates


Acknowledgements

42

The following people are responsible for helping to make this project a success:

– Students (PJ Neethling and E du Toit) and study leaders (Dr. Labuschagne and Dr. Swanepoel)

– Western Cape Department of Agriculture’s technical staff

Funding

– Winter Cereal Trust and Sasol Agricultural Trusts for funding the studies and WCT for study bursary (PJ Neethling)

–PNS for partial contribution to study bursary (E du Toit)

– Western Cape Department of Agriculture

– Western Cape Agricultural Research Trust

Thank you

Tel: Fax:

www.elsenburg.com

Contact Us

Dr Johan Labuschagne

Plant Science

+27 (0)21 808 5209 +27 (0)21 808 5331

[email protected]

DEVELOPING NITROGEN FERTILISER MANAGEMENT … · DEVELOPING NITROGEN FERTILISER MANAGEMENT...

Documents

Transcript of DEVELOPING NITROGEN FERTILISER MANAGEMENT … · DEVELOPING NITROGEN FERTILISER MANAGEMENT...