SCF00003 - Rotation renewal, profitable legume phase options

Final Report

Project Start Date
6 July 2014
Project End Date
6 July 2015
Supervisor Name
Jeremy Lemon
Organisation
Department of Agriculture and Food WA
Contact name
Jeremy Lemon
Contact phone
08 9892 8413
Region
West
Summary

Intensive cropping across Western Australian (WA) grain areas has led to a decline in cropping diversity with associated problems of declining soil fertility, increasing crop diseases and associated dependence on cropping fungicides and reliance on herbicides as the main weed control strategy. Profitable legume breaks, both crops and pastures, are needed to increase rotation diversity and develop more sustainable farming systems. Newer hard seeded and aerial seeded pasture species offer cheap seed from on-farm harvesting allowing dense sowing rates along with the potential for pastures to regenerate with dense swards after a one to three year sequence of crops.

GRDC’s Albany Regional Cropping Solutions Network (RCSN) identified legumes in crop rotations as a priority subject for the region. Four grower groups expressed interest in cooperating in the project supervised by Jeremy Lemon from the Department of Agriculture and Food WA (DAFWA). Stirlings to Coast Farmers (SCF) is the lead group with Southern DiRT and West Arthur Trials Group (WATG) participating with project staff and project trial sites. Lakes Information and Farming Technology (LIFT) is participating with additional measurements being taken from its ) funded research site. The Nyabing Farm Improvement Group (NFIG) had joined after the project started. It has good management of its MLA site and is interested in valuing legume pastures in crop rotations.

Recommendations

The project should continue as planned to capture the full value of the investment to date. The planned measurements will gather data to evaluate the cropping benefits in this phase of improved legume pastures in cropping systems. All sites are progressing as planned with good grower cooperation and grower group involvement. The agreed variation to the WATG site will meet the priorities of this group, delivering information on the cropping benefits of managing existing pastures for better returns in 2016. The 2015 season started well for most sites and will deliver credible information from the project and associated sites. This will help growers make informed decisions about the role of new pasture legumes and better pasture management in cropping systems.

The economic analysis will by nature provide indicative values for pasture investment and returns. Returns are largely from future benefits achieved when grazing established regenerating swards and weed along with crop disease control which has only limited assessment in this project. Future values will be estimated from interviews with producers who have established improved pasture systems.

Outcomes

Objectives

The purpose of this project was to demonstrate establishment, management and viability of legume phase options in cropping rotations with appropriate agronomic management packages. This was to be achieved by establishing trial sites with four grower groups to demonstrate a range of new pasture species relevant to each group and measure the benefit to subsequent crops. Measurements from the experiments will be used to estimate the economic benefits of the legume break to the rotation including grazing value, reduced inputs including nitrogen (N) fertiliser and changes to crop yields.

Planned outputs:

  1. Field production information and economic analysis of the data to include the value of the grazing and expected crop yield boost of the pasture phases will be produced.
  2. The project team will report information gathered from the project’s trial sites with field day and crop updates presentations (where held, SCF and DiRT) during 2014/15 and 2015/16.
  3. Use rural radio media (grower group staff have a working relationship with ABC through Owen Grieve) and the rural print media, plus the Grower Group Alliance (GGA) website to create awareness of the investigations and the outputs from the project.

A published report of all results and economic analyses (developed with specialist contracted economist) will be produced.

Achievements/Benefits

Methodology

The field work component of this project comprised of five sites. SCF, Southern DiRT and WATG conducted pasture legume trials during 2014, followed by crop in the 2015 season funded by this project. LIFT and NFIG conducted similar trials with pasture legumes followed by 2015 crop largely funded by MLA projects. Additional measurements to those planned in the MLA activity assessed N benefits as part of this GRDC project.

All sites were implemented using grower equipment - four sites were managed by each group’s research and development (R&D) coordinator. The LIFT site was managed by a small group of growers with consultant support.

Five new hard seeded pasture species/varieties were selected that were most appropriate for each site. Three or four control treatments of volunteer pasture and one non legume treatment were included in the design to describe fertiliser N rate responses in the cereal phase in year 2. This will describe the relative benefit of a legume break year and an indication of the crop response in terms of equivalent N fertiliser.

SCF and Southern DiRT sites were fenced for grazing control consistent with best practice grazing management in the establishment year and to obtain dry matter (DM) assessments.

Two replicates of 10 treatments made 20 plots at each RCSN funded site. Seeder width plots up to 15m wide and 200m long were established to allow header and weigh trailer grain yield measurement in the year 2 crop phase. The MLA sites were header width and longer.

Measurements year 1:

Initial soil characterisation by profile to 1m depth with N, phosphorus (P), potassium (K), sulphur (S), organic carbon (OC), and pH analysed by layer.
Pasture establishment was counted.
Two or three pasture cuts measured seasonal growth rates. Pasture composition was estimated visually at each cut.
The September cut near peak biomass measured maximum N accumulation in tops.
Pasture seed production was estimated by quadrat harvesting at two sites.

Measurements year 2:

Pasture germination densities prior to knockdown spraying
Feb/March soil samples measured N mineralisation at a time most growers sample.
May N profiles –estimated total summer/autumn mineralisation of N from legume residues.
Early crop emergence and weed counts were taken.
DM and N uptake at approx. Z30 assessed relative plant N uptake.
Grain yield to be measured together with protein will estimate N content in the grain and total N export.

Discussion

Trial locations

Stirlings to Coast Farmers – Gnowellen (Wellstead) -34.4485 118.5068

Southern DiRT – Kenmare (W Woodanilling) -33.5614 117.1877

West Arthur Trials Group – Darkan -33.3645 116.7286

Lakes Information and Farming Technology – Lake Grace -33.2593 118.4861

Nyabing Farm Improvement Group – Nyabing -33.4243 118.3206

Results by Site

Stirlings to Coast Farmers – Gnowellen (Wellstead)

Project officer: John Blake; host growers Jeff and Kate Stoney

Site 11km WNW from Wellstead. Site is 280m by 400m long

Paddock history; 2013 barley, 2012 canola, 2011 low clover pasture, 2010 barley. Longer term poor pasture alternating with crop.

Soil: gravelly water repellent sand over gravel (30 to 40cm to clay) duplex, flat site in a flat landscape

Soil test samples down full profile taken 14 March and 26 March.

Potassium levels all greater than 50ppm. Main concern is P levels at ppm and pHCaCl at 4.9 to 4.6. Serradella was deemed to be best suited to this site.

2014 details

Pasture sowing date: 25 April 2014. Sowing unit used was a DBS 12m bar.

Fertiliser rate: 80kg/ha TEK Phos. 4:1. (N:P:K:S; 0:7.2:9.9:8.1 and trace elements).

Seed: all pasture seeds were certified seed with germinations greater than 70% and purity greater than 98%. Saia oats were sourced from a neighbouring grower for the grazing oats treatment.

Legume inoculation: As the sowing on 25 April was dry (7mm for the four months prior), Alosca® granules were used at 10kg/ha sown with the legume seed. Only 9mm rain was received in the post Anzac Day rain leading to a partial germination as sub soil had many dry areas. Dry furrow walls led to large furrow row infill.

Table SCF 1: Treatments in the SCF Gnowellen site. All legume plots had appropriate rhizobium strain (S and C) drilled as 10kg/ha Alosca®.

Treatment

Two reps of each treatment randomised

Seed rate

1

Volunteer pasture year 1; nil N yr 2

2

Volunteer pasture year 1; 0.5 N yr 2

3

Volunteer pasture year 1; 1.0 N yr 2

4

Volunteer pasture year 1; 2.0 N yr 2

5

Bladder clover

9kg/ha

6

Saia oats for grazing

60 kg/ha

7

MarguritaPlant Breeders Rights serradella (dehulled seed)

9kg/ha

8

SantoriniPlant Breeders Rights yellow serradella, gland clover mix

6&6kg/ha

9

Santorini yellow serradella

7kg/ha

10

Casbah biserrula

5kg/ha

Herbicides: 25g/ha Broadstrike®# plus 55g/ha of diuron# granules and wetter applied post emergent (12 June) after first emergence of pasture species was beyond 3-leaf stage. Select for grass control (including self sown barley) applied 10 July.

SCF Results

As planned and because of the severe non wetting zones at the south and north ends of plots, the central part of the 400m plots had the most uniform establishment and is the area of all observations and sampling.

Table SCF 2: SCF Gnowellen emergence counts, first DM cuts and whole pod/burr weights.

30 May establishment

1 August Dry Matter

sown
species

vol sub
clover

sown
species

weeds

total
DM

whole
pod/burr

pl/m2

pl/m2

kg/ha

kg/ha

kg/ha

kg/ha

Volunteer pasture year 1; nil N yr 2

0

10

95

775

870

28

Volunteer pasture year 1; 0.5 N yr 2

0

23

50

770

820

20

Volunteer pasture yr 1; 1.0 N yr 2

0

14

100

790

890

25

Volunteer pasture year 1; 2.0 N yr 2

0

19

60

840

900

15

Bladder clover

85

6

405

670

1075

98

Saia oats

134

10

1365

455

1820

0

Margurita serradella

97

12

515

525

1040

648

Santorini serradella, gland clover

285

4

415

595

1010

93

Santorini serradella

116

12

480

460

940

113

Casbah biserrula

223

7

260

1,005

1,265

23

F prob.

<.001

0.106

<.001

0.024

<.001

lsd 5%

36.4

12.1

114.4

284.6

274

Capeweed suppression was achieved with Broadstrike® and diuron. Broadleaf herbicide could not be applied to the biserrula plots and broadleaf weed control was an issue in these plots although grazing 13-17 June did help.

Figure SCF 1 and 2: L, Santorini and gland clover mix; R, Margurita serradella after first broadleaf spray and grazing 14-17 June. Electric fence was installed to manage grazing on the site within the paddock.

Grazing details

13-16 June - Crash grazing over full trial site (364 weaners for three days on 12 hectares) Excluded after observations that sheep were selectively grazing the young pasture plants (not the more advanced capeweed), especially the gland clover.

Biomass cuts taken 4 August 2014 before starting cell grazing. Cuts showed the head start capeweed had in the non wetting soils with a partial start and staggered emergence.

5-21 August - cell grazing - four cells of approx. 3ha each. (North-South divisions across all plots). 363 hoggets for four days in each cell. Heavy grazing reduced capeweed dramatically but also reduced sown species (especially clovers).

1-28 September - Spring grazing of controls and Saia plots only. A total of 10 plots (5.6ha) grazed as four blocks for a week each, a total of 28 days with 363 hoggets making 1,815 grazing days per hectare.

14 October-8 December - Sheep were grazed over the whole paddock including the control and Saia plots at 9.01 sheep/ha making a further 486 grazing days per hectare on the unsown control plots.

Note: The sown pasture plots had very little growth after grazing 5-21 August due to application of sprays and prior grazing to suppress the capeweed together with dry conditions.

Spraying in September after rain with 2,4 bulk density (Db) and diuron aimed to further suppress capeweed. Pasture plots, except Margurita plots 2 and 20, made virtually no further growth and senesced prematurely (Santorini, gland clover and bladder clover). Spray-topping the whole trial on October 15 with paraquat# affected the Santorini more than other species. The trial area along with the paddock (except Margurita plots) had a second paraquat spray on 11 December to control milk thistle and re-shooting ryegrass.

The Margurita plots recovered from the herbicide treatments and continued growing and setting seed until early January. They were not grazed after August to maximise flowering and pod set.

Figure SCF 2: Wellstead DAFWA weather station cumulative rainfall showing poor start until late May and dry mid July to end of August period.

Figure SCF 4 and 5: L - Margurita plot in mid December and R – Margurita pod covering 70% of soil surface.

2015 details

The trial area was grazed in common with a few paddocks over the summer period. 200 head of cattle were grazed over an area of 200ha for 31 days which equates to approx. 300 sheep grazing days per hectare. The trial area is now being cropped along with the rest of the paddock. Calingiri wheat has been sown on 28 May with 100kg/ha of Agflow Cu Zn (14kgN/ha). Post sowing N rates will be applied as Flexi-N to volunteer pasture strips only. The pasture plots will grow without post sowing N to evaluate the N contribution from the pastures.

Soil nitrogen

Soil N 0-10cm was assessed on 7 March and 19 May across all treatments. On 19 May soil profile samples were collected at the same time to assess the likely mineral N available to the early crop. The March results were only significant at the 10% level. This showed mineralised N levels reflecting pasture production from the 2014 season with the volunteer pastures having the lower N and the Margurita serradella which grew to mid January having highest levels. An odd result is that Saia oats had equivalent N to bladder clover, higher than volunteer pastures. The Casbah biserrula was as low as the volunteer pastures. While these can be calculated as equivalent kg/ha of mineral N, the later profile sampling shows mineralisation of legume residues continued (as expected) in the period between 7 March and 19 May. The value of this N to crops will depend on seasonal and soil conditions as losses can occur from leaching, denitrification and poor root growth.

SCF Table 1: 0-10cm nitrate plus ammonium (NH4+) levels sampled on 7 March 2015.

Treatment

mineral N
(mg/kg)

mineral N
kgN/ha

N difference
from volunteer.

Volunteer pasture nil N 2015

20

30

Volunteer pasture 0.5 N 2015

21

32

Volunteer pasture 1.0 N 2015

22

32

Volunteer pasture 2.0 N 2015

24

36

Bladder clover

33

49

16

Saia Oats

30

45

13

Margurita serradella

56

83

51

Santorini serradella & gland clover

43

64

31

Santorini serradella

45

67

34

Casbah biserrula

20

29

-3

F prob.

0.08

lsd 5%

24.5


SCF Figure 1: 0-10cm nitrate plus ammonium (NH4+) levels sampled on 7 March 2015.

Soil profiles were sampled on 19 May 2015 to 60cm depth. Only the graph is presented as the data are too variable to make any conclusions. Poor communication led to only two treatments being sampled well enough for comparison. Cattle grazing and camping led to urine patches which are the likely cause of the extremely high mineral N levels in the Bartolo and Santorini plots. The Margurita treatment, which was expected to have the highest mineral N, had approx. 11kgN/ha more in the surface 10cm and 20kg mineral N/ha more to 60cm depth than the volunteer pasture treatment sampled. The decline in 0-10cm mineral N could be due to leaching of N with heavy opening rain or due to sampling error.

SCF Figure 2: Cumulative mineral N to depth on 19 May 2015. Numbers in brackets are number of reps sampled (*3 is number of cores, others are only one core per plot).

Southern DiRT site - Kenmare, 22km west from Woodanilling

Project officer Kayla Ringrose, host growers Evan Hall and Bindi Murray.

Paddock history: 2013 barley, 2012 wheat, 2011 oats cut for hay. Soil: gritty loam (35cm) duplex, flat site in lower landscape.

2014 details

Sowing date 14 April 2014; dry sown, 100mL/ha chlorpyrifos# and Talstar® insecticides applied to site. No selective herbicides were applied during the early growing season as the grower found it too hard to manage selective herbicides across the species range. Volunteer pasture, oats and vetch plots were spray topped in spring, species expected to set seed were not topped.

Table DiRT 1: plot treatments 2014

Treatment 2014

Sowing rate

Volunteer pasture; nil N in 2015 crop

na

Volunteer pasture; 0.5 N rate 2015

na

Volunteer pasture; 1.0 N rate 2015

na

Kojonup oats

45

Santorini yellow serradella

6

CadizPlant Breeders Rights French serradella

8

Margurita French serradella

6

Bartolo bladder clover

7

UranaPlant Breeders Rights sub-clover

8

RasinaPlant Breeders Rights vetch

52

All legumes inoculated with 10kg/ha Alosca® using appropriate rhizobium groups C, S and F.

Table DiRT 2: Establishment, legume %, DM, grazing removal and spring N concentration in legume species.

Treatment

19/6
establishment
/m2

1/7
%
legume

11/8
%
legume

25/9
%
legume

3/7
DM
kg/ha

14/8
DM
kg/ha

28/7
%
removal

10/9
%
removal

25/9
DM
kg/ha

DM
total
nitrogen
(%)

Bladder

236

16

36

32

179

1031

23

65

3,312

3.73

Cadiz

178

16

34

30

191

934

15

50

2,767

3.46

Kojonup

146

2

4

8

359

909

55

85

1,017

1.26

Margurita

225

16

33

30

178

1081

18

45

3,076

3.24

Rasina

70

28

35

30

228

991

50

85

2,860

4.69

Santorini

127

13

44

33

159

1,119

18

55

3,940

3.37

Urana

130

19

37

31

185

1,091

30

75

2,900

3.74

volunteer

0

3

7

23

218

933

22

30

2,629

1.45*

F prob.

<.001

0.092

0.856

0.014

lsd 5%

11

v

v

v

58

ns

v

v

564

**

v, visual estimates, no analysis. ** bulked species samples from both reps. * capeweed N content

Table DiRT 3: Grazing on the 6ha fenced site.

Date in

Date out

Number

Breed

10/07/14

13/07/14

250 - 300

Merino ewes (12 months)

27/08/14

03/09/14

250 - 300

Merino ewes (12 – 14 months)

This calculates to about 416 to 500 sheep grazing days per hectare. This is a low stock rate but commensurate with the aim of producing a large seed set for harvest or paddock seed bank for regeneration of hard seeded species and leaves residue in paddock for summer grazing.

Figure DiRT 1: Spraytopped Rasina vetch plot between unsprayed Bartolo (left) and Santorini (right) on 20 November 2014.

2015 details

The fenced trial area was grazed for three periods over the summer as detailed in Table 1. This equates to approx. 3,041 grazing days per hectare (8.33 animal equivalents/ha). The trial area is now being cropped along with the rest of the paddock with StingrayA canola and 100kg/ha Agstar extra (14kgN/ha). Post sowing N rates of 0, 21 and 42kgN/ha will be applied as Flexi-N to the planned 2014 volunteer pasture plots only. The 2014 sown pasture plots will grow without post sowing N to estimate the N contribution from the pastures.

DiRT Table 1: Trial area grazing after pasture senescence.

Animals

Date in

Date out

Grazing days

Grazing days/ha

500 Rams

13 Dec

8 Jan

13,000

2,167

1,050 ewes

24 Feb

27 Feb

3,150

525

1,050 ewes

13 Mar

15 Mar

2,100

350

Seed and pod yields

Seed production was measured on plots by collecting the top few centimetres of soil and cleaning seed from the samples. Only selected treatments were sampled due to the amount of work involved in the process. Budworm was not detected in serradella until the end of flowering when nearly all seed was damaged. The vetch seed was also consumed by budworm but as a one year fodder species, seed bank is not a consideration. Volunteer subclover plots had low seed reserves, too low to be considered a viable legume pasture. The Urana and Bartolo had reasonable seed set, amounts that will lead to good regeneration after the 2015 crop.

DiRT Table 2: Legume pasture seed yields from 2014 sown and volunteer pastures.

Treatment

Legume seed kg/ha

Santorini serradella*

546

Volunteer subclover

37

Urana subclover

358

Bartolo bladder clover

210

Cadiz serradella

0

Margurita serradella

0

* serradella seed is estimated as 30% of pod weight.

Soil nitrogen

DiRT Table 3: 0-10cm soil mineral N (nitrate plus ammonium (NH4+)) on 15 March and 13 May 2015

Treatment

March mineral N
(mg/kg)

May mineral N
(mg/kg)

Volunteer pasture 1

12

39

Volunteer pasture 2

6.5

35

Volunteer pasture 3

9

28.5

Kojonup oat

17

45

Santorini serradella

10

33

Cadiz serradella

6.5

31.5

Margurita serradella

12

43

Bartolo bladder clover

8

24

Urana subclover

12

29

Raisina vetch

14

39

F prob.

0.41

0.85

lsd 5%

9.9 (ns)

30.7 (ns)

Profile mineral N was sampled on 13 May. This showed no significant relationship with 2014 pasture treatments.

Soil N in the surface 0-10cm layer was measured on all plots on 15 March and 13 May 2015. The large site and sampling technique led to large variability reflected in Table 3 which shows no significant differences among 2014 treatments. The results do illustrate the continuing mineralisation of organic N over the summer and autumn period with about three times the amount of mineral in the top 10cm of soil over the eight weeks from mid March to mid May. See Figure DiRT 3 which shows sampling dates in relation to patch point rainfall data. Approx. 43mm was recorded on 10 April.

DiRT Table 3: Profile mineral N on selected treatments sampled 13 May 2015.

Treatment

0-10cm
kgN/ha

10-20cm
kgN/ha

20-40cm
kgN/ha

40-60cm
kgN/ha

0-60cm
kgN/ha

Volunteer pasture 2

52.5

8.3

8.3

11.3

80

Rasina vetch

58.5

12.8

10.5

13.5

95

Bladder clover

36.0

6.8

6.8

6.0

56

Kojonup oats

67.5

9.0

9.0

8.3

94

Margurita serradella

64.5

9.0

12.0

10.5

96

F prob

0.531

0.389

lsd 5%

ns

ns

DiRT Figure 1: Cumulative rainfall for nearby rainfall station ‘Horseshoe’, 1 March to 31 May 2015. N sampling dates are marked with red points on the curve. Graph clipped from Australian CliMate.

West Arthur Trials Group site - Darkan

Project officers: Janelle Smith and Michelle Gooding, host growers Neil, Jane and James Campbell, 5km S from Darkan.

Paddock history: 2013 pasture, longer term pasture with no recent cropping history.

Soil: gravelly loam duplex, clay at 30cm. Waterlogging prone moderate slope.

2014 details

Sowing date: 11 June 2014; 1L/ha glyphosate# 450 and 0.35L/ha chlorpyrifos# on 6 June, 0.12L/ha dimethoate# on 2 July

Table WATG 1: WATG Darkan site plant establishment and early DM.

Sown species/ vol subclover

Grass

Weed

Dry matter

4 August

5 August

6 August

28 August

Treatment

plants/m2

plants/m2

plants/m2

kg/ha

Oats 80kg/ha

117

25

1

146

Rasina vetch 60kg/ha

75

65

1

93

Margurita serradella 10kg/ha

29

59

1

72

BlazaPlant Breeders Rights crimson clover 10kg/ha

10

49

3

61

Prima gland clover 10kg/ha

59

91

1

60

Dalkeith subclover 20kg/ha

46

74

1

55

Volunteer pasture

27

218

23

58

Site abandoned - no statistics.

The site was abandoned due to poor establishment, variable distribution of water logging and poor weed control.

Figures WATG 1 and 2: 23 October images at the site showing variable legume survival and dense weeds.

2015 details

A new trial site was established as a follow up site from a small scale demonstration that raised great interest among members in 2014. The trial was set out by Ashton Gray, agronomist with ConsultAg in an existing sub clover pasture paddock at Scott Ewen’s property, 20km north from Darkan. Spray timing was delayed with the 2015 dry and erratic start to the season. The plots are 2.5m wide (width of hand boom) and 20m long, with the eight treatments replicated three times.

Cuts will be taken later in the season, around September depending on spray timings and recovery, to measure DM availability and will also be analysed for pasture quality. Cuts will be analysed with results including DM, crude protein, neutral detergent fibre, digestibility of DM and metabolisable energy. This will test if the removal of some DM with herbicides can actually improve pasture, by increasing the quality of what is available.

In 2016 the site will be cropped over and strips of each treatment will be harvested with a small plot harvester to allow yield or grain quality differences from improved pasture/legume content to be assessed.

Lakes Information and Farming Technology site – Lake Grace

Contact: Grant Marshall, host grower Royce Taylor 18km S from Lake Grace.

Paddock history: 2013 barley.

Soil: rep 1, 7cm sandy loam over clay; rep 3 is loamy sand with some lateritic gravel over clay.

2014 details

Sowing date: fertiliser 50kg/ha CSBP doublephos, all sown species drilled with appropriate Alosca® granular inoculum.

Table LIFT 1: LIFT Lake Grace site treatments, sowing rates and spring assessments.

Treatment

%
legume

%
grass

%
other

DM
kg/ha

legume
DM kg/ha

% N
(Leco) *

kgN/ha
in total DM

1

IzmirPlant Breeders Rights sub 15kg/ha

92

5

3

1,209

1,113

2.40

29

2

Dalkeith sub 10kg/ha

90

10

0

1,619

1,457

1.99

27

3

control/fallow

3

90

7

924

24

1.68

13

4

Margurita 12kg/ha

83

17

0

816

744

3.11

22

5

Bartolo 10kg/ha

70

30

0

490

290

2.59

11

6

Cadiz 10kg/ha

78

23

0

1,033

854

3.04

30

7

fertiliser only 50kg/ha

8

77

15

377

29

1.95

5

8

farmer mix 8kg/ha

67

33

0

726

476

2.77

18

9

AngelPlant Breeders Rights medic 8kg/ha

60

32

8

590

375

2.10

14

10

control/fallow

0

100

0

430

0

1.59

6

11

Casbah biserrula 8kg/ha

93

7

0

1,377

1,258

3.14

43

F prob

<.001

<.001

<.001

<.001

lsd 5%

471

479

0.162

16.4

* reps 1 and 2 analysed - funding constraint from addition of Nyabing Farm Improvement Group site. DM cuts from three reps.

Figure LIFT 1: View to north along rep 1 plots on 16 September 2014. L-R Cadiz, Bartolo and Margurita showing consistent grazing throughout the season. Plots are 270m long, three banked replicates

2015 details

This site has been cropped as planned this season, sown on 27 May with MacePlant Breeders Rights wheat and 60kg/ha Mallee extra compound fertiliser supplying 9kgN/ha. Rates of N will be applied across all plots similar to the Nyabing site. Neither soil sampling nor pasture emergence counts were conducted. This remains a very basic input – output trial.

Nyabing Farm Improvement Group site – Nyabing

Project officer, Fiona Hobley; host growers Braden and Kate Johnston; 21km NE from Nyabing.

Paddock history: 2013 barley, 2012 barley, 2011 canola

Soil: gravel soils (west end) to a partial clay soil type (east end).

2014 details

Sowing date: 13 March dry ‘summer’ sowing, 17 April was the main (dry) sowing of the full range of species. All treatments germinated following 22mm rain on 27 April. Fertiliser was 82% AgStar with 18% MoP at 80kg/ha of the blend. Herbicide: 1kg/ha propyzamide# applied with 0.3L/ha chlorpyrifos and 0.2L/ha Talstar®.

Table NFIG 1: NFIG Nyabing site plant establishment and early DM. Other treatments not presented are summer sown Margurita and Bartolo comparing Alosca and Nodulator legume inoculation systems.

20 Jun
DM kg/ha

23 Sep
DM t/ha

23 Sep
% legume

23 Sep
DM N%

tops
N kg/ha

Bartolo bladder clover

162

4.18

100

2.27

95

ScimitarPlant Breeders Rights medic

183

0.79

36

1.42

11

Casbah biserrula

130

1.62

53

1.78

31

Prima gland clover

185

5.10

100

2.01

103

Eliza French serradella

146

3.69

86

2.53

95

Margurita serradella

208

3.57

94

2.99

108

Dalkeith sub-clover*

223

4.10

100

2.55

105

F prob

<.001

<.001

<.001

<.001

lsd 5%

1.234

21

0.318

32.2

control (nr)

na

2.79

100

2.21

62

(nr) only one plot of control treatment (volunteer pasture), not included in stats. - for comparison only. *Dalkeith treatment analysed with missing plot as only two replicates sown.


Figure NFIG 1: NFIG Field walk with 27 producers in a total of 54 attending. 23 September 2014.

Grazing – 670 hoggets were grazed over the 15ha site for three days. This equates to 135 grazing days per hectare. All species were grazed evenly to about 2cm height.

2015 details

The site was grazed by 520 sheep for a total of six weeks on the entire 100ha paddock over the summer period. This equates to 218 grazing days per hectare or 0.6 sheep per hectare on an annual basis. The site has now been sown with La TrobeA barley and 80kg/ha Agstar (11.4kgN/ha). The site will have cross strips of an additional 30 and 60kgN/ha as Flexi-N approx. four weeks after sowing.

Pre cropping germination

Estimates of pasture legume regeneration were made on 21 April 2015 from one replicate. There were vast differences in establishment in keeping with expectations based on hard seededness and germination patterns in the first season after establishment. Data are not presented here from different sowing times in 2014 which then emerged at the same time following germinating rains together with some treatments with alternative inoculation methods which had no effect on 2014 pasture establishment and production.

NFIG Table 1: Estimated density of regenerating pasture legumes on 21 April 2015.

Species

2014 sown

Population est. plants/m2

Barley with Margurita

April

1

Bartolo bladder clover

April

2

Scimitar medic

April

50

Casbah biserrula

April

5

Prima gland clover

April

1000

Eliza French serradella

April

200

Margurita serradella

April

150

Dalkeith clover

April

100

Soil nitrogen

NFIG Table 2: Amounts of mineral N per layer to 60cm depth on 2014 pasture legume treatments sampled on 20 April 2014. Treatments have three replicates except those noted with number of reps. in parentheses. Layers 10-20, 20-30 and 30-60 were not statistically analysed.

kg mineral N/ha per layer

2014 treatment

0-10cm

10-20cm

20-30cm

30-60cm

0-60cm

Organic Carbon (OC) %

Bartolo bladder clover

47

14

7

20

87

1.63

Control (1)

41

8

5

14

67

1.66

Dalkeith subclover (2)

47

20

6

15

88

1.69

Margurita serradella

60

19

10

23

111

1.82

Margurita undersown in barley (1)

65

5

4

7

80

1.50

Prima gland clover

77

17

10

21

124

1.74

Scimitar medic

40

8

7

17

71

1.54

F prob

0.655

na

na

na

0.223

0.71

lsd 5% min.rep

82.3 ns

na

na

na

78.6 ns

0.67 ns

lsd 5% max-min

67.2 ns

na

na

na

64.1 ns

0.55 ns

lsd 5% max.rep

47.5 ns

na

na

na

45.4

0.39 ns

Soil coring on 13 April sampled to 60cm depth separated into layers. Soil analyses were converted to amounts of mineral N per hectare by adding nitrate and ammonium (NH4+) values and multiplying by a default Db of 1.5. Mineral N results reflect the variability of sampling across large sites. The statistical analysis reflects the unequal replication among treatments along with the variability. The only significant result at 95% confidence is that Prima gland clover which had the highest DM measured in spring 2014 also had the highest mineral N to 60cm depth. The biserrula treatment had the same low level of soil mineral N as the unsown control indicating the lack of nodulation in 2014. As would be expected after one pasture year, OC levels were the same for all treatments sampled.

NFIG Figure 1: Amounts of mineral N per layer to 60cm depth on 2014 pasture legume treatments sampled on 20 April 2015.

Discussion of results (compared with objectives)

Specific sites

The SCF site was on water repellent sand in a patchy 2014 season break leading to low densities and high variability across the site. Weed management was difficult due to staggered germination and low DM which delayed herbicide applications leading to DM and seed set damage on some treatments. Margurita recovered well and continued growing and setting seed until early January 2015. Grazing was successfully managed with temporary electric fencing. Seed sampling has only been collected to pods and burrs without full seed extraction due to the intensity of this procedure. The site was well prepared with multiple herbicide applications for the crop phase in 2015 at a cost to the legume production and seed set with the exception of Margurita serradella.

The Sthn DiRT site was established in a prominent roadside location between Woodanilling and Albany Highway. Establishment was successful in both seasons but weed control was not implemented during the early and mid 2014 growing season. Treatments that would not have seed set compromised were spray topped, i.e. volunteer pasture, oats, vetch, and subclover. Other treatments were not topped and the weed implications will be assessed in the 2015 canola crop. The current intention is to grow Roundup Ready® canola. The serradella treatments were infested by budworm in spring, reducing seed set.

The first intended WATG site was withdrawn by the grower prior to sowing pasture in 2014. A substitute site was selected at short notice on a long term pasture paddock. The site suffered from water logging which stopped most legume growth and nodulation which together with poor weed control has led to the site being abandoned. An alternative activity to evaluate herbicides to prepare existing subclover pasture paddocks for the following crop has been implemented by the group. It better meets the group's priorities of managing existing sub-clover pastures for composition, quality, seed set and N fixing in rotation with crops.

The LIFT MLA site was inspected in September 2014 to assess the value of the site for this project. The site was selected and established well but limited experience with managing research sites in this group led to the site being continuously grazed throughout the season. DM data are limited to one assessment near senescence under moderate grazing pressure and pasture seed set of aerial species was compromised. Some treatments were spraytopped while others were not so as not to reduce the seed set of aerial seeded species. The site has limited value for this project but the project manager has maintained contact with the group offering assistance and interpretation with harvest results.

The Nyabing FIG also has an MLA pasture species site which was well managed and had managed grazing, allowing good DM accumulation and seed set of all species. The Biserrula and Scimitar medic treatments failed to nodulate due to incorrect inoculum (poor advice) but all other species nodulated well. This site is valuable to this project with competent observations and measurements.

Project as a whole

This RCSN project is meeting most of the planned objectives. Some measurements have not been performed as well as possible and a few omitted. The pasture establishment and production phase had mixed success due to soil and seasonal conditions together with difficulties managing several species in adjacent plots by volunteer trial host growers.

The scope and intensity of measurements were ambitious, more than could be expected from grower group staff with limited experience in many aspects of the measurements required. Large plots introduce more variability than smaller sites. Point sampling such as soil profile testing, dry matter and seed harvesting often reflects this variability rather than treatment differences. Whole plot measurements, such as grain harvesting, are more reflective of treatment effects. Point sampling results can support the whole plot result but correlations may not be strong.

Despite these issues, a large amount of data have been collected and will prove valuable to illustrate the management required for introducing new aerial seeded and alternative pasture species. The 2015 grain harvest data will be a vital component of valuing pastures as break phase.

The project is yet to be completed and the main communication output, a publication of measured results in the establishment year, first crop year responses and a longer term economic analysis is still to be produced. Measurements from the establishment year do not reflect the value of regenerating pastures as herbicide inputs can be greater with light grazing required to maximise seed set.

Work to be completed

  • The 2015 grain harvest and analysis of 2015 crop measurements.
  • Legume regeneration at the break in 2016 will complete most of the field work.
  • Discussions have started with suitable consultants to undertake the economic analysis.

A publication aimed at growers and consultants will be produced by the middle of 2016. This will contain the results of the trials, more general recommendations on legume pastures in crop rotation with some grower experiences and a summary of the economic analysis.

Implications

This project is providing a focus on pasture species, inoculation, weed control and overall management together with the crop N benefits and crop responses. This project is a large-plot development and extension project, part of a much broader effort of many industry participants in developing new pasture systems in crop rotations.

In the absence of profitable crop legumes for most soils in the SW of WA, legume pastures offer several benefits to intense and continuous cropping rotations. The farm financial benefits will be better estimated at the completion of this project.

  • Crop yield boost from crop disease break and N fixation.
  • More sustainable weed control through alternative options (Integrated Weed Management).
  • Diversity of income from livestock.
  • Less hectares are sown during peak times when pastures are self regenerating.
Additional information
Acknowledgements

Many people have been involved with this project which would not have been possible without their dedication and persistence.

Grower group staff, John Blake, Kayla Ringrose, Janelle Smith, and Fiona Hobley.

Host growers, Jeff and Kate Stoney, Evan Hall and Bindi Murray, Scott Ewen, Royce and Anna Taylor, Brayden and Kate Johnston.

Published Date
14 November 2017
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