Title	Wide row cropping options CT and guidance
Description	Research Update for Advisers - Southern Region - February 2004
Authors	Dr Matt McCallum GPS-Ag and Ag. Consulting Co Ph 08 8837 3993 matthew@agconsulting.com.au Bill Long Stephen Wentworth and Sam Holmes Ag. Consulting Co. John Clinton and Derek Tiller Pinery SA
Presented	Adelaide SA

Controlled traffic in SA

The last three years have seen a rapid adoption across the cropping regions of SA of various forms of controlled traffic (CT).

These include

• Up and back sowing of crops with marker arms permanent wheel tracks and GPS guidance (autosteer)
• Up and back spraying of crops with permanent wheel tracks and GPS guidance (lightbar and/or screen).

Typically farmers adopting CT in SA are finding the following immediate benefits

• Improvements in efficiency e.g. night time operations filling airseeders and spray rigs at one end of the paddock etc.
• A reduction in fuel fertiliser and chemical costs of 5-10%
• Less fatigue.

CT has also enabled the evolution of new sowing systems e.g. wide row pulse crops. As expected longer term benefits such as reduced compaction are yet to be determined in SA. SAGITF are funding YP Alkaline Soils Group to both demonstrate the benefits and new opportunities that CT systems offer and investigate solutions to problems that new adopters face with CT.

Wheel tracks or weed tracks?

Weeds generally thrive in the absence of crop competition and weeds in wheel tracks are the single biggest barrier to future adoption of CT where permanent tracks are used. Two options of weed control in wheel tracks are being investigated. Fuzzy wheel tracks provide a cultural method for weed control in these zones through plant competition.

A seed delivery hose is positioned so as to broadcast seed on the soil surface of wheel tracks during seeding. Whilst germination and vigour may be poor competition can sufficiently suppress weeds. Applying residual herbicides in wheel tracks is another possible control method (Table 1 Ardrossan 2003).

This may be done at sowing with a spray tank mounted on the seeding rig or during the season with a simple 3-point linkage spray unit. Shielded sprayers can be used to eliminate drift onto crop rows.

Table 1 Percentage reduction in ryegrass numbers in comparison of the control (780 plants/m²). Costs based on spraying the wheel tracks only lsd(0.05) =19%.

	132DAS	Cost/ha
Control	0%	-
Kerb�� 1600ml/ha	97%	$12.54
Simazine 2220g/ha	88%	$2.33
Glean�� 100g/ha	84%	$0.88
Glean�� 50g/ha	81%	$0.44
Kerb�� 800ml/ha	73%	$6.27
Simazine 1110g/ha	73%	$1.17
Dual Gold�� 2000ml/ha	70%	$6.16
Goal�� 1000ml/ha	62%	$1.85
Dual Gold�� 2000ml/ha + Diurex�� 555g/ha	59%	$6.88
Dual Gold�� 1000ml/ha	57%	$3.08
Goal�� 500ml/ha	50%	$0.93

Key results and observations

• Fuzzy wheel tracks remained highly visible during the season so guidance was not compromised
• Populations of ryegrass and brome grass were effectively eliminated in fuzzy wheel tracks in a dry year (Ardrossan 2002) BUT control was not adequate in a wet year (Ardrossan 2003)
• Kerb® Simazine and Glean® were the most successful herbicide options. Of these Glean® was the most cost-effective although plant-back and leaching are obvious issues.

Nightspraying

The use of guidance (GPS wheel tracks) provides opportunities to spray at night. A range of herbicides has been tested over the last two years to find out whether their efficacy is reduced when sprayed at night compared to day.

Key results and observations

• Group A (Targa® Select®) OK at night except Targa® had reduced efficacy once under frost conditions at night at Ardossan in 2002
  
  
• Group B (Midas® OnDuty® Ally® Hussar® Oust® Atlantis®) OK at night except a sub-lethal rate of Ally® (2g) failed on Indian hedge mustard at night at Ardrossan in 2002 and Midas® had reduced efficacy under frost conditions at night at Ardossan in 2002
  
  
• Group C (Lexone®) OK at night although symptoms of herbicide action may be delayed
  
  
• Group G (Goal® Affinity®) Bit of a mystery? Not recommended at night due to reduced efficacy in some cases under good spraying conditions.
  
  
• Group F (Sniper® Brodal®) OK at night
  
  
• Group I (24-D amine) OK at night
  
  
• Group L (Sprayseed®) OK at night although symptoms of herbicide action may be delayed
  
  
• Group M (Roundup Max®) OK at night although symptoms of herbicide action may be delayed

Wide row cropping

Wide row spacing (0.5 to 1.0 m) of broadleaf crops is an exciting new development for broadacre farmers. Research has shown a 17% yield increase in lupins over two seasons in WA and adoption of wide row cropping is on the rise (WANTFA). The system can potentially increase yields and reduce costs by;

• Reducing disease due to less humidity in the crop canopy
• Reducing fungicide costs because of less disease and more effective application of product with banded spraying ie hitting the plant from three sides
• Eliminating the need to delay sowing because of disease potential therefore increasing water use efficiency
• Improve harvestability of crops by increasing pod height
• Inter-row weed control with non-selective herbicide
• Improved fertiliser uptake with banded placement

With lupins being a relatively minor crop in SA most of the interest is in chickpeas and faba beans. Ag Consulting Co. in conjunction with GRDC SAGITF and YP Alkaline Soils Group are conducting a three year research project into wide row cropping. Issues regarding optimum row spacing fungicides and disease water use and yields are being investigated. A range of sowing configurations (0 0.5 0.75 and 1 m) for faba bean and chickpea was investigated at Minlaton in 2002 and 2003 and at Sandilands in 2003 (Table 2).

Table 2. Wide row cropping yields and height to 1st pod (faba beans)

Faba beans	Minlaton 2002		Minlaton 2003		Sandilands 2003
Treatment	Pod ht (cm)	Yield (t/ha)	Pod ht (cm)	Yield (t/ha)	Pod ht (cm)	Yield (t/ha)
Conventional	7.4	1.2	14.0	2.7	17.8	2.8
0.5 m rows	11.6	1.0	17.9	2.2	18.3	2.5
0.5 m paired rows	12.2	1.1	16.8	2.5	23.6	2.5
0.5 m rows - 34%*	10.3	1.1	-	-	-	-
0.75 m rows	-	-	16.4	2.5	23.3	2.4
1 m rows	17.3	0.7	23.9	2.5	26.7	2.4
1 m paired rows	15.0	0.9	21.0	2.5	26.5	2.2
1 m rows - 50%*	-	-			16.7	2.4
lsd (0.05)	3.2	0.2	2.7	0.3	1.8	0.3
* reduction in sowing rate

Chickpeas	Minlaton 2002		Minlaton 2003		Sandilands 2003
Treatment	Yield (t/ha)		Yield (t/ha)		Yield (t/ha)
Conventional	0.9		1.8		2.3
0.5 m rows	0.5		1.5		2.1
0.5 m paired rows	0.7		1.5		2.0
0.5 m rows - 34%*	0.7		-		-
0.75 m rows	-		1.4		2.0
1 m rows	0.3		1.3		1.8
1 m paired rows	0.4		1.4		1.9
1 m rows - 50%*	-		-		1.6
lsd (0.05)	0.1		0.2		0.2

Cost savings in chemical can be achieved with wide row cropping shielded spraying and band spraying (Tables 3 and 4).

Table 3. Example of grass control in a broadleaf crop for conventional and wide rows

Chemical/System	Rate/ha	Area sprayed	Cost (ex.gst)
Conventional
Select��	250 ml	1 ha	$26.15
Wide rows (1 m)
Select��	250 ml	0.33 ha	$8.63
Roundup CT��	1 L	0.67 ha	$3.86
		Total	$12.49
Wide rows (1 m)
Select��	250 ml	0.33 ha	$8.63
Roundup CT��*	1 L	0.67 ha	$3.86
Sprayseed��*	1 L	0.67 ha	$6.00
		Total	$18.49
*interows may need to be sprayed twice

Table 4. Example of ascochyta control in a chickpea crop for conventional and wide rows

Spray	Chemical	Wide row (1 m)		Conventional
		Area sprayed	Cost	Area sprayed	Cost
1	Bravo�� 1 L/ha	0.33 ha	$6.73	1 ha	$20.19
2	Bravo�� 1 L/ha	0.33 ha	$6.73	1 ha	$20.19
3	Bravo�� 1 L/ha	0.33 ha	$6.73	1 ha	$20.19
4	Bravo�� 1 L/ha	0.67 ha	$13.46	1 ha	$20.19
5	Bravo�� 1 L/ha	0.67 ha	$13.46	1 ha	$20.19
6	Bravo�� 1 L/ha	1 ha*	$20.19	1 ha	$20.19
		Total	$67.30	Total	$121.14

* blanket spray may need more than one toward the end of the season

Key results and observations

• In faba bean yield penalties for wide row crops averaged 0.3 t/ha ($81/ha@$270/t) across all treatments/sites/years (varied 0 to 0.6 t/ha)
  
  
• Wide rows generally increased pod height for faba bean by 3 to 10 cm which may improve harvestability. However this may not be the case when seeding rate is reduced in wide rows
  
  
• No significant levels of disease (botrytis and ascochyta) were present in 2002 and 2003
  
  
• Lodging of faba beans may be more of a problem in wide rows.
  
  
• In chickpeas yield penalties for wide row crops averaged 0.4 t/ha ($148/ha@$370/t) across all treatments/sites/years (varied 0.2 to 0.7 t/ha)
  
  
• Cost savings in chemical use of up to $70/ha can be achieved with wide row cropping shielded spraying and band spraying
  
  
• Unlike lupins in WA wide row faba bean and chickpea crops in SA are not producing yield improvements. However wide row cropping is likely to be more profitable than oaten hay pasture or brown manuring as a herbicide resistant weed control strategy.
  
• Hotspots of ascochyta were present in all unsprayed treatments in 2003.

SA farmer experience with wide row cropping

The Tiller family from Pinery/Mallala have sown their entire faba bean and chickpea program on wide rows for the last two seasons (2002 and 2003) and 50% of their canola last year. The Tillers' main objective is to develop a lower risk/cost system for non-cereal crops. The long-term dollar returns on cereal crops far outweigh broadleaf crops at this stage but non-cereals have an essential role in weed and disease control.

Chickpea faba bean and canola crops have been sown on 0.9 to 1.0 m spacings using both their Conservapak™ and 8-row Kinze™ precision planter. A 2cm autosteer system (AutoFarm™ supplied by GPS-Ag) is central to their wide row cropping program. AutoFarm™ is used on their 4WD AGCO for seeding then transferred to their spray tractor for inter-row weed control with knockdowns and banded spraying of pulse crops with fungicides for the rest of the season.

In a paddock trial conducted this year conventional and wide row (0.9 m) canola yielded the same (1.4 t/ha) although the wide row canola was 3% higher in oil. The Tillers found no problems with windrowing or harvesting wide row canola. The plans for 2004 will be to continue with wide row canola but reduce the spacing to 0.6 m.

Ben Marshman from Owen has been trialing wide row faba beans and canola for the past three years. In a trial this year canola on 0.5 m outyielded 0.1 m spacing. A small increase in faba bean yield on wide rows vs. conventional was recorded in a previous paddock trial. Ben plans to sow all his faba beans and canola on 0.375 m spacings in 2004 with a disc seeder.