Finding more yield and profit from your farming system

Take home message

There is enormous potential to improve farm profits if the gap between average farm yields and attainable grain crop yield, which is between 50 and 100%, can be reduced. This requires finely tuned farming systems and agronomy, but in conjunction with good management of machinery, labour, finance and the timeliness of operations.

The main difference between average and top farmers is the occurrence of problems which affect yield. In practice many crops are affected by several 'profit draggers', like disease, nematodes, weeds, low nitrogen, timeliness or harvest losses, which in combination affect yield by 20-30 % and drag down profit by 50-60%.

To manage well requires attention to all the profit draggers, but good results also requires time and effort to be put into crop selection, rotations, crop frequency, risk management and farm cost choices. Teamwork, labour, safety and machinery decisions are also important.

1. Attainable yields

Water Use Efficiency benchmarks can be used to derive attainable yield for a location and season. In the higher rainfall areas of northern NSW and southern Queensland, an attainable average yield for wheat on short fallow is in the vicinity of 3.8 t/ha. This is based on average soil moisture of 140mm and 195mm of in-crop rainfall, of which 25 mm remains as harvest soil water. The 3.8 t/ha yield of wheat is produced from 310 mm at a water use efficiency (WUE) of 12.5 kg/ha/mm.

In western NSW and south-west Queensland, attainable yields decline with rainfall and soil water storage capacity. Where there is 150mm of in-crop rainfall, 20 mm of which is left as harvest soil water, and 110mm is stored in the soil during fallow, the attainable yield of short fallow wheat is 2.75 t/ha at a target WUE of 11.5 kg/ha/mm.

Attainable yields for grain sorghum, as shown in Table 1, vary between 2.7 t/ha where water available to the crop is around 245mm and WUE 11 kg/ha/mm and 5t/ha where water available is 330 mm and WUE is at 15 kg/ha/mm. In the best of the sorghum growing districts, such as the Central Downs of Queensland and the Liverpool Plains of NSW a target yield for sorghum is 6 t/ha, produced from 375 mm of water at a WUE of 16 kg/ha/mm. Figures are shown for a September plant, but there are various scenarios for sorghum, such as where sorghum is grown on long fallow which can store an extra 50mm of water, and where the crop is planted in December or early January to maximise the chance of in-crop rainfall.

Table 1. Attainable yields of wheat calculated from WUE and by APSIM

Wheat
May 30 Plant
Planting soil water In-crop Jun to mid Oct Harvest soil water* WUE kg/ha/mm Yield** average APSIM 150 mm PAWC # APSIM 180 mm PAWC #
Northern NSW
High yield Gunnedah 149 236 31 12.5 4.43 3.94 4.41
Medium yield Moree 146 191 21 12 3.79 3.33 3.52
NW NSW
High yield Coonamble 106 159 16 12 2.98 2.72 3.10
Medium yield Walgett 106 142 20 11 2.51 2.53 2.90

Table 2. Attainable yields of sorghum calculated from WUE and by APSIM

Sorghum
Sep 30 plant
Planting soil water In-crop Oct to mid Jan Harvest soil water WUE kg/ha/mm Yield average APSIM 150 mm PAWC APSIM 180 mm PAWC
Northern NSW
High yield Gunnedah 136 274 14 13 5.14 3.65 4.29
Medium yield Moree 121 252 22 11 3.85 3.08 3.72
NW NSW
High yield Coonamble 126 137 23 11 2.64 2.28 2.54
Medium yield Walgett 125 148 28 11 2.70 2.3 2.59

*Average soil water at harvest calculated by APSIM
**Yield calculated from average rainfall data and water use efficiency figures
# Yields modelled using APSIM show attainable yield is higher with increasing soil water capacity

2. Benchmarking yields using local WUE numbers

Water Use Efficiency estimates can be used as a benchmark to examine yields in hindsight or to project future yields. A better interpretation of WUE can reduce some of the variability that has limited the value of WUE in the past.

The French and Schultz model has been widely used in southern Australia to benchmark wheat yield for a given water use, with a target of 20 kg/ha/mm, allowing for 110 mm of soil evaporation. Current varieties and farming practices now produce WUE closer to 25 kg/ha/mm (Sadras and McDonald 2011).

Better benchmarks of WUE for the Northern Grains Region require soil stored moisture to be included in calculations, even if only an estimate. The application CliMate or the model How Wet can be used to estimate soil water. Deducting 110 mm for soil evaporation should be ignored because winter rainfall and soil evaporation is often below 110 mm and the deduction leads to spurious results where WUE is high in a poor yielding year, when in fact it is low due to a low harvest index.

In most years, there is little or no moisture left in the soil at harvest, but when there is heavy spring rainfall, some account can be made of left-over water by adjusting the estimate of in-crop rainfall.

This approach, where evaporation is ignored, is supported by Hunt and Kirkegaard (2011) who say; "It is water use efficiency that is important as a benchmark when reviewing management, not transpiration efficiency". Doherty et al (2010) and Sadras and McDonald (2012) also conclude that the most practical way of estimating WUE is to subtract soil water at maturity from soil water at sowing and add the rainfall that falls in between. This is what is proposed in this paper as the most appropriate way to use WUE in the Northern Region.

WUE should be more than a single number

The accuracy of using WUE to estimate yield can be improved by using a range, rather than a single number. WUE improves with yield, as a result of a better harvest index. In extremely low yielding situations, the crop has used a lot of the available water growing to the flowering stage and the WUE can be less than a half of the WUE of a high yielding crop. As yield potential improves there is generally better tiller survival, more heads per hectare, more grains per head and higher grain weights. This all serves to improve the WUE.

Figure 1. Water use efficiency of Wheat; NE NSW and SE Qld (2007-2012)

Data for wheat in NE NSW and SE Queensland, shown in Figure 1, demonstrates that WUE increases from around 9 kg/ha/mm where yields are less than 3 t/ha, to 12 kg/ha/mm for yields between 3 and 4 t/ha and is commonly above 15 where yields exceed 4 t/ha due to a favourable season. This data is derived equally from farm and trial observations and so variation at any yield or WUE level can be the result of seasonal effects or impacts on yield by disease, nitrogen or other factors.

Using several benchmarks for wheat, of 9, 12 and 15 kg/ha/mm, depending upon the yield potential greatly improves the accuracy of WUE compared to the use of one number, such as 12 kg/ha/mm. The other way WUE benchmarks can be adjusted to improve accuracy is to allow for sowing time. If the WUE for wheat planted in mid-May is 15 kg/ha/mm, this will decline by around 5% per week and would be only 12 kg/ha/mm for wheat planted in mid-June.

Chickpea has a good correlation between yield and WUE (as shown in Figure 2). At yields below 1.5 t/ha, WUE is around 5 kg/ha/mm, while above 2.5 t/ha the WUE is usually above 9 kg/ha/mm. Using three numbers for WUE; 5, 7 and 9, depending upon the yield range will improve the use and value of WUE calculations. At very high yield levels, the WUE of chickpea is usually above 11 kg/ha/mm. There is a reduction in WUE for chickpea with delayed planting, similar to wheat.

Figure 2. Water use efficiency of chickpea; NE NSW and SE Qld (2007-2012)

Sorghum also shows increasing WUE as yields increase, due to a better harvest index at high yield levels. But WUE is affected also by temperature and humidity as well as yield and harvest index. It is higher in the cooler more humid areas or growing seasons than hotter drier areas or growing seasons, in much the same way as wheat responds to later planting dates.

Figure 3. Water use efficiency of sorghum – NE NSW and SE Qld (2005-2012)

The average WUE for sorghum grown on the Darling Downs and Liverpool plains should be in the vicinity of 15 kg/ha/mm. Benchmarks for sorghum are 10kg/ha/mm for yields less than 3.5 t/ha, 13 to 15 for yields from 5 to 6.5 t/ha and 18 kg/ha/mm for yields above 6.5 t/ha. (See Figure 3).

3. The economics of profit draggers

Every disease problem, every mistake with seed, planting or variety selection, or not enough spent on inputs such as weedicide and fertiliser, can cost more than 10% in yield. It is common for three or more of these issues to be dragging down crop yields by some 30% and profit by 50-60%.

Closing the yield gap is about managing these multitude of factors which drag on yield. The gap between average farm yields and the attainable yields which result from good farming practices and systems is around 50 to 90% in northern NSW. If this yield gap could be closed, farm profitability would increase enormously, up several times the present levels, as shown by the estimates below.

Table 3. Profit from 30% less yield – Northern NSW*

Wheat Sorghum
good yield less 30% good yield less 30%

Yield (t/ha)

3.75

2.6

4.8

3.36

Price

240

240

210

210

Gross $/ha

900

624

1008

706

Fertiliser:

123

93

150

112

Seed

30

30

32

30

Fallow sprays

60

48

50

40

Weeds, Pests

35

15

55

45

Fuel & Repairs

52

52

52

52

Harvest costs

55

50

60

55

Freight & Misc.

91

74

107

85

Labour

60

60

60

60

Machinery costs

78

78

78

78

Total costs

584

500

644

558

Gross Margin

316

124

364

148

Gross Margin %

255%

39%

246%

40%

*Data from Agripath benchmarking

Good crop yields are a result of good planning and implementation of crop production involving a myriad of details, starting with the crop choice, the rotation program and how moisture is stored and used on the farm.

Combine this with good planting technology and timeliness, and the right details of fertilisers, weeds, pests and other aspects of crop agronomy and there is potential to substantially improve grain yields and profitability.

4. The farming system

The farming system needs to be designed to minimise the effects of crown rot in wheat and root lesion nematodes in wheat and grain legumes. Management of weeds, particularly glyphosate resistant summer grass weeds, is another factor driving farmer decisions on rotations. Disease control, diversification and risk management, as well as improved timeliness is often improved with a mix of summer and winter crop and making decisions on crop rotation is quite complex.

Crop yield is highly influenced by fallow rainfall storage and soil moisture at sowing. A high frequency of low yielding crops, with small margins may be less profitable than a well-planned rotation which includes some crops grown on long fallow during the change between summer and winter cropping.

Good farming systems take into account soil health, stubble cover and fallow management to reduce runoff and evaporation, thereby storing as much soil moisture as possible. A small amount of extra soil stored moisture can go close to doubling crop profitability as shown in the following example derived from APSIM modelling. At Coonamble an extra 16 mm is stored on average in a soil with a plant available water capacity of 180mm, compared to a soil with a PAWC of 150 mm. This extra water produced an extra 381kg/ha of wheat (a gain of 23 kg/ha/mm) which would improve profit from $144/ha to $219/ha.

Table 4. Effect of soil water capacity on water storage and crop yield

Soil PAWC mm Wheat May 30 Plant Planting soil water In-crop Jun - mid-Oct Harvest soil water WUE kg/ha/mm Yield average
150 Gunnedah 136 236 28 11.1 3814
180 Gunnedah 158 236 30 12.0 4351
Increase 22 24.1 537
150 Coonamble 126 201 16 8.7 2716
180 Coonamble 143 201 17 9.5 3097
Increase 16 23.4 381

APSIM modelling by G. Mclean, DAFF Qld. 2014

5. How do good farmers achieve top yields of wheat, sorghum and chickpea?

The following suggestions are ways in which good farmers achieve yields which may be high enough to more than double farm profitability.

5.1 Better wheat and chickpea yields will result from sound rotations to manage disease, nematodes and weeds

Good rotations can manage crown rot, and if wheat has to be sown after wheat, it should be planted into the middle of the old wheat rows for up to 9% extra yield (Verrell 2014). New varieties of wheat, such as Suntop, offer potential to suppress nematode populations and avoid heavy losses from these pests, not only in wheat but in subsequent legume crops. Rotation plans which include some fixed cropping plans and long fallows can pave the way for increased use of residual herbicides to help reduce costs and to better manage glyphosate resistance.

5.2 Manage profit margins with well-planned rotations and decisions based on soil stored moisture

Long fallow crop sequences can be more profitable than double crops. Do the sums! A double-crop of chickpea with a yield of 1.2 t/ha followed by wheat yielding 2.7 t/ha might have a combined margin of less than $200/ha. A chickpea crop on a long fallow with a yield of 2.6 t/ha, should have a margin close to $500/ha and could help to double farm profit. Good margins are important and too much opportunity cropping can result in reduced margins over the longer term.


Table 5. Margins from a double-crop sequence compared to a long fallow

Chickpea double-crop Wheat after Chickpea Chickpea on long fallow
Yield (t/ha) 1.2 2.7 2.6
Price 400 240 400
Gross $/ha 480 648 1040
Fertiliser 30 95 30
Seed 40 30 40
Fallow sprays 24 48 60
Weeds, Pests 72 15 80
Fuel & Repairs 52 52 60
Harvest costs 55 50 55
Freight & Misc. 53 76 74
Labour 45 60 60
Machinery costs 55 78 81
Total costs 426 504 540
Gross Margin 54 144 500

5.3 Maximise legume opportunities and yields

Faba beans, chickpea or other legume crops may improve farm profit if profitable in their own right and they provide soil and rotation benefits. If the legume is grown one year in three and provides half the nitrogen requirements of the following cereal crop it will halve nitrogen fertiliser costs.

Good seed and inoculation techniques can pay dividends if yield and nitrogen inputs are enhanced. Investment in water injection for inoculation may be profitable.

5.4 Extra soil water storage can double profit.

An extra 20 mm of soil stored water could add 400 kg/ha to yield – enough to double the profit in some situations! Soil moisture storage improves with soil health, which is about building soil organic matter with plenty of earthworms. This can be destroyed by tillage, compaction or low soil cover. Controlled traffic in combination with zero tillage improves infiltration which results in less runoff and more even moisture storage across a paddock. Good soil structure can also reduce waterlogging and its effect on crop yield and nitrogen losses.

5.5 More nitrogen for higher yields in better years

Sorghum has the potential in better growing areas to yield more than 8 t/ha in three years out of ten. It will usually not reach these higher yield levels because it runs out of nitrogen. Wheat also can benefit from adjusting fertilizer according to yield potential. Some farmers have developed ways to put more N on at planting time or soon after, while for wheat, urea is reasonably efficient, with around 5% N loss, when broadcast at tillering (Schwenke 2014), to match extra yield potential. Feedlot manure is another way to provide sorghum extra nitrogen in a good season, due to the faster mineralization of the nitrogen it contains in an organic form.

Seasonal forecasts are not helpful in most years, but when there is a strong signal, such as the 2010-11 La nina, changes should be made to the nitrogen management of sorghum.


Table 6. Nitrogen required by sorghum at Gunnedah for different soil moisture and seasonal outlooks

Soil water mm In-crop rainfall SOI <-5* In-crop rainfall average In-crop rainfall SOI >+5* Water use efficiency Yield estimate t/ha** Nitrogen required kg/ha
80 175 - - 12 3.1 52
80 - 205 - 13 3.7 63
80 - - 220 14 4.5 71
160 175 - - 16 5.4 75
160 - 205 - 17 6.2 105
160 - - 220 18 6.8 116

**Sorghum is planted on September 30 at Gunnedah
*Gunnedah rainfall from Rainman with SOI values for August and September

5.6 Develop planters to create results and more timely planting opportunities

Timeliness of planting can often result in more than a 10% improvement in water use efficiency and yield – potentially doubling crop margins. In some years, it may be the difference between a crop and not planting at all. Planters need to be fine-tuned to obtain reliable results from the deep planting of wheat, sorghum and chickpea. The planter is perhaps one of the most important machines on the farm and deserves investment to enable a good planting result with a variety of soil and moisture conditions. A poor strike can easily cost more than 10% in yield.

5.7 Better chickpea yields

Chickpea has yielded more than 4 t/ha in favourable situations, where there is a total of 300 mm of available water, but not too much waterlogging or disease. Improving the drainage of paddocks has in some instances helped farmers to double chickpea yields in the wetter seasons.

Planting chickpea two weeks after wheat, in the last half of May, will result in smaller bushes, which can leave more moisture for pod filling. They will flower in late August, when flowers are less likely to be lost by cold weather (if the average daily temp is below 15). Row spacing around 0.5 metres has been demonstrated to improve yields under high yielding conditions (Verrell and Jenkins 2014 and Mckenzie 2014).

5.8 Good harvest management will boost farm profit

Harvest time losses can be severe in wet seasons, while chickpea can lose yield through shattering in all years. A loss of 200 kg/ha of chickpea, worth $80/ha, can result from a delayed harvest of chickpea and will pay for investment in storage with in-silo (high flow aeration) drying.

Increased storage is helping farmers to manage losses and in some instances reduce freight and handling costs where direct transport of grain to the end-user is possible.

5.9 Learn from paddock variability and moisture

Somewhere on the farm, a high yielding area of crop shows up what is possible. Yield maps, EM surveys, soil moisture and fertility testing and trials measured by yield maps can help farmers understand what produces high yields and the limitations of soils on their farm. Better knowledge can lead to managing crops better or to understanding and managing paddock variability.

Moisture is the key driver of grain yields and measuring soil water holding capacity and soil water at planting time can improve decision making on farms. EM measurements allows rapid assessment of soil moisture and soil moisture variability across paddocks (Foley 2013).

5.10 Precise operations, on-time

Good results from spraying, planting and harvest and good timeliness of these operations are a result of good equipment, planning, training and staff management. Failure in any of these aspects, such as equipment breakdowns not being managed or staff doing a less than satisfactory job, will result in poor yields and profits. Capital investment in plant needs to be managed to ensure timeliness and to reduce breakdowns and the cost of repairs.

There are many aspects of farming systems, crop planning and risk management which can help timeliness. Some of these include diversification between summer and winter crop, the use of some long fallows and residual herbicides and a spread of varieties which do not have to be planted and harvested on the same date.

References

Doherty A. et al. 2010. Quantification of wheat water use efficiency at the shire level in Australia. Crop and Pasture Science, 61, 1-11.

Foley J. 2013. A 'how to' for getting soil water from your EM38 field measurements. Accessed 7.01.15 from: http://www.grdc.com.au/Research-and-Development/GRDC-Update-Papers/2013/03/A-how-to-for-getting-soil-water-from-your-EM38-field-measurements

Hunt J and Kirkegaard J. 2011. Dryland water use efficiency -What is it and how to improve it. http://www.grdc.com.au/Research-and-Development/GRDC-Update-Papers/2011/08/Dryland-wateruse-efficiency-What-is-it-and-how-to-improve-it

McKenzie K. 2014. Impact of row spacing and populations on chickpeas. GRDC grower research update, Warra. http://www.grdc.com.au/Research-and-Development/GRDC-Update-Papers/2014/08/Impact-of-row-spacing-and-populations-on-chickpeas

Sadras V and McDonald G. 2012. Water use efficiency of grain crops in Australia: principles, benchmarks and management. GRDC publication. http://www.grdc.com.au/Resources/Publications/2012/07/Water-use-efficiency-of-grain-crops-in-Australia

Schwenke G. 2014. Nitrogen volatilisation: Factors affecting how much N is lost and how much is left over time. GRDC research update. Accessed 7.01.15 from:
http://www.grdc.com.au/Research-and-Development/GRDC-Update-Papers/2014/07/Factors-affecting-how-much-N-is-lost-and-how-much-is-left-over-time

Verrell A. 2014. Row placement strategies in a break crop wheat sequence. Northern Grains regional trial results. Accessed 7.01.15 from: http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0007/520666/Northern-grains-region-trial-results-autumn-2014.pdf

Verrell A and Jenkins l. 2014. Effect of row spacing on yield in chickpea under high yield potential.

Acknowledgements

Many of the ideas presented here have been developed as part of a GRDC project: The Economics of Closing the Yield Gap in the Northern Grains Region. The authors would like to thank the GRDC and the growers who provide contributions for research for their continued support.

Contact details

Simon Fritsch
Agripath Pty Ltd
21 Bourke St, Tamworth, NSW 2340
Ph: 0428 638 501
Email: simon@agripath.com.au

Peter Wylie
Agripath Pty Ltd
4 Alfred St, Dalby, Q. 4405
Ph: 0429 361 301
Email: peterwylie@agripath.com.au

Reviewed by

Chris McCormack, Greg Giblett, Rob Long & Drew Penberthy.

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GRDC Project Code: APT00001,