Barley planting, nutrition and harvesting

Photo of participants at field day and barley breeding plot

Barley breeding plot

Planting time

Barley is very versatile in its planting time as it has a slightly lower frost tolerance (1°C) than wheat and can be planted earlier in the season. It is also often a better option than wheat for late planting, especially if feed grain prices are good. Preferred planting times are from late April to June but this will vary for each region depending on frosts and seasonal effects. In the cooler areas of southern Queensland planting can occur into July.

Early planting will generally produce higher yields, larger grain size and lower protein levels making it more likely to achieve malt quality. However, early crops are more likely to have exposure to frost and growers should assess the frost risk for their area prior to sowing. Late plantings will often mature in hot dry weather which can reduce grain size, yield and malting quality.

Planting at the right time for your area:

  • Sowing at the right time is critical for optimising grain yield and can also influence grain quality.
  • Early planting may increase the frost risk, but has the highest yield potential and is more likely to make malt quality.
  • Planting too early can result in the crop running quickly to head if a warm late autumn or warm early winter occurs.
  • Later maturing and shorter stature varieties are preferred for early planting to avoid tall lush early growth.
  • At flowering barley can tolerate 1°C lower frost than wheat.
  • A frost of -4°C at head height during flowering can cause between 5-30% yield loss.
  • A frost of -5°C or lower at head height can cause 100% yield loss.
  • A strongly negative April/May Southern Oscillation Index (SOI) is a good indicator of late frosts.
  • Hot dry temperatures during spring can reduce grain fill period and affect yield and grain size.
  • Later planting and later flowering generally results in declining yield potential due to higher temperatures and moisture stress during flowering.

Plant populations

While barley can produce a large number of tillers, best yields will be achieved with an established plant stand of 800,000 to 1.2 million plants/ha (80-120 plants/square metre). While barley can tolerate quite high plant populations without significant yield reductions, if plant populations fall below 80 plants per square metre, yield can be reduced. Lower plant populations can also encourage excess or late tillering resulting in a less even crop and delayed harvest. Late tillers often have smaller seed which also affects the quality of the crop.

Planting rate

Planting rate is the kilograms of seed needed to plant in order to establish the target plant population. To determine planting rate you need to know the target plant population, the number of seeds per kg, the germination percentage of the seed and the likely field establishment.

The number of seed per kg will vary depending on variety and the season in which the seed was produced. This varies from season to season and to calculate this figure, count the number of seeds in a 20 g sample and multiply by 50. Newer varieties tend to have larger seed and it is important to take note of this in determining planting rate.

Field establishment

Field establishment refers to the number of viable seeds that produce established plants after planting. This can be affected by factors such as seedbed moisture, disease, soil insects, depth of planting, and the germination percentage of the seed. An establishment figure of 70% means that for every 10 seeds planted only seven will emerge to produce a viable plant.

It is important to check establishment after planting in order to evaluate the effectiveness of the planting technique and make adjustments if necessary.

A guide to likely field establishment, when good quality seed with a laboratory germination of 90% or better is planted at a depth of 5-7 cm and emerges without the assistance of post-planting rains, is set out below.

Likely field establishment (%)
Soil type No press wheels % Press wheels %
Heavy clay 45 60
Brigalow clay 55 70
Red earth 70 80
Approximate seeding rates (kg/ha) assuming 90% germination from field establishments (%)
Desired population (plants/ha) 60 70 80 90
700,000 52 45 39 34
900,000 67 57 46 44
1,000,000 74 63 56 49

Use higher sowing rates for grazing crops and very early or late crops.

Planting rates can be calculated for any variety or situation by using the following formula:

Planting rate (kg/ha) = Desired population (pl/ha) ÷ (Seeds per kg x germination x establishment)

Note: germination and establishment figures are decimal e.g. 80%=0.8, 90%=0.9, etc.
Example:

Desired plant population of 900,000 pl/ha
Germination = 95%
Expected establishment = 85%
No of seeds/kg = 25,000

Planting rate (kg/ha) = 900,000 (pl/ha) ÷ (25,000 x 0.95 x 0.85)

Planting rate = 44.6 kg/ha

Row spacing

No yield reductions have been recorded for row spacings up to 36 cm. Rows wider than 36 cm have caused minor yield reductions, particularly in good seasons. Wider rows are more predisposed to lodging and will reduce the level of weed smothering due to canopy ground cover.

Planting depth

The ideal depth for planting barley is 50-75 mm. Plant emergence may be reduced if seed is sown deeper than 75 mm. Plant seed into moisture at the minimum depth possible. For successful establishment, the root must continue to grow into wet soil. Press wheels can improve the contact between seed and wet soil and reduce the rate of drying of soil above the seed. Particular care should be taken with planting depth if using seed with fungicidal dressing which may shorten the coleoptile length and make establishment from depth more difficult. Check the label before use.

The erratic nature of planting rains has resulted in some growers taking opportunities to sow barley at greater depths than the recommended 50-70mm. As a very vigorous seedling this has generally been successful for barley if good planting techniques are applied. In trials barley has emerged from as far as 15cm. A few tips to take into account include:

  • avoid the shorter coleoptile (dwarf) varieties
  • avoid seed dressings which contain triadimenol as these can shorten the coleoptile and make emerging from depth more difficult
  • try to minimise the amount of soil which is placed back over the top of the planting furrow.
  • ensure that the seed planted has good germination and vigour.

Nutrition

Nitrogen (N)

Management of nitrogen availability is vital to achieve optimal yields and quality in your barley crop. The level of nitrogen and plant available water will impact strongly on yield and protein having potentially  a major impact on crop return. Unlike wheat where premiums are available for high protein barley premiums for malting require moderate proteins of 9-12%. If you target around 12% protein this will also be maximising yield potential for barley.

A large percentage of Queensland's barley crop is classified as feed with protein levels above 12%. Older cultivation or double crop situations with lower soil N supplies can produce malt-grade barley especially in a good season, however, skill is required to balance the requirement for nitrogen to maximise yield without over fertilising and increasing the protein level.

A rule of thumb used by some is to grow malting barley, 0.4 kg of nitrogen is required for every mm of available soil moisture. Thus if there is 150 mm of available soil moisture, this will require 60 kg of nitrogen to produce a barley crop with protein between 8.5-12%. In high yielding years, grain protein can be reduced through nitrogen dilution as grain yield increases.

Nitrogen calculations for barley

Determining soil nitrogen status

Before a fertiliser program can be decided on it is important to gain an estimate of the existing soil nutrient status. Continuously low grain protein levels are indicative of a lower soil nitrogen supply. When barley protein levels are below 11.5% dry or below 10-11% (at 12.5% moisture) grain yield losses are likely.

Monitoring crop yields and protein over time can give a good indication of the nitrogen status of a paddock.

Using grain protein of preceding barley and wheat crops as an indicator of paddock nitrogen status
Barley protein
(dry basis) %
Wheat protein
(11% moisture) %
Comments
Less than 8.5 Less than 10 Acutely nitrogen deficient. Potential yield loss may be in excess of 30%. Applied N should increase yield significantly. Grain protein would be increased only if a large amount of N was applied.
8.5-11 10-11.5 Moderately to slightly nitrogen deficient. At least 15% yield loss is likely because of low soil N. Yield would probably be increased by applying N if there were no other limiting factors (e.g. soil moisture).
11-12 11.5-12.5 Satisfactory nitrogen status for optimum yield. Additional N would probably not increase yield but would be likely to increase grain protein.
Greater than 12 Greater than 12.5 Nitrogen not deficient. Yield was most likely limited by water deficit. Additional N would not increase yield but would probably increase grain protein.
If high protein and low yield occur, even in years of good rain, phosphorus may be deficient.
Indicative N fertiliser required (kg/ha) to produce the target yield (t/ha) of barley with 11.5% grain protein dry.
Target yield (t/ha) at 11.5% protein (dry) 2 3 4 5
Total N required (kg/ha) 75 110 145 180
Cropping history Estimated available soil N (kg/ha)* Balance of N required as fertiliser (kg/ha)
Double-cropped from sorghum 30 45 80 117 152
Fallowed from winter cereal 55 20 55 92 127
Fallow from chickpeas (yielding 0.5-1.0 t/ha) 65 10 45 82 117
Fallow from chickpeas (yielding 1.0-1.5 t/ha) 75 0 35 72 105

* It is assumed that 30 kg N/ha will be released from the soil as the crop is growing and the difference in soil N up to the value indicated was present at sowing.

Calculating nitrogen requirement

Another way to calculate nitrogen requirement is by measuring existing soil nitrogen and estimating a target yield and protein.

  • Calculate available soil water e.g. using HowWet, stored soil moisture and estimated in-crop rainfall.
  • Estimate target grain yield and protein %. - based on available moisture (e.g. 3.5 t/ha @ 10.1 % protein). Crop simulations such as Whopper Cropper can generate yield probabilities for a range of starting soil moisture and sowing dates.  Ideal malting barley grain protein is about 11.5% dry (optimum yield) or 10.1 % wet @ 12% grain moisture. Target for feed barley grain protein is about 12% dry (max yield) or 10.5% wet at 12.5% grain moisture.
  • Calculate how much nitrogen will be harvested in the grain. Grain N (kg/ha) = Yield (t/ha) x protein % x 1.6 (e.g. for the above target yield and protein 3.5 x 10.1 x 1.6 = 57 kg N/ha).
  • Calculate N required to grow the crop. Barley requires roughly twice the amount of N in the grain. N required for crop (kg/ha) = Grain N x 2 e.g. (3.5 x 10.1 x 1.6) x 2 = 113 kg N/ha.
    # Estimate or measure the soil nitrogen e.g. use soil tests (including the soil profile to 90 or 120 cm), or previous crop yields and proteins. Include mineralisation (generally about 30kg N/ha).
  • Calculate the extra N required. Extra N required = N required to grow crop - soil N. For example if there is 10 units of N in the soil and an estimated 30 units to be mineralised and a total of 113 units of N to grow your crop of 3.5 mt/ha @ 10.1 % protein.

The equation will be 113 (total N required) - 40 (total available or to be mineralised) = 73 kg/ha of N. If using a product such as urea which is 46% N you will need 158 kg/ha of urea. (73/0.46).

Phosphorus (P)

Phosphorus deficiency is widespread throughout the Darling Downs region with over 60% of all agricultural soils being responsive to phosphorus fertilisers. Low phosphorus levels in a high nitrogen situation can result in delayed flowering which affects the yield potential and grain filling time of the crop. For optimum performance it is recommended to use a starter fertiliser with phosphorus unless levels are very high.

Phosphorus recommendations
Bicarb P (mg/kg) Recommendations (P/ha)
0-10 Response most likely. Apply 8 kg P
11-15 Response likely. Apply 6 kg P
16-20 Response possible. Test strip of 6 kg P
above 20 Response unlikely

The combination of the fungus and the crop root is known as Vesicular-Arbuscular-Mycorrhiza (VAM). Long fallowing can increase the response of deficient soils to phosphorus due to the absence of VAM. This should not be a major concern for barley as it has a low requirement for VAM.

Other nutrients

Zinc (Zn)

Deficiency does occur in some of the alkaline brigalow soils and some of the heavy, alkaline flooded clay soils along the river systems, particularly following a long fallow. As zinc plays an important role in the efficient uptake of nitrogen for protein its significance should not be ignored and any suspected deficiencies should be addressed. Zinc deficiency can be corrected by applying a zinc fertiliser with the seed at planting or incorporating zinc sulfate monohydrate into the soil two to three months prior to planting.

Copper (Cu)

Deficiency has occurred in a band from Wandoan through Miles, Tara, and Moonie to Goondiwindi. The area affected, however, is patchy and small.

Sulfur (S)

Can be a problem in areas with a long history of cultivation. If sulphur deficiency is suspected, use a test strip to indicate potential response. It is more likely to occur after short fallow or double-crop situations, where soil sulphur levels have been depleted by the previous crop.

Irrigation of barley

Barley has a high water use efficiency rating. The plant can extract moisture from below 80 cm and given a good starting moisture profile, high yielding crops can be grown on limited irrigation. Yields of 7.3 mt/ha and higher have been recorded. Growers should target yields of 5-6 mt/ha and proteins of 10.1% (dry) or 11.5% wet basis to maximise yield and quality. Requirements for water will depend on winter rainfall and irrigation systems but one of the crucial times to apply water for achieving malt quality is grain fill. Adequate moisture during tillering and early jointing is important for maximising potential yield.

It is a good rotation crop to breaking disease and weed cycles, and providing high stubble levels.

Harvesting

Barley is generally harvested from October to late November. It can be expected to yield similar or better than wheat. The crop dries down well and desiccation is generally not necessary unless late weed growth needs to be controlled.

Barley is physiologically mature at between 30-50% moisture, which is well before it is ripe enough to mechanically harvest.

Mature barley does not stand weather damage as well as wheat. Therefore it is important not to delay harvest. Lodging can be a problem and patches of unripe crop near headlands and low-lying areas should be avoided as they can contaminate the sample and downgrade it.

When ripe, winter cereals are easy to thresh, and harvest can begin at moisture as high as 20% although generally very little is harvested above 18% moisture. If harvested above 12.5% moisture, access to an adequate aeration or drying facility is necessary (see below for information on storing barley).

Suggested header setting adjustments for barley:

  • Drum speed (rpm
    • Conventional: 700-1000
    • Rotary: 700-1000
  • Concave clearance (mm)
    • Front: 8
    • Rear: 3
  • Fan speed: high

As maintaining germination above 95% is vital, harvest and handling is of particular importance for malting barley. Even minor damage to the seed can affect the ability of the seed to germinate. Cracked grains, skinned or partially-skinned grains, and grains killed through damage to the germ, do not malt properly.

When examining a barley seed sample for damage, look at individual grains not just a mass of grain. Always examine grain's back first and ignore the crease side. Severe cracking and germ damage are nearly always accompanied by a high degree of skinning. The most common causes for this are:

  • Drum speed too high - only use the slowest drum speed that will effectively thresh the grain from the barley head. A higher drum speed is needed when harvesting crops not properly ripe and can cause serious grain damage.
  • An incorrectly-adjusted or warped concave - the initial header settings should have the concave set one notch wider than for wheat. Check the setting frequently during the day. If the thresher drum speed is correct, concave adjustments should cope with the changes in temperature and other harvesting conditions met during the day.
  • The airflow may need to be increased slightly to obtain a clean sample.

The application of heat can also affect germination of grain and this should be carefully taken into account if artificial drying is intended for malting-quality barley.

Monitoring grain loss

Monitoring for grain loss should begin before harvest. A seed count on the ground of over 26 seeds in an area 10 x 100 cm means a loss of more than 100 kg/ha. After checking for any grain on the ground prior to harvest you should check after you begin harvest to determine any harvest loss. It is recommended that a minimum of 10 counts be taken and averaged.

Quality requirements

Most grain purchasers will base their quality requirements on NACM A standards. For feed barley grain is required to meet sceenings and hectolitre weight specifications. For malting barley, as well as screenings and hectorlitre weights there are requirements for retention (above the 2.5 mm screen) and protein.

Malting barley requires moderate protein levels of between 9-12% The malting industry reports protein content at 0% moisture (dry) which will be 1-1.5% greater than the 'as is' basis, commonly used for feed grain. In line with malting industry standards, Graincorp reports all protein figures at 0% moisture basis. Feedlots generally use the 'as is' figure.

Growers should confirm receival standards with Graincorp or their local grain merchant. Specification sheets are usually available from July each season and include all relevant information. Other purchasers of barley grain may use different specifications. Graincorp provides a grower harvest information kit, including local contacts, contract options, warehousing conditions, grain protection strategies and more. Other purchasers of barley grain may use different specifications.

Storage

Barley is more susceptible to insect damage than many grains. When storing malting barley it is important to be aware of a few specific issues that will ensure the grain maintains its malting qualities.

Firstly and most importantly, maintaining germination of the grain at over 95% is vital for malting barley. Germination can be affected by grain temperature, grain moisture content and insect infestation. Any grains failing to germinate during malting will contribute to poor malt quality and brewing problems. Generally, high grain temperatures and high grain moisture content can be a cause of low germination (less than 95%). Insect infestation can have a similar effect. In an ideal world, malting barley would be kept free of insects, in aerated storage at grain temperatures of 10°C-20°C with a moisture content of less than 10.5%. However this is not generally practical and being aware of the interaction between moisture and temperature is important.

An indication of the interaction between moisture and temperature.
Barley moisture % Storage temperature Potential storage period
<10.5 10oC-20oC Very long 12-18 months
20#C-30oC Moderate 6 months
> 30oC Short 3 months
10.5 - >11.5 10oC-20oC Long 12 months
20#C-30oC Moderate 6 months
> 30oC Short 3 months
11.5 - > 12.5 10#C-20oC Moderate 6 months
20#C-30oC Short 3 months
> 30oC Very short < 3months
> 12.5 10oC-20oC Short 3 months
20#C-30oC Very short < 3 months
> 30oC Perhaps 1 month

Temperature

If possible keep barley grain at between 10 and 20°C. Above this temperature germination and malt quality can become affected. Between 20°C and 30°C short to medium-term storage presents some risk but once temperature of the grain reaches over 30°C germination is likely to be affected. Temperatures significantly above 30°C will cause grain to become non-viable. Warning: This also applies for drying grain that needs to maintain its germination (malting or seed crops). It should be dried slowly at low temperatures.

Moisture

The moisture of grain in storage will affect its ability to maintain quality over time. The lower the grain moisture the more stable its storage ability. However in practical terms it is more economical to store grain at around 12% moisture content.

Insects

Keeping the grain free from insect infestation is also another important aspect. As chemical residues can cause problems in some markets, treatment should be carefully considered. However if treatment is warranted, and there is access to sealed silos or fumigation bins, fumigation with phosphine is the preferred treatment. Where fumigation is not possible, a combination of fenitrothion and methoprene ( IGR or Diacon) is recommended. For rates and application methods it is important to follow the manufacturer's recommendations but as a guide:

  • up to 6 months- 6 ml /tonne of fenitrothion plus 5 ml/tonne of methoprene ( IGR 200g/L)
  • up to 9 months-12 ml/tonne fenitrothion* plus 5 ml /tonne of methoprene ( IGR 200g/L)

*Note there is a 90-day withholding period applied when using 12ml/t fenitrothion
Any chemical treatment of grain should be declared at delivery. Use of Reldan and Carbaryl are specifically excluded for malting barley.

Importance of aeration

Aeration is important as it evens out the moisture, cools the grain and helps reduce hot spots. Cooling the grain can also help to reduce insect infestations.

Quality requirements

The minimum protein level acceptable for malt-grade barley is 9.0. Malt protein content is reported at 0% moisture (dry) which will be 1 to 1.5% greater than the 'as is' basis, commonly used for feed grain. In line with malting industry standards, Graincorp reports all protein figures at 0% moisture basis. Feedlots generally use the 'as is' figure.

Growers should check receival standards with Graincorp Australia or their local grain merchant. Specifications are updated each season and include all relevant information. Other purchasers of barley grain may use different specifications.

Further information

Last updated 19 September 2012