Agronomy

Agronomy deals with the biological and physical aspects of crop production and is broadly described as the practise and study of field crops for use as human food, animal feed, fibre, oilseed, and some industrial products. They consist of:

• crop physiology
• plant breeding
• pest control
• soil science and management
• crop rotation
• tillage

Consider Barley (Hordeum vulgare), as an example:

Although barley is a grain very similar to wheat, it is most often used to manufacture malt, which is mostly used for brewing beer or as animal feed. All types of barley can be used to make malt, although some types are favoured by the maltsters. Any barley that does not meet the requirements for making malt is utilised in the feed industry as animal feed. Some barley cultivars are developed especially for yield and the feed industry. High yields and a typically greater protein content than malting barley are traits of feed barley. However, this will depend on nitrogen and moisture levels during the growing season. The majority of feed types outperform malting varieties in terms of output, but because malting barley is frequently sold at a premium, the gross margin can occasionally be rather close.

Barley’s roots resemble wheat’s in appearance. The primary and nodal roots are two separate systems. The seed that is germination produces the primary or seminal roots. Normally five to seven shoot out, branching out freely as they descend. The seminal roots (secondary roots), which are often deeper, have a maximum depth of 2.1 metres. Around the time that the ears (head) emerge, the growth rate reaches its peak.

Soil Requirements

Except for soils that are prone to water logging, have a low pH, or have high boron levels, barley is well adapted to a wide range of soil types. The main considerations for choosing a soil type for malting barley cultivation are the availability of nitrogen and water during grain filling.

There are numerous choices that are more suitable for soils with low soil pH or high boron levels.

Given that it can be planted earlier in the season and has a somewhat lower frost tolerance (1oC) than wheat, barley is extremely flexible in terms of planting time. Some of the Australian barley types don’t fit this description. A fast variety describes how quickly a crop can develop from planting to harvest. Several Australian late season (quick) barley cultivars must be planted later than most wheat types in order to avoid frost damage since they will suffer significant frost damage if planted early in the season.

No barley variety can tolerate extremely salinized soil. Contrarily, barley typically tolerates salinity better than wheat, making it the cereal crop of choice for sodic soils.

Nitrogen

The amount of nitrogen available will have a significant impact on yield and protein, which are key factors in crop return.

It’s critical to determine the current soil nutrient status before choosing a fertiliser programme. A lack of nitrogen in the soil is indicated by persistently low protein levels. Yield losses are likely when barley protein levels are below 11.5% dry or below 10-11% (at 12.5% moisture).

Measuring protein and crop yields over time might provide a reliable indication of a paddock’s nitrogen condition.

For every mm of available soil moisture, malting barley needs 0.4 kg of nitrogen, on average. In order to produce a barley crop with a protein content of between 8.5 and 12%, 60 units of nitrogen will be needed if there is 150 mm of soil moisture available. Grain protein can be decreased through nitrogen dilution in high yielding years.

Phosphorus
Low phosphorus levels in an environment with high nitrogen levels can delay blooming, which impacts the crop’s potential production and the timing of grain filling. Unless levels are extremely high, it is advised to apply a beginning fertiliser with phosphorus for best performance.

Aluminium and Boron toxicityCompared to other cereals, barley is more sensitive to the toxicity of aluminium. Aluminum toxicity primarily occurs in the region of medium rainfall on light-textured soils with a low pH. Aluminum becomes more readily available and more poisonous to barley as the acidity of the soil rises. Barley is sensitive to boron’s high concentration.

Eastern Australia is prone to the diseases listed below. We advise you to look about relevant barley diseases in your nation. The susceptibility of different barley types to diseases will vary. For resistance to various illnesses, some types have been carefully bred.

Crown Rot

See the information about wheat crown rot under that subject.

Net Blotch

The disease net blotch is brought on by the fungus Pyrenophora teres. Net blotches come in two different forms: spot for net blotches and net form of net blotches (NFNB) (SPNB). The fungus causes leaves to develop circular or net-like patches, which results in leaf chlorosis (death of leaf tissue). The more harmful type of the disease, known as NFNB, can occasionally result in yield losses of up to 30%, higher screens, and malting varieties that fail to malt.

The principal inoculum source is infected stubble. The optimal environment for the propagation of disease is moist for at least six hours with temperatures between 10 and 25 oC. Spores circulate with each favourable weather occurrence by dispersing in the air or by rain splash. Avoiding planting barley on top of the barley stubble from the previous season is one strategy to control the illness. It is advised to choose your types carefully because some have significantly superior resilience than others. The economic impact of the illness can also be reduced through careful monitoring and timely fungicide applications.

Spot Blotch

Little, dark blotches that form on the leaf and eventually produce leaf chlorosis and leaf loss are the symptoms of this type of blotch, which is sometimes confused for the spot form of net blotch despite being caused by a separate pathogen. This disease needs warm, muggy weather with a thick crop cover. A strong crop rotation that avoids planting barley back into last year’s barley field will lower disease levels, as would careful varietal selection, much like it does for other barley illnesses.

Powdery Mildew

On the leaf, powdery mildew develops as hairy, grey areas of fungus development. An diseased leaf eventually turns yellow and withers away. Air currents carry spores, and humid conditions are necessary for sporulation. When a crop is contaminated in the seedling stage, the growth can be significantly slowed. While other types of barley are highly vulnerable and call for some sort of treatment, certain barley cultivars are highly resistant to powdery mildew and exhibit no indications of the illness. Powdery mildew can be repressed by certain seed treatments. A timely application of a foliar fungicide can also be a very powerful remedy. As adult plant resistance is present in the majority of barley cultivars, the disease only needs to be managed prior to late tilling.