Selection

There are a range of forage crops available to producers. The right forage crop will depend on the quality and quantity of feed required to meet the enterprise production objectives as well as other factors such as soil type, climate, water availability, drainage, weeds and disease.

Careful selection is essential as it will help ensure good plant growth and grazing potential.

Crop purpose

The wide range of forage crops available to producers vary in feed quality and quantity potential – different crops will suit different production objectives.

The first step in deciding what type of crop is right is to work out the enterprise’s production requirements.

Considerations include:

• Is the crop being grown for high quality feed that will provide maximum weight gain (e.g. forage brassica)?
• Is the requirement for bulk, in which case a highly vegetative sorghum might be more appropriate?
• Is there a need for a winter crop (e.g. forage oats), to maintain high year-round growth in summer rainfall production areas?

Plant species

Having identified what is required of a forage crop, local environmental issues should be considered, including:

• Climate: Not all crops will grow in all regions, for example, some crops are frost sensitive while other crops thrive in cooler environments. A crop that suits the local conditions should be selected.
  
  
• Soil type: Different crops are suited to different soil types. While this may result in marginally reduced production in some circumstances, such as with a grazing winter cereal, other crops (such as brassica), have more precise requirements for optimal production.
  
  
• Water availability: The amount and seasonality of rainfall as well as the availability of irrigation will play a role in determining the range of forage crops that may suit a particular situation. Moisture often limits forage crop production, particularly summer crops such as sorghum, sudan grass and millet. However, if sufficient summer rainfall or irrigation is available, these crops can be very productive.
  
  
• Pests and diseases: Pests and diseases can limit the productivity of forage crops, particularly if left unchecked during establishment. If pests and diseases are a problem, producers should select forage crops that have a higher level of resistance to the pest or disease in question.
  
  
• Weeds: When selecting a forage crop, crop rotation and weed challenges that the crop may face should be considered. Weeds can reduce productivity and the choice of a grass crop may be appropriate if broad leaf weeds are a problem or, if grasses are a problem, a broadleaf crop may be appropriate. This will allow for relatively cheap and effective weed control compared with using more selective herbicides.
  
  
• Timing: The desired timing of grazing must also be considered when selecting an appropriate forage crop. The suitability of crops will vary depending upon when the crop is to be grazed to meet the production objective. All crops have particular phases in their growth cycle when they either respond better to grazing or have higher productive potential through higher digestibility or higher protein or energy content. Some crops, such as various brassica and sorghum crops, present animal health issues (e.g. hydrogen cyanide [HCN] poisoning), during particular phases of growth and it is important that producers understand when particular fodder crops will reach their greatest potential and when they should be avoided.

Crop rotation

If forage crops are being incorporated in a crop rotation, broader issues associated with weeds, soil nutrition and diseases should be considered in selecting the right crop for an enterprise.

Forage crops can be useful in a rotation if chosen carefully. Summer forage legumes such as cowpeas and lablab can fix large amounts of nitrogen, while forage brassicas can improve soil structure and release compounds that inhibit the growth of disease producing organisms that can affect other crops, such as wheat.

Forage crops can, however, act as a green bridge allowing diseases such as rust to carry over to a subsequent crops. Producers should be mindful of this and select crops in a rotation that will maximise benefit and minimise risk.