How to get the best out of your crop
Tablelands Telegraph - April 2021
Clare Edwards - Senior Land Services Officer, Pastures
I have had many enquiries about self-sown oats crops this year. This is due in part to the previous season, and also to crop management. Many landholders were unable to prepare paddocks due to seasonal conditions – eg being too wet – or not being able to use livestock to manage last years stubble. The result is self-sown crops springing up from the leftover grain. So, the dilemma is what to do with these paddocks and deciding whether they are worth pursuing.
My checklist for this enquiry starts with the question: 'what was the original purpose of the paddock'? Was it for winter/spring feed for grazing this year? Or, was it originally ear-marked as a 'clean up' crop prior to a perennial grass pasture? Or, was it planned for some grazing and grain recovery? The next question then is 'will this self-sown crop be useful for that purpose'?
To make these decisions, the next thing to do is to assess the population density of the oats. Is the oats germination uniform across the paddock? The nature of harvesting, hay-making or grazing means that the germinating seed may not be even, with some areas having a very dense germination of oats and some areas very little. This may be due to a lack of seed, stubble mulch or trash. Be aware that a very high population in some areas may ultimately be detrimental to the persistence of these seedlings, as crowding and competition may eventually kill the plants as they mature.
The next assessment is to consider the current weeds and previous weeds in the paddock. What are the weeds? Are they summer-growing, or will there be heaps of winter annual species such as ryegrass and vulpia? What herbicides are available to manage grass and broadleaf weeds? Was it a paddock about to go into pasture, and will it now have to wait for next year? By not getting rid of the weeds, are you setting the paddock up for an increase in the weed seed bank? Current weed species will also be very tough competitors to any newly germinated oat seedlings for light, space and nutrients.
The fourth point on self-sown oats is understanding that varieties have different vernalisation requirements. The longer season varieties (eg Nile, Blackbutt) are less likely to go to head if germinating in early autumn. Head initiation does not occur until there has been an exposure to periods of cold temperature over time. If oats go to head before the winter period, there will be little tiller regrowth and poor overall production.
The next consideration is around pests and disease. Many producers buy treated cereal seed for protection against insects, so be aware of earthmites (eg RLEM, BOM) and aphids. Humid and wet autumns sometimes see a rise in rust. If you had problems with BYDV last year, there may problems again this year. The recommendation in self-sown crops is to inspect your crop regularly for pests and diseases.
Lastly, consider the nutrient requirements of the crop. A soil test will certainly help in the decision-making process. Remember, some of these crops saw phenomenal amounts of grazing, grain yield and hay/silage production last year. Therefore, many of the paddocks may need phosphorus, sulphur and nitrogen. Look at taking a soil tests to help determine the appropriate nutrients. Don't forget to do a comparison in $/unit/nutrient when looking at the available products.
Self-sown cereal crops can be very economical, and I have seen some great examples. However, don't forget to do the assessment and put the effort in to make them work for you.
