SFS/BWBL - Dual-purpose crops

Summary

Dual-purpose cropping is a tool for mixed enterprise producers.  It provides livestock grazing opportunities when there are feed deficits and grain income.  It allows producers to take two bites of the cherry but at what cost?

The aim of the project is to assist decision making of producers about the value of spring-sown crops by proving the net benefits and risk evaluation (climate and waterlogging) for a range of different years, soil types and water management methods that are reliable, repeatable and representative of the High Rainfall Zone (HRZ) in Victoria.  This project forms part of MLA's Producer Research Site (PRS) program that is part of the southern Feedbase Investment Plan and supports the MLA-funded project B.GSM.0008, Step changes in meat production systems from dual-purpose crops in the feed-base.

The project recorded the grazing benefit to a mixed farming system including the opportunity to generate feed in pastures over summer and at the autumn break, hence providing producers an increased carrying capacity of the whole farm system.

The dual purpose crop that was selected to be researched was spring sown winter habit canola.  This opportunity crop can be planted in the HRZ in spring, crash grazed at least three times from December to May, then locked up and grown to produce grain.  Winter habitat canola varieties can be used in this way as they require a cold vernalisation period for the plant to become reproductive to produce grain. The growing season for this crop is then increased to 15-18 months creating opportunities for grazing and grain.
This project found for optimum crop production the key requirements for spring sowing winter habit canola are the same for autumn-sown canola; preparation, good paddock selection, supply of adequate nutrients after grazing and early sowing in mid Sept-Oct.

Once established it was very tough and could handle heavy grazing, although grazing should stop mid to end of May allowing the plants to recover enough biomass to optimise grain production.  It produced a high quality feed source that can grow lambs for sale or to bring them up to weight to be joined and enabled producers to rest pastures and provide a green containment area over the summer/autumn period.  For optimal production with the crash grazing method it would be advisable to have two paddocks to rotate the sheep in and out of or strip graze. 

The feed value in this project averaged over all sites and seasons was $467/ha based on market replacement with feed barley.  In the worst case scenario grazing spring sown canola decreased grain income by $175/ha and in the best case scenario it increased grain income by $158/ha when compared to non-grazed spring sown canola.

The main risk associated with this cropping system are related directly to the timing of rainfall events at key crop stages of establishment, grazing, winter and grain fill.  Drainage of paddocks helped reduce waterlogging risks, but in extremely wet years like 2016 waterlogging still occurred and killed plants and reduced crop yields.

This project received additional collaborative support from Agriculture Victoria, allowing the producer group to increase the scope of the research undertaken.

The group recommends that further research be done into dual purpose crops around better varieties that may cope better with waterlogging, regional set of rules around grazing timing and when to lock up the paddock for grain production and a better understanding of the plant phenology in regards to vernalisation triggers.