In a lengthy drought, equal to the longest run of almost non-effective rainfall months on record, dual purpose winter cereal and brassica crops sown between early February and early March have often survived and provided useful winter grazing and grain.
Sounds almost impossible, especially with February/March also well above average temperature, well above recommended sowing ones for these crops.
Yet these central west and north west slopes crops, including on our own farm, germinated, established at least satisfactorily, and have commonly supplied good winter spring grazing (many areas did not have a sniff of rainfall to allow these sowings).
While not by any means the answer to all drought problems, these crops have played a vital role in allowing some stock to be market finished and for several months provided vital high-quality feed.
Stocking rate (bests/ha) has been less than half of a normal year, in our example, 90 days grazing at 1.2 steer/ha. Together with partial destocking (mainly with prime animal condition into good markets), use of stored hay and purchased cotton seed adequate ground cover and low stress has been possible.
A key factor has been stored soil moisture via efficient control of fallow weeds from late spring the previous year until sowing of the winter crop. In our example, we fallow sprayed five times between mid-October 2017 and sowing in late February 2018, despite a well below summer rainfall season. A lot of the stored sub soil moisture was from a good 2018 October rain event plus one good January fall.
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There were also several light fallow rainfall events that germinated growth, hence why five controls were required over the fallow. Weeds not controlled early quickly use up stored fallow moisture and can be hard to kill if stressed.
Also important, especially when sowing rain events are light (as they commonly are) is the allocation where possible of lighter soil paddocks for winter fodder crops. I appreciate some properties don’t have this option. In mixed soil type arable areas retention of some lighter soil paddocks for fodder crops can be a high priority.
Since early March 2018 until late August (six months), like much of the state, no rain event greater than 9mm (within a few days slot) had occurred on our property. One July 9mm event was sufficient on lighter soil paddocks for winter crop secondary roots to connect with subsoil moisture and then allow grazing.
Variety choice is almost certainly also an important consideration for long crop survival from early sowing in dry years. In our case we use “winter habit” varieties like Eurabbie oats or Longswood wheat.
While these tend not to have the strongest seedling vigour in hotter sowing conditions, if successfully established they can hang on indefinitely over a dry autumn and winter without going prematurely to head.
While a relatively small seed “winter habit” brassica varieties, also commonly germinated successfully and survived well from early sowing in many cases this current drought. In our area several crops supplied good feed faster than cereal crops, probably largely because of their quickly developed taproot.
Slow maturing spring habit varieties, like newly released oat Warlock, almost certainly have stronger seedling vigour, but can become stalkier and even run to head before they can be grazed if autumn and winter is dry. Early sowing variety choice is an area requiring more detailed study.
Grazing management is important for maximum grazing from drought affected crops. Where possible retain reasonable green matter levels to allow plants to create new leaves.
Grazing into the ground, especially in “non-winter habit” types or after “winter habit” has been satisfied, leads to tiller loss and poor regrowth if soil is dry.
