With rain forecast for the next four days (in early May 2020) I take pen to paper to write about cover crops in southeast Australia. Seeding is well underway for these crops along with cereals, pulses, legumes, forages and others.
The rain we are receiving across a wide swath of this part of the country is a textbook “Autumn Break.” The Break, as its affectionately called, signals the seasonal change from dry summer to a wetter fall/autumn climate and the beginning of a new cropping season.
It is indeed autumn now but with the mild winters, most crops are sown now to take advantage of good soil moisture and to reach maturity before next summer’s heat shuts plants down.
When I first came to Australia some 10 years ago, I noticed the green, lush, so-called “summer crops” of forage rape. These were used as a highly nutritious feed for stock, to fill the summer feed gap as it had done for years. Then along came many soil ecologists across North America, Australia and New Zealand who have truly inspired us to gain a much better understanding of soil health and the synergism between plants and soil microbiology.
It has really been an exciting development for many farmers and has resulted in a plethora of “summer crop” recipes springing up here and abroad. Adoption of this technique has led to better-performing stock and much-improved soil health that can give lasting effects on subsequent crops and ameliorate soil problems such as hardpan, poor nutrient cycling, low organic matter and low water infiltration.
We had a chance to trial two cover crop recipes this summer and were pleased with the outcome.
Seeded last spring
Late spring (mid-October) we seeded, directly into a glyphosate-sprayed pasture, a crop of “cool season” covers, meaning a cereal base of rye, wheat, oats with tillage radish, fodder rape, leafy turnip, vetch, flax and chicory. Two weeks later we seeded another paddock with a “warm-season” mix. More suited for midsummer heat and dry spells, this mix included millet, sorghum, buckwheat and sunflowers in addition to tillage radish, leafy turnips, fodder rape and chicory.
We had purchased Angus steers, as we always do for part of the year, for grass-fed beef on our Alcheringa Pastoral farm in Victoria. Experience from other years has told us that good gains are hard to achieve from mid-January to the end of March. This is where the cover crops really helped us.
We sold the steers in mid-April this year. The 42 days they were on the cover crops gave the best gains seen so far with more than 2.5 lbs. per day. This is phenomenal having come out of a very dry summer with less than 15 mm from early November to the end of January, followed by only a few light showers of less than 25 mm until the rains now falling at the end of April. Our other pastures pretty much sat dormant during this time.
The “warm-season” covers were maturing as we reached late summer, but the mix was ideal for finishing the steers with an increase in energy from the sunflowers and the flax over the protein from the brassica species. We strip-grazed the cover crop with added hay supplied as a rumen scratch for the highly digestible feed. This also leaned out the crop and allowed much better utilization and cattle performance. The steers reached 1,100 lbs. on average, which is by far the best weights we have achieved.
The big surprise, despite very heavy grazing, has been that the tillage radish, leafy turnips and fodder rape is growing back. Rather than reseeding the two paddocks, they will be left for winter growth and with additional germination also from volunteer annual ryegrass we will use the feed in early spring for either grazing or silage before seeding back to a warm-season cover crop in November/December when we return from the Northern Hemisphere. Two crops of soil stimulus are a bonus.