While every farming area has a defining average monthly rainfall, like for all areas it can be erratic. Commonly within a year monthly rainfall is nowhere near average.
Therefore the need to have combinations of pastures and fodder crops (commonly each to their own paddocks) to ensure feed will grow at any given time of the year should rain occur.
The year 2017/18 for many farms, including ours, emphasised this issue. Late autumn winter and early spring 2017 was the second driest on record.
Tropical grasses for us, and lucerne for many others, played a critical part providing feed quickly when significant rain occurred in early October, occasionally in summer and again in early March 2018. Winter fodder crops sown early in 2017 and 2018, on sub-soil moisture have been critical.
A radio interview in early March, with a significant rural advocate, lamented the lack of feed even on properties in his area that received useful rain over the previous three weeks.
Clearly this reference must be to pastures slow to respond to useful rain in early autumn where annual clovers and grasses take several weeks to get going. With dry following conditions many of these early germinations of annuals failed.
In contrast well managed lucerne or tropical grasses already have their root systems in place and commonly provided excellent feed, often almost overnight following rain.
In our situation this occurred not only last October, periodically over summer but also on useful March 2017 and 2018 rain some of us were lucky enough to receive.
In paddocks with soils that have significant light textured areas, often acid through the profile and/or relatively shallow with difficult sub soils (not suited to lucerne), tropical grasses provided a similar fast response to rain with good cattle and sheep feed within days of any rain event from mid-spring through to late autumn.
Tropical perennial grasses, unlike lucerne, don’t grow when regular frosts begin and for many areas are relatively dormant from June to the end of August.
But they can use rain after annuals like sub clover have hayed off and well before they get going in autumn or early winter. And they are compatible with annuals that contribute to feed in the dormant period. Importantly well-established tropicals can last indefinitely.
Dual purpose winter crops, sown early on sub soil moisture, at least for our situation, are a “must” and underwrite winter feed supply. Last year was a great example of why it is so important to conserve moisture over the fallow period. That conserved moisture kept crops growing through the dry winter to mid spring.
While carrying capacity is typically not as high in a very dry year as a more normal one it is often still possible to run 20 dry sheep equivalents through the critical dry period with excellent weight gains.
Reliably sowing dual purpose crop on time takes a lot of our attention. Late summer early to mid-autumn is commonly erratic and low rainfall. If available lighter soils establish on less rain than heavy soils (higher probability of being able to sow early).
Stubble retention helps keep soil moisture closer to the surface. Sowing earlier than generally considered acceptable, even as early as February, can improve probability of timely establishment.
Like several farmers we are pushing the temperature limit on winter crop sowing but appreciate we need good sub soil moisture and need to accept some risk.
Next week: Research identifying more phosphate efficient pastures.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.
