Pasture type and grazing management are aspects that I believe can improve many landholder's ability to better cope with future droughts.
There are dozens of factors important to drought management, but getting the maximum pasture production per millimetre of rain, especially when it falls outside the so called "traditional" growing period, is vital.
One commonly hears statements like "that 20mm storm rain was useless because it either mainly ran off the paddock or it fell when clovers and annual grasses had dried off and all it would grow would be burrs".
Even in southern parts of NSW late spring, summer and early autumn rains are not uncommon, even in a drought year.
In drought years commonly winter annuals dry off in early spring. They won't start again until the following late autumn. For these pasture types, an ability to use storm or any rain event for over eight months is poor.
Lucerne can use rain whenever it occurs but unfortunately, many soils are not that suited to it. It also provides poor groundcover in long dry periods, requires good rotational grazing management and requires periodic resowing.
Temperate perennials have also commonly poorly persisted for many environments over the drought, including more favourable higher elevation areas, especially on lighter textured soils.
Perennial tropical grasses may to many seem only to be an option for northern environments, however, we now have good examples of them performing well in low rainfall western areas, higher altitude tableland environments, coastal, and areas well south of traditional growing districts.
Advantage of tropical perennial grasses include, provided right varieties are selected, they have a track record of lasting indefinitely (stands well over 30 years old now common, given sensible management), including through droughts like the present one.
Their active growing period is shorter in colder higher elevation districts, but even in these areas they generally have a growing period from Late October to the end of April (six months).
To compensate for a shorter growing period, because they are compatible with winter legumes, they can coexist with species like sub clover, serradella and the like. So, they form a pasture that can use rain whenever it occurs.
In southern or central NSW environments, like in northern ones, tropical grasses are compatible with winter legumes and grasses like annual ryegrass. The tropical grass advantage is that they can respond to rain that so commonly falls after winter annuals have died off.
Typical non tableland growing period for the tropicals is between mid-September and the end of May. Especially during a drought that's an eight and a half months period when winter annuals contribute nothing.
Of importance to higher elevation areas is that tropical grasses don't totally cease growth if an "out of the ordinary" late or very early frost occurs. Their growth can burn back but once warmer conditions return their growth recommences.
This current drought, especially on lighter medium textured soils, tropicals have been able to respond quickly to any significant rain event. For example, on our own property, we received two reasonable rain events, three weeks apart, in November. Within two weeks we were able to purchase additional stock (to partially restock) and these have thrived on high-quality Premier digit grass.
A few provisos are necessary if tropical grasses are to be valuable. Planning and care with establishment, especially into weed free seedbeds is important. Good quality feed, as for all pasture species, requires good soil fertility. Tropicals are like any other grasses needing good soil fertility, including nitrogen, phosphorus and sulphur.
And like most pasture species sensible grazing management helps ensure fast recovery when rain does fall. Good grazing management includes at least a minimal groundcover retention of 0.5 t/ha dry matter. Plants allowed to periodically flower and allowed to have reasonable rest periods between grazing all tend to recover far faster than those constantly grazed hard.
Next week: Paddock crop yield differences. Maximising overall yield.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email firstname.lastname@example.org or contact (0428) 752 149.