Selecting the best variety, or varieties, for a given environment is especially important for a tropical grass-based pasture. With reasonable management, even through droughts, they can last indefinitely with many stands now 20 years old and a good number over 30 years old and showing no signs of decline.
Sow a lessor variety, and commonly stands thin out within a few years, especially if droughts occur. Some species and varieties are also not my favourite because of lessor productivity. I can make this statement having being involved with many tropical grass variety trials conducted over big areas of NSW since the 1980s. Most of this research involved NSW DPI agronomists including myself.
Because of a number of consecutive dry summers seed supplies of some of the better varieties, for given areas, is currently almost non-existent. Some seed of a favoured variety/species may be available in commercial mixtures that often contain big percentages of varieties one commonly doesn’t want.
If you can’t acquire the variety you want it is best to wait until supplies improve. Bear in mind you are after a pasture to last indefinitely and it will prove far costlier to re-sow in a few years’ time, involving the normal preparation time and cost, if less persistent varieties are sown. Hopefully a few good summers are on the way or/and more seed production is undertaken in irrigation situations.
Premier digit grass is an example of a standout variety in a lot of inland environments from areas with as little as 400mm average annual rainfall to over 700mm. It is tolerant to soils with quite low soil pH with aluminium levels as high as 30 odd percent of the cation exchange capacity (CEC). Premier suits a wide range of soils from sandy to light clays and even performs well on some clay soils.
Bambatsi panic has an excellent reputation on heavy clay soils from environments as low as 60mm average annual rainfall to areas with over 70mm. It has good waterlogged tolerance including surviving moderate floods. Commonly it is grown with Premier digit in mixed soil paddocks and can perform well on medium loams to clays. A recent release of the same species, Megamax 059, has perhaps even wider adaptability especially also including many lighter textured soils.
A number of tropical species, commonly included in sale mixes, including various Rhodes grasses and some panics have not proved as persistent in many environments, including our central west district at Purlewaugh (east of Coonabarabran). How devastating this can be is exampled by a friend of mine who was adamant that Rhodes grass (two varieties) was the “bees knees” and he wouldn’t grow anything else. Unfortunately, as our trials had shown, a drought resulted in him losing the bulk of it.
Most of the wide range of summer perennial grasses have their main role in a particular environment but not necessarily in others, including Rhodes grass and panics. for example some buffel grass varieties do well in hotter north western areas. Floren bluegrass has flood tolerance and suits cracking clay soils. Kikuyu is hardy and especially performs well under irrigation.
Whatever the variety sound establishment is important. Good grazing management maximises persistence and productivity of whatever the species. Good grazing management includes not frequently grazing into the ground and periodic rest for root reserve recovery. Growing tropicals with winter legumes is also part of a good pasture. Soil deficiencies also need to be corrected for persistence, quality and productivity.
Tropical pastures are long term persistent if properly chosen and well managed. Don’t accept or devise mixtures unless you are sure you have what’s best for your property.