Not by choice thousands of landholders across NSW and adjoining states have summer growing perennial weeds such as African lovegrass and Coolatai grass. They are relatively unpalatable compared to many native (but not all) perennials as well as compared to introduced ones like Premier digit and temperate species like phalaris.
Eradication is feasible for farmers with smaller infestations and new infestations can be eliminated if detected early with appropriate killing if undertaken before seed set. But for thousands of landholders across much of the state eradication is very difficult because of widespread infestations and constant reinvasion from adjoining land including public roadways.
In our case we adjoin a public road with solid African lovegrass infestation. Our strategy is twofold. Eliminate via winter cropping combined with summer fallow herbicide weed elimination and then sow down to a tropical grass plus winter legume pasture.
Secondly in areas not designated for cropping for some time utilise as best as possible via ensuring good legume pasture component and good soil fertility.
Glyphosate herbicide used after every significant fallow rainfall event has proved successful in eliminating adult plants of African lovegrass. A cycle of three winter crops with timely fallow spraying generally ensures all adult plants are well and truly eliminated plus soil weed seed reserves should be well run down.
Well established tropical grass pastures of long term persistent species, such as Premier digit grass for many environments, can do a pretty good job of preventing African lovegrass from reinvasion. We have one paddock for example, now around 16-years-old, that remains largely Premier digit with just the odd invasion of African. Possibly one day it will need to again go to a cropping phase and re-sow to tropical.
Good establishment of a new tropical grass pasture and sensible grazing management are part of ensuring a competitive pasture that will last indefinitely. If tropical weeds like African or Coolatai can grow in an area so should a tropical grass like Premier to compete with it. That opens up a challenge for non-traditional tropical grass areas.
Where areas are non-arable or not yet designated for cropping, and with more than the odd African lovegrass plant, they can be well utilised by livestock if soil fertility is maintained and if legumes like sub clover and serradella are managed to grow with them. While African lovegrass and Coolatai are relatively low-ranking species for palatability, when other feed is largely eaten out its commonly surprising how well animals do on it and how well they will graze it.
From early April onwards this year (and last year) we were getting short of feed except for African lovegrass in a couple of native grass paddocks adjoining an infested public roadway. In a way these areas were a mini haystack of good quality, if low palatability feed in both autumn, early winter and again this spring.
Within a few weeks African lovegrass was well grazed down and animals continued to grow well over the grazing period. Normally these paddocks grow good legume during winter and spring. Superphosphate use has corrected soil phosphorus and sulphur deficiency. Soil fertility we regard as good.
My livestock advisor colleagues generally advocate availability of high protein supplement for grazing in areas with less palatable species like African lovegrass. We generally do this as a matter of routine.
Good grazing management that includes not grazing pastures to the ground, especially over long periods, rest and recovery after grazing, also help to encourage native perennials to better coexist and compete with invading weeds like African lovegrass.