1. Chris GardinerJCU , Carole WrightDAFF & Michele CoventryAgrimix
Ex -16th Australian Agronomy Conference, UNE October 2012
The germination, passage and viability of Desmanthus virgatus seed through sheep and its implication for dispersal in tropical rangelands
Chris GardinerJCU , Carole WrightDAFF & Michele CoventryAgrimix
Desmanthus spp are prostrate to erect, perennial herbaceous to suffruticose Mimosaceae legumes native to the Americas. They have great potential as pasture legumes for Northern Australia in alkaline semiarid clay soil environments where few if any other sown legumes are available. Recently Progardes Desmanthus has been released by Agrimix ( Graziers in northern regions have expressed a strong interest in faecal seeding as a cost effective way of introducing legumes into their native grass pastures.
A study exploring the germination, scarification and passage of
D.virgatus (JCU 2) seed through sheep was instigated and revealed:
Seed scarification improved germination from 23% to 80%
Most seeds were recovered 48hours post feeding
9% of seeds fed to sheep were recovered
Germination post digestion was low 3-5% however
Additional scarification post digestion resulted in 60% germination
Discussion & Conclusions: Seedling establishment is often the result of the
no. of seeds deposited in favourable microsites rather than total no. of seeds
dispersed (Harper et al 1965). Seeds in faeces benefit from; high organic
matter, moisture content, short term avoidance of grazing, short term
reduction in competition (Armke & Scott 1999). Ocumpaugh et al (1996 )
found that faecal seeding of Panicium was advantageous over broadcast
seed in terms of plant establishment & vigour. Bishop (1983) found a 90%
frequency of Aeschynomene in a paddock as a result of faecal seeding. In our
trial seed recovery from sheep was low but Armke & Scott (1999) fed
Desmanthus illinoensis to cattle & recovered 75% of the seeds fed in faeces.
Informal studies at JCU have shown Progardes seed fed to cattle and horses
readily pass through the animals and become established in paddocks.
Yet to be done however are studies: to compare the establishment of
broadcast versus faecal seeding; the cost effectiveness of each method; how the seeds are distributed throughout the paddock and the time taken to establish a good legume pasture. Desmanthus seed readily passes through cattle and can become established.
Faecal seeding may well be an effective method of establishing these valuable legumes into extensive rangelands where other more traditional methods of seeding (cultivation, aerial seeding, broadcasting) are limited or unfeasible.
Desmanthus leaf , seedling emerging from sheep faeces
Numerous Progardes seedlings emerging from cattle & horse faeces