Leucaena Evaluation for Beef Production in SW Queensland

Summary

Establishment
The first and probably biggest lesson was that establishment is complicated and risky. Despite having an establishment protocol for all members to follow, initial plantings were not successful. The project lost two participating enterprises after establishment failed more than once. Findings included:
Early planting is risky, a cold snap following early germination all but wiped out one plantation;
Heavy rain post plant compromised early plantings, and the seedbed crusted over, making it difficult for seedlings to germinate;
The seedbed must be fine, and soil must be worked enough to ensure this fine texture and ease of germination. Breaking up the surface crusting eases germination; and
Good planters were hard to acquire and in the end a planter was designed and built by one enterprise to ensure satisfactory planting.
This planter was based on a Jenke planter with precision boxes, adjustable tines, twin press wheels and a Jenke parallelogram.
Successful Methods
After early establishment failures, the three remaining enterprises varied their establishment techniques slightly. Successful establishment techniques included:
Eight metre centered row spacing on Marrett was most successful;
On Carisbrook rows with 6.5m centers were successful;
A tined air seeder was used on Carisbrook;
Planting rate was 1kg per acre;
Taramba was used on Carsibrook and a mix of Taramba and Cunningham was used on Marrett;
Using Lawsban and MAP at 30-50kg per hectare beside the seed was successful at Alicedale;
One metre between rows and twin rows are a good idea as this seems to promote a good plant population;
Planting with parallelogram tines provides good depth control;
Herbicide use
Round-up pre-planting and Spinnaker or Duel Gold after planting (Duel Gold worked better than Spinnaker on Alicedale);
Inter-row cultivation after establishment to control weeds. Yetter Wheels used for inter-row cultivation;
Hilling up seedbeds worked most successfully on Marrett and Alicedale;
Water injection aided emergence;
Fertiliser and seeding in one pass;
Good seed bed preparation is a must; and
Planting on good moisture is essential.
Trial Measurements
Establishment problems meant that grazing started much later than anticipated. Further advise suggests that the longer the delay in first grazing, the better the health and future productivity of the plant. This may have contributed to increased weight gains at Carisbrook. The delay in grazing data, means that grazing results are not conclusive and results collected over the next two years will determine the success of the project goals.
One site used electric tape to split the area and rotated cattle throughout the plot. It took several frosts to loose all leaves, however, post frost measurements would have been very difficult to take due to leaf loss. Plants remained dormant until rain and warmth of spring when leaf production became prolific.
On average 10 days of this prolific growth was enough to enable the option to regraze plants. It is therefore believed that frosting forces plants into a dormant state (even though they look dead). Post frosts, there was no damage to plants and productivity continued to increase with increasing temperatures. Frosting negated the need for slashing no slashing has been performed on any of the trial sites.
Effective grazing also managed plant heights with cattle taking off the tops of plants if they were grazed at regular intervals. The group held a free open field day for the public, and around 100 people came from across Southern Queensland and Northern New South Wales. Weed control on some plots could have been better and caused parts of the plots to be thinner than others, and in some cases, failure of emergence. Leucaena is not tolerant of competition in the seedling stages.