Oak Valley Longwood. Vic. 3665
My involvement in the Grassland's Productivity Program began in 1992. Our branch of the Grassland Society visited the then Pastoral Research Institute, at Hamilton in Victoria's cold and windy south-west. The trial is run by Geoffrey Saul and John Cayley.
We saw their phosphate trial which was started in 1977. The farmers in our group were impressed with what seemed to be a very no nonsense trial. The area was initially a low fertility area which was sown to perennial pastures with superphosphate applied.
It was originally stocked with wethers. I would say the trial came to life when they changed to spring lambing Merino ewes. This is because the pasture reaches its peak growth at the same time that the ewes needed extra feed for milk production plus when lambs began grazing. Most of their animal health problems were in the high stocking rate paddock where lower fertiliser rates were applied.
What struck us most were the high stocking rates that were maintained where the high rates of fertiliser were applied. The lack of animal health problems and the ability of the pasture to sustain its vigour were also impressive.
This led to Jim Shovelton, Richland Laboratories, heading a trial in north-eastern Victoria with our group of four farmers. The question was whether such a system would succeed in our very different soil and climate.
Jim Shovelton raised sponsors, to whom we are very grateful. The aim of our trials was to answer the following questions:
• are there limits?
• is it sustainable?
• is it profitable?
My trial was established in a paddock sown to Australian phalaris, Porto cocksfoot and a small amount of subclover which I had considered to be a productive paddock.
Out of the paddock I randomly fenced off 12 ha for the High Input plot.
Soil tests showed there was a low level of potash. In June, 25 kg/ha of phosphate and 60 kg/ha of potash were applied. Both the trial plot and the control area were stocked with spring lambing Merino ewes at 6 ewes/ha (2.5 ewes/acre).
The pasture growth was spectacular. It was as if we had also applied nitrogen fertiliser. To our surprise the immediate growth response was in the phalaris.
Our group inspected each of the four plots and agreed that my plot could carry an increased stocking rate of 7.5 ewes/ha (3 ewes/acre). Lamb marking in October boosted our confidence as
the body weight of the ewes in the High Input was 5.25 kg higher than the control. In addition, the lambs were much more robust than their cousins in the control paddock.
At weaning, the High Input lambs were heavier by 2.4 kg and had bloom like prime lambs. We found that the High Input stock were always heavier than the control.
We also found that both mobs had roughly the same meat and wool production. However, on a production/ha basis, the High Input mob was far ahead. This was despite our plan to maintain similar body weights in each paddock by adjusting the stocking rate.
Spring produced a real surplus of feed and the stocking rate was boosted to 10 ewes/ha (4 ewes/acre). This was an increase of over 50% over the original stocking rate. As 1993 was an unusual year, we decided we would eat the surplus grass with cattle rather than increase sheep numbers. Fifty heifer weaners were put in for nearly two months and, with the wisdom of hindsight, they should have been left in for longer.
The question of rates of fertiliser began to bother me. So, we fenced off another 13.8 ha on which half the High Input rate of fertiliser was applied (12 kg/ha phosphate). We set the stocking rate at 6.9 ewes per hectare. In retrospect, this was too many sheep as they did not do too well.
A year after the trial started, we again increased the number of sheep in the High Input by 25% to 12.4 ewes/ha. This is nearly 2.5 times the control.
In spring 1993 the wheels fell off when the sheep contracted footrot. We had to change the
stock to heifers with spring calves at the same stocking rate as for the sheep.
When we weaned our calves, we found the cows had lost weight in all the plots with the Half Input being the worst. Within 111 days the calves had gained the following weight:
High Input 64.25 kg/ha
Half Input 29.78 kg/ha
Control 27.08 kg/ha
During a recent group visit to Oak Valley, it was decided to increase the stocking rate in the High Input by three more cows. I feel confident the paddock will carry them.
The gross margin last year in the trial showed a profit:
High Input $275.14/ha
Half Input $172.09/ha
An increase in wool price would have made it much more profitable.
All our worst fears have been allayed. We expected animal health to be a problem but in my case the livestock have thrived and worm burdens have been low in the High Input. I expected bare ground in the autumn but to date there has been a big carry over of feed. In fact there has been too much. The pasture species have changed for the better as the undesirable ones are in decline. These include erodium, onion grass and silvergrass. The growth at the autumn break has been earlier and more prolific. Spring growth remains green longer and haying off is much later than other paddocks.
The trial has been a rewarding and stimulating adventure. Being involved with others in the trial has been valuable due to the interaction between us.
My attitude has now changed. I believe it is profitable and possible to extend the idea over my whole farm. Profitability was even possible during the depressed wool prices.
There are further challenges as the extra fertiliser and livestock will need an injection of cash. National Australia Bank should be agreeable to this as they too have been very interested through being a sponsor.
I have had to develop new skills of management such as measuring the volume of feed and understanding livestock requirements for feed. Overall, I have found the trials have been rewarding and indeed exciting.