Return to 2001 Conference Proceedings
No Till Farming In North East Australia
R.J. Esdaile, Former Director, University of Sydney, Livingston Farm, Moree NSW Australia.
Australia as you may know is the 'down under' continent. It has a landmass of 7.6M sq. km, which is roughly the same size as continental USA (excluding Alaska).
It stretches from latitude 12oS (tropical) to 42oS (very temperate). The tropical areas have very summer dominant rainfall with winter droughts, whilst the temperate areas have a winter dominant rainfall with summer droughts.
Highest rainfall is on the coastal strip around the continent, with amounts progressively decreasing as one moves further into the interior. Although we have interior mountain ranges, they are not of the scale of those on other continents. Our smaller mountain ranges do not exert the same influence on national weather, and this means lower overall rainfall as well as poorer reliability than some other nations of the world.
Australia is one of the world's significant agricultural exporters, although internationally many nations produce much more than us. The reason is that with a population of only 19 million, over 80% of production of many of our agricultural commodities is exported. With our broad geography and rainfall patterns, there is no 'corn belt' as such in Australia. The intensive agriculture is carried out on the high rainfall coastal strip. Once one goes over the mountain range/tableland area, the main grain growing area occurs, albeit in a semi-arid environment. Any intensive agriculture in inland areas is largely confined to irrigation areas.
Also, due to our latitude, and the relatively low elevation of the nation, winters are relatively warm. There is no 'freeze up' or snow, or extended dormancy period. This means that what are traditionally classified as spring crops can be planted in the autumn (fall). They will grow through the winter, for a spring harvest. This also means that weeds will grow all year round!
SOILS, CLIMATE AND FARMING METHODS
Most of Australian farming is conducted using similar methods and equipment to that used in N. America. However, due to our harsher environment, and the fact that much of the original cropping areas were covered in hardwood trees, the soils are sometimes tougher to cultivate, and may have obstacles (stumps) in them. This means that the equipment has to be very robust, and have a 'stump jump' capability. In the past much of the N. American equipment has not been tough enough to withstand our conditions.
Australian agriculture is a 'free market' system. There is no CRP, no EEP, no Conservation Compliance, and no drought insurance. We are subject to local and world market forces in the entire agricultural sector. In recent years however there have been temporary Govt. schemes to assist farmers who obviously will not make it to either exit agriculture, or radically restructure. In some cases welfare is payable for a period while this process is carried out. To encourage conservation farming there are some taxation incentives on specified capital purchases, as well as an active promotional program dubbed the 'Landcare' movement.
The more specific area of the NW Plains of NSW and most of southern Queensland is made up of flat arable land in an area of 18-26 inch rainfall. Most soils are heavy black clays that are self mulching (shrink and crack open when dry, swell and close up when wet). They are also very sticky when wet. Water holding capacity is high with the soils capable of storing up to 2 inches of available water per foot of depth. Other areas consist of hard setting heavy soils that are inclined to be sodic, and considerable areas of red loams.
In this cropping area, rainfall tends towards summer dominance. There is also some monsoonal influence. Fields are normally fallowed for 6-7 months after winter cereal harvest in November (spring) to store this rainfall. Winter crops are sown in autumn (mid April-early June) and the crop grows partially on the stored water from the fallow, and partially on the rain falling on the crop. Summer crops are planted in September-October (spring) for a March-April (autumn harvest) after an appropriate fallow. In many aspects the cropping sequences and fallowing techniques are similar to the Great Plains States of USA.
NO TILL IN NORTH EASTERN AUSTRALIA
Up until the late 1960's fallowing was normally carried out by conventional tillage methods. Stubbles were burnt after harvest, and fallows prepared by the initial use of a one-way plough, followed by a tined cultivator. Sowing was by a tined drill, with full soil disturbance at planting. No press wheels were used. Using these techniques reasonable crops were produced on relatively new soils. However this pattern eventually led to weed problems, the build up of cereal root diseases, and to unacceptable soil erosion.
In the 1960's with the release of Paraquat more interest was shown in the replacement of tillage by herbicides. Early research showed that more moisture could be stored in cereal fallows using this practice. Residue retention also assisted in erosion control. However Paraquat was poor in the control of large weeds, high water rates for spraying needed to be used, and the residue at the end of the fallow had to be burnt anyway as the seed drills of that era were only designed for bare fallow planting.
When Glyphosate was released in the 1970's, conservation farming took on a new dimension. Initial use of the herbicide was to control small weeds in wet years, replacing some of the tillage operations. Other herbicides were tank mixed for better control of hard to kill weeds.
Around the same time, Northern Australian farmers became aware of the 'ecofallow' system as used on the Great Plains, and much of this technology has been directly applied to grain sorghum growing in this area.
Sorghum consistently yields 15-20% better grown no till in Northern Australia
With the decreasing price of Glyphosate, along with increasing costs for other farm inputs, conservation farming has steadily increased in Northern Australia since that time. Most farmers initially have replaced some of their tillage operations by herbicides, with many going complete no till after 3 or 4 years.
Most of the reasons for going no till are probably similar to the experience in North America. Both research results and farmer experience in this area have shown significant benefits of no tillage such as:
Table 1. Yield gains from zero-tillage highest in dry areas Wheat yield - kg/ha
|Freebairn, Ward, Clarke and Smith 1986|
|Trials at Biloela (QLD) showed earthworm numbers at 26/sq.m. with no till and 6/sq.m. with cultivation. Water infiltration with no till and earthworms was three times the rate of cultivated soil.|
Table 2. Opportunity Cropping and Zero-tillage improve profit 320 ha Eastern Downs Farm with 240 ha cultivation
|Barley||Opp. crop1||Opp. crop|
|sunflower||zero till||120 ha|
|Overhead costs2 ($/ha)||65600||65600||70000|
|Profit: %return on capital||0.3%||5.4%||10%|
|1. Mung beans and chickpeas as double crop and opportunity crop frequency of 1.33.|
|2. Includes rates, administration, machinery depreciation and labour|
However the process has not been without pain. It seems that every year since we first started, we have taken two steps forward, and one step back, as new problems have appeared. These have to be overcome or sidestepped before we can go forward again.
Machinery development, especially for seeding, has been an ongoing saga of trial and error. Initially most farmers used the standard 'combine' (seeder/cultivator). Most years the residue would have to be burnt before planting to allow the seeder to operate. Most then moved to modified chisel plows and heavy duty cultivators. The larger implement manufacturers showed little interest. However several short line manufacturers have been very co-operative, and a whole line of no till planters has arisen.
Seeder development in Australia has to a point been similar to North America. However most farmers use tine opener seed drills fitted with a stump jump capacity and a capability to penetrate through dry topsoil. In dry years crop farmers set units to penetrate 10-15cm (4-6 inches) to reach the moist soil. Disc openers (either single disc or double disc) are not very popular, as they need too much weight to penetrate dry soil. Also in wet years the soil sticks to the discs in clay soils, and the machine easily plugs with mud.
Practically all Australian farmers use the standard boom spray for pesticide application. Units are either mounted on, or drawn by tractors, or fitted to farm vehicles, In the case of larger farms or contractors, self-propelled spray units are used. Water rates of 20-100 litres per hectare (2-10 gallons per acre) are the most common. Sometimes in wet years, or with very large areas, aerial operators are used to get the job done.
In recent years there has been some use of shielded booms, and drift reductions of up to 50% have been observed. However the benefit can largely be negated if one travels too fast or cuts back on water rates. Air jet and bubble jet nozzles as well as large droplet 'Lo Drift' nozzles fitted to standard booms have become popular in recent years.
There has been some development of weed sensing systems, using reflectance technology. This is still largely in the early improvement stage. There are a few units in the field, but they are very expensive and out of the reach of most farmers. They have potential to cut back drastically on herbicide use by spot spraying low density weed infestations in fallows, or by inter-row spot spraying in row crops, using suitably shielded units.
On Livingston Farm we have commercially used for ten years now a 'bluff plate' boom spray. A researcher in South Australia (Furness) originally developed the concept. He proposed that rather than using air generating units to propel droplets to the target, why not use the disturbed air from the forward motion of the boom to do the same job. No moving parts would be required.
The bluff plate sprayer is essentially a wedge shaped plate airfoil. It deflects oncoming air over the top of the plate, and a zone of stalled, tumbling air, which follows immediately behind the plate is dragged across the ground by the plate at the speed of the spray vehicle. The nozzles are located behind the bluff plate in the stalled air so that spray droplets are actively blown at the target. This increases the amount of spray deposited on the target, enables a finer droplet to be used, permits higher spraying speeds and reduces spray drift. However energy is required to displace the air mass, and both the boom and towing unit must have a good suspension to operate on farm land at relatively high speeds.
Recent research and farmer experience in Northern Australia has shown the benefit of controlled traffic or 'tramlining'. Some farmers have modified their tractors, boom sprays, seeders, and harvesters, to operate on a modular system and confine the wheel tracks to specific lanes in the field. This has been assisted in recent times with the advent of GPS guidance systems. There has been reasonable acceptance of this system, although the capital cost of GPS, and the modification of equipment has been a deterrent to many.
Rotational strategy is a vital part of the no till system in Australia. Monoculture mostly leads to severe outbreaks of plant disease, and a build up of weeds specific to the farming system.
Table 3. Rotation profits - Western Downs
|Wheat yield (t/ha)||1.6||2.2||2.2|
|Average for lucerne/wheat4||106|
|1. Wheat in a rotation with chickpeas, sorghum and barley.|
|2. N, 50 kg/ha|
|3. Rotation: 3 yrs lucerne, 3 yrs wheat.|
|4. Profit from lucerne phase $30/ha.|
Many farmers have an additional weapon that can greatly assist in many parts of the no till operation. For example on Livingston Farm we have had up to 5800 sheep. The main purpose of the sheep is for fallow weed control. In this role sheep can replace other methods of weed control in the fallow. Sheep are introduced and the field is 'crash grazed' for periods of 6 hours to 10 days. The aim is to heavily graze out all the weeds, remove the animals the day after the weeds are eaten, yet before they start to eat significant quantities of residue.
Some of the ongoing problems currently are:
WHERE TO FROM HERE?
Northern Australian farmers will continue to embrace no till, even though we have exchanged one set of problems for another. I would estimate that currently around 50% of the cropland of NE Australia is farmed using conservation farming techniques and 15% is no tilled. As the price of fuel escalates, no till farming will expand.
New pesticides will be found as well as new uses for older products. Unfortunately some of the 'old guard' chemicals may disappear or be severely restricted and we must show the community that we are responsible users of pesticides in order to keep these products as part of our arsenal.
Seeder development will continue. New inventions and innovations by farmers, manufacturers, research workers, and the innovators of this world will result in better and more reliable seed drills.
Improved spraying technology will become more evident, with units being able to operate at higher speeds under a wider range of environmental conditions. Water rates will drop and airfoil booms, precision sprayers, weed sensing sprayers will be developed further. This will ultimately be translated into lower rates of pesticides being used.
Rotational strategies utilising pulse crops, bio-fumigation, pastures, alternate cereal types and oilseeds will become more important as a means of weed, insect, and disease control.
Farmers will need to be smarter and more 'switched on' to handle no till. The majority of grain growers in our area now employ consultants, or utilise local agri-business agronomists to assist in such things as pesticide strategies. As well as the farmers own spray rig, contractors are assuming a bigger role in the spraying operation.
Herbicide resistance will probably get worse if we do not start to address the problem now. Already we have some weeds resistant to some herbicide groups.
Confucius says: 'When you are on a good thing- don't stick to it- rotate your herbicide groups'
Pressure from some sections of the urban community will probably increase to reduce pesticide use, or apply more restrictions. We must be responsible, and vigilant to accurately use pesticides so that all of the material hits the target (be it weed, crop, or soil) and none is lost off target to drift away and cause problems elsewhere in the environment.
In summary, no till farming is alive and well in Northern Australia, and continues to expand. Most of the joys and problems are the same as those in North America. However some of our ideas are unique. Come down and see us sometime.