Bill Crabtree visiting Agronomist from Esperance, Western Australia
on job exchange with Bob Bradley from PFRA, Brandon, Manitoba

The harsh dry climate of most of Australia and the often shallow, and sometimes sandy and infertile soils, particularly in the west, make zero tillage an attractive long-term cropping system. There are many interesting differences and similarities between southern Western Australia and Manitoba. In both places I have mixed with farmers, researchers, extension people and zero till advocates.

Like here, zero till in Western Australia (WA) only took off about 7 years ago. The drop in the price of Roundup, the growing desire to conserve fragile soils, less moisture lost from tillage in dry areas, the time, labour and machinery savings of zero tillage and the no yield penalty from zero till has encouraged zero tills adoption. Unlike here, the adoption has taken off in the last 3-5 years and now more than 50% of farmers in many regions of WA are zero tilling.

SIMILARITIES AND DIFFERENCES

Crops grown in southern WA are mostly wheat, barley, lupins, canola, oats, peas and other pulses and are mostly all sown in early May and harvested in November. Each days delay in seeding reduces yields by about 1%. At the same time, as the cold January winters stop you from growing crops, farmers in January in Australia suffer from the hot and dry that stops crop growth and irrigation is limited. In Australia, rainfall reliably exceeds evaporation only in winter, which is when the crops are grown.

In contrast to the Prairies, the Australian soils are cooling down and wetting up in May and the daylight hours are short (10.5 hours). Consequently, at seeding time, WA farmers are not as concerned as you are about the 'soil-drying-out' as their winter rains often occur weekly. Therefore, cultivating below the seed zone is not harmful for crop emergence. In fact some 4" deep, but narrow (0.5") cultivation is often used to reduce the fungal disease rhizoctonia bare patch which occurs in all crops and is worse in zero tilled soils.

No snow, but rather hot dry winds and intense sunlight (29-35 degrees latitude) during a southern Australian summer bake the soils surface. Over this soil, march the 'four-hoovedcombine' - the merino sheep, who roams inefficiently in search of food and water. Their roaming loosens the dry soil and predisposes it too wind erosion. However, sheep are an important part of farming in southern Australia.

Having sheep means that Australian farms have many fences, with 40-60% of fields (paddocks) being forages (pastures) that sheep graze throughout the year and a dug-out (dam) usually exists in each paddock. Paddocks are often 150-300 acres in size and farms are often 2,000-10,000 acres in size and each farm has a large shearing shed to harvest the wool.

Crops are often sown into pastures that would otherwise naturally regenerate in April-May after enough rain falls to germinate plants. Such a rain that occurs when temperatures drop enough to where plants will not drought afterwards is called the 'break' to the season. Annual germinating pastures can be weeds in crops, but since there are no perennial weeds to kill as the summer does that for us, low rates of Roundup (120 mL/ha) often work effectively.

These pasture 'crops' produce a lot of nitrogen and are a main reason why we apply less nitrogen than you do. Some cereal crops would only get 25 lbs N/acre while canola might get 80 lbs. The cool and raining conditions after seeding make urea 4 weeks after seeding a sensible option in WA. Our lush lupin crops can also fix large amounts of nitrogen (230 lbs/acre of N), of which only 10-20% might be exported as grain. Adding any nitrogen after these crops of lupins has often reduced 75 bush/ac wheat yields.

ZERO TILL HISTORY

We too had our Jim McCutcheons who pioneered and worked with zero till in the mid 70's through to the 90's. These pioneers were generally considered a bit strange, but are now leaders in zero till and admired for their skill in making it work. Interestingly there was reservation among Department of Agriculture staff who did early trial work which showed lower yields with zero till disc machines. The registration of Hoegrass, better legumes in the rotation, clean break crops, higher yields and the use of press wheels made for better yields.

By the late 1980's enough good agronomy was adopted for high yielding (60 bush/ac) crops to be common with high levels of stubble or trash afterwards. This trash blocks combines (seeders) much more easily than in the Plains region. Some farmers attempted to carefully burn the unspread header (combine) rows, while others burnt whole fields just prior to seeding. However, some severe winds and a poor 'break' before seeding caused severe wind erosion. Where topsoil is shallow (less than 4") over horrible non-structured clay soils, the incentive that the wind and subsequent erosion provided for change was powerful.

It was clear to everyone that zero tilled paddocks didn't blow anything like the cultivated ones and they produced a crop as well. Water erosion and soil compaction are also important issues for many farmers. The current membership of the Western Australian No Tillage Farmers Association (WANTFA) is near 1,000 from the 50 who started the movement in September 1992. WANTFA was modeled on this Manitoba North Dakota Zero Tillage Farmers Association (MANDAK) and is a sister organisation. It was this link that enabled Bob Bradley and I to exchanged places for 12 months. So thank you!

Our groups are quite similar but we differ in that our annual meetings are small and the information exchange has been through a more technically based newsletter. As of this year WANTFA are employing a full time agronomist to exchange information and a secreteriat, both will service the whole State.

SEEDING MACHINES

Which type of zero till machine to buy in western 'down-under' is not clear cut. Some environments favour discs while others knife points (0.5" narrow hoe openers). The inability of hoe seeders to seed through stubbles is their biggest problem and in rocky soils the disc seeders ride better. The ware rates on either machine type are high and changing tips every 300-500 acres occurs often in Australia. In these tough conditions tungsten carbide tips reduce the ware to about one third.

Australian farmers can zero till with some very cheap machines. Even $3,000 machines are often used or made out of scrap metal. Your machines when sent to Australia are another 10-30% dearer than they are here.

CROP MANAGEMENT

The 2-3 thunderstorms that might occur during summer may drop some rain before the true break and this will allow weeds and insects to grow. Some of these will not drought prior to the break in April-May and if these weeds are not controlled soon after germination they will be hard to kill near seeding time. Also their growth allows insects numbers to build and they can severely damage emerging crops. Some of these insects are very mobile, particularly moths which lay eggs that hatch into grubs and eat crops.

This type of situation was one of the main reasons for the poor earlier yields that farmers had with reduced tillage. However, current good zero till practice is to control the weeds early which does not allow the insects to build up. This also conserves more moisture for the crop to establish on. Although this may worsen the threat of rising ground waters.

The long cool growing season makes WA crops worse for insects and diseases than is apparent over hear. Our good wheat crops are 2-3 times more responsive to foliar disease control (Tilt) than yours. Even cereal crops may be sprayed 2-3 times for different insects. In high yielding barley or wheat crops aphids can reduce yields by 30% or 15% respectively.

CONCLUSION

Suprisingly Australian crops are grown under colder conditions than Great Plains crops. Australia has taken more quickly to zero till than in this part of the world. The Plains have more critical soil moisture concerns at seeding. The perennial weeds that you have are not a concern in Australia as our hot Australian summers kill them. This allows Australian farmers to use lower rates of knockdown herbicides.

In both parts of the world zero till stabilizes yields through a range of seasons and it also stabilizes and saves the soil from erosion. Even though we are worlds apart spacially, we have much in common - weeds, insects, diseases, fertilizers, rotations, machinery, Dwayne Beck, drought, erosion and the pain and gain that comes from adopting less tillage.