A farmer's experience by Owen Brownley*, Mt Madden, WA
GroundCover™ Issue: 40
MY WIFE Terri and I farm at Mt Madden, 25 km south-east of Lake King. We continuously crop 3,100 ha and have no sheep on our property, retaining all our stubble on the surface to feed living organisms in the soil. Crops are sown with minimum tillage, being either a flexi-coil bar on 250 mm (10") spacings, 12 mm knife points and 100 mm wide press wheels or a Great Plains triple disc seeder. Both machines have a triple air system to separate seed fertiliser and nitrogen if needed.
Wide rows for disease management
I can see some advantages in planting with wide rows of some crops like beans, canola and summer crops. Our experience with faba beans has been with 380 mm (15") row spacings, also 760 mm (30") rows. The idea here is to let the air flow between the rows, helping to dry out the moisture and humidity more quickly, making unfavourable conditions for chocolate spot and leaf disease build-up. With this system, I have started applying fungicides to the young plants at four weeks old and then every three to four weeks afterwards at half the recommended rate, attempting to prevent early spore build-up.
This should create less disease pressure later in growth when there is more biomass coverage, less drying and more humidity, making favourable disease conditions. The wide rows also give a better chance to apply fungicides down the depth of the plants instead of on the top leaves. The 380 mm (15") paired rows are probably too close, as they canopied over too early, preventing a good fungicide coverage.
Next season we will be trying single 750 mm (30") spacings for better air movement and fungicide coverage and also some 1 m (39") rows where we are likely to have some problem weeds. We will try controlling these weeds with a
knockdown chemical through a hooded sprayer between the crop rows.
To seed these crops we have been using a Great Plains triple disc seeder. Our Simplicity air seeder bin allows us to put 25,30,50,75 or 100 per cent of fertiliser with the seed and the remaining fertiliser sown through the rows either side of the seed row 250 mm away.
Good yield, clean seed
The beans last year yielded 2.7 t/ha with the cleanest, disease-free seed we have ever had. I'm not sure how well the air flow between rows helped, as the first year we tried it was our biggest drought in 20 years, and this last year was a relatively low disease year. Where we didn't spray fungicide on a 3-hectare piece, the crop was a lot more uneven and yielded less.
It'& worth a try if a half rate of diathane fungicide applied every three or four weeks for four or five applications (three last season) could increase the bean yield closer to their potential, which I believe is at least 3 t/ha: an increase of 2 t/ha at $200 or $300 per tonne is $400-$600 per hectare, costing approximately $55 for products plus application costs.
Our summer crops sown with similar seeding techniques with 800 mm row spacings gave outstanding yields in the wet of 2000 summer, and looked good again this year. We are comparing our 800 mm row spacing with WANTFA's precision planter at I m spacings with plants evenly distributed.
Ryegrass gone with discseeder
An interesting observation is that the only paddock continuously seeded with the triple disc. seeder used to have huge ryegrass numbers now has next to none. Also two cereal stubbles from last year had a lot of heads on the grounds for different reasons. The one that was sown with the triple disc had very little regrowth heads and the one sown with the knife points that shift more soil had quite thick regrowth through the next crop. Leaving seeds of any kind on the surface seemed to help with control. As soon as I can find a disc machine to suit my requirements, I will sell the tines.
Contact: Mr Owen Brownley 0898380010 email firstname.lastname@example.org
* Presented at the WA No-Tillage Farmers ASS6ciation (WANTFA) 2002 conference