ZERO TILL RAPESEED PRODUCTION |
Robert Stevenson, Oak Lake, Manitoba
Manitoba-North Dakota Zero Till Workshop
January 23-25, 1989
For many years I felt it was necessary to have a good black seedbed and incorporate Treflan to produce rapeseed. By 1984 we were zero tilling cereals and in 1985 all our cereals were zero till but oilseeds were still produced conventionally. On June 5 winds of 163 km/hr sent all my oilseed crop skyward but never affected my zero till cereals at all. We decided that was enough, there was no point farming that way and it was either stop growing oilseeds or switch to zero-till.
Oilseeds and broadleaf crops are important in zero till rotations. It is necessary to break the cycle of leaf disease which carry over on zero till stubble. We find it important to straw management as there tend to he less residue to deal with after oilseed and there is a year for the previous stubble to decompose. Rapeseed is seeded later than cereals thus it fits zero-till well. Oilseeds also tend to be higher value. For these reasons we have continued to grow rapeseed and for the last two years all my rape has been zero-till. I am convinced that not only does a zero-till program need rapeseed, rapeseed badly needs zero till. It is a crop which is very slow in establishing ground cover after seeding, thus prolonging the time it is vulnerable to erosion. It needs protection from wind which standing stubble provides perfectly. This year surface soil temperatures as high as 160 degree F caused heat canker and rape plants pinched off at the ground level and broke off when the plant bolted at flowering. Soil temperature never got that high in zero-till.
With rapeseed, or canola as we call it now, it is necessary to consider the same concerns as with all zero-till crops, those being straw management, seed and fertilizer placement, weed control, and variety selection. I'll talk about those points and how we have handled them.
It is necessary to handle the previous crop residue so it won't interfere with seeding. With canola you don't have the luxury of seeding deeper if necessary. We feel it is necessary to cut the crop at ten inches or less. The chaff must be spread with a chaff spreader and the straw chopped and spread. Otherwise the blanket of chaff and straw will make seeding difficult, delaying emergence, and lead to unhealthy plants in chaff rows. You will be unhappy with your crop. It may be necessary to harrow the stubble on a hot day before seeding to break up and scatter the straw more.
There are three fertilizer methods we have tried. We have tried broadcasting urea in front of the seeder and putting phosphate and sulfur with the seed. This works I suppose, especially if it rains immediately, but we don't really like broadcasting.
Many zero tillers knife in all their fertilizer the previous fall. It is good to have it on. It helps with spreading crop residue. It exposes some black soil helping it warm up sooner in the spring. However we find in our soil we disturb more soil than we like. Our heavy clay sticks to our knives, even at a depth of two inches. The ground dries out that much faster in the spring. There is more volunteer crop and weed growth, using up more moisture. What we would like is to set up a cultivator with 16 to 20 inch spaces specifically for knifing fertilizer. Disturbing less soil would alleviate these problems.
Last year we put an extra set of hoses and manifolds on our air-seeder and split the seed and fertilizer. We use a six inch tooth on a 12 inch space. The seed was split to each side and the fertilizer was all put down a band in the centre as a granular blend. We seeded 300 acres of canola this way and were pleased with the results. However it is more work for a busy season. All my canola will be seeded this way in 1989.
As I said we seed with an air seeder with 6 inch teeth. At one time we used a 12 inch tooth. We had real problems in heavy straw or wet conditions. Front rows of seed were buried to deep and back rows would not be covered. Plugging was more of a problem. Switching to narrow teeth has vastly improved our seed placement. If the fertilizer was on I think you could go to a 4 inch tooth, disturb less soil, and still have the rows close enough. We find we have much more flexibility on seeding date. Moisture is retained near the surface longer. Small showers; are more effective and don't just disappear. We find we are seeding shallower into firm moist seedbed when we want to. We have never had to re-seed a field of zero-till canola, in fact in 5 years I have not re-seeded any zero-till crop.
Variety selection will depend on weed spectrum and seeding date. Westar is higher yielding if seeded early. Tribute or Triton are triazine tolerant and can be sprayed for wide range of broadleaf weeds. Tobin is early maturing and fits well in zero till if you are delaying seeding due to weather or waiting on quackgrass. We have zero tilled all these varieties.
Weed control will depend on variety planted and weed spectrum. Control winter annuals the previous fall if necessary with 2-40. We use Roundup as a preseeding burn-off. 113 LIA controls annual grass weeds and many broadleafs. 112 L gives quackgrass suppression as well. We use higher rates if needed. We add a surfactant below 1 Litre/acre Roundup as well as 2 lb. ammonium sulfate per acre.
Some growers use up to 112 litre per acre of 2-4D with their Roundup as a burn-off and feel they get only a delay in crop maturity of a few days. I have never tried this. Herbicide residue is dependent on factors such as pH, soil moisture, and temperature as well as speed of crop emergence.
After crop emergence we use Poast as necessary. We spot spray Lontrol for Canada thistle. On triazine tolerant canola we tank mix Poast and Bladex, then spot spray Lontrol later. With zero till we find annual weed such as millet are much less a concern while perennials such as grass and thistle need attention.
There are a couple disadvantages to zero-till canola I want to mention. At night it will be colder in a stubble field than a black field at the ground level in the spring. This is due to less breeze due protection and heat rising off the black field. Those extra few degrees of frost can be the between losing a crop to frost. Seeding may be delayed with zero-till both for risk of frost and the need to wait for grass to be advanced enough to spray.
Economics can't be ignored if you intend to stay in business. In 1988 my brother had a 114 section of canola conventionally cropped close to a 114 section of my zero till. We compared the two fields.
| CONVENTIONAL | |
| WESTAR canola seeded May 15 | |
| Seed | $5.00 |
| Fertilizer 70-40-0-15 | |
| NH3 at 17 cents | 11.90 |
| P205 at 21 cents | 8.40 |
| S at 14 cents | 2.10 |
| Chemicals | |
| Treflan QR 25 lbs/A | 12.50 |
| Lontrel (25% of field) | 3.75 |
| Insurance | 6.00 |
| Misc. | 3.00 |
| Tillage 3 times @ 3.00 | 9.00 |
| Seeding | 4.00 |
| Spraying times 2 | 2.00 |
| Harvest | 20.00 |
| Storage | 3.00 |
| Land charge | 25.00 |
| Total Cost | $115.65 |
| Yield 26 Bu/A $7.00/Bu | $182.00 |
| ZERO TILL | |||
| |||
| Seed | $5.00 | ||
| Fertilizer 70-40-0-15 | |||
| N (urea) 20 cents | 14.00 | ||
| P205 at 21 cents | 8.40 | ||
| S at 14 cents | 2.10 | ||
| Chemicals | |||
| Roundup 1/2 1/A + surfactant and amm. sul. | 10.00 | ||
| Poast (spots) | 10.00 | ||
| Lontrel (25% of field) | 3.75 | ||
| Insurance | 6.00 | ||
| Misc. | 3.00 | ||
| Tillage (none) | 0.00 | ||
| Seeding | 4.00 | ||
| Spray 3 times | 3.00 | ||
| Harvest | 20.00 | ||
| Storage | 3.00 | ||
| Land charge | 25.00 | ||
| Total cost | $117.25 | ||
| Yield 24 bu/A $7.00/Bu | $168.00 | ||
| 8% hail damage | 14.00 | ||
| $182.00 | |||
In 1989 all my canola will be zero till again. I was going to use some Treflan but didn't have the nerve to riskit. That field will be seeded to trizaine tolerant canola.
The future of zero till canola looks positive to me. Of course a fair price for Roundup would make it more economical than tillage. Desiccation with Roundup looks very promising for zero till by giving another opportunity to control perennials and speed harvest.
In closing I want to repeat that zero till needs canola the same as canola needs zero till very badly. With the dry years we are experiencing we are glad we have gained experience with zero till canola to the point we are more comfortable with it than our old farming practices.