Farm trials on trial
Evidence shows that the odds of identifying the best hybrids in side-by-side trials are about one in 10By TOM BUTTON
If you're thinking of putting in a standard side-by-side hybrid strip test this spring, you should probably think again. There's growing consensus that the on-farm tests are more misleading than helpful.The worst scenario, agronomists and statisticians say, is to plant single strips of a dozen hybrids, then weigh them off in the fall and pick the top yielder for planting next spring. With that approach, the odds of selecting the best hybrid are one in 10.
Instead, invest in Internet connections in order to hook into a new hybrid evaluation system being set up by the Ontario Soil and Crop Improvement Association in time for harvest. It will feature instant test results from thousands of corn and soybean comparisons.
On-farm tests are not useless, says OMAFRA corn specialist Greg Stewart. Growers do, however, need to change their test design, and also be more realistic about how much they're going to learn.
Instead of planting single strips of all the hybrids you think might have a chance, it's better to focus on just a couple. A good design, Stewart says, is to put Hybrid A in half the planter and Hybrid B in the other, and then plant much or all of the field. Next fall, harvest the hybrids separately and either weigh them off or track them with a combine yield monitor.
The split planter system helps take field variability out of the test, Stewart explains. "The biggest thing we've learned from yield monitors is how much variability we have in our fields," he says. "If you plant a single strip, how would you ever know what was hybrid effect and what was field effect?"
Bob Beck, head of a Pioneer Hi-Bred International project aimed at finding the best test system, also likes the split-planter approach. Even then, the results are of limited value, Beck says.
Consider a farm with a 150-bushel yield potential and a hybrid with a six-bushel genetic advantage, Beck explains. If the farmer plants that hybrid and another in a head-to-head on-farm test, there's only a 52-per cent chance that the better hybrid will win the test. See How useful is your on-farm test?
That isn't the hybrid's fault. Instead, part of the blame goes to variability in the field. Some pockets will be drier or wetter than the field average. Some will be more fertile. And no matter how careful the grower is, some will have better populations and spacing, and perhaps better weed control or less injury.
Then there's the weather. Your on-farm test may accurately pick the winner for a specific season, but you may never see exactly that kind of season again.
Beck says growers will make better hybrid choices if they compare hybrid performance across a wide number of locations. Seed companies, for instance, publish test results from across the province and in the U.S.
That approach balances out the effect of field variability, and the peculiarities of weather patterns. While today's farmers may have been raised with the belief that the most important test was how a hybrid performs on their own land and under their own management, Beck is saying the opposite: "Environment has much more impact on hybrid performance than your individual management practices."
This fall, Ontario growers will be able to find test results on a soil and crop association web page. Local soil and crop groups will post results from regional tests, explains Brian Hall, OMAFRA crops adviser based at Clinton who is helping design the system.
Included will be on-farm tests as well as tests from seed companies that meet trial standards. Hall expects there will be thousands of test results: "In Huron and Perth alone, there were over 1,200 plots planted by seed companies last year."
Growers will be able to log on to the web page and ask for specific hybrid comparisons. They'll also be able to specify soil type, tillage type, and geographic area ranging from all of Ontario to their own township.
"It's still useful to take a look at a hybrid before you plant the whole farm," Hall says. That's the best way to get a feel for specific characteristics, such as ease of harvest. "But there's no denying the power of numbers. The more comparisons you look at, the better your chance of making the right hybrid decision."
The soil and crop system will also be fast, Hall adds. Yield
results may
be available within days of harvest.
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SEEDBED
By Keith Reid
Spreading nitrogen on wheat
How soon? How much? And what kind?The spreaders will soon be heading to the wheat fields, if they haven't already, and there are always lots of questions about nitrogen application.
Before talking about rates or timing, you need to be clear about what kind of wheat you are growing. The market is split into two classes, and they have widely different nitrogen requirements. There are the pastry wheats including soft white and soft red, and the non-pastry wheats, namely hard red winter.
The hard red wheats are used primarily for bread or crackers where high protein content is desirable. Getting this protein requires high rates of nitrogen (up to 135 pounds per acre of actual N) because nitrogen is the building block for protein. The extra nitrogen may not add more yield, but it pays for itself by potentially earning more in protein premiums.
Cookie and pastry makers, by contrast, want their wheat to have lower protein levels, so these wheats don't need or want as much nitrogen. For these wheats, it's uneconomic to go beyond the nitrogen rate that is going to be most efficient at adding bushels, not just protein.
Optimum timing of nitrogen application also varies between the classes of wheat. Little or no extra nitrogen is needed after the plant has headed out. Pastry wheats use nitrogen primarily for growing stalks and leaves, which then produce the starch to fill up the kernels.
The non-pastry wheats, on the other hand, require available nitrogen during the grain filling process to produce protein in the grain. If you apply all of the nitrogen early in the spring little will be available at grain filling time, resulting in a high yield of low-protein grain.
Pastry wheats give optimum yields with nitrogen applications from mid-March to late April. Hard reds should have the nitrogen application split between early spring for growth and yield (about 80 pounds N per acre) and at pre-boot to build protein (about 50 pounds N per acre). Alterna tively, you could plan a single nitrogen application that's delayed until the last week of April or first week of May.
Farmers growing non-pastry wheat following a legume or manure plowdown have often observed excellent protein levels, probably because of the availability of organic N late in the season.
Timing of application also affects crop results. Nitrogen solutions (28% UAN) have the advantage of even application through a sprayer, but they will burn leaves once the wheat begins to grow. This form of nitrogen should be used early in the spring while the crop is still dormant. Granular fertilizers do not cause leaf burn, but you have to be very careful to avoid uneven application.
Among the granular fertilizers, urea has the lowest cost per pound of nitrogen, which makes it very popular as a nitrogen source. Once it is spread on the soil, urea is broken down into ammonia and carbon dioxide, and the ammonia from surface applied urea can drift off into the air. Fortunately, urea breaks down very slowly under cold conditions, so the losses from urea spread on wheat are usually quite small. Loss to the air becomes a bigger concern when the soil warms up, particularly if there is no rain to wash the fertilizer into the soil. For later applications of nitrogen, one of the other fertilizers may have the advantage.
Ammonium nitrate and ammonium sulfate do not evaporate into the air if they are broadcast onto the soil surface. The drawback is that they both are sold at a premium price compared to urea (check around to see how wide the price spread is in your area - it varies). Depending on your situation, it may pay to apply a higher rate of urea to compensate for the losses, rather than switch to a different source. Or make sure you apply your fertilizer just before a rain, which will wash it into the soil and protect it from any further loss.
Other than the potential for loss to the air, there are no
significant
differences between the various sources of nitrogen. You can
expect equal
yields from any of the sources, properly applied.
Keith Reid is an OMAFRA soil and crop specialist (soil fertility) at Walkerton
kreid@omafra.gov.on.ca
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Hemp heads north
Northern Ontario growers set for planting following favourable test resultsJust as Ontario hemp producers are casting about for their best practices in growing and harvesting following Year One of commercially approved planting, so, too, are the plant scientists charged with providing variety and agronomic recommendations.
And while most of the 1998 commercial hemp acreage was planted in the southern parts of the province, findings from a northern Ontario project suggest that higher latitude conditions could be very favourable for the fibre and oilseed crop.
University of Guelph northern research co-ordinator Gordon Scheifele, based in Thunder Bay, was involved in two hemp projects. One was to determine the effect, among other factors, of latitude, environment and genetic stability on the psycho-active ingredient in hemp - delta-9 tetrahydrocannabinol (THC). Related was a general study on the feasibility of the low-THC plant as a northern Ontario crop.
Industrial hemp, by Canadian (and European Union) law, must have a THC level of 0.3 per cent or less. The first project compared THC levels among eight varieties at 32 test plots throughout the province - from Leamington, the most southerly site at 42 degrees north, to Dryden, the most northerly at 49.95 north.
Sampling showed that, regardless of variety, a clear trend was for THC levels to lower the further north a test plot was. (See High lows).
Scheifele attributes the trend to the amount of daylight the plots received. "You have a longer day length and shorter night the further north you go in summer. Even the six or so degrees between Chatham and Thunder Bay is signifcant. That's why our breeding program recommendation is for initial selection of germplasm to be done in southern Ontario - Leamington, say, where the most pressure can be put on the variety to satisfy the low THC level, then move it up north for selective adaptation."
With interest in industrial hemp renewing in just the last 10 years, plant scientists have been scrambling for varieties that fit the legal system and fulfill production quality demands. Among growers of the illegal, high-THC cannabis sativa, says Scheifele, the selection focus had been on short and hence leafy, high cannabinoid varieties - quite the opposite of what's desirable for fibre. Scheifele says there's a small body of research that indicates a completely THC-free variety won't fly: "The research suggests that if you remove or put a genetic blockage or interference on the THC production centre the plant will fail to demonstrate the vigour and strength that it has now as we know it. THC seems to be part of the plant's physiology to defend itself."
In the northern feasibility study, two-hectare on-farm strip trials were conducted at 28 farms and at five research stations. Despite drought-like conditions in a few areas, the crop's field-baled stalk yields ranged from a low of 1.8 tonnes per hectare (0.73t/acre) to 8 tones per hectare (3.23 t/acre), averaging 2.5 t/acre. Strip trial cleaned grain yields at 12-per cent moisture were 1.01 tonnes per hectare (0.4t/acre).
Scheifele expects a number of the farmers who conducted test
plotting for
him last summer to have 10-acre commercial plot licences in 1999:
"I'm
anticipating grain fields in Sudbury, Dryden, Thunder Bay and
Fort
Francis." He says a number of the test growers found hemp wasn't
as easy to
grow or harvest as they thought it might be, and "the farming
paradigm
wasn't there for a lot of them. They're used to commodity-type
crops where
you simply take it to the elevator and sell it. With hemp,
because of the
lack of processing facilities, you have to be prepared to develop
your own
market." Nonetheless, says Scheifele, hemp "would seem to me to
be
something that, in the north, might occupy land that might not
now be in
use agriculturally." - Richard Charteris
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