October 2001
Disaster alert! Rough hurricane weather ahead
New research suggests that the increased frequency of major hurricanes that we have been experiencing could last for another 10 to 40 yearsby HENRY HENGEVELD
For a number of years, the international re-insurance industry has been ringing alarm bells about increasing losses due to natural disasters, mostly from winds and floods. Last year was no exception. Globally, the number of natural disasters reached a record high of 850, killing about 17,000 people (mostly in developing countries) and causing total direct economic losses in excess of $38 billion US.For North and Central America, major land-falling hurricanes spawned in the tropical Atlantic play a large role in such losses. Single events such as Hurricane Andrew (1992) have generated economic losses in excess of $20 billion in the United States, while Hurricane Mitch (1998) alone killed some 10,000 people in Central America. Experts caution that it is only a matter of time before the American east coast gets clobbered with a $100 billion US event.
While these experts also note that larger human populations with more wealth, located in disaster prone areas, are a dominant factor in these trends, the insurance industry contends that demographics alone cannot explain the rapid increase in losses in recent decades. Weather extremes, they conclude, have become more intense and more frequent.
Now new information published by several American research centres this summer has provided some further insights into this debate, and the conclusions are far from re-assuring.
Like most weather-related disasters, the intensity and socio-economic consequences of a hurricane depend on a number of factors. One key factor is the sea surface temperature (SST), which must be at least 26 C to initiate the processes that start and strengthen a tropical storm. The higher the sea surface temperature, the greater the energy pumped into the storm by direct heating and evaporated water, and the greater the potential for an intense hurricane.
Another important factor is vertical wind shear (the difference in the wind speed at the sea surface versus that at the top of the storm), with weak vertical wind shears being more conducive to hurricane development. Other factors include the speed with which the storm centre moves over the ocean surface (slow moving storms tend to weaken because they have more time to mix surface waters with cooler waters below, thus lowering sea surface temperatures), as well as whether and where the hurricane hits land areas.
In July, Stanley Goldenberg, a hurricane expert with the American National Oceanic and Atmospheric Administration (NOAA) research laboratories in Miami, and colleagues published an analysis of North Atlantic hurricanes and related weather data that strongly suggests a long-term cycle to the intensity of major hurricane activity in the North Atlantic. They noted a period of high activity between 1926 and 1970, followed by several decades of low activity. During the past six years, hurricane activity in the North Atlantic has returned to double that of the preceding 24 years, while that in the Caribbean has increased fivefold.
When these long-term variations were compared with the multi-decade ups and downs of SSTs and vertical wind shears over the North Atlantic, the researchers found a remarkable agreement. Hurricane activity was high during periods of high temperature and low wind shear, and low during lower temperatures and high wind shear. Based on this agreement and the pattern of the long-term oscillation in Atlantic SSTs, they predict that the current high temperatures and low wind shear, and hence high frequency of major hurricanes, could last for another 10 to 40 years.
As if that wasn't enough to give insurance executives some sleepless nights, the same researchers also note that, underlying this long-term oscillation in North Atlantic climate, there has been a net warming of North Atlantic SSTs over the past century of about 0.3 C, and that the current level of major hurricane activity appears to be higher than during the previous high activity period in mid-century. This could be an artifact of poor hurricane records prior to the onset of aircraft observations in 1944. However, since warmer SSTs can contribute to more intense hurricanes, there is the real possibility that some of the intensity of current hurricane activity may be attributable to this observed net rise in ocean temperature.
Linkages between climate change, rising SSTs and hurricane behaviour are as yet tenuous, partly because of uncertainty as to how other influencing factors such as wind shear will respond. However, there is new support from the results of another scientific paper published earlier this summer by Thomas Knutson and fellow researchers at the climate-modelling centre at NOAA's Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey.
These experts found evidence from climate model experiments for a modest (3-10 per cent) increase in maximum wind speeds of major hurricanes if the tropical Atlantic SSTs were to warm some 2.5 C under warmer climates, and a more substantial increase (28-34 per cent) in maximum precipitation rates. Even modest increases in maximum wind speeds or precipitation rates can cause disproportionately greater damage.
While this hardly guarantees that eastern North America is headed for economic disaster due to Atlantic hurricanes, it does seem that nature and humans have collaborated to load the dice for at least the next few decades. The researchers advise that disaster managers in the region should prepare for rough hurricane weather ahead. While another Hurricane Hazel in Ontario may be a long way off, we might also be well advised to take note.BF
Henry Hengeveld is senior science advisor on climate change at Environment Canada.
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PurNutra's first attempts to market high-DHA cheese run into trouble
But experts remain optimistic that there is a future for high-DHA milk productsby DON STONEMAN
Ontario's first foray into commercial DHA-enhanced milk production has turned into a financial and litigation-littered minefield for a tiny producer-owned company.PurNutra Inc. began producing OmegaSmart cheese a year ago, using milk from cows fed a special, costly dietary supplement. Sales to the United States failed to surge and PurNutra couldn't afford to pay farmers for their milk for late March and the month of April. Production ceased in June.
"We had a weak link in sales and marketing," says Pete Peeters, an Omemee dairy producer and chairman of PurNutra. Marketing cheese into the United States "wasn't as simple as we thought," and the cheese had to be sold at a loss.
OmegaSmart branded cheese contains high levels of Docosahexaeonic Acid (DHA), which is found in the milk from cows fed the special diet. Consumption of this cheese is supposed to stave off heart attacks and strokes. To keep the high-DHA milk segregated, PurNutra suppliers were producing strictly for export, outside the quota system, so there was no in-quota milk income to buttress the financial crisis.
With PurNutra cheese production shut down, producers were forced to seek other, less lucrative export contracts at about 33 cents a litre. They had been receiving a price equal to the returns for in-quota milk, about 61 cents per litre.
Peeters says PurNutra still hopes to pay producers for their April and May production, probably through the licensing to other groups of PurNutra's technology for production of fluid milk and products such as yogurt. He says that every one of the half dozen producers affected has converted the debt owed to them by PurNutra into a debenture. In effect, says PurNutra lawyer Donald Good, the producers have made a loan to the company.
PurNutra's secretary, Jacqueline Fennell of Spencerville, quit her job in the winter to farm full time. She took up an off-farm job in the summer to pay bills, but remains optimistic that PurNutra will survive and prosper once it has overcome this setback. Fennell, whose dairy herd was the test herd for the rations, is adamant that the feeding ration that PurNutra has patented is different from the technology developed at Guelph with producer dollars.
Bruce Holub, a University of Guelph scientist involved in developing high-DHA milk technology, also remains enthusiastic about the future of high-DHA milk products. He points out that high-DHA levels in food can be attained by feeding animals natural products, not food additives, and that the enhanced products are made without the use of controversial biotechnology techniques. He says there are talks ongoing with Dairy Farmers of Ontario (DFO) to begin producing more DHA milk, this time for consumption within Canada.
Wes Lane, the DFO's director of communications, cautions that the talks have been very preliminary. DFO helped to fund DHA research at Guelph, but claims no control of the results. Offering the research funding as a "grant" is simpler than having the scientific work performed under contract, he says. It is also cheaper. A 35-40 per cent "university overhead charge" is applied on top of the research contract, Lane says.
Intellectual property ownership remains a key issue in the PurNutra/DHA milk debate.
Former PurNutra acting general manager Jim Stewart was replaced April 1. Stewart is now listed as vice-president of sales for Veri-Life Inc, a company which offers milk contracts on the Deloitte & Touche export contract exchange and which touts its own brand of long-chain fatty acid, high-DHA cheeses. This is a sore point with PurNutra members. At deadline, Stewart had not returned Better Farming's calls. BF
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Fencing cattle away from streams not necessarily the answer
Research by this London marine biologist suggests that cattle access to water may not be that bad for the environment - provided it is properly managedby DON STONEMAN
Casual observers assume that fencing cattle away from streams will improve water quality. Research by marine biologist and agricultural consultant Dave Hayman of London over several decades shows that it's not that simple.Hayman's research in the 1970s resulted in measures to reduce erosion and cut down phosphorus loading in streams (phosphorus causes algae blooms that eat up oxygen and kill fish). Later, his studies were an influence on the Clean Up Rural Beaches (CURB) program that aimed to reduce bacteria in streams that led to beach closures in conservation areas and on Lake Huron. The CURB program encouraged farmers to fence cattle from streams where there was relatively limited access to the water. Fences typically cost as little as $500 to $1,000. That sort of fencing worked best with dairy cattle where the pasture is used as an exercise yard, where numbers are highly concentrated and the distance of exposure to the water is limited. Hayman is now studying extensive pastures for beef cattle where the grass is a major feed source, long sections of water are exposed to livestock and fencing animals away from the water is impractical because it would cost many thousands of dollars.
Some of Hayman's work has been conducted for the Ontario Cattlemen's Association and other research will be published next year as a peer-reviewed scientific paper for a university thesis. His preliminary conclusion: cattle access may not be all that bad after all if it is managed.
Hayman measures water quality by studying the insects in the water. Insect activity "is not really specific to phosphorus, or bacteria or sediment. It is indicative of everything," Hayman says. Furthermore, he asserts that insect activity is a better indication of water quality than the number of fish in the river or stream. If a blast of pollution comes through, the insects are slower to recover than fish because they aren't mobile, Hayman explains.
Hayman has been looking at ways to keep cattle out of waterways without using fences. The first thing he found was that the longer cattle stay in the water, the more likely they are to manure in it. So a goal should be to manage pastures so that livestock spends a minimum of time in the water.
From scientific observations, Hayman has concluded that cattle won't stay long in a fast-moving stream, so efforts to keep them away can be minimal. However, they are likely to "lounge" in pools, leading to manuring problems. Also, if cattle have access to both sides of the stream, they are likely to spend longer periods of time in the water. Armed with that knowledge, Hayman says, farmers can manage their pastures to reduce environmental damage.
Hayman's studies are still in a preliminary phase, but he has noted some trends. If streams are reasonably clean, giving cattle access to cross the water appears to kill off the insects temporarily, a sign that water quality is impaired. "We also sampled 100 metres downstream from cattle crossings, and in every instance the stream recovers," he says.
Another trend in his findings: if the water quality is very poor upstream from a cattle crossing, there is an improvement in the bug population downstream from the livestock access. He suspects that is because insects and other water creatures are using up the nutrients left by cattle in the water "for their own growth cycles." Since the recovery of the stream is relatively rapid, he encourages farmers to fence cattle away from the last 100 metres of a stream flowing through a pasture. That gives the stream room to recover before it leaves the pasture owner's property.
Fencing cattle out of sections of the stream periodically in a pasture may be a way to accelerate recovery of the stream. However, a practice that doesn't seem to help is to restrict cattle to very small areas of access for crossing. That may make the damage worse. "That's one of the things that everybody is promoting, just having one spot where cows cross," says Hayman. While cautioning that his research is preliminary, he thinks "that we need to distribute that (access) over a larger section of water."
Hayman warns that in heavily populated and heavily used southern Ontario there is only so much that can be done to improve the quality of rivers and stream. In one study, he conducted on a small stream flowing into Pittock Lake, near Woodstock, Hayman found that fencing cattle out of crossing places didn't help at all. A tile drain was the main source of bacterial contamination and there were likely other sources as well.
Hayman's conclusion: there are limits to what can be done by keeping cattle out of the water. "We aren't going to have (water quality up to) drinking water standards in our rivers ever, no matter what we do." BF
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Repairing a John Deere/Cummins injection system is no cinch
When it comes to troubleshooting tractor electronics, the dice is sometimes loaded in favour of the dealersby KEITH BERGLIND
The buzzwords in gas and diesel engine development today are certainly the "electronic" controls, designed for power and fuel efficiency.In the very large truck and tractor diesels, electronics are necessary for cleaning up the smoke emissions in order to meet current and anticipated clean air standards. But all this electronic wizardry doesn't come without a price, as witness an electronic fuel injection failure recently experienced by my farmer friend, Brian.
The tractor in question is a 1993 John Deere Model 8970 with a Cummins 855 Big Cam engine. Brian bought the tractor specifically to get that engine, in which he had a lot of faith. He has a larger-than-average farm and the tractor had 4000 hours on the clock when this failure occurred.
The first warning came as he entered the yard on his first workday in May. He stepped on the clutch and tried to throttle down. There was no throttle control and the engine speed, instead of going to an idle, went above 1500 rpm. When he opened the throttle again, the speed started to rise slowly above 1800 rpm, but the speed increase did not follow the throttle action. Afraid that it might over-speed, he cut the throttle all the way back, and the engine returned to 1500 rpm.
Now, because Brian is also a trained diesel mechanic, very experienced with injection pump repair, he tried to troubleshoot the problem. After a call to brief me on his situation, we set out on an information search. Our favourite diesel shop informed us that they only work on the mechanical parts of the pump, not the electronic components. They did identify that there are two electronic parts on the pump: the EFC (Electronic Fuel Control) and the ECM (Electronic control module). Both are given to causing this problem.
Next Brian went to the Cummins dealer, who said he could fix it. The rate was $80 per hour plus $1 per kilometre travelled. Since the tractor was 90 minutes drive away, this was going to add up. Moreover, the EFC would cost just over $2000 and the ECM more than $3000. No thanks for now, he said. And, to eliminate us non-dealer mechanics, there were no shop manuals for sale.
Brian made calls to two John Deere dealers, who told him they had had dealt with similar complaints by replacing the EFC only. So Brian bought one of these units, which is about the size of a coffee cup and can be carried carefully in the palm of your hand.
The actual repair took only minutes. As you can see in the picture, the unit is held in by three small bolts. It is sealed by three o-rings, so all you do is pry it out carefully and replace it with the new one. There are two plug-on wire connectors on top. And when we started the engine, it ran perfectly. We had chosen the right part to change.
So, what's the big deal? Well, if we had picked wrong, Brian would still have had to buy the $3000 part. And the supplier won't accept returns. A big dealer could put it back on the shelf, knowing he'll need it another day. Not so a farmer. The Cummins dealer was vague about being able to completely test the module if we brought it alone to his shop.
The big problem is the secrecy of information. We couldn't buy a manual to help us troubleshoot. The Cummins dealer has an electronic diagnostic tool, which he offered to take out to the tractor. But his time and travel cost would be close to $600. The John Deere dealers were helpful, but they pointed out that they aren't allowed to work on these engines either.
These electronic diesel engines need the ORB (On-Board-Diagnosis) capabilities that we have in cars. This is a 1993 tractor. Cummins doesn't own it. Brian does. Why do he and other farmers who have repair skills have to pay top shop rates because the big diesel engine companies have designed a "captured" service market? If my Dodge car can talk to me about its faults by flashing the "engine" light on the dash, why can't this Cummins? An expensive black box in the dealer's hands only doesn't help farmers.
New fuel filters
In the box with the new part was a sheet advising that, effective immediately, 10 micron fuel filters are required to replace the original 25 micron filters. The sheet gave the new part numbers.It also advises that, when preparing the new filter, instead of pouring fuel into the centre of the filter, as shown in current shop manuals (which none of us have), fuel must be poured through the smaller fuel inlet holes in the top plate of the fuel filter. Obviously, they want cleaner fuel and they don't want you to risk adding dirt into the clean-fuel centre of the filter.
Note: For Ford PowerStroke diesel owners, this HEUI injector system also requires super-clean fuel and engine oil. Don't cheat by using doubtful fuel and oil filters. Be sure to go with the lowest micron rating and highest quality available. These HEUI injectors are very expensive to replace. BF
Keith Berglind is a licensed heavy-duty mechanic
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How best to reduce your grain drying energy costs
Heat recirculation can and does work, offering a good payback. Heat exchangers, though, are more expensive to build and require more maintenanceby RALPH WINFIELD
A large amount of energy is required to remove moisture from grain. In recent years, many dryer operators switched from propane to natural gas to reduce their fuel bills. When natural gas was cheap, there was little incentive to reduce usage to save money. That has changed for the 2001 crop year.Reclaiming drying energy will provide a payback for all continuous flow dryer owner/operators now. This is true for all column and screenless units but especially for those that include even a small cooling section. So operators should ask themselves two questions: How much can I afford to spend? How do I do it?
The math is very easy. By simple recirculation of the cooling air and a portion of the drying air you can recover 20-30 per cent or more of your drying fuel costs. Thus for each $1,000 of anticipated drying fuel costs, you can invest $200-300 and get total cost recovery in the first year. If you spent $5,000 for fuel last year and expect a fuel bill of $10,000 this year, an expenditure of $2,500 should be a very good investment.
You can reclaim drying energy in two ways -- through heat recirculation or through heat exchangers.
Heat recirculation
This method will work for all continuous-flow dryers of the cross-flow design, including screenless and belt type units, as well as top-dry batch dryers. The concept is straightforward. Air warmed by cooling hot corn and heated air passing through nearly dry corn can be recirculated directly to the blower-burner unit of the dryer. Only the cooling air is delivered into the heated air of the top-dry units.Many newer continuous-flow, column-type dryers have recirculation systems built in or retrofit kits may be available. If you are planning to build your own recirculation system, please do four things:
1. Get a copy of OMAFRA Factsheet #88-003 "Reclaiming Corn Drying Energy."
2. Do not collect drying air from more than the lower 25-30 of the drying section. The cutoff is about 50 per cent of total screen height if the bottom portion is used for cooling.
3. Do insure that the nearly saturated air from the upper drying section is diverted away from both the drying and cooling fan intakes. (Recirculating saturated air can increase fuel usage!)
4. Extend the enclosure at full width for at least ten feet in front of the dryer to provide a settling (collection) area for red dog. (This reduces fire risk and allows for collection and disposal of dry red dog.)
Heat exchangers
The only practical method of reclaiming drying energy with most batch-type dryers is to use an air-to-air heat exchanger that will only recover the "dry heat" and return it to the blower-burner unit.A number of field tests have been attempted and to date no practical and economical systems can be recommended. The problems are:
* Most batch dryers have a low annual throughput and thus few fuel savings dollars are available.
* Heat exchangers are relatively expensive to build because of the high airflow required.
* Heat exchangers must be designed to allow condensate flow and permit at least annual cleaning, which must be done to maintain efficiency and control odors. Do not build a heat exchanger above the dryer. This may seem like a good idea to take advantage of warm air buoyancy. But, remember, condensed moisture is much heavier than air and will rain down all over. Combined with red dog you will have a really smelly mess.
* The efficiency of heat exchangers increases as the difference between ambient and plenum temperatures increases. Thus, the benefit is reduced during warm summer or early fall operation.
Most batch drying systems are now of the in-bin type which are operated at relatively low plenum temperatures. By design, the deep bed (thick column) provides for relatively efficient fuel use without the need for a heat exchanger.
We can sum up as follows:
* Heat recirculation on all thin-column continuous-flow dryers can and does work.
* With increased costs of natural gas it is probably a concept that will provide a good payback on all older dryers not having the capability designed into them.
* A safe recirculation system can be built around almost all thin-column, continuous-flow dryers, including screenless and belt type units.
* Heat exchangers are more difficult to get a payback from. They are expensive to build and require more maintenance.
Please do not forget that a significant quantity of heat energy can be wasted removing the lower points of moisture from grains. They are the most energy-expensive to remove and their removal in a high temperature dryer often creates an overdried product that is reduced in quality as well as quantity.
A good aeration system is needed in all storage structures. Properly designed and operated, they can minimize spoilage and permit moisture content manipulation. System operators must fully understand equilibrium moisture contents of all grains and oilseeds in storage and make ambient (outside) air work for them.BF
Agricultural engineer Ralph Winfield farms at Belmont in Elgin County
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