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Post by Andrew on Sept 1, 2013 20:49:33 GMT
the child is stomping his foot and having a tantrum. You are the infant talking about supercooling when it is plainly evident that super cooling has nothing to do with protecting plants from being cooled below 0C  How old are you lad? At the current rate i am going to be 60 and you will still be in nappies |
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Post by numerouno on Sept 2, 2013 2:32:16 GMT
Sigurdur, your phase change energy is only revealed AFTER EVERYTHING HAS BEEN ICED UP! You don't see everything iced up in your field, as far as I can tell. Therefore, any heat you will see on your fields will come from the ORDINARY HEAT CONTENT of the WATER YOU PUMP onto the fields! You are still misunderstanding things, and apparently nothing will make you understand this right. numerouno: That is what you don't understand. YES.....I SEE everything iced up! Ice on the ground, the plants.....everything. And let me tell ya.....that ice makes a man's heart beat slower, as by having it I KNOW that my spuds have not froze. And this can happen just from heavy DEW formation. I have observed it....too many times for comfort....but observe it I have. When the outside air temp is 28F...I shudder. It takes a walk in the field to feel safe. No ice......and I am screwed. Ice....happy days are here again. I don't have water to irrigate, and must rely on mother nature doing things correctly. Sometimes she fails, sometimes she doesn't. The first time it happened, observing the ice......I was not sure what the outcome would be. IN fact....water conducts temp well. Another item that is observed that goes against what one would think. A wet spud hill that freezes saves the tuber. There is enough latent heat released that a tuber can be in the ice field and not have damage. Dry soil?.......screwed big time. Maybe I don't understand it.....but I sure have observed it. That heat HAS to come from somewhere, and the only place I can put a finger on that heat is the release of the latent heat when water freezes. Cause the soil temp and the air temp sure are not handing any heat over. If you have let the water freeze up, you are in danger. You have then used up all your phase change energy. Then you will rely only on the thermal insulating properties of the ice to prevent the cooling from going further. If you actually have gone below 0C inside the plants during the night frost. then during the warming, the thermally insulating ice will in fact make matters worse by prolonging the time it takes to recover from below 0C. Moreover, the melting of the ice will prolong the time the plants will stay at 0C after that. What we do in this country to protect from night frost is here: www.vastavalo.fi/maatalous-maanviljely-pelto-harsokatetut-175456.htmlwww.vastavalo.fi/albums/userpics/15237/normal__MG_22785.jpgA product page: www.freudenberg-nw.com/en/solutions/Pages/Frost-Protection---Winter-Coverings.aspx |
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Post by sigurdur on Sept 2, 2013 3:30:09 GMT
numerouno:
The lucky thing is that when we get early hard frost/freeze around here there is usually high humidity levels. The constant phase change as the temp falls keeps the dew freezing.
There is no way to cover 500 or 600 acres of spuds. Not economically feasible, nor timely.
I understand that at some point the phase change release of latent heat to sensible heat will stop. Then it is the insulating value of the ice itself that helps the plants respond.
Sometimes, the low temp is too long, and freeze damage occurs. But that is actually a rarity, and usually not field wide.
As I said, I think we are dealing in semantics of understanding. The latent energy can be measured, and when expressed it does work to keep the temperature warmer. Not the whole atmosphere mind you, as evidenced by the freezing temps just above the canopy.
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Post by numerouno on Sept 2, 2013 3:50:58 GMT
numerouno: The lucky thing is that when we get early hard frost/freeze around here there is usually high humidity levels. The constant phase change as the temp falls keeps the dew freezing. There is no way to cover 500 or 600 acres of spuds. Not economically feasible, nor timely. I understand that at some point the phase change release of latent heat to sensible heat will stop. Then it is the insulating value of the ice itself that helps the plants respond. Sometimes, the low temp is too long, and freeze damage occurs. But that is actually a rarity, and usually not field wide. As I said, I think we are dealing in semantics of understanding. The latent energy can be measured, and when expressed it does work to keep the temperature warmer. Not the whole atmosphere mind you, as evidenced by the freezing temps just above the canopy. As I said, there is no way I can make you undertand the phase change energy corretly. There is no "constant phase change as the temp falls"! The phase change energy only comes into play WHEN FREEZING OCCCURS, NOT ANY SOONER. The temp is then exactly 0C. When you have used up the phase change energy, your plants are technically frozen already from that point on! This is not semantics. Nobody over here sprays their fields for frost protection. They know their physics better. |
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Post by Andrew on Sept 2, 2013 4:16:19 GMT
numerouno: The lucky thing is that when we get early hard frost/freeze around here there is usually high humidity levels. The constant phase change as the temp falls keeps the dew freezing. There is no way to cover 500 or 600 acres of spuds. Not economically feasible, nor timely. I understand that at some point the phase change release of latent heat to sensible heat will stop. Then it is the insulating value of the ice itself that helps the plants respond. Sometimes, the low temp is too long, and freeze damage occurs. But that is actually a rarity, and usually not field wide. As I said, I think we are dealing in semantics of understanding. The latent energy can be measured, and when expressed it does work to keep the temperature warmer. Not the whole atmosphere mind you, as evidenced by the freezing temps just above the canopy. As I said, there is no way I can make you undertand the phase change energy corretly. There is no "constant phase change as the temp falls"! The phase change energy only comes into play WHEN FREEZING OCCCURS, NOT ANY SOONER. The temp is then exactly 0C. When you have used up the phase change energy, your plants are technically frozen already from that point on! This is not semantics. Nobody over here sprays their fields for frost protection. They know their physics better. When the dew is condensing constantly out of the moist air then we can reasonably say there is a constant phase change. Dew will be condensing over a many degree temperature range and even when frost has formed their will be a constant phase change from water vapour to ice until the ice would be absolutely dry which it never practically would be on Earth. >>Nobody over here sprays their fields for frost protection. They know their physics better. Water spraying evidently does help some farmers. Particularly in dry air areas such as parts of florida or california, in an inversion situation as described in the numerous links on this topic. Outside of extreme cold air Finland is unlikely to ever have extremely dry absolute humidity, unlike what can be found in and around desert areas and continental climates |
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Post by Andrew on Sept 2, 2013 4:24:52 GMT
As I said, I think we are dealing in semantics of understanding. The latent energy can be measured, and when expressed it does work to keep the temperature warmer. Not the whole atmosphere mind you, as evidenced by the freezing temps just above the canopy. How can it be semantics when it is totally obvious we think you have no ability to think correctly about the topic whatsoever??? Even to say it is just semantics is stupidity that is beyond my comprehension! And continually you keep on rambling on about latent heat as if Numerouno and myself have no idea that latent heat is involved in the correct scientific explanation of what is happening How can you possibly be continually so annoyingly stupid?? Semantics?  ? You have aligned yourself with the stupidity of Magellan, Icefisher and Nautonnier. What aspect of that do you not understand? We think you are a scientific cretin. Semantics? ?? |
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Post by icefisher on Sept 2, 2013 4:51:45 GMT
There is no "constant phase change as the temp falls"! The phase change energy only comes into play WHEN FREEZING OCCCURS, NOT ANY SOONER. The temp is then exactly 0C. When you have used up the phase change energy, your plants are technically frozen already from that point on! This is not semantics. Nobody over here sprays their fields for frost protection. They know their physics better. LOL! Are farmers in Finland are too dense to think of keeping the water running so the phase change energy does not run out? And are they too dense to realize that the freezing point of liquids with sugar or salt content is also depressed? Or that all foods have sugar content? The freezing point of orange juice for example is about 26 to 27F or -2.7 to -3.3C. Management of precise temperatures is very difficult as outlined in the University of Florida reference I gave you. An intentional irrigation strategy has to be carefully implemented. Since a farmer's entire income depends upon the outcome and the difficulty and imprecision involved they probably do very well if they can limit error to a one or two degrees. But thats success when the it might take more than 2 degrees to cause damage. More likely there are only two Finns that have the incorrect notion that everything freezes at 0C. And apparently remain clueless as to what their countrymen are actually doing. This source details how Finland uses the practice to increase yields. They cover the whole universe of irrigation include how farmers in the boreal region use it for frost protection from the release of heat of fusion. cdn.intechopen.com/pdfs/34017/InTech-Irrigation_of_field_crops_in_the_boreal_region.pdfIrrigation is successfully used to prevent damage due to night frost. In direct protection, the
temperature of the plant is kept above the freezing point by using latent heat fusion of
water. The crop is irrigated for the whole time that temperature is at or below zero, forming
a film of ice on the plant which releases energy, preventing the tissue from freezing.
Irrigation is started when temperature decreases to +1–0 °C, and it is stopped when the ice
on the plant starts to melt (van der Gulik & Williams, 1988; Ingvarsson, 1992; Svensson,
2003). In this way, irrigation can protect the crop until -7 – -8 °C (Ingvarsson, 1992).
In the indirect method, the soil is irrigated on the morning of the day when frost is anticipated.
Wet soil traps plenty of warmth during a day and releases it during the night, preventing frost
damage up to -2 – - 3 °C. The shelter effect is highest about 30 cm above the soil surface, so
indirect frost protection is suitable only for low growing crops (Ingvarsson, 1992).
Irrigation as a direct protection against freezing temperature is mostly used in the
production of berries and fruits where inputs are high (van der Gulik & Williams, 1988). In
Boreal region, especially in Nordic countries, first-early potatoes are so valuable that
irrigation generally is used to prevent frost damage (Wikman et al., 1996).
So this topic is done done done! and overdone! |
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Post by Andrew on Sept 2, 2013 5:21:16 GMT
There is no "constant phase change as the temp falls"! The phase change energy only comes into play WHEN FREEZING OCCCURS, NOT ANY SOONER. The temp is then exactly 0C. When you have used up the phase change energy, your plants are technically frozen already from that point on! This is not semantics. Nobody over here sprays their fields for frost protection. They know their physics better. LOL! Are farmers in Finland are too dense to think of keeping the water running so the phase change energy does not run out? And are they too dense to realize that the freezing point of liquids with sugar or salt content is also depressed? Or that all foods have sugar content? The freezing point of orange juice for example is about 26 to 27F or -2.7 to -3.3C. Management of precise temperatures is very difficult as outlined in the University of Florida reference I gave you. An intentional irrigation strategy has to be carefully implemented. Since a farmer's entire income depends upon the outcome and the difficulty and imprecision involved they probably do very well if they can limit error to a one or two degrees. But thats success when the it might take more than 2 degrees to cause damage. More likely there are only two Finns that have the incorrect notion that everything freezes at 0C. And apparently remain clueless as to what their countrymen are actually doing. This source details how Finland uses the practice to increase yields. They cover the whole universe of irrigation include how farmers in the boreal region use it for frost protection from the release of heat of fusion. cdn.intechopen.com/pdfs/34017/InTech-Irrigation_of_field_crops_in_the_boreal_region.pdfIrrigation is successfully used to prevent damage due to night frost. In direct protection, the
temperature of the plant is kept above the freezing point by using latent heat fusion of
water. The crop is irrigated for the whole time that temperature is at or below zero, forming
a film of ice on the plant which releases energy, preventing the tissue from freezing.
Irrigation is started when temperature decreases to +1–0 °C, and it is stopped when the ice
on the plant starts to melt (van der Gulik & Williams, 1988; Ingvarsson, 1992; Svensson,
2003). In this way, irrigation can protect the crop until -7 – -8 °C (Ingvarsson, 1992).
In the indirect method, the soil is irrigated on the morning of the day when frost is anticipated.
Wet soil traps plenty of warmth during a day and releases it during the night, preventing frost
damage up to -2 – - 3 °C. The shelter effect is highest about 30 cm above the soil surface, so
indirect frost protection is suitable only for low growing crops (Ingvarsson, 1992).
Irrigation as a direct protection against freezing temperature is mostly used in the
production of berries and fruits where inputs are high (van der Gulik & Williams, 1988). In
Boreal region, especially in Nordic countries, first-early potatoes are so valuable that
irrigation generally is used to prevent frost damage (Wikman et al., 1996).
So this topic is done done done! and overdone! ice cold water has less ability to provide a heat source than the slightly warmer unfrozen water had prior to freezing. Therefore, once ice begins forming on the plants, the environment immediately next to that ice must be colder than prior to ice formation |
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Post by sigurdur on Sept 2, 2013 6:37:46 GMT
Amazing that the potatoes farmers in Finland know exactly what I described via observation.
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Post by sigurdur on Sept 2, 2013 6:39:17 GMT
Of course it is Andrew. Otherwise we wouldn't need the ice to save the crop.
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Post by Andrew on Sept 2, 2013 7:22:18 GMT
Of course it is Andrew. Otherwise we wouldn't need the ice to save the crop. All you keep doing is repeating yourself. Never do you show that you are prepared to interact with what is being explained to you. Instead you insist you are correct and others are talking about magic and novel ways of creating energy Then you have the dishonesty to claim you are the one who focuses on the science. Ice protects the plants from experiencing a lower temperature than freezing, because ice and water only exist together at the freezing point.Talking to you is like talking to a brick wall with a one radio strapped to it. Endlessly you transmit but you cant receive anything. |
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Post by icefisher on Sept 2, 2013 7:57:16 GMT
ice cold water has less ability to provide a heat source than the slightly warmer unfrozen water had prior to freezing. Therefore, once ice begins forming on the plants, the environment immediately next to that ice must be colder than prior to ice formation Irrelevant. You are trying to create a false frame of reference. The frame of reference is not the temperature of the ice cold water. The frame of reference is that to create a damaging frost the ambient temperature must be below freezing, colder than the ice cold water. If the ambient temperature is not colder the water simply will not freeze. Farmers that rely on this strategy are not afraid of 32F temperatures because they are not ignorant boobs who think their crops are going to freeze at that temperature. They fear colder temperature like citrus growers are fearful of temperature dropping below 28F. So success for a citrus farmer means holding the crop encased in ice to 32F and the crop above the ice to 28F or higher in the face of ambient temperatures hitting below 28F. So it is the case that success will be defined by warming of the ambient environment by up to 8C. Now that formula will be different for crops more sensitive than citrus. Depending upon how much more sensitive it might not be feasible to protect them with this strategy and instead they need to go to the expense of greenhousing the crop. Where exactly that line is no doubt a subject matter for specialization. A specialty that ignorant boobs need not apply. |
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Post by sigurdur on Sept 2, 2013 8:10:01 GMT
Andrew: I understand the process and the mechanics very well. Published references, which are used annually, have been provided. Even in Finland it seems to be understood.
Once again. The thermal joules of sensible heat of the applied water do NOT provide much warmth.
Oooooofta. I think I will just give up trying to educate you. You are totally out of your league on this subject.
Good luck.
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Post by numerouno on Sept 2, 2013 9:13:50 GMT
There is no "constant phase change as the temp falls"! The phase change energy only comes into play WHEN FREEZING OCCCURS, NOT ANY SOONER. The temp is then exactly 0C. When you have used up the phase change energy, your plants are technically frozen already from that point on! This is not semantics. Nobody over here sprays their fields for frost protection. They know their physics better. LOL! Are farmers in Finland are too dense to think of keeping the water running so the phase change energy does not run out? That energy from running water is not phase change energy, but ordinary heat energy supplied by the running water that is considerably warmer than 0C. Phase change energy can only be expressed when there is actual freezing. If there was actual freezing, the heat from the running water would have to be used to melt the ice. |
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Post by icefisher on Sept 2, 2013 9:37:46 GMT
That energy from running water is not phase change energy, but ordinary heat energy supplied by the running water that is considerably warmer than 0C. Phase change energy can only be expressed when there is actual freezing. If there was actual freezing, the heat from the running water would have to be used to melt the ice. Yeah right Numno, they diverted a creek to create this ice all at once.  And of course icicles always form from 2 inch wide flows of water. No way in he11 could ice freeze on top of ice right? |
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