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  #1  
Old 06-26-2005, 03:34 AM
Sampiro Sampiro is offline
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Why do farmer's burn fields?

This is probably an incredibly stupid question but I'll ask it anyway:

My grandmother used to set fire to her cornfields each March/April (often to disastrous results) before planting the next crop. What is the reason for this? Is it just to get rid of the old stalks or does it somehow make the soil more fertile or... what?


For somebody who grew up on a farm I'm amazed how ignorant I am about farming, though admittedly I was always far more involved with the livestock- castrating pigs I can do, but don't ask me to keep a petunia alive for a week without a feeding tube.
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  #2  
Old 06-26-2005, 04:00 AM
Tuckerfan Tuckerfan is offline
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IIRC, it's a fast method of getting rid of stalks, weeds, etc. since you don't have to worry that you might have tilled some seeds from previous crops/weeds under the soil and have them pop up again.
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  #3  
Old 06-26-2005, 05:18 AM
Q.N. Jones Q.N. Jones is offline
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My grandfathers both farmed, and though they did it only sometimes, they did it for both reasons. Not sure it's scientifically proven that it enhances a field's fertility, but they thought it did.
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  #4  
Old 06-26-2005, 05:19 AM
Q.N. Jones Q.N. Jones is offline
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I should add the disclaimer that this information has come down to me through my dad, as both my grandfathers are dead. And my dad sometimes likes to pretend he knows more than he really does. Aah, now that I think about it, you should take my post with a grain of salt.
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  #5  
Old 06-26-2005, 07:36 AM
rbroome rbroome is offline
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Quote:
Originally Posted by Q.N. Jones
I should add the disclaimer that this information has come down to me through my dad, as both my grandfathers are dead. And my dad sometimes likes to pretend he knows more than he really does. Aah, now that I think about it, you should take my post with a grain of salt.
burning fields was a widespread practice years ago-in some parts of the country. I know that in Oregon, farmers would grow hay in quite large fields. After harvest they would burn over the fields. The resulting smoke in the air was very unpopular. The reason, according to the farmers and associated agricultural experts at the local universities, was to control insect and disease. So the argument came down to either large amounts of pesticides or large amounts of smoke. Smoke was cheaper and therefor more popular when I was there, don't know how it is now.
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  #6  
Old 06-26-2005, 07:45 AM
Rayne Man Rayne Man is offline
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This used to be quite common in the UK. After the wheat or barley crop had been harvested the surplus straw was burned in the field. This practice has now been outlawed . The main reason for this ban was the mess left by the ash blowing around, fires getting out of control , and the huge clouds of smoke which not only blotted out the sun but caused traffic accidents when the smoke drifted onto roads and reduced visibility.

I have also seen fields of sugar-cane set on fire in Trinidad. This is done to burn off the surplus leaves and also to drive out any nasty snakes and spiders before the cane-cutters get to work.
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  #7  
Old 06-26-2005, 07:48 AM
Revtim Revtim is offline
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They still burn the sugar cane fields here in South Florida every year, or at least did so very recently.

I kinda remember learning in grade school or high school this was for more than just clearing the field, and the ash added something beneficial to the soil.
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  #8  
Old 06-26-2005, 07:51 AM
enipla enipla is offline
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We used to sometimes burn our grass/yard in Illinois. It always came back much greener the next year.
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  #9  
Old 06-26-2005, 07:52 AM
Q.N. Jones Q.N. Jones is offline
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Quote:
Originally Posted by rbroome
The reason, according to the farmers and associated agricultural experts at the local universities, was to control insect and disease.
Perhaps this is the reason my grandparents said it made the fields "more fertile"--because they got higher crop yields if they burned out insects, pests, and diseases.

Every year here in Iowa, I see a few fields being burned out. So it is still done. Probably because out here, the population density is pretty low, especially out in the country.
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  #10  
Old 06-26-2005, 09:46 AM
clairobscur clairobscur is online now
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I don't know the name of this practice in english, but in the case of the agricultural communities that burn forested surfaces, cultivate the area until the soil is exhausted some years later, then move and repeat, I've been told that this practice had the added benefice of ashes providing a more fertile soil. don't know if it's true, though....
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  #11  
Old 06-26-2005, 10:23 AM
Unregistered Bull Unregistered Bull is offline
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I believe that it is still done routinely with cotton stalks after the harvest in many parts of the world to kill boll weevils and the plant that will continue growing year round in places without a freeze.
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  #12  
Old 06-26-2005, 10:25 AM
Kreekurmudgeon Kreekurmudgeon is offline
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They still burn the sugar cane fields in Louisiana, but I'm not sure why. The smoke is quite a nuisance. Burning has something to do with the next year's crop. Department of Agriculture and EPA, as well as farm groups, are working on the problem to see if a cleaner way can be found.
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  #13  
Old 06-26-2005, 10:35 AM
Rayne Man Rayne Man is offline
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Originally Posted by Kreekurmudgeon
They still burn the sugar cane fields in Louisiana, but I'm not sure why. The smoke is quite a nuisance. Burning has something to do with the next year's crop. Department of Agriculture and EPA, as well as farm groups, are working on the problem to see if a cleaner way can be found.
This a quote from the web-site of a sugar plantation in Hawaii :-

Is sugarcane still burned during the harvest?
Harvesting begins with a brief, intense field burn for two reasons. First, the burning boosts the quality and quantity of the sugar we recover. Secondly, it reduces the amount of dried cane leaves reducing the cost of harvesting, hauling and milling. There are also other benefits to burning including the reduction of vermin insects and rodents and it provides natural potash to our acidic soil. Experimentation over many decades still have not produced a more viable method of cleaning off the cane trash
.
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  #14  
Old 06-26-2005, 11:27 AM
Colibri Colibri is offline
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Aside from getting rid of the old stalks and killing off weed seeds, the minerals contained in the remnants of the earlier crop are more readily incorporated into the soil from the ash than if you had to wait for the leaves and stalks to decay. However, this depends on there not being excessive rainfall between the time of the burning and the next growing season. If there is, runoff can wash away the soil and deplete it of minerals.

The traditional form of agriculture in the tropics is called slash-and-burn. During the dry season the farmer cuts the vegetation on a new plot of land and allows it to dry. At the end of the dry season, he burns the cut vegetation and plants a crop at the beginning of the rains. It saves a lot of labor from having to haul off the cut vegetation. However, the runoff of ash contributes to the loss of soil fertility so the practice often cannot be continued in the same place for more than a few years.

Burning off pastures stimulates the growth of young fresh leaves for cattle to feed on. It also will kill off tree seedlings and prevent the pasture from becoming overgrown.
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  #15  
Old 06-26-2005, 12:08 PM
chaoticbear chaoticbear is offline
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Quote:
Originally Posted by Sampiro
farmer's[/SIZE]
And this man's a librarian!
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  #16  
Old 06-26-2005, 12:10 PM
chaoticbear chaoticbear is offline
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Gaudere, how I hate you.
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  #17  
Old 06-26-2005, 12:20 PM
Johnny L.A. Johnny L.A. is offline
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Quote:
Originally Posted by Colibri
However, the runoff of ash contributes to the loss of soil fertility so the practice often cannot be continued in the same place for more than a few years.
I saw a documentary on The Science Channel last week, that wondered if a Spanish explorer really did see a large city in the Amazon Basin. When the researcher found were 'islands' of high ground, and causeways connecting them. I don't remember the number, but the population the evidence suggested seemed to be way too large to support. The programme mentioned 'slash-and-burn', and noted what Colibri noted above. How could a large population be supported?

Charcoal was found in the soil. While ash -- and its nutrients -- is easily washed away by the heavy rains, charcoal seems to persist. Apparently they ancient farmers may have turned their crop waste and jungle wood into charcoal and used that as a nutrient.

Another thing the programme showed was 'black earth'. Valuable stuff, which is found around the ancient settlement sites. It's 'mined' by the truckload. One farmer said that he sells 60cm of the 'black earth' from a plot, and then lets it sit while a similar amount is harvested from the next plot. IIRC, the narrator said that after 20 years the mined site will have regained the 60cm that was removed. Jungle litter (leaves, grasses, etc.) gather and decompose, resulting in very fertile soil. Natural compost.
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  #18  
Old 06-26-2005, 12:31 PM
David Simmons David Simmons is offline
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Don't some of the minerals in the soil go into the stalks? Burning would return these minerals to the soil. I used to burn my bermuda grass lawn in the winter and then water the ashes in. It seemed to make my bermuda lawn the best one in the neighborhood.

Of course this was hardly a double-blind, scientific test.
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  #19  
Old 06-26-2005, 12:34 PM
Colibri Colibri is offline
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Quote:
Originally Posted by Johnny L.A.
Another thing the programme showed was 'black earth'. Valuable stuff, which is found around the ancient settlement sites.
Known in Portuguese as terra preta. Here's a bit more info.
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  #20  
Old 06-26-2005, 12:37 PM
Colibri Colibri is offline
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Quote:
Originally Posted by David Simmons
Don't some of the minerals in the soil go into the stalks? Burning would return these minerals to the soil.
Yes, I sort of touched on that a few posts up. Burning recycles the minerals in the remnants of last year's crop a lot faster than if you waited for them to decay, which is especially important in temperate areas where decay is relatively slow.
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  #21  
Old 06-26-2005, 12:38 PM
David Simmons David Simmons is offline
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Originally Posted by Colibri
Yes, I sort of touched on that a few posts up. Burning recycles the minerals in the remnants of last year's crop a lot faster than if you waited for them to decay, which is especially important in temperate areas where decay is relatively slow.
Oops. I think I skimmed the posts a little too fast.
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  #22  
Old 06-26-2005, 12:40 PM
Johnny L.A. Johnny L.A. is offline
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Originally Posted by Colibri
Known in Portuguese as terra preta. Here's a bit more info.
Thanks for that. I'd forgotten the name they used. (I was online, and only half-watching the show.)
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  #23  
Old 06-26-2005, 01:28 PM
Sampiro Sampiro is offline
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Originally Posted by chaoticdonkey
And this man's a librarian!
I grew up on a rural Alabama cattle farm that depended on the rains and the price of beef to make a profit. Some years we were too poor to afford apostrophes, so I tend to overcompensate now that I work for a wage.
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  #24  
Old 06-26-2005, 01:31 PM
Sampiro Sampiro is offline
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So this one actually does have some scientific merit. That's good to know. (I knew some farmers who literally incorporate voodoo into their farming [including one ancient fellow named Fink [so old that both of his parents had been slaves] who farmed some of my father's land and started every season by killing a chicken and sprinkling its blood on the seeds, though even in his 90s he'd have fought anybody who said this was voodoo as he was a devout Baptist.)
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  #25  
Old 06-26-2005, 01:54 PM
Sampiro Sampiro is offline
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One reason I was wondering is because I'm working on a memoir like thingy and I'm thinking of beginning with the time my grandmother burned one of her half-acre back cornfield and in so doing burned out 30 acres of my father's timberland and literally blackened the walls of our house a quarter mile away. (We literally saw black smoke from about 3 miles away driving home and set a new landspeed record for central Alabama because we knew where there's smoke, there's Grandmother.) Grandmother (easily the most evil human I've ever met- reminds me of the "I CLAUDIUS" line that "they say a snake once bit her... and died") had charged her sister (a lobotomized old maid who had spent 40 years in the state snakepit) with "watching the fire" while she went inside and cooked dinner. She came back out to find the woods on fire, deer and turkey and rabbits and dogs running every direction and the flames advancing towards our own home while her sister stood non-chalantly in the middle of the road with her dress pulled up to just under sagging boobs pissing in the road "in front a' Gawd 'n' everbody".
We got home to find a fifty foot firewall moving towards Locksley Hall (my father's grandiose name for the not so grandiose house) and two crazy old women (Grandmother- early 80s, Sister Lucy, early 70s) waiting for it at the top of the hill with a croker sack waiting for "an opportune time" to start beating it.

It took us a very long very hot hour (this is VERY rural Alabama- the only fire department is volunteer and they were all at work or out hunting and didn't have a truck anyway [not that there were any hydrants]) to fight back the flames using croker sacks, antique quilts, a water hose that wouldn't reach the fire [couldn't fill buckets because Grandmother had stolen them all and taken them to her place] and even a bucket of well water that my two 90 year old twin great aunts had drawn and walked half a mile from their cabin to pour on the fire. (The aunts didn't have running water because 1- it wasn't in the Bible 2- they "just cain't abide the taste of the pipes" and 3- they regarded relieving yourself inside the house as nasty [never mind they lived with dozens of cats]). There was no fire department that serviced this part of the state save for a volunteer bucket brigade whose members all lived miles away and had no truck and there were hydrants if they had. Anyway, when it was finally put down and the entire side yard was black and there were black streaks on the wall that are on that house to this day, Grandmother said the obvious: "This wouldn't have happened if Lucy hadn't pissed in the road."
She was also yelling "Lucy, I told you to watch that damned fire" and, I swear to Og she said this, I'm not embellishing, she really did talk like this, Lucy replied "I did watch it. It accelerated as it moved westward." Then Grandmother said something to the effect of "while you're all here... let me tell you what I need from the grocery store..."

So, short story very long and now short again, the first two lines of the memoir are currently "Grandmother said the woods caught on fire because Lucy pissed in the road. The fact that she herself had spent the afternoon soaking old tires in gasoline and setting them aflame in the fields on a windy day was at best coincidental." (Needs work, but I think it has promise.)
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  #26  
Old 06-26-2005, 04:29 PM
Sampiro Sampiro is offline
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Quote:
Originally Posted by chaoticdonkey
Gaudere, how I hate you.
P.S.- explain please
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  #27  
Old 06-26-2005, 04:42 PM
Colibri Colibri is offline
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Quote:
Originally Posted by Sampiro
P.S.- explain please
Gaudere's Law: Any post made to point out a grammar or spelling error will itself contain a grammar or spelling error.
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  #28  
Old 06-26-2005, 11:22 PM
chaoticbear chaoticbear is offline
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Thanks guys
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  #29  
Old 06-26-2005, 11:28 PM
David Simmons David Simmons is offline
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Quote:
Originally Posted by Colibri
Gaudere's Law: Any post made to point out a grammar or spelling error will itself contain a grammar or spelling error.
Its "mistake" not "error."
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  #30  
Old 06-26-2005, 11:44 PM
Colibri Colibri is offline
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Originally Posted by David Simmons
Its "mistake" not "error."
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  #31  
Old 06-27-2005, 01:16 AM
justwannano justwannano is offline
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Our neighbor burns off waterways every 3 years to stop weeds from taking over.
It appears to work.
Every 2 years he has fine looking grassy waterways the 3rd year its weedy.
This was the 3rd year.
I saw the smoke and raced over to find his wife who non chalantly explained his theory.
He did have a problem a few years back though.
It seems that his tractor had a small hydraulic fluid leak.
In case you didn't know hydraulic fluid burns.
The tractor fire was put out with no serious consequences.
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  #32  
Old 06-27-2005, 01:39 AM
Northern Piper Northern Piper is offline
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Farmers who grow flax will usually burn off the stalks from the last harvest because flax straw takes a long time to decay and the stalks interfere with the seeding.
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