Land Reclaimation

[Mobaan]

It is well known that Gum (Eucalyptus)trees are not the best for the soil (to say the least ).How can one reclaim soil fertility after the gum trees have been harvested, I see a lot of land lay barren with old gum tree stumps on it. I figure there migth be a chance to buy land cheap ,provided one has the knowledge and ability to reclaim soil fertility.

[chownah]

It is well known that Gum (Eucalyptus)trees are not the best for the soil (to say the least ).How can one reclaim soil fertility after the gum trees have been harvested, I see a lot of land lay barren with old gum tree stumps on it. I figure there migth be a chance to buy land cheap ,provided one has the knowledge and ability to reclaim soil fertility.

<{POST_SNAPBACK}>

Good question, and one I've wondered about before. I don't know about Eucalyptus trees but I have read in organic farming publications the method in general to rehab soil.

The technique starts with DEEP plowing. Before deep plowing dig a few test holes to be sure that you have soil down there and not gravel. The idea is to get some mineral rich soil back to the surface. I don't know if you can get the right types of plows in Thailand...in fact I've never experienced this first hand..I've only read about it....anyway....after deep plowing incorporate as much organic material as you can get into the top 5 or 10 centimetres and then plant a green manure crop. A green manure crop is usually a legume type plant so that it will fix nitrogen and usually in a case where the dirt is depleted you want one that will produce alot of foliage. Often the legume is planted along with a grass (rye grass is often used) to build more soil organic content. In the north the gov't gives out free seeds of a a plant called crotalaria juncea...also called sunn hemp....in Thai its Paw Teeung. I got some this year and will be planting them soon. It will be my first time doing this so I can't report results yet.

Anyway....this discourse is not meant to be instructions on green manure cropping. I just want to point you in the right direction...or at least what I think is the right direction. Let me know what else you find out....especially about Eucalyptus in particular.

[Pseacraft]

I might be a bit ignorant on this as it would apply in LOS but when we would clear land of scrub back on the farm we would first "Chain" it. This is a method of ripping out not only the scrub but also stumps by dragging a heavy, and I mean heavy, anchor chain connected between two dozers. We would also run a "ripper" blade to help pull out any root structure that would cause the scrub to grow back, kind of like how the Eucalyptus does.

There are several types of ripper blades, the ones used with dozers and good for about 1 meter, the Ag ripper we use stateside for busting out hardpan (the packed part of soil just below the reach of a moldboard plow) good for about 2 feet and the chisel plow, the most common, now themost dominate over even moldboard plowing and good for 12-18 inches. The chisel plow should perform well in the rice paddies, mind you I have not tried one but I really would like to give it a go in comparison to the normal thai diskplow. To do deep plowing like what your thinking of you would want to use either of the first two. Keep in mind that the dozer ripper is only a one or two tines so you won't get very good coverage. The Ag ripper satarts out with one but can have even more tines but the more tines you have the greater horsepower you must have. A 2WD Ford 6610 will struggle with 3 tines.

I would also be interested in what else you find out and what you try and it's results.

Eric

[ray23]

It is well known that Gum (Eucalyptus)trees are not the best for the soil (to say the least ).How can one reclaim soil fertility after the gum trees have been harvested, I see a lot of land lay barren with old gum tree stumps on it. I figure there migth be a chance to buy land cheap ,provided one has the knowledge and ability to reclaim soil fertility.

<{POST_SNAPBACK}>

Do some research on the Thai Royal projects they have done a lot of work and research on soils reclalamation.

[ozzydom]

It is well known that Gum (Eucalyptus)trees are not the best for the soil (to say the least ).How can one reclaim soil fertility after the gum trees have been harvested, I see a lot of land lay barren with old gum tree stumps on it. I figure there migth be a chance to buy land cheap ,provided one has the knowledge and ability to reclaim soil fertility.

<{POST_SNAPBACK}>

Not necessarily true, Mobaan, eucalypts are a native of oz and there are many varieties,Oz has some of the poorest soils of any continent and gum trees have evolved to do well in many conditions ranging from the Mallee gum of almost desert areas like the Wimmera region to the tallest hardwood on earth ,the mountain ash of the wilderness valleys of Tasmania. Very often eucalypt are in an area because the soil was originally poor and they are about the only species to do well there so the poor soil is not always a consequence but the reason they are there at all. I learnt this the hard way, buying scrub land with grandiose ideas only to find I could have bought good pastureland for far less than the cost of dozing,windrowing ,deep-ploughing,discing ,harrowing,fertilising and sowing and still end up with sub-standard pasture

[chownah]

It is well known that Gum (Eucalyptus)trees are not the best for the soil (to say the least ).How can one reclaim soil fertility after the gum trees have been harvested, I see a lot of land lay barren with old gum tree stumps on it. I figure there migth be a chance to buy land cheap ,provided one has the knowledge and ability to reclaim soil fertility.

<{POST_SNAPBACK}>

Not necessarily true, Mobaan, eucalypts are a native of oz and there are many varieties,Oz has some of the poorest soils of any continent and gum trees have evolved to do well in many conditions ranging from the Mallee gum of almost desert areas like the Wimmera region to the tallest hardwood on earth ,the mountain ash of the wilderness valleys of Tasmania. Very often eucalypt are in an area because the soil was originally poor and they are about the only species to do well there so the poor soil is not always a consequence but the reason they are there at all. I learnt this the hard way, buying scrub land with grandiose ideas only to find I could have bought good pastureland for far less than the cost of dozing,windrowing ,deep-ploughing,discing ,harrowing,fertilising and sowing and still end up with sub-standard pasture

<{POST_SNAPBACK}>

Good information! Do you think that eucalyptus was planted in Thailand predominently on poor soils that would support no other commercial crop? If this is true then if someone were interested in reclaiming an old eucalyptus stand then the first step would be to do extensive soil sampling and testing first....to get an estimate on how bad the soil is and how involved the reclaimation would need to be. The standard reclamation practices that have been mentioned above are methods that perform the rehab quickly (3 to 4 years possibly) but the entire process can be done more slowly and with less expense....but the time line gets pushed out to about double.....or so I've been told. I'd like to see someone do some reclamation on this type of land but I wouldn't want them to think that its going to be an easy way to make money quickly....more a labor of love I'd say.

[ozzydom]

It is well known that Gum (Eucalyptus)trees are not the best for the soil (to say the least ).How can one reclaim soil fertility after the gum trees have been harvested, I see a lot of land lay barren with old gum tree stumps on it. I figure there migth be a chance to buy land cheap ,provided one has the knowledge and ability to reclaim soil fertility.

<{POST_SNAPBACK}>

Not necessarily true, Mobaan, eucalypts are a native of oz and there are many varieties,Oz has some of the poorest soils of any continent and gum trees have evolved to do well in many conditions ranging from the Mallee gum of almost desert areas like the Wimmera region to the tallest hardwood on earth ,the mountain ash of the wilderness valleys of Tasmania. Very often eucalypt are in an area because the soil was originally poor and they are about the only species to do well there so the poor soil is not always a consequence but the reason they are there at all. I learnt this the hard way, buying scrub land with grandiose ideas only to find I could have bought good pastureland for far less than the cost of dozing,windrowing ,deep-ploughing,discing ,harrowing,fertilising and sowing and still end up with sub-standard pasture

<{POST_SNAPBACK}>

Good information! Do you think that eucalyptus was planted in Thailand predominently on poor soils that would support no other commercial crop? If this is true then if someone were interested in reclaiming an old eucalyptus stand then the first step would be to do extensive soil sampling and testing first....to get an estimate on how bad the soil is and how involved the reclaimation would need to be. The standard reclamation practices that have been mentioned above are methods that perform the rehab quickly (3 to 4 years possibly) but the entire process can be done more slowly and with less expense....but the time line gets pushed out to about double.....or so I've been told. I'd like to see someone do some reclamation on this type of land but I wouldn't want them to think that its going to be an easy way to make money quickly....more a labor of love I'd say.

<{POST_SNAPBACK}>

Eucalyptus were first planted at Chiang Mai in 1950 to re-aforestate areas which had been stripped of native timbers. It was used because it is one of the fastest growing hardwoods with good commercial value,ie.oils,timber,woodchip and paper pulp as well it was planted to alleviate flooding and help reclaim saline affected soil areas .gum trees have a huge tap root which can and does pump huge amounts of water from deep down out of reach of native trees. Oz is one of if not the driest continent and gums evolved to deal with that type of climate which is how LoS has become through deafforestation. Yep your right about the soil testing, you cant fix it until you know the problem. Possibly with the comparably low land prices here there would be good capitol gains to be had,wish I was a few years younger,but I have this aversion to leaving jobs unfinished.

[Sel]

Eucalypts (not sure of all species) actually produce chemicals (distributed around thier upper roots) that are toxic to other plants. Kind of like a natural herbicide. They're a pioneering species meaning that they like to grow on bare (disturbed) land. They produce these toxins to suppress competition and grow very fast (tall) to to eliminate any light reaching competing plants under their canopy.

The reason why they're the dominate tree in Australia is most likely due to the arrival of humans and they're use of fire in hunting. Previous, the dominte forest type was rain forest along the east coast. Australia has very inorganic soils. Rain forest are only very fertile due to the top humus layer, if it's removed the soil undernieth is usually very poor (Oz anyway) Fire disturbance and the consequential removal of forest litter left good bare land for euclyptus to invade and of course eucalyptus need fire to release they're seed so they became dominant.

Soils in Issan are poor. They are classed as sandy. The region itself has a large salt deposit underlying the topsoil. Deforestation and subsequent raising of the water table has resulted in secondary salinisation. Basically the soil in the region is getting more acidic. I would say that acidic soil being a regional problem would be impossible to change in the long run unless with a grand project. You could add something like lime for short term solutions but any advantages of increasing the nitrogen, phophorus and potasium in your hard won alkaline soil would be leached away reasonably quickly.

Eucs generally like sandy soils of acidity in the range of 5.5 to 6.4. Your best bet would be to replant in Eucalyptus. I doubt that the eucs in Thailand are grown as a source of timber as it is notoriously difficult to mill into straight boards (requiring the right techneque and mills) and I've never seen it in the timber supply shops. It's most like used in pulp and paper. I think there are a few big processing mills around as CP grows alot of Eucs for this purpose. Mills require large supplies, the more the better. They would most likely cut and remove your trees as part of the sale and advise if they require any pruning to improve fiber characteristics etc. You would make more money than rice but you would probably be on a 5 or 7 year rotation for your money. That's prbably why the land lies bare as you need to re-invest and wait for the payoff and poor farmers need to live now not in the future.

[bina]

Soils in Issan are poor. They are classed as sandy. The region itself has a large salt deposit underlying the topsoil. Deforestation and subsequent raising of the water table has resulted in secondary salinisation. Basically the soil in the region is getting more acidic. I would say that acidic soil being a regional problem would be impossible to change in the long run unless with a grand project. You could add something like lime for short term solutions but any advantages of increasing the nitrogen, phophorus and potasium in your hard won alkaline soil would be leached away reasonably quickly.

wouldnt the salinity mean the soil is very alkaline?? acidic soil is like in bogs, etc with lots of leaf breakdown... i though also that eucs are an alkaline producing tree (they poison the ground around them)... or am i mixing my chemical analysis up??

[Sel]

Mixing around

acid is pH below 6 while alkaline is pH above

salinity meaning the soil is becoming salty and therefore more acidic.

The nature of cropping rice for example would increase soil salinity on the surface in a place like Isaan. The water used would desolve the salts below (in this case in the underlying salt deposit which is like a locked up storage area for salt until you add water), be evaporated and through the process bring more salt to the surface.

[chownah]

Mixing around

acid is pH below 6 while alkaline is pH above

salinity meaning the soil is becoming salty and therefore more acidic.

The nature of cropping rice for example would increase soil salinity on the surface in a place like Isaan. The water used would desolve the salts below (in this case in the underlying salt deposit which is like a locked up storage area for salt until you add water), be evaporated and through the process bring more salt to the surface.

<{POST_SNAPBACK}>

Acid is less than 7 and alkaline is greater than 7....7 is neutral.

What I've been reading treats salinity and acidity as seperate issues.....but it seems like I've heard that saline soils are also acid....I'd like to find some info on this before I would want to make a statement to that effect, though.

[ozzydom]

Eucalypts (not sure of all species) actually produce chemicals (distributed around thier upper roots) that are toxic to other plants. Kind of like a natural herbicide. They're a pioneering species meaning that they like to grow on bare (disturbed) land. They produce these toxins to suppress competition and grow very fast (tall) to to eliminate any light reaching competing plants under their canopy.

The reason why they're the dominate tree in Australia is most likely due to the arrival of humans and they're use of fire in hunting. Previous, the dominte forest type was rain forest along the east coast. Australia has very inorganic soils. Rain forest are only very fertile due to the top humus layer, if it's removed the soil undernieth is usually very poor (Oz anyway) Fire disturbance and the consequential removal of forest litter left good bare land for euclyptus to invade and of course eucalyptus need fire to release they're seed so they became dominant.

Soils in Issan are poor. They are classed as sandy. The region itself has a large salt deposit  underlying the topsoil. Deforestation and subsequent raising of the water table has resulted in secondary salinisation. Basically the soil in the region is getting more acidic. I would say that acidic soil being a regional problem would be impossible to change in the long run unless with a grand project. You could add something like lime for short term solutions but any advantages of increasing the nitrogen, phophorus and potasium in your hard won alkaline soil would be leached away reasonably quickly.

Eucs generally like sandy soils of acidity in the range of 5.5 to 6.4. Your best bet would be to replant in Eucalyptus. I doubt that the eucs in Thailand are grown as a source of timber as it is notoriously difficult to mill into straight boards (requiring the right techneque and mills) and I've never seen it in the timber supply shops. It's most like used in pulp and paper. I think there are a few big processing mills around as CP grows alot of Eucs for this purpose. Mills require large supplies, the more the better. They would most likely cut and remove your trees as part of the sale and advise if they require any pruning to improve fiber characteristics etc. You would make more money than rice but you would probably be on a 5 or 7 year rotation for your money. That's prbably why the land lies bare as you need to re-invest and wait for the payoff and poor farmers need to live now not in the future.

<{POST_SNAPBACK}>

Sel .> aborigines are supposed to have arrived in oz 40-60,000 yrs ago ,eucalypts spread north to the islands and PNG via land bridges millions of years ago, also its acacia that need fire to release their seed not euc,s.

[ozzydom]

Mixing around

acid is pH below 6 while alkaline is pH above

salinity meaning the soil is becoming salty and therefore more acidic.

The nature of cropping rice for example would increase soil salinity on the surface in a place like Isaan. The water used would desolve the salts below (in this case in the underlying salt deposit which is like a locked up storage area for salt until you add water), be evaporated and through the process bring more salt to the surface.

<{POST_SNAPBACK}>

Acid is less than 7 and alkaline is greater than 7....7 is neutral.

What I've been reading treats salinity and acidity as seperate issues.....but it seems like I've heard that saline soils are also acid....I'd like to find some info on this before I would want to make a statement to that effect, though.

<{POST_SNAPBACK}>

correct chownah

[ozzydom]

Soils in Issan are poor. They are classed as sandy. The region itself has a large salt deposit underlying the topsoil. Deforestation and subsequent raising of the water table has resulted in secondary salinisation. Basically the soil in the region is getting more acidic. I would say that acidic soil being a regional problem would be impossible to change in the long run unless with a grand project. You could add something like lime for short term solutions but any advantages of increasing the nitrogen, phophorus and potasium in your hard won alkaline soil would be leached away reasonably quickly.

wouldnt the salinity mean the soil is very alkaline?? acidic soil is like in bogs, etc with lots of leaf breakdown... i though also that eucs are an alkaline producing tree (they poison the ground around them)... or am i mixing my chemical analysis up??

<{POST_SNAPBACK}>

euc,s like most native plants prefer acidic soil some species as low as 3.0 ph in which not much other than another native will survive, also nitrogen is low under trees because natural composting of litter there uses up nitrogen in the breaking down process. there are 600 species of eucalypt evolved to grow in virtually all conditions in oz.from mallee in desert sand to wet forest in tassie and on bare rock in the Blue Mountains.

[chownah]

...... also nitrogen is low under trees because natural composting of litter there uses up nitrogen in the breaking down process.......

<{POST_SNAPBACK}>

I know a bit about natural composting and in general it will tend to make nitrogen available in the soil for other plants and micro organisms to use. It is this natural composting that creates the rich soils of the temperate climate zones. Perhaps there is something special happening under a eucalyptus tree that releases this nitrogen back into the air......anyone know about this?

[Sel]

Eucs were of course around before aborigines got to australia, they were just not the dominant forest type. Removing the dominate forest (rainforest) at that time by fire gave a competative advantage to eucs.

Eucs in general do need fire to release thier seeds from thier pods

the pH measures hydrogen ion concentration. It's the most fundemental measurement in soil analysis as it affects cation exchange capacity and overall availability of other nutrients. You could have a lot of nutrients in your soil but if the soil is too acidic then they are locked up in unusable forms for most plants and are therefore unavailable. Saline soils are not acidic they tend to be basic pH no greater than 8.5 (but are called neutral having low Na). The large quantities of neutral salts affect plant growth by affecting osmotic pressures (increasing). As op increases it becomes difficult for plants to uptake water and nutrients. Salt concentration of the soil is inversely proportional to soil water content so arid conditions make the soil more saline.

Sorry, what I should of said is that the soil pH in Isaan is getting worst as organic material is removed as crop. Salinity is getting worse due to generally arid conditions and dissolving the underlying salt pan when cropping rice bring more salts to the surface through evaporation.

Small quantities of nitrogen are release to the atmosphere due to burning. Most of it is removed with the harvested crop.

I would say nitrogen under eucs is low due to the above two problems.

[ozzydom]

Eucs were of course around before aborigines got to australia, they were just not the dominant forest type. Removing the dominate forest (rainforest) at that time by fire gave a competative advantage to eucs.

Eucs in general do need fire to release thier seeds from thier pods

the pH measures hydrogen ion concentration. It's the most fundemental measurement in soil analysis as it affects cation exchange capacity and overall availability of other nutrients. You could have a lot of nutrients in your soil but if the soil is too acidic then they are locked up in unusable forms for most plants and are therefore unavailable. Saline soils are not acidic they tend to be basic pH no greater than 8.5 (but are called neutral having low Na). The large quantities of neutral salts affect plant growth by affecting osmotic pressures (increasing). As op increases it becomes difficult for plants to uptake water and nutrients. Salt concentration of the soil is inversely proportional to soil water content so arid conditions make the soil more saline.

Sorry, what I should of said is that the soil pH in Isaan is getting worst as organic material is removed as crop. Salinity is getting worse due to generally arid conditions and dissolving the underlying salt pan when cropping rice bring more salts to the surface through evaporation.

Small quantities of nitrogen are release to the atmosphere due to burning. Most of it is removed with the harvested crop.

I would say nitrogen under eucs is low due to the above two problems.

<{POST_SNAPBACK}>

Your in the wrong game sel, you should have been in the Tasmanian Forestry Service ,you could have saved them all the big bucks they paid me to shoot down seed limbs and dried out on plastic sheets where the seeds fall out all ready for propagation and I mean 100,s of 000,s of them. Your statements make about as much sense as a redback humping a goanna.burning actually invigorates the soil as it releases potash form of pottasium ,aborigines have known that for centuries.

dont follow your reasoning that nitrogen is removed with the harvested crop, unless you mean the crop ie.rice should be headed then the residue ploughed in , cos until it has been composted in the till it actually lowers nitrogen content in the composting process. If nitrogen is low under some euc,s it was probably low from day one,try looking in a temperate rain forest where euc,s are the predominant species ,no shortage of nitrogen there even under 300foot mountain ash where growth of lush vegitation thrives.

I work on the been there ,done that principal , not the know it cos I read it one.

[Sel]

Yawn! ozzy you're the winner in the itchy crotch department

But setting fire to the forest that you worked in was obviously not part of thier management strategy. Funny how you needed to lay the 'seed limbs' out to dry. I thought you were saying that euc seeds (in general) are released just like that, of course the natural way would be through fire.

I spose aborigines would know about the ash thing for paint pigments but they are nomads and have never developed agrarian practices of cultivation. (Preservation techneques aside) Slash and burn techneque is a reasonable way to put nutrients back into the soil in easily available form ready for the seasons crop but the same plot isn't used for several years to allow for recovery in successful societies that practice the like.

Not sure about the rice thing really as i'm a forstry scientist and haven't worked with rice specifically. I just assumed most of the organic matter in modern Thai farming is burned off and weathered. I thought I was in agreement about isaan soils being &lt;deleted&gt; in nitrogen (available nitrogen anyway) from day one though I haven't seen a soil analysis just guessing since the soils in the region are classified as sandy.

Not a bit surprised that there isn't a shortage of nitrogen in a tasmanian rainforest considering there would be a deep humus layer. I've been picturing the soil under eucs in thailand.

[bina]

Saline soils are not acidic they tend to be basic pH no greater than 8.5 (but are called neutral having low Na). The large quantities of neutral salts affect plant growth by affecting osmotic pressures (increasing). As op increases it becomes difficult for plants to uptake water and nutrients. Salt concentration of the soil is inversely proportional to soil water content so arid conditions make the soil more saline.

Sorry, what I should of said is that the soil pH in Isaan is getting worst as organic material is removed as crop. Salinity is getting worse due to generally arid conditions and dissolving the underlying salt pan when cropping rice bring more salts to the surface through evaporation.

i thought so: salinity = alkiline and also often, hardness (its the aquarium thing; hard water vs. soft water and acid vx. alkaline ( and salinity of course) for the different fishes such as discus, oscars etc... could never keep it straight.

in around udon thani i saw salt farms, these obviously cause salinization of the soil, etc... we did have a huge discussion once about all this in the issaan forum called farming in issaan.... i think euc. leaves also are bad for the soil, the same as our awful pine forests in israel: once chosen cause they were fast growing, their leaves don't allow undergrowth to develop so wildlife has nothing to eat and they also burn like crazy the flames leap from top to top, we live in the jerus. corridor and have witnessed many fires like this.... the salinizing of the water i tasted unforutnately in issan near ban chiang, the well at friend's house was undrinkable, so to salt leaching.... all this ties in with the thread about drought in the news forum also....

certain crops 'leach' more nutrients then others from soils, which is why rotation, letting fields lie fallow, or double cropping w/nitrogen producing plants is used by smart farmers: cotton, tobacco, sugar cane are the big bad no no's but also the big time cash crops, just like euc's....

the area around the Dead Sea is a good example of plant adaptation to saline land and low rainfall; and of course the animal life has adapted also... unfortunately issaan wildlife was not made to live in saline conditions since thailand is supposed to be semi tropical w/high rainfall (lots of soft water?)

slash and burn techniques were fine when there were not a lot of people slashing and burning and the amount of return growth matched the amount of destroyed greenery; with pop. growth, the slash and burn overtook the growth, so not a very effective method ....

too bad all these 'farang' farmers dont do soil analysis and give us the results so we can learn first hand and no speculation... and the other thing:

theory apart and reality apart: vegetables and animals never read the books on theory so first hand experience is usually better when mixed w/the theory when applied.

[chownah]

.......Saline soils are not acidic they tend to be basic pH no greater than 8.5 (but are called neutral having low Na). The large quantities of neutral salts affect plant growth by affecting osmotic pressures (increasing). As op increases it becomes difficult for plants to uptake water and nutrients. Salt concentration of the soil is inversely proportional to soil water content so arid conditions make the soil more saline.

Sorry, what I should of said is that the soil pH in Isaan is getting worst as organic material is removed as crop. Salinity is getting worse due to generally arid conditions and dissolving the underlying salt pan when cropping rice bring more salts to the surface through evaporation.

Small quantities of nitrogen are release to the atmosphere due to burning. Most of it is removed with the harvested crop.

I would say nitrogen under eucs is low due to the above two problems.

<{POST_SNAPBACK}>

I'm wanting to learn more. Do you have an internet link talking about soil salinity and its relationship to alkalinity?

When you talk about salt concentration being inversely proportional to the soil water content are you talking about the concentration of salt in the soil or of the salt in the water in the soil?

You say that the lack of nitrogen in the soil under eucs is due to two problems...one is burning I think....what is the other?

[ozzydom]

I

Yawn! ozzy you're the winner in the itchy crotch department

But setting fire to the forest that you worked in was obviously not part of thier management strategy. Funny how you needed to lay the 'seed limbs' out to dry. I thought you were saying that euc seeds (in general) are released just like that, of course the natural way would be through fire.

I spose aborigines would know about the ash thing for paint pigments but they are nomads and have never developed agrarian practices of cultivation. (Preservation techneques aside) Slash and burn techneque is a reasonable way to put nutrients back into the soil in easily available form ready for the seasons crop but the same plot isn't used for several years to allow for recovery in successful societies that practice the like.

Not sure about the rice thing really as i'm a forstry scientist and haven't worked with rice specifically. I just assumed most of the organic matter in modern Thai farming is burned off and weathered. I thought I was in agreement about isaan soils being &lt;deleted&gt; in nitrogen (available nitrogen anyway) from day one though I haven't seen a soil analysis just guessing since the soils in the region are classified as sandy.

Not a bit surprised that there isn't a shortage of nitrogen in a tasmanian rainforest considering there would be a deep humus layer. I've been picturing the soil under eucs in thailand.

<{POST_SNAPBACK}>

I will let your snide remark go through to the keeper,suffice to say that as a "forestry scientist" ? your forestry management skills could do with a bit of work.

you should know that standing old growth forest is not fired on purpose in fact a fire there is a catastrophe.Some forests have not been burned in living memory so father xmas must deliver seedlings in those areas.

Seed limbs are harvested because where the seeds fall naturally are not necesarilly where they are required, the seed capsules are harvested green before laying out for drying and releasing there seed which is then propagated in a nursery or formed into a caplet of water soluble fertilizer for aircraft sowing in areas where clear felling and burning has been carried out.

One of the reasons aborigines used burning off was that they knew that the regrowth that followed attracted there food source animals back to that area.

See Sel, its easy to post your views without nasty personal remarks

[Sel]

If we're talking about aust. i would think that

1. the soils are poor in nitrogen to start with. i.e. the original rock that was broken down isn't a good source.

2. Lack of a good humus layer or conditions for nitrogen fixing bacteria to thrive. Maybe due to fire disturbance or the tanins in euc foliage (not sure what affects tanins would have)

If isaan

1. I'm actually not too sure if isaan has acidic soils (acidic soils by there nature would have low levels of nitrogen) Thought I saw it somewhere but looking around haven't been able to confirm

2. Salinity problems. Adding available N may be well but if saline conditions are present it is difficult for nutrient uptake (and water) by plants to occur

Here are some interesting articles on salinity problems in issan

http://www.fao.or.th/Rap03-08.htm

http://recmert.kku.ac.th/international/income/toppage20.htm

Nitrogen cycle

http://www.visionlearning.com/library/modu...ewer.php?mid=98

gardening

http://www.earthandtable.com/glossary/soil...nts.html#manure

[ozzydom]

If we're talking about aust. i would think that

1. the soils are poor in nitrogen to start with. i.e. the original rock that was broken down isn't a good source.

2. Lack of a good humus layer or conditions for nitrogen fixing bacteria to thrive. Maybe due to fire disturbance or the tanins in euc foliage (not sure what affects tanins would have)

If isaan

1. I'm actually not too sure if isaan has acidic soils (acidic soils by there nature would have low levels of nitrogen) Thought I saw it somewhere but looking around haven't been able to confirm

2. Salinity problems. Adding available N may be well but if saline conditions are present it is difficult for nutrient uptake (and water) by plants to occur

Here are some interesting articles on salinity problems in issan

http://www.fao.or.th/Rap03-08.htm

http://recmert.kku.ac.th/international/income/toppage20.htm

Nitrogen cycle

http://www.visionlearning.com/library/modu...ewer.php?mid=98

gardening

http://www.earthandtable.com/glossary/soil...nts.html#manure

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[url=http://203.209.62.252/tropicalsandysoils/information.htm will give you an insight of the problems of Isaan soils.

[url=http://farrer.riv.csu.edu.au/ASGAP/eucalyptus.html

[url=http://farrer.riv.csu.edu.au/ASGAP/acacia.html#prop will show you the differences in propagation of euc and acacia

[Mobaan]

Hi friends ,folks ,neighbors,

all your musings about trees in Oz and near the Dead Sea make interesting reading (for rainy afternoon) . Lets stop bikkering at each other and perhaps come back to the original topic "Reclamation of land previously under Eucalyptus in the Udon area of Issan."

Has anyone out there ever done it ,or seen it done ? The hint about the Royal Projects is a good one . Once I am back in the area (july ) I will follow up on that.I believe the nearest Royal Project is East of us near Sakhon Nakhon .

[ozzydom]

Hi friends ,folks ,neighbors,

all your musings about trees in Oz and near the Dead Sea make interesting reading (for rainy afternoon) . Lets stop bikkering at each other and perhaps come back to the original topic "Reclamation of land previously under Eucalyptus in the Udon area of Issan."

Has anyone out there ever done it ,or seen it done ? The hint about the Royal Projects is a good one . Once I am back in the area (july ) I will follow up on that.I believe the nearest Royal Project is East of us near Sakhon Nakhon .

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Hi Mobaan, Did you have any ideas in mind about what you would want to do with reclaimed land . ie. rice paddies, pasture ,sub -development. ultimate useage would be a

big .consideration in how you went about it

[aletta]

There was a very interesting article in the Bangkok Post by a guy with a 20 year old Eucalyptus plantation who said that at that period of time the plantation was in balance with what taken out currently being replaced by 20 years of leaf litter.

[Mobaan]

Good thinking--one should know the way out of a room before one enters it.

I do not like the ricepaddy idea -trending more towards vegetables /produce growing . If worked by machinery the soil would have to be pretty clesr of stumps /roots etc,but if mainly/partly worked by hand that would not hamper the procees too much, But how serious is the problem with root extracts poisionig the surrounding area? Once the tree is dead ,is that still a problem?

[chownah]

Good thinking--one should know the way out of a room before one enters it.

I do not like the ricepaddy idea -trending more towards vegetables /produce  growing . If worked by machinery the soil would have to be pretty clesr of stumps /roots etc,but if mainly/partly worked by hand that would not hamper the procees too much, But how serious is the problem with root extracts poisionig the surrounding area? Once the tree is dead ,is that still a problem?

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I have no direct experience with eucalyptus but I have alot of experience with organic gardening and have read extensively on the subject. If you want hard facts about dealing with eucalyptus removal I don't think you are going to find it here....and even if you did would you trust the source? If I were going to invest alot of time and money on this type of project I certainly would not base my decisions on what people here (myself included) say.....getting a link or other source of info is the best you can do here.

Having said that I'll give you my thoughts on eucalyptus roots. Since eucalyptus roots are organic they can be broken down by decay processes. I have never heard of some plant or animal produced material which did not break down naturally. The question is how long will it take. By using organic gardening/farming methods you will radically increase the rate at which this happens compared to the natural processes. The same thing can be said about the toxins that are in the leaves or that drip off of a tree in the sap.....all of these can be broken down with natural decay processes which can be done more rapidly with organic gardening/farming techniques.

Learning about organic gardening/farming techniques will take time and practice....the same thing is true of learning non-organic gardening/farming techniques. Many times people who have little/no experience in gardening/farming are interested in doing some project of this type and they go out and look for information that will assure them success in this endeavor. This is like trying to learn how to oil paint and thinking that the first thing you will do is a masterpiece. Farming is not a simple thing....it is an art and a science....best to learn to walk before you try running.

[ozzydom]

Good thinking--one should know the way out of a room before one enters it.

I do not like the ricepaddy idea -trending more towards vegetables /produce  growing . If worked by machinery the soil would have to be pretty clesr of stumps /roots etc,but if mainly/partly worked by hand that would not hamper the procees too much, But how serious is the problem with root extracts poisionig the surrounding area? Once the tree is dead ,is that still a problem?

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not a problem, once tree is felled and stump dies white ants get into them.

dozer hire is cheap here, the stumps are only small so a dozer will rip them out roots and all ,just push them in a heap and burn ,adds potash to soil,the poisons you mention are more for repelling vermin like white ants,sometimes shrubbery grows right up to gum trees simply for the protection it supplies.

[ozzydom]

Good thinking--one should know the way out of a room before one enters it.

I do not like the ricepaddy idea -trending more towards vegetables /produce  growing . If worked by machinery the soil would have to be pretty clesr of stumps /roots etc,but if mainly/partly worked by hand that would not hamper the procees too much, But how serious is the problem with root extracts poisionig the surrounding area? Once the tree is dead ,is that still a problem?

<{POST_SNAPBACK}>

I have no direct experience with eucalyptus but I have alot of experience with organic gardening and have read extensively on the subject. If you want hard facts about dealing with eucalyptus removal I don't think you are going to find it here....and even if you did would you trust the source? If I were going to invest alot of time and money on this type of project I certainly would not base my decisions on what people here (myself included) say.....getting a link or other source of info is the best you can do here.

Having said that I'll give you my thoughts on eucalyptus roots. Since eucalyptus roots are organic they can be broken down by decay processes. I have never heard of some plant or animal produced material which did not break down naturally. The question is how long will it take. By using organic gardening/farming methods you will radically increase the rate at which this happens compared to the natural processes. The same thing can be said about the toxins that are in the leaves or that drip off of a tree in the sap.....all of these can be broken down with natural decay processes which can be done more rapidly with organic gardening/farming techniques.

Learning about organic gardening/farming techniques will take time and practice....the same thing is true of learning non-organic gardening/farming techniques. Many times people who have little/no experience in gardening/farming are interested in doing some project of this type and they go out and look for information that will assure them success in this endeavor. This is like trying to learn how to oil paint and thinking that the first thing you will do is a masterpiece. Farming is not a simple thing....it is an art and a science....best to learn to walk before you try running.

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There is no big deal in reclaiming ex eucalypt country,most of the farmland in oz was once just that,only these days we use dozers instead of *clydesdales.*

If its standing forest you just push every thing over with a dozer then you rip the roots up with a brush rake (like a big rake instead of a dozer blade) this takes the roots and leaves the soil, pile the debris in rows or heaps to dry ,where it can be salvaged as firewood (added income) or simply burnt in situ when dry.

Meanwhile you plough the land ready for sowing,some prefer to lay a crop of oats or legumes first up to be ploughed in , get a soil analysis done ,fertilise to rectify deficiencies and away you go. Depending on water availability,income can be had during the process, firewood, green feed etc.

* for the uninitiated clydesdales are draught horses.(working them is how I learnt to swear)