Green manures, cover crops and nitrogen fixing trees

[Foreverford]

Howdy folks. This is the first time posting and would like to find a source to purchase seeds for green manuring. Sesbania Rostrata looks promising for what I'd like to try but am open to anything available anywhere. Farming is science and science is experimenting (I'll use almost anything if I can just find where and how to buy it). My family has been farming for nearly 15 centuries on the same small mountainside and it is all good (still can't really make much money at it but haven't ever had the bank take it either) and obviously been organic most of the time. I helped write the first Health and Safety legislation that created organic standards in California thru the CCOF.

Sorry for being verbose but I don't want to be treated as a novice beginner (treated as a failure is no problem as I've failed more than one year in the farming game) I really really want to buy something that I can start to use this year. We used to use a lot of fava beans. The farms are in Buri Ram near Surin but I will travel anywhere to buy whatever may be available. I've got a Ford 6600 with a "three" two "sevens" (anyone need to buy a brand new "seven") an adjustable 18 blade disc, a 2.3 meter Howard Rotovator and a 2.5 meter box scraper that I custom made so I feel I can incorporate whatever green manures I can get to grow. This is the first year and we're growing Hom Mali and got lucky so far as it is almost all well over head high (no poisons but still using chemical fertilizer) but it would sure be nice to see the sun for a day or two. Like some say if god didn't want to make farmers he never would have made Ford tractors. Thanks for any help.

[mrissara]

Try

rice seed center, Surin (044) 513693

rice seed center, KalaSin (043) 812117, 812118

Ask for "Sa-No-African" seeds

Edited October 31, 2008 by mrissara

[Smithson]

This thread may be interesting, it talks about sunn hemp for green manure, pls post any info you're able to find

http://www.thaivisa.com/forum/Improving-So...amp;pid=1721199

[Lickey]

Or this thread, winged beans [tue pru] a good nitro replacment plant and a cash crop.

http://www.thaivisa.com/forum/Winged-Beans...hl=winged+beans

or go straight to this site,

http://www.leafforlife.org/PAGES/PSOPHOCA.HTM

And welcome to the forum Foreverford,

Cheers, Lickey.

[Smithson]

Or this thread, winged beans [tue pru] a good nitro replacment plant and a cash crop.

http://www.thaivisa.com/forum/Winged-Beans...hl=winged+beans

or go straight to this site,

http://www.leafforlife.org/PAGES/PSOPHOCA.HTM

And welcome to the forum Foreverford,

Cheers, Lickey.

That's interesting, we've got the winged beans growing now. What's the best way to put them back into the soil? Will using the leaves and stems as a mulch work or is composting them a better idea?

[Lickey]

Hi smithson, it seems the beans can be used either way, composted or mulch, i never did get to plant the 3 rai with beans, [you know what its like, Mrs in a hurry to get things done ect] but we do have 2 areas with the beans, and when they grow to thick, i thin them out and compost them, to get seed, leave them on the plant till they go brown and dry, seperate the seeds from the pod, sun dry them and then rub in a sieve or calendar to remove the coating, soak a few hours then plant,

This is what Chownah had to say,,,

There is probably no need to swap the leaves for manure....pound for pound the leaves are likely to be just as good as the manure....I don't know this for sure for winged beans as I have not had time to research winged beans yet but a high quality green manure crop will have (kilo for kilo) about the same nitrogen content as manure. Of course if you can get more kilo of manure than the feed you supply then you could be making a gain....it depends on alot of factors.

Cheers, Lickey.

[JungleBiker]

Hi Foreverford,

You might be interested in "stylo" (Stylosanthes guinensis) and in particular the variety "Ubon Stylo". You can buy good quality scarified seed from the Faculty of Agriculture, University of Ubon Ratchathani. It is normally planted by farmers as a forage crop for raising livestock, but being a legume, I think it would be good as a green manure/cover crop. You can read more about this and other tropical forage crops at: http://www.tropicalforages.info/ (see the forage fact sheets). The web page (English version) of the faculty showing their contact details at the bottom is at: http://www.agri.ubu.ac.th/eng/

Best regards,

JB.

[Foreverford]

Try

rice seed center, Surin (044) 513693

rice seed center, KalaSin (043) 812117, 812118

Ask for "Sa-No-African" seeds

Thanks much and running hard right now. Down to watch the women play volleyball in Phuket then a big pro-am golf tourney in Hua Hin. Now who says a farmer can do nothing but lose money bust his knucles and get greasy??? I think it was John Fogerty with "Creedence who sang about "who'll stop the rain". "Whoever it is I wish they'd cut out quick" that's Dylan and we could all use anybody's good wishes to turn it off. Pop's -in-law has some rice in the lowert area and it's pretty full of leeches and they're having to go in now and cut so they can get it out of the wet stuff and to higher ground. Vietnam is getting washed off the map as we speak as i see it. I know Willie Nelson could make a song of it all. I assume the "Sa-No-African" is the sesbania hopefully I'll be calling today and will update everyone when i get the hang of using this forum as this is a first for me in anything like this. Just like a farmer got to know everything in the world about everything but always will be a bit dumb about most of it. Thanks

[jaideeguy]

What about the simple soybean?? You get food from it and, if innoculated... nitrogen as well as humus and food crop as well.

can the innoculant be bought here??

[Foreverford]

What about the simple soybean?? You get food from it and, if innoculated... nitrogen as well as humus and food crop as well.

can the innoculant be bought here??

Thanks Jaideeguy. I'm looking at all options and know this was actually the ancient use for this "nowdays" foodsource. I really like your logo, reminds me of just before a little league baseball game. I had about a half dozen free games on the local Menlo Park pizza parlor pinball machine and the guys came in and said tough luck they were going to unplug it and move it as they were setting up some music gear to play in the 15' x 15' back room. It was the first time I remember smelling patchouli oil as beautiful young girls in long skirts came in with the gang. Many years later I found it was the Warlocks first gig and and the rest I guess is just old dead history. Peace and Love me

[Foreverford]

Try

rice seed center, Surin (044) 513693

rice seed center, KalaSin (043) 812117, 812118

Ask for "Sa-No-African" seeds

I've tried these numbers nummerous times at different times of the day without luck. I would assume that maybe everyone is out in the field but no luck with an answer. thanks

[Foreverford]

This thread may be interesting, it talks about sunn hemp for green manure, pls post any info you're able to find

http://www.thaivisa.com/forum/Improving-So...amp;pid=1721199

Great news here and info. I'll be adding some more in a few days with i get my facts and figures and time together. Chownah is a superstar

[Foreverford]

This thread may be interesting, it talks about sunn hemp for green manure, pls post any info you're able to find

http://www.thaivisa.com/forum/Improving-So...amp;pid=1721199

Thanks Smithson

I finally found a supplier of seed. Sun Hemp is called Paw Teung (pahh teu enhg) here and it goes for 40 baht a kilo if you are buying in bulk (I bought 200 kilos). They say 3-5 kilos per rai for green manure and Chownah has said he has had success in the 8 kilo a rai amount for broadcasting and discing. It germinates extremely fast, 4-5 hours soaking in warm water for me got some of the seeds to start showing its roots. Be careful not to soak too long if you want to "pre-emerge" your seeds as any longer than that or a delay in planting could be trouble. We just planted that and Sahnoh African (sesbania rostrata 40 baht a kilo and 3-5 kilo to a rai) last thursday the 25th and I will try to inform as the results come in. We are trying a few different methods to grow these two along with another bean that I don't have the name right now that is lima bean in size. The "Sanoh" is reputed to be a difficult grower with germination up to two weeks. Below is the contact of the company.

Thai Tanaht Praset in Chai Badan formely known as Lam Narai on Highway 21 half-way between Saraburi and Petchabun they are on the right side of the road about a kilo or two from the main clock tower on the highway.

Suenee 081-8202626

Tua Plu seeds in bulk are impossible to locate still but I will continue to look. I'd love to at least get a few cans but can't find them.

036-461701

Too too long on the computer and too sick to give more now but will update

[drtreelove]

I don't know about your area or about current availability, but in Chiang Mai I got free jack-bean seeds from the 'Land Development Office' (about 10k north of the SuperHwy on the Mae Rim (107) hwy, on the west (Doi Pui) side between the hospital and the (121) ring road).

At that time they had black beans, sesbania and others too. We didn't need a 'tabien baan', only my wife's ID, filled out a form with address and amount of rai. They calculated coverage rates and based the allotment on that; we pulled around back with the pickup and they loaded us up with the appropriate number of sacks of seed. I was only seeding about 4 rai, so I don't know what their upper limit is.

The land development office also does free soil analysis. The only problem is that it takes 45 days (sent to Lampang) and is a very basic NPK report with no interpretation or recommendations. I get better, more complete, 2 week soil analysis reports from Mae Jo University soil science department for 500 baht. And they have a soil science professor available to interpret and make recommendations for amendments if needed.

But you don't need a soil analysis to 'green manure'. don

[Foreverford]

mulch great stuff !! I like to use a mixture of coconut fibre (brilliant for retaining moisture), banana plants; old leaves, chopped up trunks once they have fruited and thinned suckers (all a good source of organic pottasium), burnt rice husks and weeds (altough I burn any that are seeding). I collect all these towards the end of the rainy season and start to compost them using my homebrew BIM. Once the hot phase of composting is over (about 3 weeks) and I'm happy the materials are no longer using up nitrogen to decompose I apply it my vegetable beds to a depth of about 5 inches. This is not like well matured compost used for potting but a very coarse material which breaks down slowly over the growing season, in fact the banana leaves and coconut fibre take about 10 months to fully decompose. I top this off with another 5-10 inches of rice straw into which i make planting holes down to the level of the first layer fill them with homemade potting compost and then either direct seed our plant out plug plants. By the end of the following wet season everything has completely broken down giving maybe an extra 2 inches of topsoil and I start again. This has created raised beds on clay soil from scratch without buying in any "din dam". I started after the end of the rainy season (when the clay became workable but still had good moisture content by loosening the soil to a depth of 12 inches watering in some gypsum (an organic clay breaker) and proceeding as above 3 years ago. I now have some half decent soil !! Sure its a slow process and the area I was working on was only a kitchen garden but mulch really works!! My new project is a 2 rai site and I'm taking a different approach, It's paddy field I bought a couple of years ago and after a couple of rice harvests off it I'm turning it into my home plot. In the past 2 months I've had dug 2 fishponds the spill from which has raised the level of the plot by 50-70 cms I've just finished a post and rail perimeter fence made from eucalyptus. I'm gonna try the permaculture method using NFT's and sheetmulch to try and establish a wide range of fruit trees (a forest garden). See my earlier document link for some of the methods and the thinking behind it. I'm familiar with the mulch mats used in the U.K. and have started making my own by sandwiching corrugated cardboard with layers of old feed sacks using pva glue, hopefully the plastic feed sacks will slow down the termites but who knows. Love the idea of recycled matresses and will try and pump the mother-in-law for info as she used to make and sell them according to the wife. I know that in the U.k. the use of carpet is now frowned upon by organic growers due to the residue of cleaning chemicals in them (sometimes you just dont think of these things) !! My old man taught me the trick of reclaiming wasteground years ago when he took over a very neglected allotment plot just outside Barnsley by growing comfrey pissing all over the place, laying carpet and leaving it for an entire year. You can imagine the locals (most of whom used their plots to house their pidgeon lofts and were hard as nails coal miners) faces when this southern softie turned up and proceeded as aforementioned !!! A year later though I helped him roll up the carpet and it was pure loam not a weed in sight and more worms per square foot than I've yet to see again !! He grew some fantastic veg on that site for over 10 years !! I believe he stumbled across the method in an old book by Henry Doubleday . Other methods proscribed included reversing your car over over tough brassica stalks to crush them and speed up the composting process and collecting dogends from pub ashtrays to make a nicotine insecticide, definitely a man before his time !! happy organics folks

Have a look at the green manure posting over the last few months. Paw Tuengh is a readily available bean used in Thailand and 4 hours in warm water and you can see it ready to sprout.Get it in some wet earth and in two months you'll see it flower and chop it up and work it in or add to the compost and underground you'll have that beautiful nitrogen fixed to its roots that was once part of the air you breath. Very quick germinating and growing plant that will break down extremely easily. This is the simplest form of doing organic soil enhancement on large parcels of land and is very inexpensive and a real pleasure. Note there should be some form of composted manure in the soil to guarantee that the legume will be able to fix nitrogen. Probably had water buffalo on your 2 rai forever. Enjoy and loved the stories of you and your pop showing folks that there are a few different ways to do things. Choke Dee

[jandtaa]

Cheers for the pointer FF !! I,ve been looking into green manures and plan to use a mixture of 2 or 3 maybe more rather than a monoculture (possible candidates thua dam- cow pea/ thua daeng-rice bean/ krham pa-white hoary pea/ thua pae yi-lablab bean/ mahae- pidgeon pea/thua phra-jack bean) , this one sounds excellent for short term cover and if I mix it with a couple of other species I should be able to get ground cover for the duration of the wet season (a period for which I will be returnig to the U.k.). I will also plant plenty of sweet potato-man thet (excellent for long term ground cover as well as providing a crop). At the moment I am bringing on seedlings of NFT's such as sesbania-kae ban/leucaena-krathin as well as senna siamea-khi lek ban ( this is not a nitrogen fixer but has a high nitrogen leaf content, ideal for mulch and well suited to pollarding) . The idea being that the green manures are short to mid term plants (improving the soil and suppressing invasive weeds)while the NFT's are mid term nitrogen fixers to be coppiced/pollarded shortly after the onset of the wet season to provide mulch for the fruit tree seedlings (mango, jack-fruit, longan, lychee,guava, coconut as well as some more unusual local fruits which are planted at the same time), during the dry season the NFT's provide shade for the fruit trees. I also have seedlings of Tamarind which will be my long term nitrogen fixers and I'm also trying to locate Inga edulis-Ice cream bean tree for this same purpose. Very interested in the link posted by camille , thanks! Because we are trying to imitate a natural forest (allbeit with solely fruit trees) but speed up the natural cycle by "chopping and dropping" the NFT's, shredding will speed this process even further and fungii is essential to the ecosystem !! I think I have seen shredders on sale in Chiang rai in a variety of sizes, I know that they are used for shredding the residue of maize plants after the harvest and maybe would be suitable for our purpose ! Gradually as the fruit trees grow the NFT's are phased out/shaded out and the end result should be a closed canopy of edible forest !! Also incorporated into the system are other edible plants such as eggplants, chillies, gingers, bamboos, fruit bearing vines, pineapples, roots, edible fungii and herbs ("stacking" the plants in both space and time). Well thats the theory !! now to put it into practice !! (see a thread called forest garden for some other useful links) happy organics folks !! Jandtaa

Edited February 23, 2009 by jandtaa

[Foreverford]

Cheers for the pointer FF !! I,ve been looking into green manures and plan to use a mixture of 2 or 3 maybe more rather than a monoculture (possible candidates thua dam- cow pea/ thua daeng-rice bean/ krham pa-white hoary pea/ thua pae yi-lablab bean/ mahae- pidgeon pea/thua phra-jack bean) , this one sounds excellent for short term cover and if I mix it with a couple of other species I should be able to get ground cover for the duration of the wet season (a period for which I will be returnig to the U.k.). I will also plant plenty of sweet potato-man thet (excellent for long term ground cover as well as providing a crop). At the moment I am bringing on seedlings of NFT's such as sesbania-kae ban/leucaena-krathin as well as senna siamea-khi lek ban ( this is not a nitrogen fixer but has a high nitrogen leaf content, ideal for mulch and well suited to pollarding) . The idea being that the green manures are short to mid term plants (improving the soil and suppressing invasive weeds)while the NFT's are mid term nitrogen fixers to be coppiced/pollarded shortly after the onset of the wet season to provide mulch for the fruit tree seedlings (mango, jack-fruit, longan, lychee,guava, coconut as well as some more unusual local fruits which are planted at the same time), during the dry season the NFT's provide shade for the fruit trees. I also have seedlings of Tamarind which will be my long term nitrogen fixers and I'm also trying to locate Inga edulis-Ice cream bean tree for this same purpose. Very interested in the link posted by camille , thanks! Because we are trying to imitate a natural forest (allbeit with solely fruit trees) but speed up the natural cycle by "chopping and dropping" the NFT's, shredding will speed this process even further and fungii is essential to the ecosystem !! I think I have seen shredders on sale in Chiang rai in a variety of sizes, I know that they are used for shredding the residue of maize plants after the harvest and maybe would be suitable for our purpose ! Gradually as the fruit trees grow the NFT's are phased out/shaded out and the end result should be a closed canopy of edible forest !! Also incorporated into the system are other edible plants such as eggplants, chillies, gingers, bamboos, fruit bearing vines, pineapples, roots, edible fungii and herbs ("stacking" the plants in both space and time). Well thats the theory !! now to put it into practice !! (see a thread called forest garden for some other useful links) happy organics folks !! Jandtaa

Wow you'e truly a superstar. Great ideas and lots of time and work spendt just getting the knowledge to try and put it into place. This is the first year for the green manures here in Thailand and just planted the Paw Theung and "Sanoh African" (sesbania rostrata). The Sesbania is suposed to be etched with, I believe, Sulphuric acid, for a half hour before planting but i didn't and it took a long time to germinte but is very small,still, las week with a New year's planting. It is supposed to attain a 2 meter height.

The reason I wrote is because I truly believe that Chippers (shreders) are the key to a lot of global warming problems as everything that gets burned, if it was chipped or shredded would make it very compostable and also not a fire danger. I've used some chippers that w part of a tractor trailer rig and we put 3 foot diameter Cypress trees through it to make mulch that we used to to top dress the deep rough to occlude weeds at the Harding Golf Course in San Francisco during a re-build of the course a few years back (President's Cup will be there this summer for the World angainst the US in Ryder Cup Format). I think it is one of the most impoortant pieces of equipment any municipality can own and if you as an individual can afford to get a functioning one for yourself congradulations let us all know of your success and a lot of Choke dee to ya.

[jandtaa]

Hi folks

^cheers Smithson no I don't have a copy and while I can read a small amount of Thai (menus, recipes etc. large bodies of text give me a fackin headache does it have many photos/ illustrations ??

Have managed to get hold of my legume seeds to green manure with, gave the wife a list and sent her off shopping (it was also clothes market day in town so no other incentive was needed !! not much available from the local seed merchants in any quantity and I haven't the time or transport to get to any of the uni's. The only ones available in bulk around here were rice bean and soy bean (available by the kilo although the rice bean is on order from a hill tribe trader and should come next week ) also some small packs (chia tai brand) of cow pea and winged beans. then the missus came up trumps with seed pods of pigeon pea from a neighbours garden (apparently good to eat with laap dip).

had already collected seeds of leucanea and sesbania as well as senna siamea and a couple of varieties of acacia (as yet unidentified but they did have nitrogen fixing nodule on the roots) from the roadside and neighbours gardens. In fact people keep turning up with different seed pods for me, the word is out the crazy farang is off on another one of his crazy schemes !! Will post some photos as I'm struggling to identify some of the seed without trekking off to see the tree it was collected from and hopefully some of you good folks can help out !!

All this has led me to review the material I have collected on legume seed innoculation ( I really don't have the strength to search for innoculants in the local ag shops but this article contains a contact in Thailand (will try it and report back !!) have already taken a soil sample from each plant site and have started to research whether it was possible to use compost/em/seaweed extract to help with innoculation turned up a blank so far but who knows ?? Came across this article in the process which might be of interest to people.Especially the fish emulsion which you can find more info and recipes for in the EM section of my PDF collection. I save the time and effort of brewing my own by nicking the oil off the surface of the mother-in-laws "pla raa" !! those of you in the north and Issan will be familiar with this delightful condiment no doubt !! Also very interesting about pigeon pea increasing the available P in the soil (I shall be researching this further !) as this is something I have so far struggled to increase significantly  by organic means although guano and to a lesser extent duck shit followed by chicken shit do provide it .

article from ECHO;

"WHAT ABOUT RHIZOBIA INOCULANTS? I don't recall any mention of them in the 'Seeds Available from ECHO' listing. Isn't it likely that many of the legume seeds will need rather specific rhizobia inoculants at planting time?" wrote Bob Tillotson in Thailand. "Does the seed [velvet bean] need to be inoculated to fix nitrogen or will it naturally do it on its own?" from Jim Triplett in Guam. Similar questions regarding legume inoculation come up often. The following attempt to answer these questions is based on an article by Dr. Paul Singleton with NifTAL which was sent to us by one of our readers, Brian Hilton. The article, "Enhancing Farmer Income Through Inoculation of Legumes with Rhizobia: A Cost Effective Biotechnology for Small Farmers," addresses a series of questions. We will summarize these and add a few others.

What are rhizobia and what do they do? Rhizobia is a genus of soil bacteria that infect the roots of legumes and can fix (make available to the plant) atmospheric nitrogen. Unlike disease-causing bacteria, rhizobia enter into a symbiotic relationship with the plant. The legume provides the bacteria with energy and the bacteria provides the legume with nitrogen in a form it can use.

Does one rhizobium work with every legume? No, rhizobia are selective and grouped according to which legume species they will colonize. The rhizobia of some species, e.g. leucaena, are very specific. Others cross-inoculate many species. For example the "cowpea family of inoculant" will inoculate Acacia albida, Cajanus cajan (pigeon pea), Desmodium spp., Lespedeza spp., Mucuna spp. (velvet bean). Some species, such as peanut, called "promiscuous," can be inoculated with any of a number of rhizobia. Often one rhizobium strain will provide some biological nitrogen fixation (BNF) but will be less effective than another. Unless some strain of inoculant suited to the legume species you are growing is present in the soil, no BNF will take place.

Which of my crops are most likely to respond to inoculation? Responses are likely from species whose rhizobia are quite specialized such as soybeans and leucaena. Areas with a distinct long dry season of 6-8 months are also likely to respond due to existing rhizobia populations dropping off more quickly under these conditions.

How do I know if I need to inoculate my plant? Rhizobia live in nodules on the roots and can be easily seen. Well nodulated legumes will have nodules on the tap root. (Dig the plant and remove the soil carefully or the nodules will fall off.) Not all nodules are effective, however. Cut several nodules in half. Nodules that are effectively fixing nitrogen will usually be red or pink inside.

How are rhizobia introduced? Most commonly legume seeds are coated with the appropriate inoculant just prior to planting. A sugar or gum arabic "sticker" is used to attach the powdery inoculant to the seed. If healthy, nodulating plants of the same species are already growing in the area the proper rhizobia should already be available and need not be purchased. Just add about 5 g of soil from such a plot to each hole as seeds are planted.

Can I maintain my own inoculant? Yes. After a successful crop, soil will always retain some inoculum until the next season. Replanting the same species in the same soil year round will serve to increase inoculum for that crop. But, this practice may also increase the occurrence of some diseases.

Why doesn't ECHO carry inoculant for the legume seeds it distributes? This would seem to be the wise thing to do. However, it is challenging enough to preserve and monitor the viability of our stored seeds. Viability of inoculum is even more difficult to monitor and maintain which is why we leave this enterprise to those set up to do the job well.

How much rhizobium is needed to inoculate a seed? It takes about 100 grams of inoculant to sufficiently treat one pound of leucaena seeds. A hectare of soybeans requires 286 grams of inoculant. Quality is more important than quantity. The best inoculant contains a billion rhizobia per gram, but it doesn't take long for quality to drop. This is why inoculation is done just prior to planting. Since you can't tell if inoculant is good or bad by looking at it, care should be taken to purchase from a good source and handle it properly. Inoculant should be protected from heat, light and desiccation and used as soon as possible. If a cool storage area is not available, a pot buried in a shady area is a good option. If transportation is required, a container covered with a damp cloth works well.

Where can rhizobia be obtained? Many countries manufacture inoculants for a number of crops. Contact your local agricultural extension agency or national department of agriculture to see if they have the inoculant you are looking for. If it needs to be imported, probably the best source for trees would be AgroForester Tropical Seeds (P.O. Box 428, Holualoa, HI 96725, USA; phone 808/326-4670; fax 808/324-4129; e-mail [email protected]). Liphatech Company (3101 West Custer Avenue, Milwaukee, WI 53209, USA; phone 800/558-1003 or 414/351-1476; fax 414/351-1847) has inoculant of many species, including GMCCs which are not trees. ECHO has a running list of sources we have come across to date; let us know if you cannot find a source. More information on this topic can be obtained by contacting the University of Hawaii NifTAL Center (Nitrogen fixation by Tropical Agricultural Legumes; 1000 Holomua Road, Paia, HI 96779, USA; phone 808/579-9568; fax 808/579-8516; e-mail [email protected]). Other possibilities include the international agricultural research center nearest you (e.g. CATIE, CIAT, ICRISAT, IITA, IRRI, etc.), UNESCO (Microbial Resource Centre, Karolinska Institute, 10401 Stockholm, SWEDEN), or the BNF Resource Centre (Soil Microbiology Research Group, Rhizobium Building, Soil Science Division, Department of Agriculture, Bangkok 10900, THAILAND; fax 662-5614768).

Some concluding remarks: Each situation is different. If farmers can obtain inoculant quickly and reasonably it can be a low-cost input with high returns. If planting something like soybeans for the first time in an area, special efforts should be made to obtain proper inoculant. Legumes will grow without rhizobia, they will just require mineral sources of nitrogen like other plants. Even with proper inoculation, factors like low phosphorous, low pH and insect damage will limit yield. It should also be noted that it can take up to 20 days for biological nitrogen fixation to get going, so an application of nitrogen just after germination can help even if rhizobia are present. Return to CONTENTS.

PIGEON PEA AND CHICKPEA RELEASE PHOSPHATES. (Based on an article in International Agricultural Development, April 1992.) We all know that legumes such as these two plants add nitrogen to the soil. Now scientists at ICRISAT in India have shown that they make available more phosphates. They do not add phosphate to the soil, but rather break up phosphate compounds in such a manner that phosphate that was already present but unusable by plants is now available. If you work where phosphate is one of the most limiting nutrients (a common situation in tropical soils), you might want to work these crops into your rotation.

How do they work? Studies show that the roots of pigeon pea exude acids (piscidic acid) which release phosphorous when it is bound up with iron. Chick peas release another acid (mallic acid) from both roots and shoots. In calcareous soils (alkaline soils with high calcium content), this acid breaks up insoluble calcium phosphate. Normally this release would only occur if the pH of the soil were lowered.

Both plants "are deep rooted, so their ability to release more phosphates means that valuable nutrients are being brought up from the deeper soil layers. Residues from both crops are adding extra phosphates which will benefit the crops which follow in the rotation. It is possible that some varieties ... exude more acid than others. So this trait could be another characteristic for selection [by plant breeders]." 

Any thoughts guys ??

happy organics Jandtaa

Edited March 24, 2009 by jandtaa

[Lickey]

My mind is boggling with al this organic info, im going to have to sort it into sections, print it and put in the old fashioned folders, for quick reference,

It transpires today that the local agri [goverment office] were selling pigeon seeds for 100bht for 100kilo, mrs bought 100 kilo, and also ordered 1000k of chicken shit at 1900bht,

Question is do i need to compost the crap first or can i spead it, plough it in and 2/3 weeks later, broadcast the peas?

Thing is, around here, [and most of Thailand] chickens and cows are grazing animals, and there crap is full of seeds, so i dont want to plant a whole load of weeds as well, It wont be a big problem to compost it first, now the tamarind harvest is near finished and the leaves are falling, i have plenty of N to add, plus rotted banana culms and leaves, already mixed with un-treated sawdust,

Advice on this very welcome,

Thanks, Lickey..

[jandtaa]

My mind is boggling with al this organic info, im going to have to sort it into sections, print it and put in the old fashioned folders, for quick reference,

It transpires today that the local agri [goverment office] were selling pigeon seeds for 100bht for 100kilo, mrs bought 100 kilo, and also ordered 1000k of chicken shit at 1900bht,

Question is do i need to compost the crap first or can i spead it, plough it in and 2/3 weeks later, broadcast the peas?

Thing is, around here, [and most of Thailand] chickens and cows are grazing animals, and there crap is full of seeds, so i dont want to plant a whole load of weeds as well, It wont be a big problem to compost it first, now the tamarind harvest is near finished and the leaves are falling, i have plenty of N to add, plus rotted banana culms and leaves, already mixed with un-treated sawdust,

Advice on this very welcome,

Thanks, Lickey..

Hi Lickey 

I have red several times (from permaculture forums but nothing scientific if you get my drift) that pigeon pea can tolerate "hot" poultry manure although I would advise to keep it to a minimum as if there is sufficient nitrogen available to the plant in the soil it will not produce nodules and fix atmospheric nitrogen. I've uploaded some more PDF's on green manures and leguminous nitrogen fixers here jandtaas docs- green manures for the tropics and here jandtaas docs-Nitrogen fixing trees and legumes  including some info on pigeon pea which includes rates for broadcast sowing etc...Have you thought about sowing a polyculture, mixing some shorter term legumes and ground cover amongst the more mid-term pigeon pea ?? I agree about the weed seed in the manure (the reason I favour a "hot" composting method plus it will kill any pathogens present.) although if you have bought a large quantity of chicken shit I guess it comes from a C.P. style intensive operation rather than free range flock so weed seed should not be a problem. Although you may want to think about the fact that manure from such a source is not strictly organic due to chemical inputs in the system (pedantic I know and sometimes when you need to buy in bulk from off farm sources the only alternative !! What about using your guano ?)

Totally agree about the amount of info becoming unmanageable in the present format (one of the reasons I store my PDF's as I do.The sooner I get myself an ink tank printer the better as I much prefer a good old fashioned filing system and the ability to read and digest info at my leisure instead of being tied to a screen !!) All the more reason I feel the need for this thread to become a sub-forum A.S.A.P. as it really needs its own pinned topics and seperate threads to help new members and existing browsers locate relevant information !! I would be more than happy to volunteer my services to organise the posts we have so far and along with yourself and Smithson ( If he's interested ) coming up with a list of pinned topics we feel is appropriate. I'd even volunteer to moderate (don't know whether this is possible, how are moderators chosen number of posts ?? Or is it a closed shop?? ) If you didn't want to do it youself.. I certainly don't want you to feel I'm trying to ambush this excellent thread that you've started !! Maybe you can have a word with a freindly moderator ??

p.s. Any chance of posting me a kilo of pigeon pea seed as I only managed to get the pods from a single plant ??

happy organics Jandtaa 

Edited March 13, 2009 by jandtaa

[Lickey]

My mind is boggling with al this organic info, im going to have to sort it into sections, print it and put in the old fashioned folders, for quick reference,

It transpires today that the local agri [goverment office] were selling pigeon seeds for 100bht for 100kilo, mrs bought 100 kilo, and also ordered 1000k of chicken shit at 1900bht,

Question is do i need to compost the crap first or can i spead it, plough it in and 2/3 weeks later, broadcast the peas?

Thing is, around here, [and most of Thailand] chickens and cows are grazing animals, and there crap is full of seeds, so i dont want to plant a whole load of weeds as well, It wont be a big problem to compost it first, now the tamarind harvest is near finished and the leaves are falling, i have plenty of N to add, plus rotted banana culms and leaves, already mixed with un-treated sawdust,

Advice on this very welcome,

Thanks, Lickey..

Hi Lickey

I have red several times (from permaculture forums but nothing scientific if you get my drift) that pigeon pea can tolerate "hot" poultry manure although I would advise to keep it to a minimum as if there is sufficient nitrogen available to the plant in the soil it will not produce nodules and fix atmospheric nitrogen. I've uploaded some more PDF's on green manures and leguminous nitrogen fixers here jandtaas docs- green manures for the tropics and here jandtaas docs-Nitrogen fixing trees and legumes including some info on pigeon pea which includes rates for broadcast sowing etc...Have you thought about sowing a polyculture, mixing some shorter term legumes and ground cover amongst the more mid-term pigeon pea ?? I agree about the weed seed in the manure (the reason I favour a "hot" composting method plus it will kill any pathogens present.) although if you have bought a large quantity of chicken shit I guess it comes from a C.P. style intensive operation rather than free range flock so weed seed should not be a problem. Although you may want to think about the fact that manure from such a source is not strictly organic due to chemical inputs in the system (pedantic I know and sometimes when you need to buy in bulk from off farm sources the only alternative !! What about using your guano ?)

Totally agree about the amount of info becoming unmanageable in the present format (one of the reasons I store my PDF's as I do.The sooner I get myself an ink tank printer the better as I much prefer a good old fashioned filing system and the ability to read and digest info at my leisure instead of being tied to a screen !!) All the more reason I feel the need for this thread to become a sub-forum A.S.A.P. as it really needs its own pinned topics and seperate threads to help new members and existing browsers locate relevant information !! I would be more than happy to volunteer my services to organise the posts we have so far and along with yourself and Smithson ( If he's interested ) coming up with a list of pinned topics we feel is appropriate. I'd even volunteer to moderate (don't know whether this is possible, how are moderators chosen number of posts ?? Or is it a closed shop?? ) If you didn't want to do it youself.. I certainly don't want you to feel I'm trying to ambush this excellent thread that you've started !! Maybe you can have a word with a freindly moderator ??

p.s. Any chance of posting me a kilo of pigeon pea seed as I only managed to get the pods from a single plant ??

happy organics Jandtaa

Thanks for your informative reply Jandtaa, just to get up to speed here, Mrs told me tractor was on the farm today, discing over where i wanted to put the chicken crap, leave for 2 weeks then sow the peas, we havent got the crap yet or the seeds come to that, but i try not to look suprised anymore, but as i mentioned sometime before, i do get the Inspector Dreyfus twitch and snigger, [Pink Panther films] .the mrs says, well, its the only time tractor avaiable for long time, and special price too, 2 way cut, 1 rai, 500bht, so the land is prepared, about 6rai, what do i do? Ive been thinking about making heaps of compost in the area to get rid of the acid from the crap, then manually spread it around, hard work in the heat!again, im not sure where the crap is coming from, free range or factory, i agree, sounds a lot from a free range farm, but i think it could be older and better from free range, and Dahl, i like curries very much and its also a chicken feed, so im getting nearer to a sustainable farm. Im not sure if i need another quicker growing legume than pigeon pea, the ground seems pretty good here, planted 1200 banana and 800 papapya and were selling in 6 months of planting, mind you, it was the wet season!!

Hey, youve not nicking my thread, i got this stared because i want to learn about organic farming in thailand, i dont want a dead farm, and i dont want a jungle, i want to see everything in natures harmony,

Soundman did say a sub-forum was difficult to set up, and know Bina is the mod for the farming forum, If Bina doesnt pick-up on this post in a few days, i will PM her and suggest it.

Keep up the good posts, Thanks, Lickey..

[jandtaa]

Hi folks

Recently started collecting seed pods from local legume or NFT's as well as some of the shorter term nitrogen fixers so here's a start (excuse any bad Thai spelling and transliteration as the missus isn't here to check !! also some species have a couple of names )

SENNA SIAMEA - KHI LEK BAN - ขี้เล็กบาน

LEUCAENA LEUCOCEPHALIA - KRATHIN - กระถิน

SESBANIA - KAE BAN - แคบ้าน

GLIRICIDIA - KAE FARANG - แคฟรั่ง

here's some of the shorter term legumes ;

PIDGEON PEA - ถั่วมะแฮะ

LAB-LAB BEAN - ถั่วแปบ/ถั่วแปะยี้

COW PEA - ถั่วพุ่ม 

RICE BEAN - ถั่วแป

WHITE HOARY PEA - ครามปา

FLEMINGIA - มะฮะขี้นก

INDIGOFERA - ครามใหญ

cheers Jandtaa

[teletiger]

Jandtaa, as you are collecting your legume seeds locally, I would suggest using kee vuar from locally grazed cattle. Should contain all the inocculants you need.

Just a word on leucaena. we've got a 500 metre hedgerow of the stuff bordering our land. Great for feeding cattle (30% because of toxins), very drought tolerant and makes a very high quality charcoal. But, be warned. It can be highly invasive. Not too bad in a field situation where it can be ploughed, but can play havoc with gardens. (mine in particular ) Very fast growing with a deeeep taproot. Anything, but cutting it to below ground level will see it magically springing up.

Regards.

[jandtaa]

Jandtaa, as you are collecting your legume seeds locally, I would suggest using kee vuar from locally grazed cattle. Should contain all the inocculants you need.

Just a word on leucaena. we've got a 500 metre hedgerow of the stuff bordering our land. Great for feeding cattle (30% because of toxins), very drought tolerant and makes a very high quality charcoal. But, be warned. It can be highly invasive. Not too bad in a field situation where it can be ploughed, but can play havoc with gardens. (mine in particular ) Very fast growing with a deeeep taproot. Anything, but cutting it to below ground level will see it magically springing up.

Regards.

Cheers for the info TT

Yeah I was aware that some of the legumes can become invasive. I was gonna plant some along the fenceline and also a few in an area where I want to start the permaculture "forest garden as mid term nitrogen fixers. In this area I will pollard them and use the prunings ( high in nitrogen ) to mulch the the fruit trees, hopefully this will help keep them under control. I've just found a supplier of legume seed up here in CR and purchased a few kilo each of rice bean and black bean and along with my collected seeds will plant up in the next couple of days. broadcast about 12 sacks of cow manure over the areas about 4 days ago and we've had a couple of nights of rain so hopefully that will do the trick with the innoculation !! I've also got some soil taken from where the parent plants of the legume seeds I collected were growing and I'll mix this in with the seed before I sow. I'm also gonna divide the area up into test squares and control areas and apply some different treatments EM etc, mono and poly-cultures and different sowing densities and observe the results .

regards J       

[tjeffrutherford]

Hi all,

Great thread on green manures, NTFs. Thanks a lot!

On the former, I've had decent luck with the Land Development Department office in Chiang Mai. I showed up out of the blue, speaking broken Thai and asking about green manures. I walked off with a free 50-kg. sack of black beans (my annual allotment for a 3 rai plot). I've done that the last two years. The first year, I broadcast it around the seedlings in my nascent forest farm at the beginning of the rains. Stuff grew like wild, suppressing weeds and, theoretically, fixing nitrogen. I'd go in ever week or so and wack it back with the scythe. The next year I broadcast it in the paddy, but we weren't able to keep out the neighbor's flood and the seedlings all died.

This year, we broadcast baw teuang (sun hemp; Crotalaria juncea) in the paddy, with mixed results. The problem wasn't with the seeds, but with our irrigation skills. We got about 40 percent cover, and we'll get it right next time. The sun hemp grows like crazy in crap soil (e.g. raised paddy soil cum concrete) and little water. We planted it as a pretty yellow boundary line, in the sunnier parts of the forest farm, and in veggie beds as a green rotation. You can wack it back for mulch or compost and it shoots up again. (You need to be careful to not let it get too fibrous.)

We got seeds from both the land development guys (they only had a couple kilos) and the royal project up north of Chiang Dao (who had about the same amount for us). We used that to produce seed (under 90 days) and got enough to plant it all over the place. We also found other sources of seed: a local ag supply shop could get it for 35 baht a kilo, but the CM Uni multi-cropping center would sell it for 15.

Apparently, paddy farmers in Mae Sariang (Mae Hong Son) grow sunhemp as a rotation between dry-season garlic/onions and wet-season rice. They plow it in after a month or so, and don't need to use synthetic fertilizers. Apparently.

--

Jaandta, I'd be interested to hear about your experiences with indigoferra. UHDP grew that on a plot to shade out imperata grass and improve the soil. Seems to have worked. No cogon grass, anyway. And I stumbled upon a UHDP partner in Chiang Dao (Palaung people) who grew a little grove of it in the middle of sloping corn fields. It was brilliant! After four years the soil was rich and loamy and full of organic matter. The soil next door in the corn field was a yellow rocky mess. You can't eat or sell indigoferra, but as a mozaic rotation for upland farmers -- improved-fallowing of knackered land for a few years -- it would seem to have promise.

The Palaung up there have been relay cropping lab lab beans with maize -- with an upland rice rotation thrown in every few years -- on the same sloping fields for 25 years. The yields are decreasing a bit, but they still produce.

Thanks for the great contributions to these really important topics.

Cheers,

Jeff

Hi folks

Recently started collecting seed pods from local legume or NFT's as well as some of the shorter term nitrogen fixers so here's a start (excuse any bad Thai spelling and transliteration as the missus isn't here to check !! also some species have a couple of names )

SENNA SIAMEA - KHI LEK BAN - ขี้เล็กบาน

LEUCAENA LEUCOCEPHALIA - KRATHIN - กระถิน

SESBANIA - KAE BAN - แคบ้าน

GLIRICIDIA - KAE FARANG - แคฟรั่ง

here's some of the shorter term legumes ;

PIDGEON PEA - ถั่วมะแฮะ

LAB-LAB BEAN - ถั่วแปบ/ถั่วแปะยี้

COW PEA - ถั่วพุ่ม

RICE BEAN - ถั่วแป

WHITE HOARY PEA - ครามปา

FLEMINGIA - มะฮะขี้นก

INDIGOFERA - ครามใหญ

cheers Jandtaa

[jandtaa]

Good to see you in the forum Jeff

the ag shop in CR just before ban cheewit mai bakery looks to have recently expanded it's range (could just be the time of year ) and was selling two sizes of rice bean (the larger one was what I call red kidney bean) two sizes of black bean (I chose the smaller of both varieties) as well as soya bean, mung bean and a couple of others I couldn't identify (it was just chance that I noticed on passing and didn't have my list with me !!). they were all selling for 20 baht a kilo and 25 for the larger sized beans. Also had a good range of mushroom spore (thats for a later time) and EM and molasses.Good idea to save seed I hope to be able to do the same ! Haven't tracked down any indigoferra seed as yet considering bringing some back from the UK .

regards Jandtaa 

[drtreelove]

I'd like to put out a question about nitrogen fixing legumes, a controversial issue that I've wondered about for years and never got a satisfying answer. I haven't scoured these threads or Jandhaa's PDFs, but I have asked several plant and soil scientists and received different answers.

The question is about how much nitrogen actually ends up available in the soil from the growing of legumes. The common assumption is that legumes fix nitrogen in root nodules and even if the tops of the plants are removed from the field, the available nitrogen level in the soil will be increased.

I have come to believe that the fixing of atmospheric nitrogen by the legume roots benefits the legumes directly so that they don't demand excessive soil nitrogen, and only if the leafy green part of the plant is incorporated into the soil will the soil nitrogen level be added to; the nitrogen fixation itself doesn't really add to available nitrogen in the soil. How do you all see it? Or can someone help me find an article that clarifies this issue? Jandtaa, you've probably already got a PDF on it.

[jandtaa]

Hi Don 

Yes I have also come to the conclusion that the nitrogen increase made available from the legumes is through the incorporation of the top part of the plant into the soil. For example the soybean contains 93% nitrogen in the top of the plant and 7% in the roots and cowpeas 84 % in the tops and 16% in the roots.Another factor to bear in mind is the carbon to nitrogen ratio of the green manure crop.This is because this ratio has an effect on the soil micro-organisms ability to break down organic material of the green manure. As plants mature the fibrous (carbon ) material increases and their nitrogen content decreases. This is the reason green manure crops are recommended to be dug in shortly before or during flowering. The ideal C:N ratio is 15:1 to 25:1. Ratios above 25:1 can result in nitrogen being "tied up" by soil microbes in the breakdown of carbon-rich crop residues, thus pulling nitrogen away from crop plants. Adding some nitrogen fertilizer to aid the decomposition process may be advisable with these high carbon residues. The lower the C:N ratio, the more N will be released into the soil for immediate crop use.I will try and put together a table of Nitrogen content of green manures we might commonly find available here in Thailand and post it here when I get a chance. To find the C:N ratio of a green manure you can apply the following; Most plant materials contain close to 40% carbon. To determine the C:N ratio of any plant material, divide 40% by its nitrogen content.

Also of note "The portion of green-manure nitrogen available to a following crop is usually about 40% to 60% of the total amount contained in the legume. For example, a hairy vetch crop that accumulated 180 lbs. N per acre prior to plowing down will contribute approximately 90 lbs. N per acre to the succeeding grain or vegetable crop. Dr. Greg Hoyt, an agronomist at North Carolina State University, has estimated that 40% of plant tissue nitrogen becomes available the first year following a cover crop that is chemically killed and used as a no-till mulch. He estimates that 60% of the tissue N is released when the cover crop is incorporated as a green manure rather than left on the surface as a mulch. Lesser amounts are available for the second or third crop following a legume, but increased yields are apparent for two to three growing seasons."

In addition to nitrogen from legumes, green manures can help recycle other nutrients on the farm. Nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), and other nutrients are accumulated by cover crops during a growing season. When the green manure is incorporated, or laid down as no-till mulch, these plant-essential nutrients become slowly available during decomposition by soil micro-organisms.The breakdown of green manures in soil also influences mineral nutrient availability in another way. During decomposition of organic matter, carbonic and other organic acids are formed as a byproduct of microbial activity. These organic acids react with insoluble mineral rocks and phosphate precipitates, releasing phosphates and exchangeable nutrients.

By their extensive and often deep rooting systems green manures can also "mine" nutrients from the subsoil whilst at the same time acting as a "biological plow" as it were improving the soil structure which can be of great importance in a "no-till" system (There's more info on this in the "soil" thread).

Added to this their ability to enhance soil and water conservation and their use as a weed supressor (some are in fact alleopathic I did post somewhere in a thread on eucalyptus and bamboo and use rye grass back in the UK for this purpose.I need to do some further research regarding this in Thailand) and it would indeed seem that green manures have a wide variety of roles on the organic farm !!

I know your original question was about the nitrogen fixing ability but I thought I would put together a general overview for the benefit of members reading this thread.

I'm led to believe that the situation is a little different concerning the use of Legume trees in an agroforestry situation using permaculture methods. I believe that when the trees are coppiced or pollarded and the prunings used as mulch there is significant die-back of the root system and nitrogen is made available in the soil from both the root nodules and obviously from the mulchings. I'm guessing that the legume trees have similar nitrogen properties to the green manures in regard to the amounts of nitrogen in both the roots and top growth and that the amount of nitrogen released is minimal. However because we are trying to imitate a natural ecosystem (although some what speeded up) every little helps as this is a long term situation.

Hope this is of some assistance Don and would be interested to here any further views yourself or others have on the subject.

Cheers J       

 

[teletiger]

Jandtaa, not sure I understand all your figures there. Nitrogen fixing is normally expressed in terms of Urea. (easier for my little brain too) I.e. 90lbs nitrogen= 90/2.2/2.8=14.5 kilos of urea per acre.

From all the figures I've seen, that would be very low. Figures of 100+ kilos per acre are the norm? Am confused now. Duh

Regards.

[drtreelove]

Hi Don

Yes I have also come to the conclusion that the nitrogen increase made available from the legumes is through the incorporation of the top part of the plant into the soil. For example the soybean contains 93% nitrogen in the top of the plant and 7% in the roots and cowpeas 84 % in the tops and 16% in the roots.Another factor to bear in mind is the carbon to nitrogen ratio of the green manure crop.This is because this ratio has an effect on the soil micro-organisms ability to break down organic material of the green manure. As plants mature the fibrous (carbon ) material increases and their nitrogen content decreases. This is the reason green manure crops are recommended to be shortly before or during flowering. The ideal C:N ratio is 15:1 to 25:1. Ratios above 25:1 can result in nitrogen being "tied up" by soil microbes in the breakdown of carbon-rich crop residues, thus pulling nitrogen away from crop plants. Adding some nitrogen fertilizer to aid the decomposition process may be advisable with these high carbon residues. The lower the C:N ratio, the more N will be released into the soil for immediate crop use.I will try and put together a table of Nitrogen content of green manures we might commonly find available here in Thailand and post it here when I get a chance. To find the C:N ratio of a green manure you can apply the following; Most plant materials contain close to 40% carbon. To determine the C:N ratio of any plant material, divide 40% by its nitrogen content.

Also of note "The portion of green-manure nitrogen available to a following crop is usually about 40% to 60% of the total amount contained in the legume. For example, a hairy vetch crop that accumulated 180 lbs. N per acre prior to plowing down will contribute approximately 90 lbs. N per acre to the succeeding grain or vegetable crop. Dr. Greg Hoyt, an agronomist at North Carolina State University, has estimated that 40% of plant tissue nitrogen becomes available the first year following a cover crop that is chemically killed and used as a no-till mulch. He estimates that 60% of the tissue N is released when the cover crop is incorporated as a green manure rather than left on the surface as a mulch. Lesser amounts are available for the second or third crop following a legume, but increased yields are apparent for two to three growing seasons."

In addition to nitrogen from legumes, green manures can help recycle other nutrients on the farm. Nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), and other nutrients are accumulated by cover crops during a growing season. When the green manure is incorporated, or laid down as no-till mulch, these plant-essential nutrients become slowly available during decomposition by soil micro-organisms.The breakdown of green manures in soil also influences mineral nutrient availability in another way. During decomposition of organic matter, carbonic and other organic acids are formed as a byproduct of microbial activity. These organic acids react with insoluble mineral rocks and phosphate precipitates, releasing phosphates and exchangeable nutrients.

By their extensive and often deep rooting systems green manures can also "mine" nutrients from the subsoil whilst at the same time acting as a "biological plow" as it were improving the soil structure which can be of great importance in a "no-till" system (There's more info on this in the "soil" thread).

Added to this their ability to enhance soil and water conservation and their use as a weed supressor (some are in fact alleopathic I did post somewhere in a thread on eucalyptus and bamboo and use rye grass back in the UK for this purpose.I need to do some further research regarding this in Thailand) and it would indeed seem that green manures have a wide variety of roles on the organic farm !!

I know your original question was about the nitrogen fixing ability but I thought I would put together a general overview for the benefit of members reading this thread.

I'm led to believe that the situation is a little different concerning the use of Legume trees in an agroforestry situation using permaculture methods. I believe that when the trees are coppiced or pollarded and the prunings used as mulch there is significant die-back of the root system and nitrogen is made available in the soil from both the root nodules and obviously from the mulchings. I'm guessing that the legume trees have similar nitrogen properties to the green manures in regard to the amounts of nitrogen in both the roots and top growth and that the amount of nitrogen released is minimal. However because we are trying to imitate a natural ecosystem (although some what speeded up) every little helps as this is a long term situation.

Hope this is of some assistance Don and would be interested to here any further views yourself or others have on the subject.

Cheers J

Good stuff, thanks.