Discussions regarding green manure crops in rice paddies
(6/2/01 - 10/3/01)

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postings: 10
countries: Costa Rica, Honduras, Nepal, Thailand, United States,
organizations/institutions/companies: McKean Rehabilitation Center, Jajarkot Permaculture Programme, Minifarms, Cornell University, COSECHA

Date: Sat, 02 Jun 2001
From: Klaus Prinz
To: MULCH-L@cornell.edu
Subject: Re: green manure crops in paddy

Dear Friends,

With regard to do some farmer managed plots on S.R.I. (System of Rice Intensification) in northern Thailand we have discussed how greenmanure can be integrated into the system, instead of using more labor intensive compost. Often mungbean is used, which however does not provide much organic matter; in few cases Sesbania rostrata is used for which seeds cannot be obtained easily.

Is there any on-line information on other suitable greenmanure species which can tolerate stagnant water for use in paddy cultivation? I appreciate your comments and recommendations.

Klaus Prinz
McKean Rehabilitation Center
Chiang Mai, Thailand

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Date: Mon, 04 Jun 2001
From: Chris Evans
To: MULCH-L@cornell.edu
Subject: Re: greenmanure crops in paddy

We're about to plant SRI plots & are trying also to integrate green manures and/or mulch systems. The plan is to sow mustard when planting out, and with 1st weeding (2-4 wks after planting) this gets incorporated after a 2nd crop of GMs are sown. These in turn will be incorporated at time of 2nd weeding, another 2-4 weeks later. This can go on for 1 or even 2 cycles further, until the rice closes canopy. Apart from mustard, I guess you can also use buckwheat, chicory, fenugreek, etc. - basically anything that can germinate & grow fast, & reach a good size in 2-4 wks. So its habit of the GM which is important - anything which does this. For that reason I question S.rostrata as it is too slow to start, & doesn't bush out so much. At any time the GM can be replaced by a mulch

Also don't be sure that the GM - whichever you use - can replace compost, at least at first. We've found GMs are better at enhancing production & need some fertility to do that. Compost is needed to maintain a balance of matter in the soil, at least until a perennial mulch system can be established.

Sorry, don't know of flood-resistant GMs. It's such an un-natural system, it's difficult to find plants to go with it. Azolla is the obvious. Good luck on your search

Best

Chris Evans
Jajarkot Permaculture Programme
Kathmandu, Nepal

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Date: Mon, 04 Jun 2001
To: MULCH-L@cornell.edu
From: Donald Kass
Subject: Re: greenmanure crops in paddy

Dear Klaus et al.,

There are some green manures that are flood tolerant. Soybeans can take flooding until flowering. There was an IRRI publication on this and I did some research on it. Liming to reduce Mn toxicity--a problem in flooded soils can increase flooding tolerance. There is a large literature on alfalfa tolerance to flooding---some of it might be applicable to the tropics.

Aeschynomene --a common weed in rice paddies--will fix nitrogen under flooded conditions--it has aerial nodules as I think have some Sesbanias. There is always Erythrina fusca, though a tree, it is a good nitrogen fixer and tolerates flooded soils. There is even a literature recommending it for lowering water tables in cacao soils. In an earlier incarnation, I believe Chris Wien of Cornell looked at flood tolerance in cowpeas. I will try to find the reference. In the meantime, look at the Kowalski book.

Don Kass
CATIE, Costa Rica

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Date: Mon, 4 Jun 2001
To: MULCH-L@cornell.edu
From: H. David Thurston
Subject: Re: greenmanure crops in paddy

Dear Klaus,

You might want to check on the rice bean. Rice bean can be grown on a wide range of soil types, including heavy paddy soils, although maximum yields require fertile loam. Although traditionally planted after rice, it cannot withstand waterlogged conditions (National Academy of Science, 1979). The cultivars of rice beans are well adapted to practically the same areas as cowpeas.

Check this URL with info on the rice bean:

http://www.css.cornell.edu/ecf3/Web/AF/RiceBean.html

Dave Thurston
Dept. of Plant Pathology
Cornell University

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Date: Mon, 04 Jun 2001
To: MULCH-L@cornell.edu
From: Donald Kass
Subject: Re: greenmanure crops in paddy

The Wien reference is:

Wien,C., Lal, R. and Pulver, E. 1977. Effects of transient flooding on growth and yield of some tropical crops. In Lal, R. and Greenland, D.J. eds. Soil physical properties and crop production in the tropics. p. 235-244. John Wiley and Sons, NY.

There was also some information in Rachie, K. Grain legumes for the lowland humid tropics. Advances in Agronomy 26 (1974). I can't find the exact reference. Nodulation can be stimulated by flooding. There was once a proposal to cultivate soybeans in saturated soils:

Troedson, R.J., Lawn, R.J., Byth, D.W. ,and Wilson, G.L. 1983. Saturated soil culture--a water management option for tropical and subtropical soybean. Soybean in subtropical and tropical cropping systems. Symposium held in Tokyo, Japan, Oct. 1983. Abstract.

We found that soybeans did better if flooding occurred earlier in the growing season:

Campos, W., Kass, D., Smith, M. and Diaz-Romeu, R. 1983. Adaptation of Nine Soybean cultivars to flooding on a typic dystropept. Agronomy Abstracts p. 43.

There are several temperate pasture legumes such as white clover which are considered to be flooding tolerant. Has anyone determined similar things for the tropics?

Don Kass
CATIE, Costa Rica

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From: Ken Hargesheimer
Date: Mon, 4 Jun 2001
Subject: rice and GM
To: MULCH-L@cornell.edu

I know nothing about rice production but are there any ideas for you in the books by M Fukuoka:

• One Straw Revolution
• Natural Way of Farming
• Road Back To Nature

Ken Hargesheimer

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Date: Thu, 07 Jun 2001
From: Chris Evans
To: MULCH-L@cornell.edu
Subject: Re: greenmanure crops in paddy

Good references.

Our experience is that white clover doesn't like waterlogging, which is precisely why Fukuoka floods it, to weaken it which allows the rice to get away. It always gets knocked back in the monsoon except at high altitudes (>1800m). I feel that vetches have a lot of possibility for perennial GMs perhaps in clovers place for the tropics. ALso try looking up Roland Bunch's experiences in central/south America.

Chris Evans
Jajarkot Permaculture Programme
Kathmandu, Nepal

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Date: Sat, 09 Jun 2001
To: MULCH-L@cornell.edu
From: Rick and Ellen Burnette
Subject: Re: greenmanure crops in paddy

Dear friends:

Regarding the possible use of woody legumes species for the production of green manure for wetland rice (in the case of S.R.I systems), I came across a few references in the publication "Green Manure in Rice Farming", a compilation from the proceedings of "The Role of Green Manure Crops in Rice Farming Systems" symposium (sponsored by IRRI) in 1987. In one entry (Woody species as green manure crops) Brewbaker and Glover referred to work in Coimbatore, India during the 1950s which showed that gliricidia planted 2 m apart along bunds produced 4 tons of leaf dry matter/ha (equivalent to 120 kg N). When 5 tons of gliricidia mulch/ha was applied 3 weeks before planting, rice and straw yields were reportedly increased by 15-45%.

Previously, Klaus Prinz referred to the use of Sebania rostrata as a rice green manure, however he mentioned that seeds of these species are difficult to locate in northern Thailand. In the same article, Brewbaker and Glover also refer to three other species of the genus which are more widely grown: S. bispinosa, S. grandiflora and S. sesban (supposedly all of these will tolerate soggy soils?). They state that in India, S. bispinosa is widely grown as a green manure crop, in which seeds are sown at the onset of the monsoon, with 2 to 3-month-old plants being incorporated before the rice is transplanted.

In the same publication, Arunin, Dissataporn, Anuluxtipan and Nana (Potential of sesbania as a green manure in saline rice soils in Thailand) state that as Sesbania spp. tolerate salinity, acidity and flooding, they show great potential as green manure crops for paddy rice. They recommend growing sesbania as a green manure crop to replace uneconomical second crops which follow the main rice crop in rainfed systems.

Perhaps woody legumes, such as Sesbania spp. can help boost the soil organic matter levels needed for S.R.I. systems.

Rick Burnette

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From: Klaus Prinz
To: MULCH-L@cornell.edu
Subject: greenmanure in rice
Date: Sat, 8 Sep 2001

Dear Friends,

I would like to come back on my previous inquiry on gm in paddy fields.

Best thanks to everybody who shared recommendations.

In the meantime we found out that only seeds of Sesbania rostrata are available through the Department of Land Development (DLD) and later produced by farmers Together with MCC of Chiang Mai University a field day was held where practices and experiences of use of S.r. was demonstrated.

Besides that Mungbean (Vigna radiata) and Ricebean (Vigna unguiculata) can be used, of which seeds are available on the market or can be produced by farmers. All crops would be grown prior to field cultivation ( ca April - May) and ploughed in.

I found some data on these gm-crops which however are not complete or seem to be inaccurate. For instance:

fresh biomass of S.r. and V.r. = 17 to/ ha respectively 25 to/ha. V.u. ?.

and dry matter = 3.9 to/ha and 4.3 to/ha . V.u. ?.

Please advise on correct figures or let me know on which websites these can be found..

Best regards.

Klaus Prinz
Chiang Mai, Thailand

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From: Roland Bunch
To: MULCH-L@cornell.edu
Date: Wed, 3 Oct 2001
Subject: Re: greenmanure in rice

Dear Klaus,

I did hear while I was in Madagascar this last year that a good number of paddy rice farmers using the SRI system were planting clovers (Trefolium spp) in their paddies around the rice (of course, with SRI there is less water used than with other paddy rice systems). Would you be interested in hearing more about that?

Sincerely, Roland Bunch
COSECHA
Tegucigalpa, Honduras