postings: 4
countries: Thailand, USA
organizations/institutions/companies: Cornell University, McKean Rehabilitation Center(?), World Bank

From: "Klaus Prinz"
To: MULCH-L <MULCH-L@cornell.edu>
Subject: crawling cowpea
Date: Thu, 31 Mar 2005

We had previously some exchange on mixed cropping of 'crawling' cowpea in upland rice and to which extent this could be applied in order to reduce weed growth.

Recently I visited with GAA extension staff (German Agro Action) several Kammu villages in Muong Mai District, Phonsaly Province. Talking with local farmers I inquired about mixed cropping of vegetables in upland rice and learned that they are using the same kind of 'crawling' cowpea which Karen hillfarmers in northern Thailand are using mixed in rice. At that village (Ban Saen-Ard) where I got the samples, they are called in Lao language, according to certain properties:

tua hom- fragrant smell,
tua lai - speckelt/striped,
tua ohrn - soft pods

Mr. Damrong Tayanin, a Kammu scholar at Lundt University in Sweden, wrote me that in Kammu language this kind of cowpea is called "siipaay." Farmers are mixing 200-300gms to 10 kg of rice seed, which is the same rate as Karen farmers are using. As reported they do help to reduce weedgrowth so that 2 weedings usually are sufficient.

Greetings,

Klaus Prinz
Chiang Mai 50000
Thailand
09-9541411
66-5312 - 4081(10/04/05)

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To: MULCH-L@cornell.edu (MULCH-L)
From: Peter Hobbs
Subject: Re: crawling cowpea

Dear Klaus: Thanks for this. Now if we could get some seed distributed for testing!! One of the areas of focus in the rice-wheat consortium, is to grow rice without puddling and transplanting -- either direct seeded, zero-till and even on permanent beds. The main constraint is weeds and one hypothesis for overcoming this problem is to grow a cover crop (or a mixed crop as you are doing with this legume) to help smother weeds, but also provide the permanent soil cover important when considering zero-tillage. The cover crop is NOT incorporated since that just brings more weed seeds to the surface, but kept as a mulch. The rice is seeded into the mulch after the cover crop is knocked down with roundup or other means. I am copying this to Raj Gupta, the RWC facilitator, who may like to get some seed.

Peter Hobbs
Department of Crop and Soil Sciences
Cornell University

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From: E. Styger
Subject: CC in irrigated rice systems
To: MULCH-L@cornell.edu (MULCH-L)
Date: Mon, 4 Apr 2005

Dear Peter and Mulchers,

Your e-mails raise a very interesting issue on how cover crops and improved fallows can be integrated in irrigated rice systems. Could you share your experiences as well indicate some good literature for it?

Many thanks in advance!

Erika Styger
Agriculture and Rural Development
The World Bank
1818 H Street NW
Washington DC 20433

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To: MULCH-L@cornell.edu (MULCH-L)
From: Peter Hobbs
Subject: Re: CC in irrigated rice systems
Cc: R.Gupta

Dear Erika:

Good to hear from you. Unfortunately, I left the RW areas of South Asia a few years ago when we started working on this topic. I have copied this to Raj Gupta, the RW consortium coordinator since I know he has some data on this topic. I believe they have had some success growing direct seeded rice with sesbania and then killing the sesbania with 2,4D (glyphosate doesn't work well with this greenmanure crop) and letting it mulch and supply nutrients to the rice. Some broadleaf weeds are also killed and competition helps control many weeds. I would also like them to look at growing a GM or other cover crop after wheat harvest and then knock it down and without plowing sow zero-till rice into the residue. That way, weeds and the cover crop are killed and no new weed seeds are brought to the surface for germination. One problem is that farmers would have to have a source of water at a very hot and dry time of the year to grow the cover crop. We can also use the cheap! zero-till drill available in South Asia for wheat to plant rice into the residue mulch. So far, this is not been experimented with, but work may start soon. The problem is finding funding for these new resource conserving technology research activities, a hard thing these days.

Another issue for rice is developing rice genotypes that do better under aerobic conditions since most rice varieties in South Asia are selected under puddled, transplanted conditions. Abiotic and biotic stress tolerance, competitiveness with weeds, better rooting and other factors will be needed. IRRI recently started work on aerobic rice and immediately had problems with the rice root nematode. Whether this organism proliferated more when the soil was switched to an aerobic system and with time may be controlled by diversifying the microbial population, is not known. Use of cover crops may help get more microbial diversity into microbially degraded rice paddies. Hope this helps.

Best Regards,

Peter Hobbs