Yes the fields are flooded, but only the part of the year that the
rice is actually growing. I have heard that in Viet Nam some farmers
use blue-green algae to add nitrogen to the soil at this stage, but I
can't confirm if that is true.

The time that the fields are fallow in the farms I am thinking of in
Thailand is during the dry season. It doesn't rain for months and it
is really quite hot, especially in the sun as these fields are. It
is quite a different set of circumstances from when I plant hairy
vetch in my garden for the winter in New York!

Anyway, thanks for the tip on cress. I will look into that.
Meanwhile does the new information about the conditions bring any
ideas to anyone's mind?

Thanks

Katra wrote:

In article ,
Gerry wrote:

Does anyone know of a green manure cover crop such as vetch that is
suitable for a tropical climate? I am looking for something that
would work in the rice fields of Thailand. Thanks.

Aren't rice fields flooded? So you would need a water plant?
What about cress? And that could be a secondary money crop as well.

K.