I asked this question in a gardening NG but didn't get far so I am
trying here.

I see posts in NGs and references in books and web sites to companion
planting. There seems to be a fairly widespread belief that some plants
do better when in proximity to others and that some combinations are
harmful. Some sources list a number of feasible mechanisms that could
be the causes of this phenomenon but other than the obvious (ie the tall
upright plant shades the prostrate one) there is little evidence
included that shows the effect actually happens. Also many sources
state without attribution things like:
"it has long been known that companion planting is beneficial....." or
"scientific studies have shown that companion planting is ....." or
"research in this area has consistently shown that companion plants
offer no pest control benefits under controlled conditions."

These references are rather unsatisfying as they don't name the original
research that the author appears to be relying on. At this point I have
an open mind on the subject and I would like to know more but I want
more than just what was handed down by grandpa even if he was a wizard
farmer.

Can anybody give me references to particular studies which approach this
issue in a thorough and scientific way? I am interested in studies that
might attempt to prove/disprove that this actually happens or to show
that proposed mechanisms actually work or not. I would expect such a
study would include some sort of measure of just how beneficial or
harmful given combinations might be, as I can't see how you could say a
combination was significantly good/bad without being able to measure the
benefit/harm.

David

On 11/13/02 8:44 PM, in article
, "David Hare-Scott"
wrote:

I asked this question in a gardening NG but didn't get far so I am
trying here.

I see posts in NGs and references in books and web sites to companion
planting. There seems to be a fairly widespread belief that some plants
do better when in proximity to others and that some combinations are
harmful. Some sources list a number of feasible mechanisms that could
be the causes of this phenomenon but other than the obvious (ie the tall
upright plant shades the prostrate one) there is little evidence
included that shows the effect actually happens. Also many sources
state without attribution things like:
"it has long been known that companion planting is beneficial....." or
"scientific studies have shown that companion planting is ....." or
"research in this area has consistently shown that companion plants
offer no pest control benefits under controlled conditions."

These references are rather unsatisfying as they don't name the original
research that the author appears to be relying on. At this point I have
an open mind on the subject and I would like to know more but I want
more than just what was handed down by grandpa even if he was a wizard
farmer.

Can anybody give me references to particular studies which approach this
issue in a thorough and scientific way? I am interested in studies that
might attempt to prove/disprove that this actually happens or to show
that proposed mechanisms actually work or not. I would expect such a
study would include some sort of measure of just how beneficial or
harmful given combinations might be, as I can't see how you could say a
combination was significantly good/bad without being able to measure the
benefit/harm.

David



There's a link here that might help get you started. I live in the
central U.S. but don't remember seeing any intercropping. I've read some
farmers might sow turnips into a corn field toward the end of the corn
growing season. They turn cattle out into the fields after corn harvest.
The turnips make good cattle feed.

http://www.pprc.org/pprc/rpd/fedfund.../annualme.html

Dean






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David Hare-Scott writes

These references are rather unsatisfying as they don't name the original
research that the author appears to be relying on. At this point I have
an open mind on the subject and I would like to know more but I want
more than just what was handed down by grandpa even if he was a wizard
farmer.

I have seen work purporting to show improvements using companion
planting. You might like to look up the UK organic sites, there is at
least one 'experimental' organic farm doing research.

I have seen UK work on mixed planting. You might enquire from HGCA site.

Quite a bit on mixed varieties of cereals. The idea being that disease
spread may well be inhibited where only (say) 1/3 of the crop is
particularly susceptible to each major disease. The results, from what I
remember, were that the mixture behaved slightly better than the average
of the three varieties, but never as well as simply planting the best in
the first place.

Some years ago there were trials of peas and (IIRC) spring wheat.
Obviously it's quite tricky doing work on a field scale using
conventional agricultural equipment. Both crops must come to maturity
simultaneously, be separable and not severely compete with each other in
the field. From what I remember these trials tended to result in either
all peas or all wheat, depending on individual circumstances allowing
one to dominate the other. With impressively poor yields of whichever
managed to take over.

Intercropping is quite widely practised. I noticed it was common south
of the atlas in berber fields. From the layout my wife and I decided
that the idea was quick maturing crops between slow maturing crops so
allowing best use of land and erratic rainfall. It's nothing different
to what I did for years. For example planting radish between swiss
chard, or climbing beans either side of winter broad beans. Harvesting
the early species then allows light and rootgrowth for the later
species, minimising the area-time of bare ground.

I have never seen any convincing work on transferred disease or pest
control, except for the (now abandoned) UK GM sugarbeet trials. There
they found (with RR beet) that pests (particularly aphids) preferred the
weeds left between the beet. Early aphicides were thus not required.
When the field was oversprayed with roundup the pests and predators
migrated to the beet with heavy pest mortality. The result was a saving
of one or two insecticides. This was entirely unexpected. I imagine a
similar mechanism could be used for companion planting if the companion
species was not required to contribute to the output.

--
Oz
This post is worth absolutely nothing and is probably fallacious.
Note: soon (maybe already) only posts via despammed.com will be accepted.

"Oz" wrote in message
...
David Hare-Scott writes

These references are rather unsatisfying as they don't name the original
research that the author appears to be relying on. At this point I have
an open mind on the subject and I would like to know more but I want
more than just what was handed down by grandpa even if he was a wizard
farmer.

I have seen work purporting to show improvements using companion
planting. You might like to look up the UK organic sites, there is at
least one 'experimental' organic farm doing research.

I have seen UK work on mixed planting. You might enquire from HGCA site.

Quite a bit on mixed varieties of cereals. The idea being that disease
spread may well be inhibited where only (say) 1/3 of the crop is
particularly susceptible to each major disease. The results, from what I
remember, were that the mixture behaved slightly better than the average
of the three varieties, but never as well as simply planting the best in
the first place.

Some years ago there were trials of peas and (IIRC) spring wheat.
Obviously it's quite tricky doing work on a field scale using
conventional agricultural equipment. Both crops must come to maturity
simultaneously, be separable and not severely compete with each other in
the field. From what I remember these trials tended to result in either
all peas or all wheat, depending on individual circumstances allowing
one to dominate the other. With impressively poor yields of whichever
managed to take over.

Intercropping is quite widely practised. I noticed it was common south
of the atlas in berber fields. From the layout my wife and I decided
that the idea was quick maturing crops between slow maturing crops so
allowing best use of land and erratic rainfall. It's nothing different
to what I did for years. For example planting radish between swiss
chard, or climbing beans either side of winter broad beans. Harvesting
the early species then allows light and rootgrowth for the later
species, minimising the area-time of bare ground.

I have never seen any convincing work on transferred disease or pest
control, except for the (now abandoned) UK GM sugarbeet trials. There
they found (with RR beet) that pests (particularly aphids) preferred the
weeds left between the beet. Early aphicides were thus not required.
When the field was oversprayed with roundup the pests and predators
migrated to the beet with heavy pest mortality. The result was a saving
of one or two insecticides. This was entirely unexpected. I imagine a
similar mechanism could be used for companion planting if the companion
species was not required to contribute to the output.

I am told they do some intercropping in India with cotton that they plant on
1 meter checker board spacing. If there were plenty of moisture or
irrigation was available a short starred crop that came off before the
cotton was 6 or 8 weeks old and started using moisture at a high rate would
be compatible.

We also used mung beans as catch crop after wheat some years it if very
short seasoned and we had a good market for them. Some one need to do some
breeding on them a develop a variety that doesn't shatter so badly.

Gordon