Cover Crops and Nematodes

[dice]

duajones was asking about cover crops
some weeks ago. Winter Rye came up
as one popular selection.

Some research from the early '90s from
Oregon indicated that the ability of
some rye and oat cover crops to suppress
nematode populations is cultivar-specific:

http://ifs.orst.edu/pubs/forge_nematode_story.html

There is doubtless more recent work on this,
and growers in the South might look for more
recent research local to their regions.

[duajones]

here is another link

http://www.sare.org/publications/factsheet/0605.htm

[dice]

Good article. They didn't mention it, but the
legumes (castor bean and RKN-resistant
soybean cultivars) would also add nitrogen
to the soil via root-fixing of nitrogen.

[johno]

I don't have the link handy, but there is research on using mustards to help with this also.

[duajones]

Nandina from GW mentions the use of mustard powder here

http://forums.gardenweb.com/forums/l...122032681.html

[dice]

I get the impression that it is the foliage (or "biomass"
in agricultural terms) of mustard that supplies nitrogen
(recycles it, actually).

The mustard uses nitrogen from the soil to grow in
fall and winter (until killed by frost), and when you
turn the mustard back into the soil in spring, the
mustard breaks down, releasing nitrogen back into
the soil, much as would alfalfa that had been grown,
mowed, and turned back into the soil the next spring.
The mustard conserves nitrogen that would have been
lost to leaching from winter rains, and it does a better
job of this than many other plants that one could grow
instead (mustard probably has less carbon and uses up
less of its own nitrogen as it decays than stemmy grass
crops, etc).

I haven't read a lot about it, but that's my impression
from what I have read.

[MsCowpea]

I don't think mustard is a cover crop planted for it's nitrogen contribution to the soil.

It would , of course, contribute biomass as you indicated but it releases a chemical that is antagonistic to nematodes.

Just went and looked it up as I could not remember the name.

glucosinolate compounds (excellent link-covers a bit of everything)

http://attra.ncat.org/attra-pub/nematode.html#cropro

I also found this interesting as they combined the use of a brassica with the concept of solarization.

http://www.faculty.ucr.edu/~atploeg/...arization.html

The actually use of mustard powder is something that Nandina is experimented with with the thought to utilize these chemical compounds I guess.

I currently have sun hemp (recommended CC for Florida) planted and have just received sesame seeds to plant.
Sun hemp contributes tremendous amounts of biomass and nitrogen to the soil and is a nematicide to certain nematodes.

I still think the most important thing to do is add lots of organic matter to the soil.

[dice]

So, mustard is a good cover crop in more ways
than one. (I didn't really forget the subject, just
hadn't heard that mustard was a nematode
inhibitor. Thanks for the info.)

[MsCowpea]

There is a problem with mustard though--it is an aphid magnet.

I have given up growing it for the time being as it gets so bug ridden down here.

Planting a cover crop that attracts bugs that also likes your future tomato crop is something I worry about.

I know, for instance, that thrips can get on the sunhemp I planted so I will have to make sure that should that occur I will have to take 'measures' to prevent them from pupating in the soil.

[dice]

That (aphids on mustard cover crop) wouldn't
be an issue up here in the northwest for a fall
cover crop, because it is too cold for the aphids
(and the tomatoes). So far they haven't shown
any taste for swiss chard, garlic, or parsley, which
are the only things still growing in the vegetable
garden into October. (They love fava beans,
though. I should plant some for a fall cover
crop and see exactly how long the aphids hang
around before the cold gets them.)

[gardenhappy]

Has anyone had experience using the mole cricket nematodes to kill off mole cricket larve?? I just bought them from arbico organics and have never used this method before,always used garlic/hot pepper spray,gerrn cover crops and never had a problem but i have lost half my garden to mole crickets!!!!

[JimmyWu]

Here's a link to a farmer using Italian Mustard as a cover crop on his farm.The yellow revolution

[BVGardener]

Thanks for posting that Jimmy. Being someone that is having to deal with rkn, I really appreciate articles such as this one.

Jay

[annecros]

That was a great article. We nave RKN issues as well - now I'm glad for those winter greens I grew! Will look into the Italian Mustards, although I would prefer something edible.

[gardenhappy]

I know that marigolds(Tagetes),growen as a cover crop then tilled under does work but not until the next growing season because you have to till into the ground for them to work against the nematodes,It has helped a ton here,that and the nematodes!!!! Now i'm finding grubs and grass hoppers!!!! We always planted winter rye,red clover,and barley up north,but i'm wondering down here if it will heat my soil up for summer gardens to much???? On crops bringing in pest,some organic books tell us to grow eggplants as a trap crop,when covered in say aphids then you pull them and burn them,same way with nasturtiums in beans,as a trap crop.