Organic at
Cornell Home
OCS Home
Experiments:
•Vegetable
•Grain
•Compost
News
People
Learn with us
Collaborators only
|
Weed learning module
Answer ...
Does the fact that fewer seedlings emerged from the green manured soil than from the alley soil show that the hypothesis is correct?
We can never prove that a hypothesis is correct because there could always be some other process going on that we have not taken into account. In this case, one obvious possibility is that the green manure may contain short lived toxins that inhibit seed germination or kill the seedlings. One plant poisoning another is known as allelopathy. Many crop, cover crop and weed species show allelopathy in the lab, though the effect often cannot be seen under field conditions. To our knowledge no toxic effects have been reported from pea or powell amaranth residue. Inclusion of sterilized soil treatment as would control for allelopathy. If the sterilized and non-sterilized green manured soil both reduce weed emergence equally relative to the non-cover crop soil, then we can assume that disease fungi are not responsible. Even this is not a perfect test, however, since decay organisms might be required to release the toxins! Life in the soil is very complicated, and usually strong conclusions require multiple experiments that support one another.
Return to text.
Return to weed learning module main page.
© Copyright, Department of Horticulture, Cornell University.
Logo graphics by Rachel Kennedy.
Design by Craig Cramer.
Mention of trade names and commercial products is for educational purposes; no discrimination is intended and no endorsement by Cornell Cooperative Extension or Cornell University is implied. Pesticide recommendations are for informational purposes only and manufacturers' recommendations change. Read the manufacturers' instructions carefully before use. Cornell Cooperative Extension and Cornell University assumes no responsibility for the use of any pesticide or chemicals. Some of the links provided are not maintained by Cornell Cooperative Extension and Cornell University. Cornell Cooperative Extension and Cornell University are not responsible for information on these websites. They are included for information purposes only and no endorsement by Cornell Cooperative Extension or Cornell University is implied. Cornell Cooperative Extension provides equal program and employment opportunities.
|
