Zeedman
Garden Master
For about 10 years, I used inoculant on all of my legumes - the proper type for each. Some of those were hard to find (such as garbanzo) and fairly expensive; so I conducted an experiment to see how effective they really were. I planted 2 rows (inoculated vs, un-inoculated) of several species for comparison. The intent was to compare the dry seed weights, and to inspect for nodule formation.I had to use inoculant to introduce that bacteria that sets nitrogen to my soil. Now those nodules are on the roots when I pull the plants up. From what I've read not all nitrogen fixing bacteria are the same. Some fix more nitrogen than others. Not sure what strains you have.
The experiment was only partially successful. The garbanzos were destroyed by a combination of mice & bad weather... but there was no visible difference in apparent vigor or nodule formation. For peas, beans, runner beans, and limas, there were no significant differences between treated & untreated. Soybeans were heavily nodulated & bore the same whether treated or not. Only for cowpeas was there a significant difference; the treated row was much more vigorous. Nodule formation in the treated row was extremely heavy. Even the plants at the end of the untreated row (3' away) were noticeably more vigorous, so the bacteria apparently traveled a few feet.
My conclusion is that the bacteria for cowpeas may not be able to survive my winters, so in my location, annual inoculation of cowpeas & yardlongs is beneficial. The bacteria for beans, peas, and soybeans apparently persists in the soil from year to year, and mechanical tillage spreads it throughout the gardens...
OR... the bacteria may be over-wintering on clover, and may be more efficient at cross-species colonization than conventional knowledge would have us believe.
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