Saturday
Mar132010
Pea's tell me : inoculant vs no inoculant
Saturday, March 13, 2010 at 6:17AM
Last spring I decided it was time for me to get down to the heart of the matter when it comes to snap peas, variety and the question about adding inoculant at planting time or not... But before I get into my findings of a year ago there's obviously a small disclaimer here: these results are for my soil conditions, my planting techniques and the very wet year last year.
So with that out of the way - I have a rather sandy soil that actually holds a lot of water (yes - should not be - but it is). I also have lots of naturally growing white clover all over the place... so that suggests my soil is already rife with N-fixing bacteria (although they are different spp.). But - on to the results.
Last spring I planted 4 distinct test patches: classic Sugar Snap and the more resistant Super Sugar Snap - both with and without inoculant. Both of these seeds were untreated as it seems treated seeds and inoculant are intuitively opposed to each other (a lot of treatment is anti-fungal not bacterial so this statement depends on treatment) . I also planted a patch of treated Sugar Snap (Thiram as the treatment - a fungicide).
So what did I discover? Well - first and foremost you stand there after you plant your seeds and wait... and the seeds treated with thiram emerged sooner and in greater numbers. What I should have added to the test was treated + inoculant as thiram has no effect on Rhizobia nodulation1. I also noted that after you watch these guys grow until late June - the "more disease resistant" crop of the Super Sugar Snap fellows were not so "super" in terms of production. They had lots of good growth but just didn't set peas like Sugar Snap.
Now - the last column is important to note - we had a wicked wet spring and summer last year. Somewhere in June we got 5" of rain in a 24 hour period... so these peas had to deal with drenching rains and cool damp disease conditions. Here - it was very clear that the Super Sugar Snap peas that had been inoculated did the best (likely because they could uptake more nutrients - had more root surface area to get oxygen from the flooded soils and have the bred in disease resistance).
So what am I going to do this year with my data and insight? Well - if you read here - I'm going to do a face-off between two different untreated seeds and see how things grow. Ideally - I'd be planting thiram treated Sugar Snap peas - but I didn't want to order just those from one place and pay all that shipping... so I bought what I could and we will watch for the outcome.
So with that out of the way - I have a rather sandy soil that actually holds a lot of water (yes - should not be - but it is). I also have lots of naturally growing white clover all over the place... so that suggests my soil is already rife with N-fixing bacteria (although they are different spp.). But - on to the results.
Last spring I planted 4 distinct test patches: classic Sugar Snap and the more resistant Super Sugar Snap - both with and without inoculant. Both of these seeds were untreated as it seems treated seeds and inoculant are intuitively opposed to each other (a lot of treatment is anti-fungal not bacterial so this statement depends on treatment) . I also planted a patch of treated Sugar Snap (Thiram as the treatment - a fungicide).
| Germination - 1w | 2w-harvest | harvest volume | disease resistance | |
|---|---|---|---|---|
| Sugar Snap | good | vigorous | high | moderate |
| Sugar Snap (I) | good + | vigorous | v. high | moderate |
| Super Sugar Snap | very good | vigorous - | average | high |
| Super Sugar Snap (I) | very good | vigorous + | high/average | last to die |
| Sugar Snap (T) | best in class | vigorous + | v. high | moderate |
So what did I discover? Well - first and foremost you stand there after you plant your seeds and wait... and the seeds treated with thiram emerged sooner and in greater numbers. What I should have added to the test was treated + inoculant as thiram has no effect on Rhizobia nodulation1. I also noted that after you watch these guys grow until late June - the "more disease resistant" crop of the Super Sugar Snap fellows were not so "super" in terms of production. They had lots of good growth but just didn't set peas like Sugar Snap.
Now - the last column is important to note - we had a wicked wet spring and summer last year. Somewhere in June we got 5" of rain in a 24 hour period... so these peas had to deal with drenching rains and cool damp disease conditions. Here - it was very clear that the Super Sugar Snap peas that had been inoculated did the best (likely because they could uptake more nutrients - had more root surface area to get oxygen from the flooded soils and have the bred in disease resistance).
So what am I going to do this year with my data and insight? Well - if you read here - I'm going to do a face-off between two different untreated seeds and see how things grow. Ideally - I'd be planting thiram treated Sugar Snap peas - but I didn't want to order just those from one place and pay all that shipping... so I bought what I could and we will watch for the outcome.
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