Root Development and the EI...??


Junior Poster
Dec 29, 2005
I was wondering, when you dose the Estimative Index on a newly established planted tank, could that inhibit the development and growth of a plant's root system? I would assume that plants would utilize the ferts in the water column more readily that those in the substrate because they are avalable vs. ferts in the substrate which the plant would have to establish a root system to extract...

Do plants become less efficient in their use of nutrients when the Estimative Index is being used??

Tom Barr

Staff member
Jan 23, 2005
Re: Root Development and the EI...??

In general plants do become less efficient in their uptake of nutrients, this makes sense in terms of enzymes.

Why spend all this effort and energy making very high affinity enzymes that can only take in say 0.5 - 2 micro molar of NO3 when a low affinity system can operate at a high NO3 level and taken in lots more NO3 for growth but only does well when the concentration is 50-500 micromolar?

Basically the plant adapts and places a lot more effort to produce growth by scavaging for nutrients a lot more if the concentration is low in the water column.

So they can make these enzymes the high affinities, and also see about going after any root sources for nutrients. What other choice does the plant have?

None, it cannot run away to green pastures.

If you have good nutrients in the soil/sediment/substrate and the water column, then the plant can take the nutrients from where it wants and this allows the best growth in terms of nutrients.

I think "efficient use of ferts" is a bit misleading. This is not bad in terms of growth, you will get more growth because there is more avilable and the plant does not have to work as hard to concentrae it inside the plant/uptake is easier, but less efficient.

If I was really hungry and have only 10 grapes left for 2 days, I'd eat one every few hours, If I knew I have a few bags laying around, I'd eat all 10 now and get the rest as well. Most things tend to be more wasteful, in times of plenty.

I think in general what you are asking is:
Are plants better off having water column ferts vs substrate based ferts after as trim when they are rootless?

I'd say definitely, no roots!
Does EI/water column ferts inhibit root growth? I'd also say yes.
Why make roots if you have plenty from the water column already other than to stay put and not get blown around?

Tom Barr