Author Topic: Crop varieties have been bred to have smaller root systems: Nutrient Problems  (Read 2985 times)

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Offline Alison in Kentucky

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So, this makes it even more important for us, as market farmers to consider seed saving.  We can only do so much by ourselves, but we can cooperate with others to keep our seedbank of important varieties alive. It's important to do it right - so we keep the important genetic intact, but with a good reference book and some good management, we can and should do it.

Alison Wiediger, Au Naturel Farm

Check Out All the Books on Seed Saving & Plant Breeding at Back40Books:

« Last Edit: March 16, 2009, 02:39:08 AM by CatManDo »

Offline CatManDo

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Root systems are not only smaller, but "beyond the old simplistic in 
and out nutrient budget" thinking there are surely other unbeknown and 
unintended consequences of breeding for commercial production. Not 
only are the root systems smaller, but they are even likely, without 
positive selection, to loose their abilities to interact with the 
mycorrhizal hyphae that do remain. Other interactions with soil life 
are also likely lost in breeding for commercial systems. For example, 
organic acid N uptake may be lost in commercial varieties:

Reeve, J.R., J.L. Smith, L. Carpenter-Boggs, J.P. Reganold. Soil-based 
cycling and differential uptake of amino acids by three species of 
strawberry (Fragaria spp.) plants Soil Biology and Biochemistry Volume 40, Issue 10, October 2008, Pages 2547-2552

Reeve, J.R., J.L. Smith, L. Carpenter-Boggs, J.P. Reganold. Glycine N 
uptake by classic and modern wheat varieties. Soil Biology and 
Biochemistry (in review).

Reeve, J.R., J.L. Smith, L. Carpenter-Boggs, J.P. Reganold. Variation 
in organic N uptake and availability among strawberry species, 
management and soil type.  Plant and Soil (in review). _________________________________________
Barry Lia \ barrylia@comcast.net \ Seattle WA
S&S Center for Sustainable Agriculture

Offline Lady Beetle

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Over the decades many  conventional commodity crop varieties have
been bred to have smaller  and smaller root systems. The thinking
goes: why put crop yield  energy into building extensive root systems
 when the applied  synthetic fertilizers provide a soluble source of plant
nutrients right near the surface of the soil??

   Well, smaller root systems make the crop more vulnerable to droughty 
conditions for one thing. And the chemical fertilizers and pesticides 
that don't volatilize or run off into the waterways also negatively 
impact beneficial mycorrhizae fungi -- whose miles of hyphae act as 
pipelines to deeper down water and soil nutrient sources. And of 
course, those fertilizers contain a lot of embedded petro-energy, 
while increasing greenhouse gases.... looks like a losing proposition 
to me.

   While researchers are in the process of developing organic crop 
varieties with more extensive root systems that are not reliant on 
soluble chemicals another option for farmers is to use deep rooted 
cover crops whose extensive root systems harvest  deeper down and 
migrated nutrients from lower soil horizons -- and which enhance 
mycorrhizae and build soil organic matter to hold it all in topsoil 
-- while also sequestering atmospheric CO2 in more intractable soil 
glomalin carbonaceous forms. Ah, the synergy of holistic biological 

Ruckytucks Farm