Soil Ecology in Agriculture
Joel Gruver (Teaches at Tufts University) posted to the
Organic Gardening list a set of principles which apply
to agricultural soils. This is a response and summary:
My summary of Joels ideas are indented.
Nutrients: - Soil life depends upon organic material.
- Most organisms like a ph of 6-7
- Plants + active soils (living) retain nutriments.
- Mulch also helps retain nutriments.
I think Joel is looking at crop land and may not consider forests
agricultural activities. For someone who is working with forests
the ideal ph is lower.
Soil life: - moderate disturbance of soil increases diversity.
- level of disturbance influences which plants survive.
- diversity allows greater density of living organisms.
- complimentary life forms resist invasions of others.
In a garden this says our disturbance can be beneficial and increase
diversity if we are careful. An easy mistake to make is too much
tilling which allows nutriments to be lost. We can create stable
plantings which help each other resist weed invasions.
Energy: - ecosystems rarely capture more than 1% of solar energy.
- modern breeding has not changed the solar efficiency.
- modern farming is energy driven (fossil fuel).
- we can replace fossil fuels with nutriment conservation
and reduced tillage.
I prefer viewing soil as a life form which is much more diverse
than Joel's descriptions. If we combine the ecology of desert
environments and forests then (IMO) we find much cycling of
nutriments and each area has a different set of cycles. It is
more than just the soil and more than just plants. In forests
the fungi dominates and we still have much to learn about it.
In the desert the rules are different and one ecologist said
the diversity is larger than other areas but totally ignored
by everyone. The cycles are there but many are not understood
and without them the plants may not be able to survive or
withstand the invasion of other plants.
jeff
