vitality of our soil

Jon B jeb926 at io.com
Thu Nov 18 13:30:00 EST 1999


Anthony:
Here are a couple of excellent web sites that contain information on
soils - although they may not contain direct responses to your questions,
they are nonetheless good starting points. I highly recommend "The
Pedosphere and its Dynamics."

Online Soil Science Course - The Pedosphere and its Dynamics (great site)
http://www.pedosphere.com/

Soil Biological Communities
http://www.id.blm.gov/iso/931/soil/soil.htm  

Soil Quality Institute
http://www.statlab.iastate.edu/survey/SQI/

National Soil Survey Center
http://www.statlab.iastate.edu/soils/nssc/

World Soil Resources Web Site
http://www.nhq.nrcs.usda.gov/WSR/
 

Soils are extremely complex systems and their ability to provide the
essential nutrients for plant growth depend on many factors:
soil pH, mineralogy, amount of weathering (influenced by soil age,
topography, climate), microbial activity, and current/past management
practices - this list is by no means comprehensive. The majority
(approximately 97%) of biomass is made up of water and organic
material (carbon); only 3%, on average, is comprised of minerals -
obtained from soil uptake. So, the bulk of a plant's material is derived
from water and air.

The level of nutrition (either animal or human) provided by plants will
depend on the plant's genetics, environmental conditions during growing
season, and whatever fertility is available. A constantly-cropped soil can
become depleted in some of the essential elements (nitrogen & phosphorus,
for example). That is one of the reasons fertilizers are used - to add
supplemental levels of required nutrients. The amount of fertilizer used
will depend on the soils, plants being grown, and the desired yields. The
seed only supplies enough energy for the plant to get roots started and
initiate leaf growth. Once the roots and leaves start growing,
photosynthesis in the leaves takes care of the energy needs and the roots
uptake water and nutrients.

Hope that helps,

Jon Brandt

"a. n-m." <wylechiote at hotmail.com> wrote:
> In my botany class we have yet to go into detail about the soil that plants 
> grow in. I am not sure if soil is topic discussed in botany. If anyone can 
> help or direct me to more info. concerning soil I would appreciate it. I 
> often wonder about how  nutritious the fruits and vegetables are that we 
> eat. If crops are yielded from the same soil year-after-year, do the crops 
> remain as nutritious as the prior year. Does the seed itself supply all the 
> nurtients the plant needs for growth? Do fertilizers provide the nutrients?

> Anthony

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