b.stev

Soil as Habitat for Microbeschemical properties

CHEMICALS in the soil aid their growth

MICROBES USE SPECIFIC CHEMICALS

many require, carbon, in order to

survive

others survive utilising certain

compounds

WHY ARE MICROBES IN SOIL?

“aerobes” : need O2

“anaerobes”: don’t need

oxygen

NUMBERS OF MICROBES IN SOILa small teaspoon of soil contains approx

Algae 1000 - 1

million

Fungi 100,000 – 1

million

Bacteria 100 million – 1

billion

ONLY:through microbial action do organic fertilizers become useful to plants

(Texas A and M University, 2008)

A microbial process is ESSENTIAL to how a nutrient cycles through the soil

CHEMICAL is absorbed for use

a PRODUCT excreted in another form

FOR A PLANT: it is whether a chemical is absorbed

if a microbe had not processed the

chemical, the plant would be deficient of its product

ALSO regulates the quantities available to

plants

THE same principal applies to these subjects:

ANIMALS - what it is that the animal ingests as

nutrient

DECAYING MATTER - replenishing organic

material

EXCRETIONS – breakdown animal waste

WEATHER FLUCUATIONS - work to maintain

equilibrium

(Texas A and M University, 2008)

years of RESEARCH has been performed

on nutrient cycles & how this occurs

the MAIN CYCLES are: nitrogen/ carbon/ sulphur/ water/

phosphorus

the next picture: shows the cycle of

nitrogen

observe what occurs in the soil

this is all because of microbial action

there is a COMPLEXITY of chemical reactions occuring

this is the habitat that microbes

utilise & maintain as part of the

“,Nitrogen Cycle,” within soil

(Pidwirny. M. Dr, 2008)

EXACTLY what do MICROBES do IN THE SOIL?

“Lets take the - Nitrogen cycle, & look at it closely”

NITROGEN is extracted from the air &

placed into the soil from microbial

action

the plants absorb the product

it is even given back as nitrogen gas to

the air

nitrogen gas in the air is altered to ammonia in the soil

N2 + 3H+ + 3e- = NH3

NH3 + H+ = NH4+

THEN ammonia is altered to ammonium ion

2NH4+ + 3O2 = 4H+ + 2H2O + 2NO2

-

THEN ammonium ion becomes nitrite ion

O.K: lets look closely – first,

2NO3- + 12H+ + 11e- = N2 + 6H2O

ALSO: nitrogen gas is made from nitrate & is then emitted into the air

2NO2- + O2 = 2NO3

-

nitrite ion is THEN altered to nitrate

each EQUATION is performed by a different microbe

PLANTS use the nitratenitrate as a nutrient

(Wikipedia, 2008)

These reactions all occur simultaneously

The HABITAT has an

equilibrium between the different chemicals &

it is the microbesmicrobes that work to maintain this

Bibliography

Wikipedia. (2008). Nitrogen cycle- wikipedia,the free encylopedia. Retrieved September 20, 2008, from http//:www.en.wikipedia.org/ wiki/Nitrogen_cycle - 45k -

Pidwirny. M. Dr. (2008). 9(s). The nitrogen cycle. Retrieved September 20, 2008, from http//:www.physicalgeography.net/fundamentals /9s.html - 15k

Trakhtenberg. I. (2001). Activities. Retrieved September 20, 2008, from http//:www.soil.gsfc.nasa.gov/activ_98/microact.htm - 16k -

Texas A and M University. (2008). Welcome to soil and crop sciences at Texas A and M University. Retrieved September 20, 2008, from http//: www.organiclifestyles.tamu.edu/soil/microbeindex.html - 32k -