Soil Fertility

Carolina MedinaSoil & Water Science Dept.

University of Florida

Nitrogen Cycle

Nitrogen Cycle

Crop Residue

Animal Manure Chemical Fertilizers

Bacteria Fixation

Lightning Fixation

N Sources

Nitrogen Cycle

DenitrificationN2

NO3-

N2O

Nitrification

NH4+ NO3

-

Mineralization

Organic N NH4+

N Processes

Nitrogen Cycle

Plant Uptake

NH4+, NO3

-

Leaching

NO3+

Run off fromfertilizers

TransportMechanisms

The Harber-Bosch process

NN 22 HH 22

NHNH 33

Phosphorus Leaching in FL soils

Eutrophication

Polluted Water

Very less availableLess available

Readily available

Where Potash comes from?

Sylvinite

Potash Pile

Mining Equipment

Carbon Cycle

http://epa.gov/climatechange/kids/carbon_cycle_version2.html

Importance of Soil Organic Matter

Soil Chemical PropertiesCation-exchange capacity

Soil Physical PropertiesSoil aggregation Water holding capacity

Energy source for microbes

Factors determining SOM levelsMicrobial Activity

pHSoil MoistureSoil AerationSoil TemperatureC/N Ratio

Physical FactorsSurface placementParticle Size

Environmental FactorsClimateVegetation