Potassium is essential for many plant and biological functions. It makes up 2.6% of the Earth's crust and 0.2% of the human body. Potassium was first isolated in 1807 and comes from minerals like feldspar and mica in the soil. Plants accumulate potassium, making fresh fruits and vegetables a good dietary source. Potassium is lost from soil through erosion, runoff, leaching, and harvesting of plants, so fertilizers are needed to replenish potassium in agricultural production.

1. Potassium cycle

2. History of Potassium Cycle
• Potassium comes from the word "potash"
• Potassium metal was first isolated in 1807
in England by Sir Humphry Davy, who
derived it from caustic potash (KOH,
potassium hydroxide)

3. Properties of Potassium
• symbol K (from Neo-Latin kalium) and is
an alkali metal
• Potassium makes up about 2.6% of
the weight of the Earth's crust and is the
seventh most abundant element.

5. • Potassium accumulates in plant cells, and
thus fresh fruits and vegetables are a
good dietary source of it
• .

6. Biological Role
• is the eigth or ninth most common element by
mass (0.2%) in the human body
• Potassium is necessary to many plant functions,
including carbohydrate metabolism, enzyme
activation, osmotic regulation, and protein
synthesis.
• Potassium is essential for photosynthesis, for N-
fixation in legumes, starch formation, and
translocation of sugars.

7. • A good supply of K promotes production of
plump grains and large tubers. plump grains
and large tubers pictures

8. Potassium sources
•Primary Minerals, the original sources of
potassium are the primary minerals, such
as:
Feldspars - Orthoclase and microcline -
KAlSi3O8
Mica - Biotite - KAl(AlSi3O10)(OH)2
Mica - Muscovite - K(Mg, Fe)(AlSiO10)
(OH)2

9. • Potassium in the crystalline structure of primary
minerals is not available to plants and it accounts
for 90-98% of the total soil K.
Potassium Fertilizers
They consist essentially of potassium in combination
with chloride, sulfate, nitrate or polyphosphate,
and include the following:
Potassium chloride (KCl)
Potassium sulfate (K2SO4)
Potassium nitrate (KNO3)
Potassium phosphates (KPO3, K4P2O7, KH2PO4,
K2HPO4)

11. Potassium losses
• Erosion-erosion is one of the main pathways through
which K is lost from the soil.
• Runoff-runoff is one of the main pathways through
which K is lost from the soil.
• Leaching-annual leaching loss of K from the soils in a
humid region under agricultural production (receiving
only a moderate rate of K fertilizer) is usually about 25
to 50 kg K/ha.
• Harvesting-plants take up very large amounts of K.

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