6. Potassium (K)

Question 1

Potash Fertilizers?

• Mainly derived from?
• Fertilizer products in use?

Answer 1

Potash fertilizers are mainly derived form:
- Geological saline deposits

Fertilizer products in use:

• are mainly high concentration materials
• are water soluble
• are quick acting

Question 2

1. Potassium (K) fertilizers and formulations?
Potassium Chloride?
- Mostly found as?
- Method of placement?
- Color?

Answer 2

1. Potassium Chloride (KCL) (0-0-60).
   Muriate of Potash (MOP).

Mostly found as:

• KCl (sylvite) mixed with NaCl (halite) in the mineral sylvanite.
• In processing the ore is crushed and the KCl and NaCl are separated

Due to the high salt content:
- KCl should not be placed directly with the seed.

Most of KCl fertilizers are:

• White
• Some are reddish due to amounts of Iron Oxide
• Both are idnetical for agronomic use

Question 3

2. Potassium (K) fertilizers and formulations?
   Potassium Sulphate?

• Contains?
• Found in?
• Facts (3)?

Answer 3

2. Potassium Sulphate (K2SO4).
   Sulphate of Potash (SOP)

Contains:

• 48-53% of K2O
• 17-18% of S

Found in:

• Mineral depsoits mixed with other minerals.
• Processed by separating components by rinsing in water.

!*Less soluble than KCl. Not commonly used in irrigation water.

!*Sometimes applied as a foliar spray if K and S are both needed.

!*Also used to supply K to Cl-sensitive crops such as tobacco and potatoes

Question 4

3. Potassium (K) fertilizers and formulations?
   Potassium magnesium sulphate (K2SO4·2MgSO4)

Name?
Commercial name?
Places found?
Contains?
Effect on soil pH?
Water-solubility?

Answer 4

3. Potassium magnesium sulphate (K2SO4·2MgSO4).

• Langbeinite.
  Commercially Sulpomag
• Unique mineral found in only few locations in the world (Carlsbad, New Mexico)

Contains:

• 21-22% K2O
• 10-11% Mg
• 21-22% S
• Unlike other Mg and S Fertilizers it has neutral effect on soil pH.
• Is water soluble, but slow to dissolve

Question 5

4. Potassium (K) fertilizers an formulations?
Potassium Nitrate (KNO3)?
Name?
Valuable for?
Contains?
Forms of applications?

Answer 5

4. Potassium Nitrate (KNO3).

Saltpeter.

• Popular fertilizer for high value crops that need nitrate from N and also K.
• Popular as K source for crops that sensitive to Cl.
• Contains 13% N and 44-46% K2O.
• Applied to soil and as a foliar treatment to stimulate fruit development when root activity is declining.