4. Phosphorus (P). Sources, Formulations and types.

Question 1

Effect on environment?

Answer 1

Soil errosion
Runoff
Leaching losses of P from agricultural fields are considered a major conttributor to hypoxic areas around the world.

Question 2

1. P Fertilizer sources and formulations?
   Phosphate rock?

• Exists in?
• Water solubility?
• Acidic soils?
• Method of processing?

Answer 2

1. Phoshphate rock (PR).
   - Exists in old marine deposits.
   - If PR applied directly, water solubility may be too low to meet the needs of a growing crop.
   - PR can be effective P source if used on acidic soils
   - Over 90% of the PR used is processed into soluble P fertilizers by reacting it with acid, which makes it agronomically and economically effective as a crop nutrient source.

Question 3

2. P Fertilizer sources and formulations?
Single superphosphate (SSP)?

• Method of production?
• Deficiency/ efficiency?

Answer 3

2. Single superphosphate (SSP).
   - Single superphosphate produced by reacting rock phosphate (RP) with sulphuric acid.
   - Other P fertilizers have largely replaced SSP because because of relatively low P content.

Question 4

3. P Fertilizer sources and formulations?
Triple Superphosphate (TSP)?

• Name?
• Which crops popular for/ Crop application?

Answer 4

3. Triple Superphosphate (TSP)
   - [Ca(H2PO4)*H2O] or monocalcium phosphate.
   - Popular for legume crops where N fertilizers is not needed.

Question 5

4. P Fertilizer sources and formulations?
   Monoammonium phosphate?
   (NH4H2PO4)
   MAP.

• Concentration?
• Contains?
• Solubility?
• Methods of application?

Answer 5

4. Monoammonium Phosphate MAP
   (NH4H2PO4)

• The most concetrated P source among solid fertilizers.
• Contains 10-12% N and 46-61% P2O5 most commonly produced as 11-52-0. (NPK)
• Is highly soluble and quickly becomes available to plants as NH4+ and H2PO4- in the soil solution.
• MAP Can be be made into a powdered form and used in suspension or clear liquid fertilizers, or applied as a foliar spray added to irrigation water if MADE with purer dorms of phosphoric acids.

Question 6

5. P Fertilizer sources and formulations?
   Diammonium phosphate.
   [(NH4)2HPO4].
   DAP.

• Popularity?
• Method of production?
• Contains?
• Efficiency/Defficiency?
• Warnings? Methods of placement?

Answer 6

5. Diammonium phosphate DAP
   [(NH4)2HPO4]

• Most widely used P fertilizer in the world
• Produced by reacting ammonia with phosporic acid
• Standard grade is 18-46-0. (NPK)
• Popular because it has a relatively high content of two commonly needed fertilizer materials.
• Easy to handle and store.
• High ammonium content can damage the roots so it is advised to place fertilizer in a band about 10cm from the seed row.

Question 7

6. P Fertilizer sources and formulations?
   Polyphosphate.

• Forms of use?
• Method of production?
• Contains?

Answer 7

6. Polyphosphate.
   - Popular Liquid phosphate fertilizer
   - Produced by reacting ammonia with phosphoric acid
   - Produced as 10-34-0 or 11-37-0 (NPK)

Question 8

1. Types of P Fertilizers?

Water soluble types.

Answer 8

1. Water-soluble types - (quick-acting)

• Single superphosphate
  (18-20% P2O5);
• Triple superphosphate
  (45% P2O5).

Question 9

2. Types of P Fertilizers?

Partly Water- Soluble types.

Answer 9

2. Partly Water- Soluble types - (quick- and slow-acting)

- Partly acidulated phosphate rock
23-26% P2O5
at least one-third water-soluble

Question 10

3. Types of P Fertilizers?

Slow-acting types.

Answer 10

3. Slow-acting types.

• Dicalcium phosphate (citrate-soluble)
• Basic Slag (citric acid-soluble)

citric acid - лимонная кислота

Question 11

4. Types of P Fertilizers?

Very slow-acting types.

Answer 11

4. Very slow-acting types.

• Rock Phosphate (finely-powdered soft type)
• 30% P2O5 (formic acid-soluble)

formic acid - муравьиная кислота

Question 12

5. Types of P Fertilizers?

Multi-nutrient fertilizers containing P.

Answer 12

5. Multi-nutrient fertilizers containing P.

• NP
• PK
• NPK