"darseet" wrote in message
om...
1. What is the reaction of urea by which it releases nitrogen in
soil?

Nitrification (Has to convert to nitrate to become useable.)


2. By which reaction potassium & phosphorus enters the soil to make
it fertile?

Phosphorus-
1. Decomposition of rock containing the mineral apatite, and organic matter.

Potassium-
1. Decomposition of mineral rocks such as feldspar, muscovite, and biotite.
2. Decomposition of organic matter in the soil and clippings, or straw,
returned to the soil.
3. Release of potassium from the surface of clay minerals within the soil by
freezing, thawing, wetting, and drying.