Phosphorous cycling Flashcards
how does phosphorous originate
the weathering of primary minerals
does phosphorous cycle through the atmosphere like carbon and nitrogen
no, it doesn’t
what are the problems with phosphorous
- next to N it is the most limiting nutrient for crop production.
- amount of P in soils is low
- the majority of P compounds found are unavailable for plant intake
- no more than 0.01% of the total P is available
- plants take up P and inorganic Phosphate ions
-when available forms of P are added to the soil as fertilizers or manure the P quickly reacts with the cations and mineral surfaces in the soil
when P fertilizer is added how much percent of it is used by the crop in the first year of application
only 10-30%
how easy is it for plants to find P nutrients
next to N it is the most limiting nutrient for crop production
amount of P in soils is low
- the majority of P compounds found are unavailable for plant intake
- no more than 0.01% of the total P is available
how do plants take up P nutrients
plants take up P as inorganic Phosphate ions. the majority of P compounds found are unavailable for plant intake
what did P fertilizers use to consist of
they were animal-based and consist of bones, guano, manure. bones were acidified to increase P availability
how are P fertilizers now produced
by the apatite minerals contained in phosphate rock
how are P ions that plants usually take up present in the soil
usually as H2PO4- or HPO4^2-
what does fixation refer to
The chemical process that renders P unavailability to plants
what are the processes that leads to fixation
precipitation reactions and adsorption to Al and Fe oxide surfaces
when does net immobilization occur
it occurs if the organic residues have C:P ratio more then 250:1
when does net mineralization occur
if organic residues have C:P ratio less then 250:1
what is the biggest way P is lost
crop removal
why is P considered an investment
because it’s like a bank account the added P will increase the P in the soil
