Fertilizer (or fertiliser) is any organic or inorganic material of natural or synthetic origin (other than liming materials) that is added to a soil to supply one or more plant nutrients essential to the growth of plants.[1] Conservative estimates report 30 to 50% of crop yields are attributed to natural or synthetic commercial fertilizer.[2] Global market value is likely to rise to more than US$185 billion until 2019.[3] The European fertilizer market will grow to earn revenues of approx.
Component functions[edit]
The three elements promote plant growth in three different ways. In simple terms, these are:
##N – nitrogen: promotes the growth of leaves and vegetation[2]
##P – phosphorus: promotes root and shoot growth
##K – potassium: regulation of water and nutrient movement in plant cells, purportedly promoting flowering and fruiting[3]
Method for converting an N-P-K value to an actual composition[edit]
The factors for converting from P2O5 and K2O values to their respective P and K elemental values are as follows:
##P2O5 consists of 56.4% oxygen and 43.6% elemental phosphorus. The percentage (mass fraction) of elemental phosphorus is 43.6% so elemental P = 0.436 x P2O5
##K2O consists of 17% oxygen and 83% elemental potassium. The percentage (mass fraction) of elemental potassium is 83% so elemental K = 0.83 x K2O
##Nitrogen values represent actual nitrogen content so these numbers do not need to be converted.
Using these conversion factors we can determine that an 18−51−20 fertilizer contains by weight:
##18% elemental (N)
##22% elemental (P), and
##17% elemental (K)
In the U.K., fertilizer labeling regulations allow for reporting the elemental mass fractions of phosphorus and potassium. The regulations stipulate that this should be done in parentheses after the standard N-P-K values.[4]作者: 鬼迷心窍 时间: 2013-11-17 22:48:16
zzxcb123 发表于 2013-11-17 09:17
Fertilizer (or fertiliser) is any organic or inorganic material of natural or synthetic origin ( ...