thaipan2000 Posted October 17, 2011 Share Posted October 17, 2011 hello is't enyone know the numbers on the chemical nutrients bags ex 15-15-15,46-0-0. Link to comment Share on other sites More sharing options...
krauti Posted October 17, 2011 Share Posted October 17, 2011 hi taipan, the three numbers mean in the order: Nitrogen/Phospate/Potassium. 46-0-0 is Urea, a fully nitrogenic fertilizer. check the web for further explanation. best for you krauti Link to comment Share on other sites More sharing options...
Scoop1 Posted October 17, 2011 Share Posted October 17, 2011 (edited) Hi taipan, the number represents the amount of the particular nutrient in the mix,as a percentage, for example, Calcium Nitrate = 18.8% Calcium and 15.5 Nitrogen, what are you using it for , to fertilize what? 15-15 15 = 15% Nitrogen 15% Phosphorous 15% Potassium = NPK 15-15-15 Cheers Scoop1 Edited October 17, 2011 by Scoop1 Link to comment Share on other sites More sharing options...
WatersEdge Posted October 17, 2011 Share Posted October 17, 2011 It should be clarified a bit to say that the NPK numbers on the bag are Weight Percent with N P205 K2O as the compounds weighed. It gets a little confusion at first, since those formulas don't exist in real life They are just a method of describing what has developed over time in the fertilizer industry. From there we have many actual chemical formulations, which all are converted to the standard terminology. For instance: Urea 46-0-0 is chemical formula (NH2)2CO, which to manufacture is Two Ammonia NH3 with One CO2, then a Water H20 is thrown out. 2NH3 + CO2 => (NH2)2CO + H2O Nitrogen has atomic weight 14 Hydrogen 1 Carbon 12 Oxygen 16 So adding those constituents together to reach the Molecular weight of Urea Two N @ 14 => 28 Four H 1 => 4 One C 12 => 12 One O 16 => 16 ============================= Molecular Weight 60 The Percentage then of N is 28/60 => 0.4666 => 46.7% By identifying the chemical compounds mixed into any fertilizer formula, you can derive the NPK number from it. A couple of years ago there was a strong thread on fertilizers here on the Farm Forum. There is an Excel fertilizer calculator that I put up at that time which demonstrates these calculations and enables cost comparisons of various fertilizer formulas. Please note that in the case of Phosphorous P and Potassium K, there is a big difference between the P2O5 Phosphate weight and the P Elemental weight and the K2O Potash K Elemental In some calculations Elemental weight is used, so you need to determine if the writer means Compound or Elemental weight. It's meant to be confusing so that Fertilizer Salesman can hold something over you. But it's not actually all that bad after you get into it. Nothing like a good spreadsheet calculator to make it all clear. Link to comment Share on other sites More sharing options...
andycrosby Posted October 17, 2011 Share Posted October 17, 2011 <deleted> I BET YOUR GLAD YOU ASKED Link to comment Share on other sites More sharing options...
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