Nutrient Application Details

Read the fertilizer bag label carefully every year! Nutrient amounts in fertilizer can differ from year to year, even for the "same" product.

N, P, and K are applied at 10 g / m²/ year by elemental mass, before the growing season of each treatment year. The micronutrient mix is added once, at the first treatment application, into K addition plots.

To calculate how much fertilizer to add: divide 10 by the fraction of the target element (not compound) in the fertilizer. For example, you should apply a urea fertilizer that is 46% N at a rate of: (10 / 0.46) = 21.7 g fertilizer per m² each year. A fertilizer labeled 46% P₂O₅ is 20% P by atomic mass, so you should apply that fertilizer at a rate of: (10 / 0.20) = 50 g fertilizer per m² each year. A fertilizer labeled 50% K2O is 41.5% K, so you should apply that fertilizer at a rate of: (10 / 0.415) = 24 g fertilizer per m² each year. Example table of calculations below.

Nitrogen: N should be applied as granular, non-sulfur coated, 60-90 day release urea. Time-release urea is polymer-coated to delay absorption and prevent loss due to volatilization. If time-release urea is not available, you can use ammonium nitrate instead, but please avoid this if at all possible! If you use ammonium nitrate, divide up the total amount and apply it in increments over the course of several months.

Phosphorus: P should be applied as P₂O₅, also known as "triple super phosphate" (TSP). Make sure your P fertilizer is not sulfur-coated and does not contain added sulfur. The amount of sulfur should only be 1-3%.

Potassium: K should be applied as potassium sulfate (K₂SO₄).

Micronutrients: Micronutrients should be applied as "Micromax", and should only be applied in the first year, in plots where K is added. Contact DRAGNet HQ if you can't find Micromax and we will try to help. In the United States, Micromax can be purchased from BGF Supply Co.

Fertilizer Suppliers:  Fertilizer availability varies greatly. Contact DRAGNet HQ or DRAGNet colleagues in your area if you can't find fertilizer.

Example fertilizer calculations: