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Glyphosate and many other agrochemical active ingredients include plant nutrients that may become plant-available after degradation of the active ingredient. The Plant nutrition courier offers an application that calculates the amount of nutrients starting from the chemical formula.

The calculator is freely available to subscribers on the Plant nutrition courier and to those who have purchased the Plant nutrition courier 2019-02 issue; the capital-sensitive password is on page 9 of this issue of the digital magazine.




How to use the calculator

Login with the password published in the Plant nutrition courier 2019-02 issue (page 9) and the EXCEL spreadsheet calculator will open. The white, green-bordered input fields are pre-filled with an example calculation of the phosphate supply with Roundup Weather Max (active substance: glyphosate-potassium).

While filling in the input fields, the application calculates the amount of nutrients per kilogramme of product (both the elemental and the oxide form are displayed). If the content of active substance and the dosage per hectare are entered, the application also calculates the amount of nutrients per hectare (kg/ha).

The plant-availability of the nutrients strongly depends on the degradation of the active ingredient in soil. The organophosphorus herbicide glyphosate, for example, breaks down relatively quickly, while the organophosphorus herbicide glufosinate is known to be relatively persistent. Not all glyphosate-phosphate will become plant-available, because a part of this nutrient is fixed, depending on soil characteristics and phosphate saturation of the soil.