The basic calculations and general terminology of the 2 main fertigation methods.There are 2 main methods of Nutrigation, the quantitative and the proportional one, and for each method a different calculation is used. 1. The Quantitative method – In this method the fertilizer is applied in the system according to the irrigation stage and the calculation is based on the total amount of fertilizers (using a bypass fertilizer tank) according to the plant needs per each growing stage. We are using the terminology of quantity (grams or Kg / Ha/Day). In this method the concentration of the solution will reduced gradually till the fertilizer tank will empty completely in other words the concentration of the gradients in the solution will be high in the beginning (with the highest E.C) and gradually will reduced till just water will be in the tank (with the E.C water). This methods is usually applied for orchard as well as for heavy soils where not a precise nutrition is required , and in general for a simple out-door fertigation. Example of quantitative calculation for fertigating 1 unit of K20 from MultiK 13-0-46 for the establishment stage of Tomato. 1 unit : 46/100 = 2.17 Kg of MultiK These 2.17 Kg per Ha of MultiK x 0.13 will provide also 0.283 Kg of N-NO3 2. Proportional method – In this method the concentration of the nutrients solutions is kept constant during the entire period using pump or injectors and the calculation is based on PPM (part per millions or grams per M3 of water). This method is applied in low C.E.C – low nutrients retention capacity such as sandy and medium soils, and mostly for greenhouses and where a precise nutrition is required, and in general for sophisticated fertigation. Example of proportional calculation for fertigation of 50 ppm or grams/M3 of water of K20 from MultiK 13 – 0 – 46 for the establishment stage of Tomato 50 ppm / (46x10) = 0.108 Kg or 108 Gr of MultiK in 1 metric cube of water These 108 grams per 1 M3of H20 x 0.13 will provide also 14.04 grams or ppm of N-NO3. In the next post I will focus and explain the general terminology and calculations for salinity conditions usually for soilless media. Thanks Oded Rottenberg,

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