Suitability of Fertilzers for Nutrigation

When selecting fertilizers a few factors should be considered and it is very important to be familiar with the chemicals aspects of Nutrigation with the irrigation water

There are 2 main types of water that should be known enabling us to optimize the fertilizers and avoiding possible precipitations. 

1).Hard water in general a water with high calcium content above 60 ppm and Mg above 30ppm, high bicarbonate content above 150 ppm , and alkaline pH above 7.5. Both Ca & Mg in the water might be combined with phosphate and /or sulfates from the fertilizers used and to form insoluble sedimentations , and calcium forms insoluble calcium carbonate ( CaCO3 ). In this kind if water it is recommended to chose an acid reaction sources such as Haifa- P , Haifa-MAP or Haifa-MKP , to inject acids into the irrigation system to dissolve precipitates , and to add Ca & Mg only in the required concentration needed . 

2).Saline water a water with high EC above 2.5 - 3 and with high Cl concentration above 150 – 350 ppm . In this kind of water adding fertilizers might further increase the EC and may be resulted in crop damage. It is recommended to check the susceptibility of the crop to salinity (for instance to use high saline water for more resistible crop such as Tomato , and to use a lower saline water for susceptible crop such as Bell Pepper.) , to select fertilizers with a low salt index , and to irrigate above the plant water requirements in order to flush possible accumulated salts below the root zone. 

The use of two or more tanks allows the separation of fertilizers which react amongst themselves or with the water and might form precipitates. It is important to place in one tank the calcium and magnesium ( haifa Cal with Magnisal ) and in the other tank the phosphates and sulfates for a secure nutrigation. In case of more than 2 tanks it is recommended strongly to use a special tank exclusively for the calcium. 

Oded Rottenberg 

Haifa Mexico