POGO Salinity Index

The parameter salinity index is a calculation that relates salinity and the presence of available water, i.e. it is essentially the ratio of salinity to available water. electroconductivity and the volumetric water content VWC.

The so-called “salt washing” is the extra amount of irrigation needed to remove salts from the substrate; in other words: if our greens need 8 mm of water but the electroconductivity of such irrigation water is high enough for those salts to compete for the available water, then additional water needs to be added to eliminate that effect. We are then managing the salinity indexor, in other words, the ratio of salts to available water.

However, the salinity index will indicate such particular things as increases in mowing residues due to applications of different fertilisersfoliar burns due to high salt loads in irrigation water, etc.

As the ratio of electroconductivity (EC) to available water increases, this means that the salinity in the system is more and more concentrated. Many might think that there is a direct relationship between EC and available water... that is, as the available water increases so does the EC. But this only happens if salts are available to pass into the soil solution. If in a substrate-grass system there is not a large amount of salts available for transfer to the soil solution, or if the irrigation system does not provide additional salts on a regular basis, then we may even see the EC decrease the more it is irrigated. There is no direct correlation between EC and available water.

There are no ideal salinity index values; in an ideal situation, however, we should have enough moisture to handle the salts that are present. Once you have determined your ideal salinity index value, your POGO will tell you at any time where you are in relation to that ideal value and therefore you will be able to manage each situation or measure the different positive or negative effects of any agronomic practice.

Thus, in situations with high saline content in irrigation water, we can find values such as the following:

O with low saline content in irrigation water:

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