Important Elements to Consider in Irrigation Water Quality Testing

The characteristics of water including chemical, physical and biological conditions are critical in determining the quality of water. It is important to understand these properties in your small-scale farming or gardening operation that relies on irrigation for growth. This is because the water quality will affect the rate of growth and productivity of the pertinent plants. Ideally, you can collect water samples and send them to a testing laboratory for analysis. Here are the primary elements that you should have tested to help you assess your water supply's suitability for irrigation.


Nitrogen is an essential plant nutrient, and it is responsible for stimulating plant growth. Basically, it contributes to formation of chlorophyll, the green pigment in leaves that harnesses sunlight for photosynthesis. You should commission a test for this element in your water supply because both insufficient and excess levels have implications. Low nitrogen content in your irrigation water could mean that the plants require artificial application of the nutrient. This can be incorporated into the soil or special sprinklers to improve plant growth. When in excess, nitrogen will cause excess foliage growth, stunted root development and even increased soil salinity. The nitrogen problems in your water reservoir can be resolved through induced denitrification.

Substances Causing Scale Deposits

The presence of slightly soluble salts in your irrigation water often translates into formation of scale deposits on the plants. Generally, the substances will be dissolve in the water in the reservoir but revert to a solid after the water evaporates due to exposure to the sun. This is a long-term problem, and the white material will lower the quality of your flowers, leafy vegetables and even fruits. If you have noticed this material on your irrigated plants, consider commissioning a test for the common slightly insoluble salts. These include calcium, sulphate compounds and bicarbonate. The management method will depend on the type of salt and concentration. For example, bicarbonate can be reduced by using acid to neutralise the compound.

Magnesium Problems

Magnesium is an important element in production of chlorophyll, and consequently, it is indispensable for growing plants. Low levels will result in formation of rusty brownish marks on the leaves and some yellowish spots between the leaf veins. Fortunately, the material can be applied artificially if the water and soil are determined to be deficient. Excess magnesium content is not apparent on the plants, but it will cause infiltration problems in the soil. Therefore, if the water quality test reveal excess magnesium, special artificial additives might be required for resolution.