Clean irrigation water is of major importance for profitable cultivation, as it is the highway of every company. There is a correlation found between contaminated water and fungal or bacterial infection in plants. The presence of microorganisms can cause growth/production stagnation, impaired root growth, and other kind of plant development or defence problems.

Taking samples of your water (e.g. basin, before and after filters or end of irrigation line) on a regular base will help to demonstrate the microbiological quality of the water. It gives insights into the number and types of microorganisms present, pH levels and dissolved nutrients. Important to keep in mind, clean water will always contain microorganisms. Which is fine; only when they start to increase in high numbers, risks are popping up.

Growers often tell us, we have clean starting water, so we do not need to do anything about our water quality. But the eye does not always show the truth. When it comes to the quality of water and irrigation systems, the quality of fertilizer tanks are often a reality check. From the many water quality analyses we have performed at our own laboratory facilities, we have noticed that the fertilizer tanks are a common source of contamination. More than 70% of all taken fertilizer samples where above the threshold of the amount of fungi for healthy irrigation water (<20 cfu/ml) (figure 1). This can be of great risk, these fertilizers will be mixed and dosed into the irrigation systems and the spread of fungi and bacteria starts.

Figure 1. From all samples taken from fertilizer tanks that are analysed in our laboratory 70% of the samples show fungal counts above the threshold value of 20 cfu/ml. Values vary between 30 and >3000 cfu/ml.

Fungi and bacteria are simply just everywhere around us, keeping them 100% out of the water is simply not possible. But with the right hygiene protocol, we can keep the infection pressure as low as possible. The first step is to clean the fertilizer tank during crop rotation.

1. Make sure you fully empty the tank

2. When necessary clean dirt manually

3. Disinfect the surface of the tank with 4% Intra Hydropure

4. Let it stay for a minimum of 6 hours

5. Rinsing is only needed when trace-elements will be added afterwards

However, it is not only important to start a new cultivation round with clean fertilizer tanks, it is much more important to keep the tanks clean during cultivation and therefore to clean and disinfect the tanks every time you would make a new batch of fertilizers. Spray with the 4% of Intra Hydropure on the surfaces of the tanks every time the tank is empty.

Why do microorganisms thrive in fertilizer tanks?

Microorganisms need nutrients, warmth, moisture, and oxygen to grow, and these are all present in fertilizer tanks. Especially fungi thrive in low-pH and high-nutrient environments. A pH between 4 and 7 are the perfect circumstances for fungi to grow. They acquire energy by absorbing dissolved nutrients and minerals. In the field we see the trend of adding more and more products based on organic substances (e.g. seaweed, biological stimulants, etc.) in the nutrient solution, please take in mind these can cause an explosion of fungal and bacterial growth in the fertilizer tank, but also in your irrigation system. Always measure the level of pollution in your system before you will start with these kind of additives.

Take home message

Bacteria and fungi are all around us and in low numbers they are also not a thread. However, when number of bacteria or fungi start growing, they can become pathogenic and cause diseases. When the fertilizer tanks or the irrigation lines are not cleaned on a regular base, microorganisms and biofilm growth is happening rapidly. Nutrients stick to the walls of the lines and will not reach the plant, fluctuations of pH levels will occur and therefore nutrient products will not have their desired effects. Think twice before adding organic based products, make sure everything is clean, and know the quality of your water. Use Intra Hydropure for a guaranteed clean irrigation system and to clean the fertilizer tank on a regular base to safeguard the health of the plants.

Intra Hydropure is a multifunctional disinfectant, a widely used and well-known ECHA BPR registered stabilized hydrogen peroxide product. After reaction with organic material, Intra Hydropure will decompose into water and oxygen with no harmful residues left behind. It is suitable to clean and disinfect irrigation systems, gutters, facades, cultivation tables, irrigation mats, nursery boxes, and go on. It is part of the Intrahorti Hygiene program.