Oranges [photo] 


OFOS™: Basic guidelines and requirements

For producers considering using  as a nutrition and irrigation tool, there are certain guidelines regarding the storage and handling of fertilizer. The pump station and application system should meet certain requirements. Knowledgeable people should be used to choose and install the hardware. However, Omnia Fertilizer can provide certain guildelines to ensure that the producer gets the most benefit from the system. Figure 1 shows a schematic representation of a simple system.

Figure 1: A simple application system

Handling and storage

The safe handling and storage of fertilizer is important. Suitable chemical tanks should be used. Nutritional salts can be corrosive and plastic couplings and pipes are recommended. Retention walls around the tanks which form a retaining dam can limit product losses and prevent pollution. It is recommended that the size of such a retaining dam has to be at least the volume of two tanks, in case a of a crack or a leak in a tank or pipe. Such a retaining dam can be seen in Figure 2.

Figure 2: Mr Christo van der Walt next to a retaining dam

There should be at least three fertilizer tanks in which three different products can be offloaded. Products from the Omnia CUSTOM range cannot always be mixed and stored together, and therefore two tanks are needed. The third tank is for a possible third product from the CUSTOM range, or for any other additions to the programme. This can include acids, biostimulants or system cleaning agents.

Every tank should have a 80 micron filter at the offloading and delivery point; this will ensure that clean product is loaded in and out. This is illustrated in Figure 3.

Figure 3: A basic sketch of the offloading point

Fertilizer application

The injection point for nutrients into the mainstream water can be located in front of or behind the filters. Omnia prefers that the products are applied after the filters. Please note that every product should have its own injection point and that these injection points should be at least 1.2 meters apart. There should preferably be a short extension in the line where the product is added to the main stream water. This generates the necessary turbulence at the injection point to ensure proper blending and also prevents erosion of the system walls.

This injection of the products should be done at a higher pressure than that of the system (e.g. if the system is under pressure at 2 bar, nutrients will have to be injected at 3 bar). If the products are pumped in before the filters, a simple stop valve can be installed to stop the flow of product as soon as the filters backwash. Contact the system installer if you need something like this.

The application of nutrients needs a constant flow. This can be done using a flow meter. With
, which is based on the optimisation of nutrient concentration, it is critical that the user has a monitoring system in place to ensure the correct amounts of product are applied over a pre-calculated time period. Several methods exist – from simple measuring systems to highly complex computers.

By completing a simple questionnaire, prospective  users can make use of Omnia's expertise to point out shortcomings in the system. Sufficient system information is needed to be able to generate a thorough programme. Your Omnia agriculturalist will be able to provide more information.

By Uys Meiring (Senior Technical Advisor: Specialities) and Japie Wiese (Landboukundige)