Liquid fertilizer [photo] 


The benefits of liquid fertilizer

By Derick Wessels and Pieter de Wet, Omnia Agronomists: Free State Business Unit

The ever increasing need for more effective outputs with the lowest possible inputs is still an important challenge for the modern day farmer. The greatest motivator behind technology and advanced equipment in farming is to make it easier and more effective. When the focus is on fertilization, the balance between cost effectiveness and convenience is of the utmost importance. Fertilizer is still one of the farmer’s greatest direct expenses, and therefore the right type of fertilizer and correct application methods are critical.

For decades, Omnia Nutriology® has been the leader in liquid fertilizer technology. As with Omnia’s compound products, these also ensure even distribution of nutrients in every granule/drop. Therefore, an even distribution of nutrients is one of the most important benefits when liquid fertilizer is compared to dry fertilizer mixtures. Germination problems and damaged seed are huge risks with seed placement. However, scientists (Gasser and Penny, 1967) showed that liquid fertilizer can mitigate these risks more effectively than granular fertilizer.

Whether liquid fertilizer leaches more than granules, is one of the most common questions that Omnia agronomists are faced with. Leaching is defined as the loss of water soluble plant nutrients from the soil profile due to an excess of water. A leaching trial on sandy soils with an average clay percentage of 12% was conducted this year. Fertilizer in the form of nitrogen, phosphate and potassium was applied independently in liquid and granular form, at 200 mm beneath the soil surface. Soil samples were taken seven months later, after 421 mm rainfall, at 100 mm intervals.

Figure 1: Example of fertilizer placement. KCL (granular) and KCl (liquid) 200 mm under the soil surface.

The results clearly indicate that the liquid fertilizer did indeed move deeper into the soil, while still remaining within the root zone. Please note that an excessive amount of fertilizer was applied specifically to determine the leaching effect and therefore cannot be compared to normal application rates.

Figure 2: Leaching trial in the Wesselsbron area (2017/2018 season)

Omnia’s liquid products contain a wide range of micronutrients such as zinc, sulphur and boron that is taken up by the plant more readily than those applied in a granular fertilizer (Wallace and Meuller, 1978). Liquid fertilizer also affords the client the opportunity to add certain raw materials such as K-humate and specific trace elements to their blends. The distribution of the above-mentioned elements is homogenous, which further benefits the crop. New product formulations, as well as unique formulations per area (such as when a certain area experiences a specific deficiency), is determined by trials and newly acquired knowledge.

Liquid fertilizer can also be applied through the irrigation system. This enables the producer to apply the right amount at the right concentration at a specific time and crop growth stage. Micronutrient deficiencies revealed by OmniSap® analyses can be rectified with a top dressing. The distribution of elements is also better with fertigation, without the need for heavy equipment in the field to apply the fertilizer.

The physical benefits of liquid fertilizer include easy handling and therefore a reduction in accidents and injuries on duty. With the increasing cost of labour and equipment such as bulk fertilizer trailers, liquid fertilizer offers a more affordable solution. Flow meters and good control can assist in managing liquid fertilizer to the drop. Precision farming with the purpose of applying nutrients variably can be simplified by making use of hydraulic motors when applying the fertilizer.

Storage costs of fertilizer is not something that should be underestimated. Omnia’s liquid fertilizer plants are well distributed throughout South Africa’s main planting regions to ensure sufficient, timely delivery without the need for large capital expenditure in storage space. Any fertilizer left over can easily be carried over to the next season without any losses due to slaking or caking. The risk of theft is also reduced with liquid fertilizer. Liquid storage tanks can be moved with ease to hired land far away from the farmer’s homestead without the need to build a store.

Figure 3: Timely delivery from local liquid plants

As the saying goes: time is money. Liquid fertilizer can save the farmer a lot of time. It reduces the time that equipment is left standing on the field and also allows for faster application. Fertilizer application can even continue during light rain. Calibration of liquid equipment is simple, more accurate than granular and can be done quickly. These are all factors that can save time.

It is quite easy to enlarge the storage capacity for liquid fertilizer on implements so that a larger surface can be covered in a certain time. Large tracked tractors can carry up to 2000 litres of liquid fertilizer on their frames with ease, which enables the client to plant large areas without any difficulty.

Figure 4: Wheat planter fitted with liquid tanks

Axioteq offers technical support to Omnia clients regarding calibration, conversions and parts. This service can give any producer peace of mind and ensure a good experience with liquid fertilizer.

  • Wallace, A. and R.T. Mueller. 1978. Complete neutralization of a portion of calcareous soil as a means of preventing chlorosis. Agron. J. 70:888-890.
  • Gasser, J. K. R.; Penny, A. 1965: Alternative fertilisers for grass. Rothamsted Experiment Station, Report, p. 53.
  • Leaching trial, 2017/2018 season, Wesselsbron area, Derick Wessels