Pivot irrigation and fertigation

The pivot irrigation method is a mobile irrigation system that makes it possible to irrigate large areas. It has evolved over time and now takes various forms: circular, mobile, corner or lateral pivots.

One of the main doubts farmers have when fitting out their plots is which irrigation system to install, which is why it is important to know the advantages and disadvantages of each irrigation system.

The most important factors when deciding which irrigation method to use include considering the type of plot in terms of the surface area to be irrigated, as well as the dimensions, morphology and orography of the land and crop.

Pivot irrigation: advantages and disadvantages

The main advantages of pivot irrigation are as follows:

• Better use of water: the most notable benefit of irrigating with a centre pivot or lateral is that there is better use of water as it is applied precisely and evenly across the furrows. Moreover, we can control the length of time and amount of water to be applied and produce less wastewater.
• Lower costs: when irrigating with a centre pivot or lateral, everything is automated, so there are fewer costs and more savings.
• Higher return on investment: year after year, the long life of a pivot system cuts costs and uses less water while reducing energy costs because it requires a lower working pressure. This leads to a higher return on investment.

However, it also has a number of drawbacks, such as longer irrigation times, which could be a problem for areas with restrictions on irrigation times, or the fact that the pivot itself is more expensive to maintain.

Fertigation with pivots

Firstly, we need to define the fields of application of fertigation. Fertigation means the application of nutritional products to crops. These include the following categories:

• Bio-nutrients: products that stimulate plant growth by providing compounds that are directly usable by plants, mainly amino acids.
• Amendments: these applications are products that will affect the physico-chemical and biological properties of the soil and irrigation water.
• Fertilisers: products that provide plants with the necessary nutrients. There are organic fertilisers (organic matter) and mineral fertilisers (mineral matter from natural or synthetic sources).

Fertiliser application in pivot irrigation

Generally speaking, pivot irrigation systems are totally suitable for fertigation and chemigation treatments, provided that good equipment is used. However, bear in mind that when applying fertilisers using the pivot irrigation system, there are both limiting factors and benefits.

Benefits

• Application of nutrients during the plant’s entire growing season.
• The application of fertilisers that are highly mobile in the soil allows the fertiliser content in the soil profile to be carefully controlled.
• The possibility of applying fertilisers during the whole growing season, coupled with high soil mobility, allows the dose of fertilisers applied to be reduced.
• Less mechanical damage to the crop due to less cultivation with tractors.

Limitations

• The mobility of different fertilisers in the soil is a limiting factor in the type of fertiliser to be used.
• Higher fertiliser costs, as the solubility of the fertiliser must be very high and not cause precipitation problems.
• The volatilisation of some fertilisers, such as ammonium-rich fertilisers, and corrosiveness must be taken into account as many parts of the irrigation system come into contact with fertiliser products and only resistant materials should be used in their construction.

Do you want to know more about fertigation and how to increase crop productivity? Contact ITC now!