Are you getting the most out of your fertiliser?

Improve nutrient use efficiency with Controlled Release Fertilisers (CRF)

Controlled release fertilisers (CRF) are helping farmers get the most out of their nutrients. Just one single application of controlled release fertilisers, can manage the nutrition during a complete crop cycle. Coated fertilisers make fertilisation plans much easier and reduce environmental impact.

Efficient use of crop nutrients is becoming increasingly important; from feeding a growing world population, to minimising risk of environmental harm and making best use of scarce, and increasingly expensive inputs to crop growth.

Innovation is key

For almost 200 years, agriculture and horticulture has used the addition of fertilisers to enhance crop growth by supplying the key elements that plants need to boost yield and quality. Fertilisers have played an important part in significantly raising the yield of the land, so ensuring that every hectare supports more and more of the world’s population.

Estimates show that between 1960 and 2020, the number of people that can be fed from a hectare of land has more than doubled to 5.6. Innovations such as controlled release fertilisers (CRF), that match nutrient availability to crop need, will play an important role in meeting these future demands.

Increasing productivity

Fertilisers can indeed double or triple farm productivity: for every single kg of nutrients applied, farmers obtain approximately 5-30kg of additional produce (although this will vary per crop). Yet the statistics on average nutrient use efficiency – the proportion of nutrients actually used by crops in the first year after application – are stark.

For fertilisers applied to major cereal crops, nitrogen efficiency is around 40-65%, potassium efficiency in the region of 30-50% and phosphorus efficiency just 15-25%.

The above figures are for plots managed by agronomic researchers. Values for nitrogen use efficiency on fields managed by farmers are even less encouraging. Up to 70-80% of applied N can be lost when fertilisers are improperly managed. (Fertilizer International 474, p32).

The nutrient uptake dilemma

Despite the successful increase in crop production, to which fertilisers have made a significant contribution, there remains the dilemma. Crop nutrients are applied to crops on a few occasions in a growing season; whereas, crops take up nutrients a little at a time hour by hour and day by day.

Early in the season as small annual crops establish, or as perennial crops emerge from winter dormancy, uptake is quite small each day. Many fertilisers are soluble and volatile, so applied early in the season large amounts of nutrient are available – far more than the crop’s immediate need.

Nutrient losses

Nitrogen not taken up can be lost, either through leaching – a process whereby the nutrient is washed through the soil and into drainage systems – or through volatilisation. The latter is particularly significant from urea-based fertilisers where the element is converted to ammonia and can be lost to the atmosphere as gas.

For the farmer, or grower, these losses affect crop and economic performance. The crop does not have some nutrients for growth and the grower loses the value of the fertiliser that is lost.

There are also potentially negative consequences for the environment. Fertilisers leached to waterways can, in extreme conditions cause algal blooms that threaten aquatic life; it can also reduce water quality. Losses to the atmosphere can add to the problems of climate change. Ammonia, while not one of the gases normally classed as greenhouse gas, is injurious to the atmosphere and health.

What is nutrient use efficiency?

Having the right nutrients available to match crop needs plays an important part in achieving a high nutrient (or nitrogen) use efficiency (NUE). This is a measure of how well all the nutrients come together for optimum crop performance. The major nutrients – nitrogen, phosphorus, potassium – as well as calcium, magnesium and sulphur are linked, in as much as a shortage of one can impair the ability of a crop to fully utilise other elements that may be in plentiful supply.

How CRF technology can help

Help is at hand in the form of ‘controlled release fertilisers’ (CRF) that use smart technology to provide nutrition at a rate that matches much more closely the availability of nutrients to the plant’s need.

The principle is simple, the technology complex. The E-Max Release technology developed by ICL is described as an ‘innovation’ in controlled release nutrients. In essence, the fertiliser is covered in a special coating that – once in contact with the soil and associated moisture – begins to take up water. As the moisture content builds up in each granule of fertiliser, so the osmotic pressure increases and nutrients start to ‘escape’ into the soil via micropores in the coating.

Thus the nutrients disperse gradually into the zone around the roots and are available as the plant requires it. This minimises the risk of valuable nutrients being lost from the crop and ending up causing adverse effects to air or water.

ICL Fertilizers produces a range of blends and can tailor the contents of each fertiliser to the needs of specific crops.

Reducing applications – save time and cost

There is also the question of cost. Every time fertiliser is applied there is an application cost. According to the latest John Nix Pocketbook applying granular fertiliser costs around £7.50/ha, while liquid fertiliser application can be as much as £10/ha. Therefore, every application has a significant cost.

Today, the question of cost is exacerbated by the significantly increased cost of fertiliser, especially nitrogen which means nutrients need to be kept in the soil not just for environmental, but also economic reasons.

Eighty-two per cent increase in NUE

In a 2021 seed potato trial executed by Eurofins a 82% increase in Nitrogen Use Efficiency (NUE) was demonstrated.

ICL Agromaster (Controlled Release Fertilizers) showed a 10% increase in yield, 82% increase in nitrogen use efficiency and a positive return on investment.

For the full potato trial report PDF email plantnutrition@icl-group.com

Today, CRF products tend to be used mainly in high value crops including field and root vegetables, fruit and certain amenity sectors. However, as the cost of nutrients increases, it is likely that this technology will find a use in broad-acre crops as growers seek that elusive goal of achieving high nutrient efficiency.

ICL CRF technology is available in three different product ranges:

1. ICL Agroblen gives growers complete control over their nutritional programme. Agroblen contains a 100% coated NPK granule to provide a controlled release of the nutrients over a pre-determined length of time. With Agroblen, growers can apply multiple applications or just once a year depending on the crop’s needs. The ideal combination of efficiency and simplicity..
2. ICL Agromaster combines ICL’s advanced technology with specially selected conventional granules. This powerful combination provides nitrogen control and high-quality performance in one uniform product.
3. ICL Agrocote products are N, P or K coated products based on one of the ICL coating technologies. These technologies provide from 1-6 months release longevity.