Benefits of Slow and Controlled Release Fertilizers

In general plants must be supplied with nutrients during the whole vegetation period. In horticulture this is achieved by applying quickly soluble fertilizer once to twice a week, for example. This kind of fertilizer application is very labour-intensive and requires considerable specialist knowledge, so as to select the correct rate of application, appropriate time of application and correct composition for the particular plants to ensure optimum plant production.
With the use of slow and controlled release fertilizers the full amount of nutrients necessary for the whole vegetation period can be applied at the time of planting or at the earliest stages of plant growth, in the form of a nutrient pool. The nutrients are continuously released from this pool to the plant's roots adapted to the needs of the plants.
Slow and controlled release fertilizers can be used for soils and growing media wherever a long lasting nutrient supply is required.

What are the differences between slow and controlled release fertilizers?

Slow Release Fertilizers (SRF):
The nutrients, mainly nitrogen, are present in the fertilizers in a form, which is not available to plants. These components are converted in the soil by physiochemical effects or microorganisms into nutrient forms, which are available to the plants.
AGLUKON's SRF (PLANTOSAN for horticulture; AZOLON for turf) contain methyleneurea as slow release component, which is converted by microorganisms. As this process, just like plant growth, is temperature dependent, the nitrogen is supplied in accordance with the plant requirements.

Controlled Release Fertilizers (CRF):
The nutrients are "packaged" in coated fertilizer granules and are released through the coating over a certain period of time. Coating material and release mechanism vary between different products available from different suppliers.
AGLUKON's CRF (PLANTACOTE) are coated with a uniquely tough and resilient coating material. The nutrients are released by a natural membrane process, which is controlled by the thickness of the coating and the soil temperature. The declared release time refers to an average soil temperature of 20-21 ^oC (68-70 ^oF). Higher temperatures accelerate the nutrient release, lower temperatures delay it.

General Benefits of CRF

• Easy and safe to use.
• Reduced risk of incorrect fertilizer application.
• Labour saving.
• Minimized nutrient losses by leaching or fixation.

Environmental aspects

The use of SRF and CRF is an ideal measurement for reducing nutrient losses in the horticultural practice. As the nutrients are released only in that small amounts which are actually required by the plants, the nutrients can be taken up by the plants completely and are protected against losses by leaching with the rain/irrigation water or by fixation to the soil. The non released nutrients are protected against leaching by their nutrient forms or by the coating. In comparison to that, the risk of losses is high when using conventional fast release fertilizers, as the complete nutrient amount is available in soluble forms and surplus amounts, which are not used by the plants, can be easily leached with the drainage water.
This environmentally positive aspect was proven in a number of trials for AGLUKON's   AZOLON- and PLANTOSAN SRF and PLANTACOTE CRF.

Safety

The safety of SRF and CRF is a very important issue. As the complete nutrient amount for a whole vegetation period is supplied in one single application at the beginning of the growth, it is of utmost importance, that the nutrients are released continuously according to the demand of the crops and that there is no uncontrolled release. A high initial release could lead to damages to the plants due to salt stress, a too low release could lead to damages due to nutrient deficiencies.
AGLUKON's SRF and CRF release their nutrients very safely throughout the growing season. Specially PLANTACOTE offers a high crop safety. Thanks to its flexible and stable coating, PLANTACOTE is very safe, even under the most trying conditions. Mechanical stress and severe frost do not disrupt the coating whilst, even under hot conditions, there is no risk of flash release. Therefore, salt scorch is avoided.
Due to the delayed release mechanism, PLANTACOTE is especially safe to young plants during the sensitive establishment period. Therefore, it is ideally suited for dibbling.