A. The difference between slow-release fertilizer and controlled-release fertilizer
Slow-release fertilizer is a new type of fertilizer that can slow down or control the rate of nutrient release, as opposed to fast-acting fertilizer. Broadly speaking, slow-release fertilizer includes two types of slow-release fertilizer and controlled-release fertilizer.
B. It has some advantages as follows
1. Small solubility
The slow release of nutrients in the soil will reduce the loss of nutrients.
2. Long-term and stable fertilizer effect
The same can supply a constant supply of nutrients to the plant throughout the production period.
3. Slow release
However, a large application will not result in high soil salinity and “burn” the seedlings.
4. Cost saving
The same reduces the number and frequency of fertilizer applications, thus saving costs.
C. Slow-release fertilizer
However, the rate of nutrient release from the fertilizer is slowed down by chemical and biological factors.
① Slow-acting nitrogen fertilizer
Slow-acting nitrogen fertilizers are also called long-lasting nitrogen fertilizers. The same slow-release fertilizers generally have very little solubility in water.
②After application to soil
Again, the fertilizer gradually decomposes under the action of chemical and biological factors. The most important thing is the slow release of nitrogen to meet the nitrogen demand of the crop throughout the growth period.
D. Controlled release fertilizer
However, the water-soluble fertilizer is encapsulated in the film by means of an external coating that allows for the slow release of nutrients.
①Contact with moist soil
Because the wrapped fertilizer granules are in contact with moist soil, the moisture in the soil penetrates through the wrapper to the inside and is able to dissolve some of the fertilizer..
Therefore, this part of the water-soluble nutrients slowly and continuously diffuse outward through the micro-pores on the envelope.
Again the rate of fertilizer release depends on the temperature of the soil as well as the thickness of the film.
④The higher the temperature
the faster the fertilizer dissolves and travels across the membrane. The thinner the membrane, the faster the penetration.
⑤Different film-forming substances
Depending on the film-forming material. There are non-organic film-forming fertilizers, organic polymer film-forming fertilizers, and thermal resin film-forming fertilizers. Among them, organic polymer coated fertilizer section is the most researched and the most effective controlled release fertilizer.
E. Slow-release fertilizer and controlled-release fertilizer
Slow-release fertilizers and controlled-release fertilizers are both fertilizers with longer fertilization effect than quick-release fertilizers, however, in this sense there is no strict difference between slow-release and controlled-release fertilizers.
However, slow release and controlled release fertilizers are different from each other in terms of the mechanism and effect of controlling the rate of nutrient release.
(1) Slow-release fertilizer
Similarly morning slow release fertilizer it is influenced by many external factors such as soil pH, microbial activity, moisture content in the soil, soil type and irrigation water when it is released.
(2) Uneven release
However, fertilizer release is not uniform, and the rate of nutrient release and the crop’s nutrient requirements are not always perfectly synchronized. At the same time most of them are monomer fertilizers, mainly nitrogen fertilizers.
(3) Controlled release fertilizer
Most of them are N-P-K compound fertilizers or full nutrient fertilizers coupled with trace elements. Most of them are for monomeric fertilizers, mainly nitrogen-based.
(4) Soil temperature
However, soil temperature also has a great influence on the growth rate of plants in a relatively large temperature range. When the soil temperature increases, the rate of release of controlled release fertilizer will be accelerated. Likewise the plant grows faster and its demand for fertilizer increases.
(5) Controlled-release fertilizer nutrients
Therefore, the rate of nutrient release of controlled-release fertilizer is more in line with the rate of plant demand for nutrients. Thus, it can meet the nutrient demand of crops in different growth stages.