Controlled-release fertilizer

Concept of controlled-release fertilizer

Various regulatory mechanisms are used to delay the initial release of nutrients. According to crop needs, the release amount and release rate of fertilizer nutrients are controlled to keep the release of fertilizer nutrients consistent with crop needs, thereby achieving the purpose of improving fertilizer efficiency. Currently, the most common controlled-release fertilizer is coated fertilizer, that is, a layer of film is wrapped around the traditional quick-acting fertilizer particles, and the rate of nutrient diffusion from the membrane to the outside of the membrane is controlled through the micropores on the membrane, so as to synchronize with the absorption of crop nutrients according to the set release mode (release rate and continuous effective release time).?

Release Principle of Controlled Release Fertilizer

The release principle of controlled-release fertilizer is that in the process of nutrients in fertilizer changing from solid to liquid, the release rate is consistent with the law of nutrient absorption by crops. In this way, when crops absorb more nutrients, they release more, and when they absorb less nutrients, they release less, which greatly improves the utilization rate of fertilizer. When fertilizer is applied to the soil, soil moisture enters from the membrane pores, dissolves some nutrients, and then releases through the membrane pores. When the temperature rises, the plant growth accelerates, the nutrient demand increases, and the fertilizer release rate also accelerates; when the temperature drops, the plant grows slowly or hibernates, and the fertilizer release rate also slows down or stops. On the other hand, when crops absorb more nutrients, the nutrient concentration outside the fertilizer particle membrane decreases, causing the concentration gradient inside and outside the membrane to increase, and the fertilizer release rate accelerates, so that the nutrient release pattern is consistent with the law of crop fertilizer demand, so as to maximize the utilization rate of fertilizer.

Advantages of controlled-release fertilizer

1. Improved fertilizer utilization rate. To prevent oversupply of fertilizer, fertilizer nutrients are slowly released, changing the characteristic of over-concentrated nutrient supply of ordinary instant fertilizers and reducing the loss of nutrient elements. Compared with ordinary chemical fertilizers and compound fertilizers, the nutrient release curve of controlled-release fertilizers is closer to the demand change curve of crops, that is, the utilization rate is higher, which is more beneficial to the growth of crops. Generally, the utilization rate of controlled-release fertilizers can be increased by 10%-30%.

2. Improved crop yield and quality. Controlled-release fertilizers have long-term and stable effects, and can continuously supply the nutrient needs of crops throughout the growth period, increasing the yield of 667 square meters by 10%-25% compared with conventional fertilization technology.

3. Reduce the amount and frequency of fertilization, save labor and cost. Under the same target yield, the use of controlled-release fertilizers can reduce the amount of fertilizer by 10%-40% compared with traditional fertilizers; most crops only need to be fertilized once, and no additional topdressing is required, which can effectively reduce labor costs.

4. It eliminates the problems of fertilizer leaching, evaporation, volatilization and fixation, and reduces the environmental pollution caused by fertilization. Controlled-release fertilizer improves fertilizer utilization, effectively reduces nutrients from evaporating, seeping into the ground or flowing into rivers, reduces fertilizer non-point source pollution, and improves soil fertility.

5. Effectively save energy.