Seaweed fertilizer is a kind of fertilizer produced by using marine brown algae or adding a certain amount of nitrogen, phosphorus, potassium and trace elements. There are a variety of forms, the market is mainly liquid and powder, a small part of the particles.

The main components of seaweed fertilizer are the natural bioactive substances extracted from seaweed, which are beneficial to the growth and development of plants, and the mineral nutrients absorbed and enriched in seaweed from the sea, including seaweed polysaccharides, phenolic polymers, mannitol, betaine, plant growth regulators (cytokinin, gibberellin, auxin, abscisic acid, etc.) and nitrogen, phosphorus, potassium And iron, boron, molybdenum, iodine and other trace elements. In addition, in order to increase fertilizer efficiency and chelation, humic acid and trace elements were added.

In order to better improve the utilization rate of seaweed fertilizer, in addition to choosing good brands and varieties, we can also start from the following directions:

1. Spraying concentration should be appropriate. In a certain concentration range, the speed and quantity of nutrients entering leaves increase with the increase of solution concentration, but excessive concentration is prone to fertilizer damage, especially for trace element fertilizers. Generally, the concentration of large and medium elements (nitrogen, phosphorus, potassium, calcium, magnesium and sulfur) is 500 to 600 times, and the concentration of trace elements such as iron, manganese and zinc is 500 to 1000 times.

2. Spraying time should be suitable. When foliar fertilization, the longer the wetting time, the more nutrients the leaves absorbed, the better the effect. In general, it is appropriate to keep the leaves moist for 30 to 60 minutes, so foliar fertilization is best carried out in the evening when there is no wind; Spraying fertilizer in the morning with dew will reduce the concentration of solution and affect the effect of fertilization. Foliar topdressing can not be carried out on rainy days or before rain, because nutrients are easy to be leached out, which can not achieve the desired effect. If it rains 3 hours after spraying, it should be sprayed again on sunny days, but the concentration should be reduced appropriately.

3. Spray evenly, carefully and thoughtfully. Foliar fertilization requires small droplets and uniform spraying, especially the upper leaves and the back of the leaves.

4. Spraying times should not be too few, and there should be intervals. The concentration of foliar topdressing is generally low, and the amount absorbed each time is very small, which is much lower than the demand of crops. Therefore, the frequency of foliar fertilization should not be less than 2 to 3 times. At the same time, the interval should be at least more than one week, and the spraying frequency should not be too much to prevent harm.

5. Leaf fertilizer should be used properly. When foliar topdressing is applied, mixing two or more foliar fertilizers can save spraying time and labor, and the yield increase effect will be more significant. However, there must be no adverse reaction or reduction of fertilizer efficiency after mixing, otherwise the purpose of mixing can not be achieved. In addition, the concentration and pH value of the solution should be paid attention to when the fertilizer is mixed. Generally, the pH value of the solution is about 7, which is beneficial to the absorption of leaves under neutral conditions.

6. Add wetting agent to fertilizer solution. There is a layer of cuticle with different thickness on the leaves of crops, so it is difficult to penetrate the solution. 

Therefore, appropriate amount of wetting agent and surfactant can be added into the leaf fertilizer solution to increase the surface tension, increase the contact area with the leaves, and improve the effect of foliar topdressing.