The best time for fruit trees to ＂expand＂ and topdressing in July

At present, it has entered a hot summer, this period is the peak of fruit tree fertilizer demand, fruit development, flower bud differentiation need a lot of nutrient supply, if fertilizer, lack of fertilizer, it is very easy to appear premature aging.
First of all, we must ensure adequate supply of fertility. In summer, when fruit trees need fertilizer in the peak period, the most effective way to supplement fertilizer is underground and aboveground together. In some places, because of the poor watering conditions, the method of injecting fertilizer gun can be adopted, which not only saves time and effort, but also achieves quick results. Of course, it is also an expedient measure.
7. August is the most efficient period of nutrients for fruit trees. In this period, the demand for potassium fertilizer is the largest, the absorption speed is the fastest, the fertilizer utilization rate is the highest, the effect is the most obvious, and the yield increase effect is remarkable. At this time, just like when a child grows up, it is very important to apply high potassium water-soluble fertilizer.
A scientific, reasonable and effective supplement of potassium from late July to early August has basically formed a consensus on promoting sugar and color, expanding fruit and cleaning face, improving taste, flavor and increasing benefit. Potassium is not only a necessary element in plant constitution, but also a "transport leader" of other elements. Potassium is one of the most active elements among various elements.
If potassium is sufficient, the utilization rate of other elements can be greatly improved. This is because:
（1） Potassium can promote sugar transport. Through phloem, plants transport the sugar produced by photosynthesis to other parts of plants for use or storage. The transport system of plants needs to consume energy. If the potassium supply is insufficient, the transportation system will fail, which will lead to the accumulation of photosynthetic products in leaves, resulting in the slow down of photosynthetic rate and the normal development of storage organs. Sufficient potassium supply can promote these processes to keep running rapidly.
（2） Potassium can promote water and nutrient transport. In the process of transporting water and nutrients to different parts of plants through xylem, the transfer of nitrate, phosphate, calcium, magnesium and amino acids will be inhibited if potassium supply is reduced. Just as potassium plays an important role in phloem transport system, the role of potassium in xylem transport system is usually closely related to specific enzymes and plant growth hormone. Only sufficient potassium supply can ensure the efficient operation of these systems.
（3） Potassium can promote protein synthesis. The role of potassium in protein synthesis is closely related to the above functions. Among them, potassium plays a key role in transporting amino acids to protein synthesis sites, enzyme activation and charge balance. Studies have shown that potassium is required in every major step of protein synthesis.
In recent years, those with large fruit production have increased the amount of fruit per mu from 5 kg to 10 kg. At this time, the amount of high potassium water soluble fertilizer should be increased. In the past two years, many Demonstration Garden owners began to apply high potassium water soluble fertilizer twice. The method is still the most scientific and economical.
Secondly, the photosynthetic capacity of fruit trees is also an important way to meet their own needs. Even if the fertilizer is sufficient, due to poor photosynthetic capacity, fruit trees "eat only but not work" will become weaker and weaker. Of course, some fruit growers say that the investment in fruit trees in the early stage is too large and they don't want to invest any more. In this paper, we suggest that we should not save the "tail money". The fruit expansion period is just like the puberty of a child. It is the time to grow up and grow up. At this time, topdressing and nourishing can achieve immediate results.
Finally, it emphasizes: why should we pursue high potassium in this period
After years of repeated emphasis, most fruit farmers have known the four key periods of fruit tree topdressing.
The first period is from germination to flowering. This is the first growth peak of fruit tree roots, and the main purpose of topdressing is to promote root growth, fruit bearing and new shoot growth. Quick acting nitrogen fertilizer should be the main fertilizer. In September of last year, orchard with insufficient base fertilizer, weak tree vigor and poor flower bud quality should pay special attention to this fertilization.
The second topdressing was before flower bud differentiation. At this time, the spring has stopped growing, autumn shoots have not yet begun to grow, fertilization will not cause excessive growth, it is the key period of fruit tree topdressing. Especially at this stage, the flower bud began to differentiate and the young fruit expanded.
The third time is from late July to the first and middle of August, which is the period of fruit expansion, that is, the period of maximum nutrient efficiency. Everyone likes this top dressing because the fruit will swell immediately after applying fertilizer. At this time, fertilizer is also very easy to choose. We can simply judge whether the fertilizer is good or bad by the expansion degree of the fruit and the sweetness of the fruit after fertilization.
The fourth fertilization will reach the end of August and the first and middle of September, which is the best time to apply basic fertilizer.