It's a crucial time for grapes to grow larger and become more colored and sweet. This is another time when people are using fat. In order to reduce the unnecessary loss caused by improper use of fertilizer, several fertilization errors need to be noticed.
1. Nitrogen and phosphorous potassium during critical period
Nitrogen is the "life element" in the process of growing grapes, many people think that more nitrogen in berry fruit expands to the mature stage, to the "fill" fruit expands the required nutrients, but too much nitrogen in the bulking issue application vegetation with the fruit for nutrients, and delayed time to market.
Phosphorus in grapes grow organs have the function of root, in the mature period we thought grape root is very slow and does not need to provide p, then no longer pay attention to the supplement of phosphorus, but neglected the grapes in mature period need more photosynthetic product of synthesis and sugar transport transformation, all these need enough phosphorus to provide energy, if do not have enough phosphorus supply will affect the fruit expands and turn color.
Potassium can promote sugar conversion and transport, has been widely defined as "add sugar coloring" elements, this is true, but for various reasons for people formed the mind-set of potassium is higher, the better, but I don't know too much will reduce the uptake of magnesium, potassium, in turn, leads to the formation of a photosynthesis product is blocked, it will affect the mature grape quality.
2. Effects of fruit indexes
Coloring: anthocyanin is the main factor of fruit coloring. Lack of phosphorus will lead to insufficient energy required for transportation, and the sugar formed by photosynthetic products will accumulate in a large number of leaves, and cannot be transported to fruits to promote the formation of anthocyanins, which will affect fruit coloring.
Flavor: the fruit is sour, then sugar, then color, and finally flavor. This phase strictly prohibits all causes the shoot tip leaf to flourish the use of fertilizer habit, otherwise will cause the waste of nutrients, it is difficult to form the original flavor of the variety.
Comprehensive above, it is recommended that you choose in grape sugar increasing coloring period high low nitrogen phosphorus potassium type water soluble fertilizer for drip irrigation or blunt, cooperate with the foliar spraying calcium, magnesium and boron element, from the Angle of the fertilizer management can ensure grape sugar coloring.
It is worth mentioning that carbon is an important element in the formation of photosynthetic products and its use in grape coloration is conducive to the improvement of grape commodity. This is one of the reasons why humic acid fertilizers have been widely used in grapes in the past two years.