Firstly, the causes of fruit cracking are analyzed.
There are many reasons for fruit cracking, but the most important ones are water imbalance, excessive temperature difference and calcium deficiency. There are other reasons, and I will analyze them one by one.
1, water imbalance leads to fruit cracking
The root cause of water imbalance is that in water management, drought first followed by waterlogging, excessive water control in the early stage of fruit expansion and excessive watering in the late stage of fruit expansion. So, under what circumstances will the water supply be unbalanced?
(1), fruit cracking caused by previous drought.
The early drought either means less watering or drought, or it may be that there is something wrong with the root system of our crops.
① Drought caused by improper watering.
Water too late or too little in the early stage, no matter what fruit and vegetable crops, when fertilizing during the first fruit expansion period. For example, when melons and watermelons set fruit for the first time, we usually apply swelling fertilizer, tomatoes should apply swelling fertilizer after the first ear of fruit, cucumbers should apply swelling fertilizer after harvesting root melons and so on. In short, water should be poured when fertilizing this time.
(2) Water is heavy but plants are short of water.
Although there is plenty of water, plants still show symptoms of water shortage. The reason for this situation is not the lack of water in our fields, but the physiological lack of water caused by weak roots. As we all know, at present, the soil in our greenhouse is seriously acidified and salinized, and problems such as root retting and root burning are prone to occur in the early growth stage. Especially in winter, when the ground temperature is low and the manure is not decomposed, root diseases such as root rot and Fusarium wilt will occur prematurely.
(2) Fruit cracking caused by late waterlogging.
Many of our farmer friends don't pay attention to the size of water when watering. Anyway, they think that watering is the way it is, but they don't know that it will bring many problems. Excessive waterlogging in the later period, especially excessive watering in the coloring period, is also easy to cause fruit cracking. When watering fruits and vegetables for the second time, you must not exceed the first time. The later, the more you should learn to control water. The more you water, the greater the risk of cracking.
2. Excessive temperature difference leads to cracking.
The fruit is small in the early stage after fruit setting, and there is no problem of excessive temperature difference between day and night. However, in the later stage of expansion, if the temperature difference between day and night is too large, especially when it is cold and hot, it will easily lead to inconsistent temperatures inside and outside the peel and pulp, which will easily lead to fruit cracking.
3. Cracking caused by calcium deficiency
Calcium deficiency is also one of the main reasons for fruit cracking. Many fruit and vegetable farmers will ask, how can you be short of calcium when you have made up a lot of calcium fertilizer? In fact, there are two kinds of calcium deficiency, one is underground calcium deficiency and the other is underground calcium deficiency.
It is not difficult for us to understand that there is a lack of calcium in the field, but what we don't understand most is that we still show symptoms of calcium deficiency when we supplement a lot of calcium. This is mainly related to the absorption of calcium. As we all know, calcium is difficult to move in plants. Improper management in the field, such as temperature, root problems, excessive application of potassium fertilizer during fruit expansion and melon expansion, will lead to calcium absorption by plants and eventually lead to fruit cracking.
4. Fruit cracking caused by other factors
Although these factors are not the main factors, they are also one of the common causes of fruit cracking.
(1), improper use of hormone or foliar fertilizer.
During the fruit expansion period, we often have the habit of using hormones to expand the fruit. All fruit swelling hormones are auxin, especially those hormones that make fruit swell quickly, such as clofenuron and pyrazole. Although fruits expand rapidly, most of them are at the expense of plant growth potential. The faster the effect is, the greater the risk of melon cracking.
Many inferior foliar fertilizers on the market, in order to satisfy farmers' psychology of quick success and instant benefit, often secretly add some hormones, such as fruit swelling hormone, rooting hormone, etc., most of which are hormones, so we must pay attention to careful screening when choosing foliar fertilizers.
(2) Dew condensation time on fruits and vegetables is too long.
After the sun rises in the morning, the longer the dew time on the melon and fruit, the greater the temperature difference between the inside and outside of the peel and pulp, and the greater the risk of cracking and peeling.
(3), insufficient leaves, aging
In the coloring period of fruit expansion, we have the habit of beating leaves If we beat the leaves too early, the sun will shine directly on the fruit, which is also one of the reasons for the fruit cracking. In addition, the leaves are seriously aging, and the probability of fruit cracking is relatively high.
(4) Cracking caused by boron deficiency
The epidermis of boron-deficient fruit is easy to be corked, but this kind of crack is generally not a big crack or a ring crack, but a small crack or skin crack will easily appear under the tension of pulp expansion.
In addition, pests and diseases will aggravate the phenomenon of fruit cracking, but it is not the cause of fruit cracking.
Second, the prevention and control measures of fruit and vegetable cracking in greenhouse
Understand the causes of fruit cracking, and then analyze our field management measures, we will find the problems and then solve them.
1, good water and fertilizer management
In order to do a good job in water management during the growth period of fruit trees, one principle is generally grasped: sufficient water in the early stage, moderate water in the middle stage and appropriate water control in the later stage.
When choosing foliar fertilizer, you must choose the products produced by regular manufacturers. We can at least judge the quality of foliar fertilizer by some simple methods. The easiest way is to open the package of foliar fertilizer and smell it. If there is a pungent smell, it is generally added with hormones such as sodium nitrophenolate, so it should be used with caution.
2. Control the reasonable temperature difference during fruit expansion.
In the fruit expansion period, it is not only an important measure to reduce fruit cracking, but also an important means to increase sugar and color. The temperature difference between day and night of tomato is controlled at about 65438 03℃, and that between watermelon and melon is controlled at about 65438 05℃, which is beneficial to loading and preventing melon from cracking.
3. Supplement medium and trace elements
Supplementing trace elements is also one of the main measures to prevent fruit cracking in production. Many of our farmers have no habit of applying calcium fertilizer as base fertilizer, which must be changed. No matter what kind of fruits and vegetables, including base fertilizer, do not need to be colored, such as watermelon. Calcium fertilizer should be supplemented at least twice during the whole growth period. Colored varieties, such as tomatoes, should be supplemented with calcium fertilizer three times during the whole growth period.
It is necessary to choose the appropriate time and absorbable calcium for calcium supplementation. Part of ionized calcium can be selected as base fertilizer, and calcium chelate with better quality can be selected as topdressing.
In cultivation management, if plants have shown symptoms of element deficiency, they can be supplemented by foliar spraying, and the symptoms of calcium deficiency can be alleviated in about 5~7 days. It is best to add some amino acids to the calcium fertilizer, because no matter what kind of calcium, its fluidity is poor, and amino acids are small molecules with good fluidity, which can drive calcium to be quickly absorbed by plants.
During the coloring period, calcium must be supplemented. The coloring period is the core of the whole growth period. If the color is not good, all our previous efforts will be in vain. It is not recommended to supplement calcium alone during the coloring period, and the ratio of calcium to potassium should be adjusted. Especially in the color change period, we use more potassium fertilizer, which will antagonize calcium, and the phenomenon of calcium deficiency is more serious. Adjusting the ratio of calcium and potassium will color the fruit and promote the sugar content.
In addition, adding boron fertilizer in the flower and fruit period can also play a good role in preventing fruit cracking.
Although there are many reasons for fruit cracking, not all of them will happen. As long as the field management is checked, it is easy to find out the causes of fruit cracking and find out the solutions.