Causes and preventive measures of cracked jujube

In recent years, the problem of split jujube has been perplexing the majority of jujube farmers, bringing varying degrees of loss to jujube production, with a serious loss of more than 50%. The problem of split jujube is the most difficult problem to solve in jujube production, which deserves the great attention of fruit tree science and technology workers and jujube farmers. Through years of practice, the author has taken some measures according to the causes of split jujube, which can effectively solve the problem of cracked jujube, which is summarized as follows, which can be used as a reference for fruit tree science and technology workers and jujube farmers.

First, the cause of cracking jujube

The first reason: successive years of application of chemical fertilizer and drought caused soil consolidation, lack of soluble calcium that can be absorbed by jujube roots, resulting in jujube cracking. Chemical fertilizer has been used in China for more than 30 years, and the number of chemical fertilizers has increased year by year. The main types of chemical fertilizers are ammonium bicarbonate, calcium superphosphate, diammonium phosphate, ammonium sulfate, potassium sulfate, potassium chloride and so on. After the application of this kind of chemical fertilizer in the soil, the carbonate ion, phosphate ion, sulfate ion and chloride ion in the fertilizer combine with the calcium ions in the soil to form calcium carbonate, calcium phosphate, calcium sulfate and calcium chloride insoluble in soil. it reduces the soluble calcium in the soil, resulting in calcium deficiency. At present, soil calcium is deficient in most parts of China, especially in the arid areas of northern China, and soil drought is one of the reasons for calcium deficiency. When the soil is dry, it is not conducive to the activity of soil microorganisms. Most of the calcium elements fixed in the soil can be transformed into soluble calcium through the metabolism of microorganisms.

The second reason: the decrease of groundwater level and the uneven dry and wet soil lead to jujube cracking. Before the 1970s, the phenomenon of jujube cracking basically did not occur, mainly because the groundwater level was high at that time, even if there was no rain or watering, the jujube root system was not short of water, which would not cause uneven dry and wet soil.

II. Measures to prevent cracking of jujube

According to the above two causes of cracked jujube, we should consider activating calcium in soil, replenishing calcium on leaf surface and maintaining soil moisture, and take practical measures to prevent cracked jujube fundamentally.

1. Covering grass in orchard

10-20cm thick chopped straw was covered in the concentrated distribution area of root system. If the pure jujube orchard with high density is planted, the whole garden can be covered, and the time of grass mulching is better from June to October; at this time, the temperature and humidity of grass mulching are higher, which is beneficial to the multiplication of microorganisms in the soil and the activation of calcium in the soil; autumn can prolong the growth time of roots, and summer and winter can reduce the temperature difference of soil, which is beneficial to the growth of roots, especially the growth of surface roots. Grass mulching can well maintain soil moisture and keep soil moisture in a constant state, therefore, it can prevent the occurrence of cracked jujube. Long-term grass mulching will significantly increase the content of organic matter in the soil, such as wheat straw, wheat bran, crushed corn straw and so on.

2. Plastic film mulching tree disk

Generally speaking, the jujube tree is covered with plastic film 1-2 meters wide on both sides of the tree. Can maintain soil moisture, so that the soil will not be too dry, effective prevention and control of jujube.

3. Adopt the technology of storing fertilizer and water in holes.

On the inside of the vertical projection of the fruit tree, four holes with a diameter of 30-40cm and a depth of 40-50cm were dug, and each hole was vertically buried with a grass handle with a diameter of 20-30cm and a length of 30-40cm. The grass is made of all kinds of crop straw or weeds, the height is lower than the ground 10cm, soak through with water, and then put into the hole, the grass had better fill the soil around with mixed biological bacterial fertilizer and organic fertilizer, and then fill it with water. The hole is covered with a 1-square-meter plastic film, surrounded by soil pressure, inserted a hole in the middle, and usually sealed with stones to prevent water evaporation. Because a large amount of irrigated water and Rain Water can be stored in the hole, the water can be permeated and preserved in the deep layer, so that part of the root system can maintain sufficient water and prevent jujube from cracking.

4. foliar calcium supplement

The author used "anti-shrinkage and anti-cracking king" 600 times, sprayed once in flowering stage, young fruit stage, fruit expansion stage, middle growth stage and late growth stage, for a total of five times. after 3 years of use, it can effectively prevent the occurrence of split jujube.

If the above four techniques are used together to prevent jujube cracking, the effect is better.