Summer and Autumn Management of Fresh Jujube

First, promote the expansion of jujube fruit

Fruit size depends on the genetic factors of the variety itself, but scientific management measures have a great influence on fruit size. The main technical measures to increase fruit size in production are:

The main results are as follows: 1. Strengthen the management of soil fertilizer and water, increase the application of organic fertilizer, deeply turn the soil and improve soil permeability, so as to achieve sufficient nutrition for tree growth, so as to ensure jujube fruit expansion and yield increase. Before the fruit expands, appropriate amount of phosphorus and potassium fertilizer should be applied. In general, the topdressing of 0.75 kg potassium sulfate or potassium magnesium fertilizer per tree in full fruit stage can be applied either by flushing or hole application, which can not only increase the fruit number, but also increase the sugar content of the fruit and make the flavor better. Increase foliar fertilizer. Leaf fertilizer can be sprayed for 7 to 8 times in the whole growth period, mainly nitrogen fertilizer in the early growth stage and phosphorus and potassium fertilizer in the middle and later growth stage, which can effectively improve the photosynthetic efficiency of leaves. In the critical period of water requirement for the growth and development of jujube trees, timely irrigation should be made to meet the water needs of the trees, which is a necessary condition for increasing the number of fruits.

2. Strengthen summer shearing to regulate nutrient supply and timely wipe buds in the growing season, remove over-dense branches and coring, improve tree nutritional status, save nutrition, and concentrate nutrients on jujube fruit.

3. Reasonable load, strict control of fruit setting, timely dredging of excess flowers and fruits, hanging and fixing fruit according to jujube, so as to make the fruit evenly distributed on the tree. Generally, the jujube fruit between 3 leaves and 8 leaves of jujube is of high quality.

4. The timely delayed harvest period is the key period for the rapid increase of fruit weight and the improvement of fruit quality before physiological ripening, and the harvest period should be delayed appropriately.

5. Spraying plant growth regulator according to the experiment in Hebei and Shaanxi, starting from the hard core stage of jujube fruit, spraying Zaofeng No. 2 every 10 days or so for 2 or 3 times, the jujube fruit expanded obviously and the effect of increasing yield was significant.

Second, promote the coloring of jujube fruit

Color is an important index of fruit quality. The main factors affecting fruit coloring are sugar content, light, temperature, nutrients, water and so on. In production, the main technical measures to promote jujube fruit coloring are as follows:

1. Proper water control and timely water supply before harvest can ensure the normal growth and development of fruit, but irrigation should be properly controlled in the near maturity period, which is beneficial to the coloring of jujube fruit.

2. Scientific fertilization and reasonable pruning and fertilization should be dominated by supplementary nitrogen fertilizer in the early stage of growth and phosphorus and potassium fertilizer in the middle and later stages of growth. At the same time, summer pruning should be carried out in time to improve the ventilation and light transmission conditions in the garden so as to promote fruit coloring.

3. Leaf picking is mainly used for large fruit fresh varieties. Generally, about 30 days before the jujube fruit is harvested, the sticking leaves and shading leaves around the jujube fruit are removed in stages and in batches, so that the jujube fruit is fully colored by light. Be careful not to pick too many leaves at one time to avoid sunburn.

4. Change the orientation of the branches in order to make the fruit shine evenly and achieve comprehensive coloring, the branches can be transferred 10 days after picking leaves, change the orientation of the branches and increase the light in an all-round way. It was carried out in 2 to 3 times.

5. Laying reflective film during fruit coloring period, laying silver reflective film under the crown or between rows can increase the light in the crown and make the fruit in the inner chamber and lower part of the crown fully colored.

Third, prevent fruit cracking and physiological fruit drop

1. To prevent fruit cracking. Many jujube varieties often have different degrees of fruit cracking in the event of rain during the ripening period. Most of the fruit cracking occurs in the brittle ripening stage (the pericarp begins to turn red locally to all red). The cracked jujube fruit is not only damaged in shape and quality, but also easy to rot and deteriorate (some varieties taste bitter after cracking), but also can not be fully mature, resulting in that the dried varieties do not meet the requirements of the standard grade after processing, and the fresh varieties are not edible. The loss to production is great. In general, the loss of fruit cracking accounts for 10% to 30% of the total output, and the loss in severe years is as high as 50%.

In order to prevent fruit cracking, on the basis of selecting anti-cracking fruit varieties, the early sunburn of pericarp should be prevented. Plastic film mulching or timely irrigation under the tree, especially from mid-late August to early September, can not make the garden too dry, which is an effective measure to prevent fruit cracking. The effect of plastic film mulching under the tree is very obvious, and the mature fruiting tree covered with plastic film to the edge of the crown can basically prevent the occurrence of fruit cracking. Film mulching should be carried out before the end of the rainy season in early August. Conditional jujube orchards can also cover straw and green manure. Irrigation to prevent drought requires that the soil water content of 20 cm on the surface should be kept above 14% from mid-August to early September and should be irrigated in time before the occurrence of drought. Organic or inorganic calcium fertilizer can also be sprayed on the leaves every 15 days before the white ripening period until harvest.

2. The prevention of pre-harvest physiological fruit drop starts about 15 days before ripening. The light ones account for 10%-15% of the total output, and the heavy ones account for 40%-60%, which has a great impact on the output of jujube trees. The causes of physiological fruit drop before harvest are not only related to the characteristics of varieties, but also directly or indirectly related to wind damage, high temperature and drought, excessive rainfall, lack of sunshine, excessive nitrogen fertilizer, diseases and insect pests and nutritional imbalance.

In order to prevent fruit drop before harvest, on the basis of selecting good varieties, soil fertilizer and water management and pest control should be strengthened to improve tree resistance. Spraying 50~70mg/kg naphthylacetic acid (sodium), 20mg/kg anti-falling hormone or Zaofeng No. 2 at about 10 days before white ripening and at the later stage of white ripening can reduce the physiological fruit drop by 20% and 80% before harvest. Hormone spraying should be carried out in the evening to increase the absorption of leaves and fruits, and pay attention to the uniform distribution of fruit noodles and stalks.