Problems and Countermeasures in the Cultivation of Winter Jujube in Dagang, Tianjin

1 Is there a problem? 1. 1 unscientific fertilization? The soil organic matter in Dagang District is deficient, most of which is below 1%. Over the years, more than 85% of winter jujube orchards have not been applied with organic fertilizer, and the land is neither drought-tolerant nor waterlogging-tolerant, and the soil is generally hardened and malnourished. Dagang District is located in the swamp alluvial plain along the Bohai Bay. Land is composed of river impact and regression. Low-lying saline-alkali, sticky and diverse soil. The problem of "fecal alkali" is easy to appear when applying organic fertilizer. In addition, most jujube farmers believe that the darker the leaves, the better their growth. Long-term application of chemical fertilizer and annual topdressing of urea and diammonium lead to weak tree vigor, no fruit and poor quality. In recent years, the bitter taste, light taste, dark color and increased pests and diseases of winter jujube are all related to excessive nitrogen application. Unscientific fertilization leads to the decline of jujube fruit yield and quality, which affects the industrial benefit and development potential. ?

1.2 Does continuous enucleation also affect the fruit setting rate?

Picking is the key technology to control nutrient growth, adjust nutrient distribution, maintain good tree shape and promote high yield and high quality of winter jujube. However, in several years of cultivation practice, it was found that after topping for more than 4 years, the fruiting branches were exposed, the number of effective jujube plants decreased, the germination period was delayed, the germination period was uneven, the flowering period was inconsistent, the fruit setting period was difficult to determine, the jujube hung less and thicker, and even turned into lignified secondary branches, which did not fall off for a long time, the ratio of dry to thick crown width decreased, the later nutritional growth increased, and the peeling was serious. ?

1.3 Excessive use of hormones leads to higher yield and lower quality?

At present, the phenomenon of excessive use of "920" in winter jujube cultivation in Dagang is widespread, ranging from 3 times to 5-6 times a year, and the concentration ranges from 30 mg/L to150 mg/L. Winter jujube is big, but it has thick skin, bran, slag, dark color, poor taste and light flavor. The yield is high, but there are many residues and the quality is reduced. ?

1.4 Poor pest control and high pesticide residue?

In recent years, diseases and pests of winter jujube have become more and more serious. According to statistics, Zaoyuan uses drugs 22-24 times a year, with an average of 18- 19 times. Even so, the control effect is not ideal, and the pests and diseases are controlled, but the pesticides are seriously exceeding the standard, and the supermarket refuses to enter, so the benefit is not high. Due to improper control mechanism and control technology, it took money and effort, but it didn't work, leaving a high residue. ?

1.5 cultivation management can't keep up?

The management of winter jujube is not only technically demanding, but also labor intensive, and the labor cost can not be ignored. Let's talk about picking first. From early April to mid-August, especially in May, when the new shoots of winter jujube trees grow vigorously, it needs 1 time, and each person can handle more than 30 five-year-old winter jujube trees every day at most. It is necessary to master the techniques of picking up, staying, being light, heavy, long and short. Moreover, it is one of the necessary conditions for high yield of winter jujube trees, which is highly technical. The morning and evening, width, depth, height and quantity should be flexibly mastered according to the site conditions of the trees. At this time, it coincides with the "ear planting" festival, and farmers have to compete for seeds and harvest. If employees are hired, it is both high-tech and expensive, which makes the management of most jujube orchards unable to keep up and it is reasonable not to produce high-quality jujube fruits. ?

2 solution?

2. 1 scientific fertilization?

Based on the law of water and salt movement, the problems of saline-alkali and fecal alkali can be solved or alleviated by lowering the tree disk below the ground 15 ~ 20 cm. Using furrow application to prevent basal fertilizer from spreading under trees can also alleviate fecal alkali to some extent and improve the utilization rate of organic fertilizer. The base fertilizer must be fermented before application. In alkali-prone areas, sheep manure is not used or less, and cooked chicken manure is mainly used, and about 5% humic acid fertilizer or microbial fertilizer is mixed in the application, which has good effect. At the same time, the nutrient analysis of soil and plant leaves was carried out, and the balanced formula fertilization technology was implemented according to the analysis results. Emphasis is placed on the combination of chemical fertilizer and organic fertilizer, heavy application of basic fertilizer, rational application of chemical fertilizer, balance of tree potential, and improvement of quality and yield of winter jujube. It is necessary to demonstrate and popularize, so that jujube farmers can see the actual effect and improve the enthusiasm of scientific fertilization. ?

2.2 Reasonable pruning?

According to the spatial position and tree requirements, select 1 non-cored branches, adjust their growth direction and length at any time, and cut off the original branches in the second year to achieve renewal. Annual renewal can prevent the disadvantages of continuous coring and maintain the best stock age and vitality. ?

2.3 Reduce the use of gibberellin (920)?

Cooperate with organic cultivation of winter jujube, popularize bee pollination method, gradually phase out the use of "920", and cooperate with other non-chemical cultivation techniques to solve the problem of quality degradation of winter jujube, restore its original variety taste and flavor, and realize the original ecological cultivation of winter jujube. ?

2.4 Scientific prevention and control of pests and diseases?

Establish a pest observation and early warning mechanism, accurately grasp the critical period and characteristics of pest occurrence, formulate measures, use various information platforms to communicate in time, guide drug use and set up a professional service team to unify the way, time, variety and drug concentration. Avoid spraying every day, scattered spraying and interval spraying to prevent pests from moving away. Reduce the frequency of drug use and pesticide residues, and improve the control effect.

At the same time, it is necessary to strengthen pesticide supervision, effectively implement the agricultural distribution and prosecution system, purify the pesticide market, and prevent fake and shoddy pesticides from causing damage to jujube farmers. Do a good job in propaganda, demonstration and optimization, promote the use of efficient biological pesticides and biological control methods, fundamentally solve the problem of pesticide residues and maintain ecological balance. ?

2.5 Strengthen the research and development of new management technologies for winter jujube?

Strengthen the research and development of key technologies of pollution-free production management in jujube orchard, reduce the growth quantity and frequency of new shoots of winter jujube trees, replace nail opening, reduce labor intensity and labor cost, increase technology popularization and improve the management level of jujube farmers. ?

(Date of receipt: 2007-11-27; Tel: 022-63109117)