In recent years, farmers in many areas in China have begun to plant walnuts, and pecans have received much attention from everyone. In the recent period, people often ask how the pecans occur in large and small years. The following small series will talk to you about the reasons for the results of pecans and the measures to overcome the years of pecans.

1 Reasons for the results of pecan size and overcoming technical measures

1.1 The current status of pecan size and its harm

The phenomenon of pecans in small and small years is the difference in tree growth and results, nutrient accumulation and consumption, and the difference in fruit yield during the interannual period. The phenomenon of pecans in large and small years is often phased out. This is a physiological response in which the tree body automatically regulates the balance between vegetative growth and reproductive growth in the same climate and low cultivation level. Some trees are particularly weak, or have suffered from natural disasters such as pests and diseases, droughts and floods for several years, and will continue to appear for several small years, and then another big year; others are managed for several consecutive years. A small year will appear again after the year. In the New Year, the output is high, but in the small years, the output is extremely low, and even the harvest is not high. The annual average output of the new year plus the small year is far less than the annual stable production. The phenomenon of large and small years not only directly causes economic losses to forest farmers, but also the production tools, storage and packaging equipment are not fully utilized; for consumers, the normal and stable supply of market fruits cannot be guaranteed, affecting the normal development of the food industry.

1.2 Reasons for the results of pecans

1.2.1 Nutritional disorders

The long leaves of the pecan tree in the year are generally carried out simultaneously with the flowering results. The carbohydrates produced by the leaves and the nutrients absorbed by the roots, in addition to ensuring the growth of the leaves and fruits in the current year, there is also the accumulated nutrients for flower bud differentiation in the same year. With the results of the flowering of Hunchun, the nutrition can keep up with stable production for years. If the results are too much in the past, the nutrient consumption is too large, and there is not enough nutrients for flower bud differentiation or flower bud differentiation is not complete, then it will become a small year next year. When the small flowers and fruit are reduced, and the ability to produce a large number of shoots and the formation of most flower buds, it will become a new year in the third year, thus forming a vicious circle of years of results.

1.2.2 Hormone imbalance

Fruit tree flowering results, in addition to the control of nutrition, but also the regulation of the type and content of hormones in the receptor. When the whole year, flowering, fertilization and fruit development can produce more gibberellin in the tree, and less flower buds will become a small year. On the contrary, the amount of flower and fruit in the small year is reduced, the formation and content of gibberellin are less, the hormone content which promotes the formation of flower buds is relatively increased, and the flower bud formation is also increased, and the third year becomes a big year.

1.2.3 Natural disasters and pest damage

Typhoon, freezing damage, drought, locust plague and serious pests and diseases can cause early defoliation in autumn, reduce nutrient synthesis and accumulation of nutrients in the tree, weaken the tree body, and incapable of forming flower buds, leading to a young year.

In addition, the soil and water loss is serious, the organic matter content is low, and the results in many years are many, which is also one of the main causes of the years.

1.3 Technical measures to overcome the results of the year and year of pecans

1.3.1 Green grass, green soil, improved soil

Pecan forests, like fruit gardens, promote green manure every year to increase soil organic matter content, improve soil structure, and cultivate deep, wide, and dense root groups. This is a fundamental measure to overcome the large-scale results caused by malnutrition. Natural grass or artificial grass can be promoted when conditions permit.

Advantages of natural grass: First, it can prevent typhoon storms from scouring the soil and leaching nutrients; secondly, it can stabilize the temperature and humidity of the soil root distribution layer, which is beneficial to root growth; third, it can increase soil organic matter content; fourth, it can save labor. However, the disadvantage of natural grass is that it is prone to contradiction between grass and tree competition. The solution is to mow the lawn mower during the vigorous growth period of the pecans, especially at the peak of root growth.

The key to artificial grass greening is to choose grass species. On the basis of artificial grass and green, it is advisable to plant local green manure such as rape, radish, Chinese milk vetch and day lily. In addition to the high tolerance of the gravel, shallow soil and other drought-tolerant mountain farms, rapeseed should be planted under the pecan forest, but do not harvest. Sowing from the end of August to the beginning of September, castration before the flowering period in early April, directly fell to the forest or covered around the rhizosphere. Radishes with high gravel content and shallow soil layers can be used to sow radishes. It is advisable to plant Chinese milk vetch and day lily in areas with good soil moisture, deep soil layers and relatively fertile soil.

1.3.2 Scientific fertilization to coordinate the imbalance between vegetative growth and reproductive growth

According to the growth of the branches and leaves of the tree and the development of the fruit, the lack of nutrients is supplemented in time, and no nutrients in the tree or soil are used to promote the vigorous growth of the tree, ensuring the need for nutrients in the current year and flower bud formation. When pecan is planted, it is best to apply base fertilizer. 0.5~1 kg of organic fertilizer can be mixed with 0.25-0.5 kg of superphosphate. After application, the soil is planted. From the current year to the third year, block grass cuts cover the rhizosphere every year. From the 4th to the 7th year, organic fertilizer or organic-inorganic compound fertilizer can be applied. At the beginning of March, each plant applies 0.5-1 kg of pure organic fertilizer (cake fertilizer, etc.), and organic-inorganic compound fertilizer 0.25~1 can also be used. Kg, increasing usage year by year. After the 7th year, each plant applied 0.5-1 kg of organic-inorganic compound fertilizer, and applied potassium fertilizer 0.05-0.1 kg year by year.

1.3.3 Thinning and fruit thinning and flower preservation

In the New Year, according to the size and growth of the canopy, the amount of fruit is preserved, and too many overly dense fruits are removed to prevent the overburden of the year and the appearance of the following year. In the younger years, while reducing the nitrogen application, the overgrown pecan branches can be topped or smeared to improve the fruit setting rate and yield.

1.3.4 Reasonable pruning

In the New Year, cut off too many flowering branches, reduce the amount of fruit hanging in the year, promote the vegetative shoots, increase the formation rate of flower buds and the yield of the next year. The effect is the same as that of thinning flowers and fruits.

1.3.5 Spraying hormones and nutrients

There are two kinds of application in pecan forest: one is the physiologically active substance triacontanol, and the flowering crown is sprayed with 0.01~4mg/kg of triacontanol, and the average fruit setting rate is increased by more than 28%, of which 0.05mg The effect of /kg concentration is stable, and it is sprayed at the young fruit stage, and the effect is good. The second is ethylene, mainly ethephon, which inhibits cell division and elongation, loosens fruit stems, promotes early maturity of fruit, and is easy to harvest. The application of the harvesting net in the tall tree body of the pecan forest can minimize the occurrence of casualties.

1.3.6 Strengthen prevention and control of pests and diseases and natural disasters

The focus is on the control of pecan flower buds, pecan ulcer disease, root rot disease, blight and leaf-feeding pests. The prevention and control should gradually shift from chemical control to biological and physical control, and try to use low toxicity and high efficiency. There is no residual bio-pesticide control and the physical vibration control represented by the frequency-vibration insecticidal lamp.

2 Reconstruction of low-yield pecan forest

2.1 Hickory weak tree rejuvenation

2.1.1 Reasons for formation

First, the site conditions are poor, the soil layer is thin, the organic matter content is less than 1%, the soil water retention capacity is poor; the second is extensive management, low fertilization level, unreasonable intercropping of high-stalk crops and strong fertility potato crops. And weeds with strong natural growth competitiveness, compete with pecans for fertilizer and water, affecting the growth of pecans; third is the result, poor root development, poor absorption, weak shoot growth, low photosynthetic capacity, leading to young and middle pecans The result tree showed premature aging.

2.1.2 Technical measures for pecan weak tree rejuvenation

(1) Turning the soil to green and improving the soil: Establish a soil management system for land conservation. From the beginning of pecan colonization for 5 to 7 years, the green manure in winter and spring is interplanted every year. Winter green fertilization in winter sowing can choose Ziyunying, Huanghuahuan, etc. Spring and green spring fertilizer can choose peanuts, legumes (including nitrogen-fixing bacteria).

When sowing green manure, it is necessary to apply base fertilizer, suitable topdressing in the growing season, and legume green manure should pay attention to increase the application of phosphate fertilizer to increase the yield of fresh grass and achieve the purpose of “reducing nitrogen with phosphorus”. During the castration period, it is advisable to cast and turn over the flowering period with the highest fresh grass yield and nutrient content, or to apply some green manure after composting or tanning to improve fertilizer utilization.

Turn over the green manure, each time about 20 ~ 30 kg per plant, while layering the appropriate amount of cake fertilizer, manure and so on. In the more acidic mountain, when burying green manure, apply 1~2 kg of lime per 100 kg of green manure to neutralize the organic acid produced by the decomposition of green manure and reduce the acidity of the mountain soil to facilitate the growth of pecan roots.

The method of turning the soil should be carried out according to the slope of the forest, and the slope with a slope of 25° or more should adopt the no-till method of only hoeing and unsoiling the soil every year to facilitate soil and water conservation; the slopes below 25° can be used for scales. Pit type tumbling, the depth of soil should not exceed 15 cm; the slope of 10°~25°, combined with the repairing of the terrace and horizontal belt, along the contour line, the method of excavation and filling according to the plant spacing, gradually transforming the slope into a horizontal belt For slopes below 10°, the tree hole expansion method is generally used. Starting from the edge of the fixed planting point, gradually expand the hole outwards, digging 10-20 cm deep in the canopy range every year, and digging 30 cm deep outside the crown width, expanding year by year to promote the development of the root system. When turning over soil, try to damage the coarse roots with a diameter of more than 1 cm. The topsoil and the heart soil should be piled separately. The bottom layer and the root layer are filled with topsoil, and the soil is paved to promote weathering. At the same time, the effect of combining the base fertilizer is better.

(2) Reasonable fertilization: Applying quick-acting fertilizer from March to April in spring, which is beneficial to spring shoot growth and flowering results. Applying organic fertilizer in September can increase leaf assimilation capacity and tree nutrient accumulation, laying a foundation for flower bud differentiation and new shoot growth in the coming year. The fertilization method is based on the size of the canopy. It is required to dig an annular groove around the canopy. The slope will dig a semi-circular ditch above the trunk, fill the bottom of the ditch with compost, manure and other organic matter, and then apply phosphorus and potassium fertilizer, acid soil, and then Adding lime to cover the soil, the effect is better. Remember not to apply too much at a time, otherwise it will be counterproductive.

(3) Stopping the fruit and promoting the shoot: the weak roots of the pecan tree are poorly developed, the absorption capacity is low, the shoot growth is weak, the leaves are small and small, the photosynthetic function is low, and the nutrient accumulation is small. In the 1 to 2 years after the weak tree rejuvenates, some of the flowering branches can be appropriately cut off, and the fruit can be fully thinned at the flowering or young fruit stage to reduce the burden on the tree and promote the growth of the shoots.

(4) Cut off the diseased dead branches in time: Cut off the dead branches on the pecan trees in time, and cut the thick dead branches from the base, pay attention to the smoothness of the wounds, and apply the wound protection agent after the diseased branches are trimmed. And timely transport it out and burn it.

2.2 How to overcome the result of the production tree

Pecans usually start in 8 to 10 years after planting, and begin to enter the fruiting period 20 years later. However, due to extensive management, there are still many pecan trees that should enter the promising period, with little or no normal results.

2.2.1 Reasons for not producing results

First, due to partial application of nitrogen fertilizer or excessive nitrogen fertilizer, vegetative growth is excessive, flower buds are difficult to form, even if a small amount of flower buds are formed, when the young fruit development needs more nutrient supply in early summer, it will compete with the foliage to produce intense nutrients. It falls off due to weak competitiveness. Second, the flowering period is continuous rainy weather, lacking favorable pollination timing, causing annual flowering without result, or little result.

2.2.2 Technical measures to overcome the failure of the production tree

(1) Control excessive fertilizer and water: excessive fertilizer and water, especially excessive nitrogen fertilizer, the branches are long, nutrient accumulation is small, flower bud formation is difficult. It can control fertilizer and water in summer and autumn, inhibit its vegetative growth, in order to accumulate nutrients and promote flower bud formation. Appropriate early application or less application of spring fertilizer to improve flower bud quality and fruit set rate.

(2) Implementing methods such as root-cutting, ring-cutting or ring-shaped peeling: For steeply long trees with good growth and poor results, ring cutting, ring rafting or ring-shaped peeling can be used to significantly increase the fruit setting rate. The ring cutting is performed by cutting a knife or a cross knife on the bark at a height of 1 to 1.5 m, deep into the xylem, temporarily blocking the downward transport of the contracted light product, increasing nutrient accumulation above the wound, promoting flower bud differentiation, and improving Fruit set rate and yield. Circumcision is carried out 2 to 4 weeks before the flower bud differentiation of pecans, which can promote flower bud differentiation; it can reduce flower and fruit detachment and increase fruit set rate and yield during flowering or late flowering. Trees with less flowering should be sooner rather than later, and trees with more flowering trees are not easy to ring. Personal experience can also be applied depending on the length of the tree and the amount of fruit retained. The tree is prosperous and can handle several more, and vice versa.

(3) Treatment of topping, pulling branches, and stilts: The growth of new shoots in Wangshu is large and the tree stands upright. In the long-term topping of the new shoots, the elongation can be temporarily stopped, the branches are promoted, and the branches are formed into flower buds. Pulling branches usually use a rope or a bow puller to pull the branches apart; the sticks are used to spread the backbone branches with sticks or thick branches. They can open the tip angle, weaken the top edge, and ease the tree potential to facilitate flower bud formation and results. When using, the opening angle of the backbone branches should be greater than 45°, and if less than 45°, the effect is not obvious. After a growing season, the base angle of the branches has been fixed, and the sticks and ropes can be removed.

(4) Artificially assisted pollination and vibrating branches: The pecans were shed under normal conditions for 3 days, and the female flowers had the ability to fertilize after 10 days of maturity. Therefore, when the flowering period encounters continuous low temperature and rainy weather, the natural pollination of pecan is affected, and artificially assisted pollination can be adopted to increase the fruit setting rate. Artificial-assisted pollination can be carried out in succession at different altitudes, that is, flowering at low altitudes, pollen storage can be pre-collected, and pre-acquired pollen is artificially assisted pollination when the climate is poor at high altitudes. When the rain occurs in the low-altitude area, the female flower can be used to wait for the pollination characteristics. After the weather is fine, the pollen is pollinated. If you want to operate easily, you can choose to bloom the male flower branches in the sunny and windless weather, and insert them into the pollinated canopy, vibrate the bamboo rafts to make the pollen scattered, and carry out artificial supplementary pollination.

2.3 aging pecan tree update

2.3.1 Characteristics of senescent pecan tree

Some nutrients are scarce, the organic matter content is low, the soil layer is solid, the topsoil is knotted, the ventilation and the ability to maintain the fertilizer and water are weak. Therefore, the root growth of the plant is poor, the short leaves are small, and the photosynthetic capacity is decreased. At the same time, the old tree canopy is tall, the inner scorpion is empty, and the long-term suffering from natural disasters such as droughts and floods, pests and diseases, many crowns are incomplete, the results are few, some have lost economic cultivation value, they have to dig to replant or from the ground. Cut off at 0.2 to 0.5m, re-cultivate with germinating strips; some trees are still relatively healthy, and can be harvested by strengthening water and fertilizer management and crown regeneration.

2.3.2 aging tree update technical measures

(1) Change the soil and add the guest soil: After the old garden soil is turned over, pick it out and replace it with new soil. The soil change is carried out in a radial or slat-like manner in years, avoiding too many roots at one time and affecting growth. This applies to pecan forests that are convenient and small in size. If the original pecan forest soil layer is shallow and the soil and water loss is serious, the soil can be improved by the guest soil method. The soil is applied under the canopy and the soil layer is thickened to facilitate root growth, restore the tree potential and increase the yield.

(2) Adding organic fertilizer: Organic fertilizers such as green manure, foliage, mountain grass, manure and compost are supplemented by nutrients to ensure the supply of various nutrients.

(3) Plastic pruning: Many pecans are now planted in dense forests with high density, high trunks and narrow canopies. If they are not trimmed, they will not only affect the yield, but also increase the unsafe factors during harvesting. The results of this type of pecan forest are shifted outwards, and the result layer is concentrated in the upper part of the canopy. For the old pecan tree with a height of more than 8 m, the top branch can be cut. The pecan is hard and the wound heals slowly. Therefore, the razor must be flat. The wound is coated with a 1:10 concentration of dixon, and the tin foil is wrapped to promote healing and prevent the wound from rot. The pecan pruning period can be carried out before the deciduous winter to the spring germination. First, the thin branches, the dense branches and the diseased branches are cut, and then the spring shoots with only the male inflorescences or the bad female flowers are cut in the late spring, reducing Nutrients are ineffective.

(4) Use Meng Meng: When the canopy is degraded, the characteristics of the spurs on the backbone can be used to cut off the main branches of the aging tree that have withered or incompetent ability, and use the underlying wound to sprout new branches and re-form. The crown is the result. When the canopy is incomplete, it can also be used to re-cultivate the buds to form new backbone branches, fill the canopy, enlarge the photosynthesis area, and increase the yield.

Well, the above is all the contents of the pecan years and years. If you have any questions in this regard, please come to Huinong.com to learn more!

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