1, requirements of walnut on environmental conditions
(1) temperature
Walnut is a warm-loving tree species, and the suitable temperature range and frost-free period are: annual average temperature 9 degrees-16 degrees, extreme minimum temperature minus 25 degrees-minus 2 degrees, extreme maximum temperature below 38 degrees, and frost-free period 150 days.
(2) Lighting
Walnuts like light. After entering the fruiting period, it is more necessary to have sufficient lighting conditions. The annual sunshine hours should be more than 2000 hours to ensure the normal growth and development of walnuts. If it is less than 65,438+0,000 hours, the core-shell and nucleolus will be stunted. In cultivation, light must be considered from the aspects of garden selection, planting density, cultivation method, shaping and pruning.
(3) Soil
Soil is the foundation for the growth and development of all plants. The huge root system and tree body of walnut need deep soil layer (more than one meter) to ensure its good growth and development.
(4) Humidity
Walnut is resistant to dry air, but sensitive to soil moisture. Too dry or too wet soil is not conducive to the growth and fruiting of walnuts. Therefore, soil and water conservation engineering measures should be taken in mountain walnut orchard; On the flat land, the drainage problem should be solved. The groundwater level of walnut orchard should be 2 meters below the surface.
(5) Others
Walnut likes loose soil and good drainage, and it doesn't grow well in the soil with high groundwater level and high viscosity. But it grows best in weak alkaline soil containing calcium. The adaptive range of soil PH value is 6-8, and the soil salt content should be below 0.25%, which has little influence on the growth results. Too much salt will lead to death. Walnuts like fat.
2. Walnut Garden
Before building a walnut garden, it is of great significance to carefully choose the garden. When choosing and evaluating the location of the garden, climate conditions, soil thickness and groundwater level are generally the key points.
(1) Selection of Mountain Garden
There is little difference in soil and climate conditions in hilly areas, which is connected with flat land types. Especially at high altitude.
On the high gentle slope, the soil erosion is light, the soil type changes little, the soil layer is thick, the water condition is good, the traffic is convenient and the management is easy. In the foothills, the place with gentle slope, convenient transportation, abundant sunshine, smooth air, deep soil layer and high soil fertility should be considered as the place for walnut orchard construction.
When planting walnuts in low mountain areas and Zhongshan areas, the garden should be built on the sunny slope with soil thickness greater than 1 m and high fertility.
(2) Garden site selection on the flat land.
Different types of flat land have different effects on the growth and development of walnut because of different causes, topography and soil. The establishment of walnut orchard on flat land should be rationally utilized and planned according to the characteristics of different flat land types and the requirements of agricultural zoning. Alluvial plain should pay attention to choose places with high terrain and good drainage to build gardens; Before establishing walnut orchards in desert areas and old rivers, we should first build windbreak and sand-fixing forests, break through the impermeable layer, improve the soil, and solve the problem of irrigation and drainage before opening the orchards for planting. Low-lying saline-alkali land, the salt content should be less than 0.25%, it is suitable to build terraces with a height of about 1.5 meters, and build gardens after sand pressing, but it is not suitable to build gardens on heavy saline-alkali land; Because of the high wind speed in Haiti, walnuts are vulnerable to wind damage, so windbreaks should be built before establishing walnut orchards to create good conditions for young trees to grow faster.
3. Planting method
It varies with site conditions, cultivated varieties and management level. Generally speaking, the principle of high and stable output per unit area and easy management should be adopted. Eating walnuts early, because of its early fruiting and small tree body, can adopt the planning dense planting form of 3x3m or 4x4m. When the crown is closed and the light is poor, it can be planned to be thinned to 6x6 or 8x8 meters.
Grafting seedlings of improved varieties and proper close planting are beneficial to early fruiting and high yield.
Step 4 cultivate
Improving the survival rate of transplanted young trees is an important content of walnut orchard construction, and it is also the basic work to realize strong trees, early eating and high yield. Only by ensuring the planting quality can young trees grow healthily, pass the development stage smoothly and lay a good foundation for increasing production.
(1) soil preparation
Prepare for soil maturation and fertility improvement in advance.
(2) Raising seedlings
Only high-quality seedlings can effectively use the cultivation conditions and achieve the goal of more fruits. It is required that the varieties of seedlings are pure, the taproots and lateral roots are complete, there are no pests and diseases, and the resistance is strong. It is best to be a strong seedling of 2-3 years old, with a height of more than one meter, a trunk diameter of not less than one centimeter, and more fibrous roots to ensure survival and robust growth.
(3) Planting method
Before planting walnut seedlings, cut off the injured and rotten roots, then soak them in clear water for half a day or dip them in mud to make the roots absorb enough water to survive. The diameter and depth of planting holes are generally not less than 0.8-1m. After the planting hole is dug, the topsoil and soil fertilizer are mixed and filled in the bottom of the pit, then the seedlings are put in, the roots are extended and filled in layers, so that the roots are evenly distributed and the soil is flush with the ground. After comprehensive practical use, plant a tree tray, fully irrigate it, and seal it with soil after seepage. Seedling planting depth can be slightly greater than the original seedling depth of 5 cm, and then irrigation after seven days of planting.
(4) Post-planting management
Effective cold-proof measures such as bow burying and soil burying should be taken before young trees overwinter; Survival and replantation; Small trees are fixed; In addition, management of fertilization, irrigation, intertillage weeding and pest control should be carried out according to specific conditions.
4. Key points of close planting and high-yield garden cultivation
In order to achieve the goal of high yield, we must strengthen the cultivation techniques and measures, especially the following links:
(1) Suitable site selection
According to the characteristics that walnut is a positive tree species that likes light and is rich in fertilizer and water, try to choose a garden with flat terrain, deep and fertile soil, drainage and irrigation conditions, and sunny leeward, which is convenient for various operations.
(2) Carefully prepare the soil
Soil preparation before planting is beneficial to the survival of planting and the growth and development of trees in the future, and it is an important pre-planting operation. According to the topography and soil characteristics of the selected garden, it can be carried out according to local conditions. There are generally two forms.
Slope land: To build a garden on the slope land, in order to facilitate various operations and maintain soil and water, it is necessary to build horizontal terraces. Then, planting pits or ditches are dug on the horizontal terraces according to certain plant spacing.
Flat land: planting pits and ditches can be dug directly when the garden is built on flat land. The planting pit has a length of 1m and a depth of 80cm. Planting ditch width 1m, depth 80cm. When planting pits or ditches need to be filled with soil, organic fertilizer should be mixed, about 50 kg per plant.
(3) Improved varieties and strong seedlings
Selecting excellent varieties and strong seedlings is an important condition related to the success or failure of the construction of dense planting high-yield garden. In order to maintain the consistency of fine varieties, it is necessary to use cloned seedlings of fine varieties, and the strong seedlings can be directly grafted to build gardens.
(4) Reasonable close planting
Dense planting high-yield garden emphasizes a word "dense", but it is not as dense as possible, but scientific and reasonable.
(5) thinning flowers and fruits to increase fertilizer.
For high-yield trees, it is very necessary to increase fertilizer in addition to properly thinning out some excessive female flowers or young fruits. According to the number of plants per mu, 2-3 tons of organic fertilizer can be applied every year. Topdressing chemical fertilizer (calculated as compound fertilizer) 30-40 kg. Organic fertilizer should be applied in late autumn or early spring; As topdressing, chemical fertilizer is applied in 2-3 times, usually before flowering, before fruit hardening and after fruit harvesting.
(6) timely irrigation
During the growth and development of walnut trees, all physiological activities need water to participate. Although walnut is not strict in water requirement, sufficient water supply is absolutely necessary to increase yield and improve quality.
(7) plastic trimming
Because of the high planting density, it is more important to control the rapid outward migration of branches of well-cultivated trees in close-planted high-yield gardens. Generally, the height of the trunk is about 50 cm, and it is best to cultivate it into a tree structure of the trunk of the central leadership.
5, Carya cathayensis pest control
(1) bud maggot
Bud maggot is an important pest of Carya cathayensis. In the middle and late April, when the male inflorescence and female bud of Carya cathayensis are first opened, it is easy to happen in the woodlands with high humidity beside Yinshan Mountain and ravine. Bud maggot larvae suck the sap of male inflorescence and female flower bud of Carya cathayensis, which makes the injured male inflorescence bend and expand, and the calyx of female flower bud expands, which leads to the failure of female flower to open and wither, which seriously affects the yield of Carya cathayensis.
Prevention and control methods are:
(1) crown spray. In the first half of April, when the male inflorescence is 1-2 cm long and the female flower bud is initially formed, spray 5% imidacloprid EC 1000- 1500 times, and the liquid must penetrate into the flower bud when spraying.
② Ground control. Before the emergence of adults in late March and early April, when the male flowers show bracts about 0.5cm, spread a shallow shovel on the ground with protective net (dosage 1 2Kg/mu), or use 40% phoxim EC 800- 1 0,000 times, or use 52.2% farmland 800- 1 0,000 times. Spray four times in a row.
(2) Aphid control
Hickory aphids overwinter with eggs in the cracks between hickory buds and branches, and the damage peak is in early April, feeding on hickory buds. After the injury, the leaves atrophy, the male flowers wither, the female flowers do not bloom, and the tree is weak.
Prevention and control methods are:
(1) injections, injecting drugs. At the end of March and the beginning of April, when the concentration of 10% imidacloprid EC or 30% acephate EC is 1: 0- 1: 1, use a small sharp axe to make a round hole at the chest height of the trunk with an interval of 10 cm, and add the liquid medicine to the xylem.
(2) Crown spray. At the beginning of April, spray with 5% chlorpyrifos EC 1000- 1500 times solution.
(3) Branch blight
Most germs invade young and short branches, starting from the top and then spreading down to the trunk. The leaves on the damaged branches gradually withered and fell off. The color of the cortex of the injured branch changes gradually, first yellowish brown, then reddish brown, and finally brown. All the wood in the cortex of the cut branches turned black.
Prevention and control methods are:
(1) Remove dead branches and burn them centrally;
(2) increasing the application of organic fertilizer to enhance the tree vigor and improve the disease resistance;
③ From April to May, spray 600-700 times of 70% thiophanate-methyl or 500 times of 20% clothianidin copper every 7 days for 3 times in a row.
Three. Introduction of main walnut varieties
1, Liaoning first
Liaoning Economic Forest Research Institute was bred by artificial hybridization. The tree is stout and straight, with an average strength of 3.8. Under good cultivation conditions, secondary branches often appear. It can bear fruit in two years, with strong sustained high yield, and the grain yield per square meter of crown projection area is more than 200 grams. Nuts are round with a little shoulder at the top; The inner partition wall is membrane-like or degenerated, so it is very easy to take kernel, and the kernel can be complete. The kernel rate is 55-60%, and the seeds are full and yellow-white. Strong resistance, showing disease resistance, wind resistance and cold resistance. This variety is suitable for planting in places with good soil conditions, surrounding greening, intercropping between forest and grain, and early dense planting.
2. Lin Zhong No.1
It was cultivated by artificial hybridization in Forestry Research Institute of Chinese Academy of Forestry. The tree has moderate growth, round crown, strong branching and short fruiting branches, belonging to short branch type. The yield is good, and the grain yield per square meter is more than 200 grams. The branching rate of lateral branches reached 100%. Nuts are small, spherical, smooth and beautiful. The weight of a single fruit is about10g, the shell is extremely thin, the kernel rate is about 65%, the kernel color is light and the flavor is good. This variety is suitable for early dense cultivation and moderate pruning. Nuts can be increased to 14g with sufficient fertilizer and water.
3. Xifu 1
It was bred by Shaanxi Fruit Research Institute from the seedlings of Juglans mandshurica in Fufeng every other year. The tree grows moderately, and the tree is half open. The branches are stout and medium in length, belonging to the medium-short branch type. The average number of branches per mother branch is 65438 0.9, with many branches and large branching angle. 2-year-old, the kernel yield per square meter of crown projection area is more than170g. Nuts are oval, and the top and bottom are round. It is easy to take benevolence, full of benevolence, and light in color. The kernel yield is 58-64%, and the taste is rich. Strong resistance to stress, drought, cold and disease.
4. Xiangling
The fruit trees cultivated by Henan Academy of Forestry have excellent characteristics such as dwarfing, high yield, edible nuts, wide adaptability, fast growth and strong resistance to pests and diseases, which have been introduced by countries all over the world. Since 1984, more than 40 excellent varieties and clones and 38 excellent families have been introduced from different sources in China.
Fourth, experts commented that there is a great market space for walnuts.
The country with the largest annual output of walnuts in the world is the United States, with an annual output of 226,000 tons, of which 75% is in the United States.
Domestic sales, 25% export, accounting for 10% of the world's total output. China ranks second, with an annual output of 6,543,800 tons of walnuts. The annual output of Turkey is close to that of China, reaching 1.2- 1.5 million tons; The annual output of walnuts in France is 20,000-25,000 tons, and that in Italy is 60,000 tons.
The largest nuclear planting area in the world is China, with an area of about 6.5438+million mu, which exceeds that of other countries in the world.
The total area ranks first in the world. Followed by the United States, the planting area is 6.5438+0.2 million mu; There are 4 million walnut trees in Turkey; There are 2 million strains in France; There are 6 million plants in Hungary; There are 400,000 strains in Poland; There are 5.03 million strains in Spain.
Walnut is an important foreign trade material in China with high exchange rate. According to the exchange rate, about one ton of walnuts can be exchanged for wheat.
8.6 tons or 13 tons of fertilizer. Because of its milky color, sweet taste and careful grading, China's walnut kernel is favored in the international market.
With the deepening of people's understanding of the nutritional and health care value and medical efficacy of walnuts, and the increasing variety of walnut foods, the demand for walnuts is rising. According to the forecast of FAO, the world demand for walnuts will increase by more than 10% every year in the next10 year.
Looking forward to the situation of walnut production and marketing, the prospect is broad. But as far as China's specific situation is concerned, the following problems must be studied and solved in order to develop walnut industry:
1. Strengthen the management of existing walnut trees, popularize comprehensive supporting yield-increasing technologies and adopt new technologies.
2. On the basis of improved variety breeding, vigorously promote asexual reproduction, accelerate the realization of improved variety and improved variety of walnuts, and improve their quality and yield.
3. Formulate reasonable commodity walnut price policies and purchase and sale standards, and encourage the development of improved walnut production. Reference: /E_ReadNews.asp? News ID=222