How are strawberry seeds collected, processed and sown?

Growing Techniques Jan 1, 1970 0 views

The strawberry is a perennial herbaceous plant of the genus Fragaria in the rose family (Rosaceae). Its propagation methods include seed propagation and division propagation. Division propagation is mostly used in production, while seed propagation is more often used for long-distance introduction of varieties or for raising strawberry seedlings for breeding new varieties, and can also be used for courtyard landscaping with dual-purpose fresh-eating planting.

Seed collection

When strawberries are harvested from May to June, select well-developed, fully mature fruits for seed collection. Peel off the skin, put it in water, wash away the pulp, take it out and dry it. Alternatively, dry the peeled skin directly, then rub it to pieces, and the skin and seeds will separate.

Seed treatment

Pour the strawberry seeds into warm water at 60-70°C and soak and wash them while stirring constantly, until the water temperature drops to about 25°C, then stop. Continue soaking for 2-3 hours, then take them out and rub them with your hands until the seed coat is clean and glossy. Then rinse them clean with clear water and cover them with several layers of wet gauze. Place them at 25-30°C for germination. Three times a day (morning, noon and evening), wet the gauze with warm water to keep the seeds in a moist environment. Once 60-70% of the seeds have sprouted (white tips showing), they can be sown.

Sowing method

Before sowing strawberry seeds, first irrigate the seedbed with a light flooding, then level the bed surface with a rake. When the water in the bed has seeped down, you can sow. Strawberry seeds are small, so broadcasting is best. The sowing rate is preferably 2.5-4.5 grams per square meter. After broadcasting, immediately spread the prepared covering soil evenly over the bed surface, with a covering thickness of 0.3-0.5 cm. Shade with straw mats, and remove them once the seedlings have emerged uniformly.

Seedbed preparation

For the strawberry seedling bed, choose fertile loam soil and apply sufficient base fertilizer. For the base fertilizer, dry stable manure in the sun, then crush it and apply it to the seedling land still to be plowed. The application rate is 5-10 jin per square meter, and compound fertilizer should also be added appropriately. After spreading the fertilizer, carry out careful plowing, with a depth of about 33 cm. After plowing, harrow finely and level, and build ridges and beds 0.8-1 m wide and 8-10 m long, keeping the beds level to facilitate drainage, irrigation and management.

Seedling stage management ⟧13⟧1. Watering: Strawberry seedlings are not suited to flooding irrigation; sprinkler irrigation can be used to meet water needs. After 6 true leaves, light flooding irrigation can be used.

1. Watering: Strawberry plants are not suited to flood irrigation during the seedling stage; sprinkler irrigation can be used to meet their water needs. After they have 6 true leaves, light flood irrigation can be used.

2. Weeding: During the small seedling stage, weeds should be pulled out frequently and promptly.

3. Replanting: Once strawberry seedlings have grown 3-5 true leaves, they can be transplanted, thinning where dense and filling in where sparse.

4. Topdressing: When strawberry seedlings have grown to 6 true leaves, the first topdressing can be carried out, preferably with urea.

Strawberry planting techniques and daily management methods

Strawberries are widely popular for their bright appearance and pleasant fragrance. Every year in February and March, when strawberries ripen, the strawberries packed in small baskets or small crates by the roadside quickly sell out, and some people go directly to strawberry farms to pick them themselves. The income from growing strawberries is also quite considerable.

Strawberry planting techniques and daily management methods

1. Choose suitable varieties or mix-plant different varieties: Choose varieties such as Fengxiang and Mingbao that flower abundantly under low-temperature conditions, have a large amount of pollen, produce large and uniform fruits, color well, have mild acidity and few deformed fruits. Varieties such as Qiuxiang, Baojiao Zaosheng and Quanmingxing have less pollen and produce more deformed fruits, so varieties such as Chunxiang and Dana should be planted as pollinizer plants to facilitate pollination and fertilization, reduce deformed fruits and increase the proportion of large fruits.

2. Choose disease-free strong seedlings: Disease-free strong seedlings have well-developed root systems and strong disease resistance, and the strawberries they produce are large, high-yielding and of excellent quality.

3. Apply sufficient high-quality base fertilizer: Applying more high-quality decomposed farmyard manure can provide sufficient nutrients for strawberry growth, flower bud differentiation, flowering and fruit setting, and fruit development, enlarging the fruit size and increasing the sugar content and coloring of the fruit. Apply 2000 kg of decomposed chicken manure per mu as base fertilizer, combining furrow application with broadcast application.

4. Practice crop rotation and avoid continuous cropping: Crop rotation can improve the disease resistance of strawberries and reduce the number of deformed fruits and diseased insect-damaged fruits. The open space between greenhouses can be fully used for cyclical rotation.

5. Increase light: Insufficient light from 2 weeks before flowering to the flowering period will affect pollination and fertilization and produce deformed fruits. Insufficient light during the fruit coloring period will lead to bland fruit and poor color. On the premise of ensuring the temperature inside the greenhouse, the added straw curtains should be uncovered as early as possible and covered as late as possible. Hang reflective film on the north side inside the greenhouse to increase light using reflected light. On cloudy or snowy days, incandescent lamps can be used for supplementary lighting.

6. Ridge cultivation and plastic film mulching: Ridge cultivation can reduce contact between the fruit and water dripping from the greenhouse film, enhance sunlight exposure to the fruit, reduce the occurrence of gray mold, and promote fruit coloring. Plastic film mulching can raise soil temperature, lower air humidity, avoid direct contact between the fruit and the soil, and help keep the fruit surface clean.

7. Strictly control temperature: The suitable greenhouse temperature is 22-25°C during the day and 8-10°C at night during the flowering period, and 20-24°C during the day and 6-10°C at night during the fruit swelling period. Too high a temperature inside the greenhouse will shorten the fruit development period and make the fruits smaller.

8. Water and topdress in moderation: Water moderately during the flowering and fruiting period, preferably by drip irrigation. Insufficient water during the flowering period will lead to poor pollination and fertilization and produce deformed fruits. Insufficient water during the fruit swelling period will affect fruit swelling. During the flowering and fruiting period, continuously spray 0.3% potassium dihydrogen phosphate solution 3-4 times.

9. Auxiliary pollination: Poor pollination and fertilization is the root cause of deformed fruits, and using bees for auxiliary pollination can effectively reduce the occurrence of deformed fruits. Generally, during the flowering period, place 1 box of bees in each greenhouse for pollination.

10. Timely prevention and control of pests and diseases: Spraying pesticides during the strawberry flowering period can easily induce deformed fruits. If pests and diseases occur during the flowering period, spray during a period with few flowers. Before spraying, move the beehives out of the greenhouse, and move them back 1 week after application.

The growing environment of strawberries

1. Temperature: Strawberries prefer a warm and cool climate. The root growth temperature is 5-30°C, with an optimum of 15-22°C; the optimum temperature for stem and leaf growth is 20-30°C; buds suffer frost damage at -15 to -10°C; the temperature must be kept at 5-15°C during flower bud differentiation, and 4-40°C during the flowering and fruiting period. When strawberries are overwintered in summer, if the temperature is above 30°C and the sunshine is strong, shading measures need to be taken.

2. Light: Strawberries are light-loving plants, but they also have fairly strong shade tolerance. Under strong light, the plants are short and sturdy, the fruits are small, deeply colored and of good quality. Under moderate light, the fruits are large, pale in color, low in sugar, and the harvest period is longer. Too weak light is unfavorable to strawberry growth.

3. Water: Strawberry roots are shallowly distributed and transpiration is large, so strawberries have strict water requirements, but these differ slightly at different growth stages. In early spring and at flowering, strawberries need the water content to be no lower than 70% of the soil's maximum water-holding capacity; during fruit growth and ripening, the demand is greatest, reaching more than 80%; after harvest, when runners are sent out and new adventitious roots form, the soil water content must also be no lower than 70%; autumn is the period when the plants accumulate nutrients and form flower buds, and the soil water content must also not be lower than 60%. Strawberries are not tolerant of waterlogging and require good soil permeability, so pay attention to field drainage during the rainy season.

4. Soil: Strawberries are best grown in fertile, loose neutral or slightly acidic loam soil. Overly heavy clay soil is not suitable for cultivation. In sandy soil, apply more stable manure and irrigate frequently, and strawberries can also be grown.

Strawberry seed collection methods

Strawberry storage

1. Store in a ventilated place

Strawberries contain a lot of water and their skin is very thin, so they rot with the slightest touch. Therefore, to store strawberries well, handle them carefully and gently. When you bring them home, put them in a ventilated place; this way they can be kept for one to two days.

2. Store in the refrigerator

To store strawberries well, you can also put them in the refrigerator. First put the strawberries into a fresh-keeping bag and tie the bag opening tightly; this prevents the strawberries from losing water. The temperature in the refrigerator should be kept between 0 and 3°C and must not fluctuate; this way they can be kept for three to six days.

3. Seal with plastic wrap

Strawberries you cannot finish eating can be sealed with plastic wrap; this way the strawberries will not change color or rot within a day. But remember that the plastic wrap must be sealed well, with no gaps.

4. Drain and refrigerate

Strawberries spoil more easily after touching water, so to store strawberries well, it is best to wash only as many as you will eat and put the rest in the refrigerator; this way they can be kept a little longer.

Besides planting, picking and selling, which require a certain amount of care, storing strawberries is also something worth paying attention to. The skin of strawberries is very fragile, and once a ripe strawberry is touched during picking, the skin is easily damaged. This is why merchants are unwilling to let customers pick their own when buying strawberries.

High-yield planting techniques and cultivation management key points for walnuts

Cultivation of walnut seedlings

To ensure the quality of seedlings for afforestation of walnut bases and avoid the quality variation brought by using local common walnut seedlings for propagation, efficient and rapid propagation and grafting techniques are used to cultivate grafted walnut seedlings, that is, using one-year-old iron walnut seedlings for grafting in place or transplant grafting to cultivate grafted walnut seedlings. Its main advantages are:

1. It can well maintain the excellent traits of the mother plant and accelerate the achievement of improved walnut varieties.

2. It can significantly increase yield and improve quality.

3. It can dwarf the plant and bring fruiting earlier.

4. It can make full use of iron walnut germplasm resources.

Planting of walnuts

Walnut planting starts with the selection of the planting site. Choose flat land, terraced land and gentle slopes as the walnut planting base, and carry out full or block site preparation. When planting, ensure large holes with spread roots, close contact between roots and soil, filled-back pond soil, sufficient watering, heat and moisture retention, and sufficient nutrients, so as to ensure the survival of the planted walnuts and favor the rapid growth of the walnut trees. In order to master practical and feasible walnut planting techniques, the forestry department has explored for many years and achieved very good experience, referred to as the "six ones" technique of walnut planting, namely "choose a good plot of land, dig a large pond, apply a load of farmyard manure, plant a strong seedling, water with a bucket of clear water, and cover with a piece of plastic film".

1. Plot selection

Choose relatively concentrated, contiguous land such as flat land, terraced land and gentle slopes with loose soil and good drainage as the walnut planting base. Walnuts grow best on calcareous, slightly alkaline soil. The walnut is a deep-rooted tree species, and its root system needs a deep soil layer of more than 1 m to maintain good growth and development. Too thin a soil layer easily forms "little old man trees", or causes repeated dieback of shoots year after year, unable to form a yield.

2. Site preparation and planting

Seedling planting is an important foundational task in establishing a walnut base, and every planting step must be handled well to improve the survival rate and planting results.

① Site preparation: Digging the planting ponds in advance favors soil maturation and increases the water content in the planting ponds. Digging the planting ponds can be done as early as summer. The pond specification length × width × depth is 100 cm × 100 cm × (80-100) cm. After the pond is dug, backfill it layer by layer with topsoil and then leaves and weeds (or organic fertilizer) until it is close to the ground surface height, with a slight depression to facilitate water collection. The backfilled pond is left until planting time. In places where there are no conditions to dig ponds in advance in summer, they can also be dug and planted on the spot before planting. The pond is 100 cm long and wide and 80-100 cm deep. When digging, pile the topsoil and subsoil (stone) from the pond separately. If the soil is sticky and heavy or the lower layer is gravel or an impermeable layer, the planting pond should be enlarged and deepened, and foreign soil should be used for improvement. When backfilling the pond, mix 25-50 kg of farmyard manure (stable manure, green manure, compost, etc.) and 1 kg of ordinary superphosphate or 1.5 kg of calcium magnesium phosphate fertilizer with the topsoil and fill it into the pond. Where farmyard manure is lacking, leaves, weeds, turf soil, organic garbage, etc. can be used instead. The positions of the ponds are generally arranged horizontally, that is, each row is on the same level.

② Planting season: As the saying goes, "Plant trees early, do not wait for spring to dawn." The time for planting walnuts should be after the seedlings enter dormancy in late autumn or before the seedlings sprout in late winter and early spring, that is, from the ninth lunar month to the first lunar month of the following year. Planting is not suitable during the vigorous growth period in summer.

③ Planting method: The walnut planting method is generally determined according to the mountain terrain. Where the mountain is gentle and the slope is not steep, rectangular planting can be used; if the slope is steep and the terrace surface is narrow, a triangular arrangement is preferable.

④ Planting density: Preferably 12-16 plants per mu. On flat land, the row spacing is 7 m × 8 m or 6 m × 9 m, about 12 plants per mu; on sloping land, the spacing is 6 m × 7.5 m or 6 m × 7 m, about 15-16 plants per mu. Usually, walnut plots have a better effect when intercropped with crops, using cultivation instead of tending and using short-term crops to support long-term ones, so as to produce walnuts above and grain below and achieve multiple benefits; only thus can high yield and high quality be obtained.

3. Planting techniques

Planting techniques can be summarized in the eighteen-character formula "place straight, orient, stand upright, cover with soil, lift gently, tread firm, make a basin, water, cover with film".

① Place straight: When planting, place the seedling in the center of the prepared pond, aligned front, back, left and right.

② Orient: Set the seedling in the direction it faced before transplanting.

③ Stand upright: Hold the seedling straight and let the root system spread out in all directions.

④ Cover with soil: Cover with nutrient soil mixed with fertilizer.

⑤ Lift gently: After the root system is completely covered, gently lift the seedling once so that the root system spreads out and fits closely with the fine soil, then gradually fill in soil. The planting depth should be such that, after the soil settles, it is consistent with the depth at which the seedling was buried in the original nursery.

⑥ Tread firm: During the soil filling process, tread while filling, treading once for each layer of soil filled, until the soil is filled to 5-10 cm above the ground surface.

⑦ Make a basin: Build a ring-shaped soil ridge around the pond.

⑧ Water: Water thoroughly to settle the roots, 50-80 kg per plant.

⑨ Cover with film: Cover each plant with 1 piece of agricultural plastic film 1 m × 1 m. Cut a small hole about 6 cm in diameter in the center of the film, let the seedling stem pass through it, and after it lands, cover the small hole with fine soil, and bury the edges below the ground surface topsoil.

Management of walnuts

Walnut management refers to the follow-up management after walnut planting, that is, a series of management tasks such as watering and fertilizing, shaping and pruning, and loosening soil and weeding.

1. Water management

In the dry season of the year after walnut planting, supplementary watering is needed 2-3 times, 25 kg per plant each time. Where conditions permit, irrigate 1-2 times each year before walnut flowering. Walnut trees are quite sensitive to surface water accumulation and excessively high groundwater levels, so drainage should be done promptly. In areas with a relatively high groundwater level, deep ditches can be dug to lower the water level. According to the growth depth of the walnut root system, a drainage ditch about 2 m deep can be dug to lower the groundwater level to below 1.5 m from the surface. In low-lying areas prone to water accumulation, drainage ditches can be dug around them, which can both block outside water from flowing in and drain surface water accumulation.

2. Trunk determination and shaping

Trunk determination and shaping is an important technical measure in walnut cultivation management. Because walnut varieties differ, their trunk determination and shaping techniques vary.

For trunk determination and shaping, when walnut plants have grown to 80-100 cm after planting, determine the trunk, retaining 3-4 main branches in a sparse stratified form or natural open-center form.

① Sparse stratified form (with trunk form) generally has 6-7 main branches, arranged in 2-3 tiers. Its characteristics are: the crown is semicircular, ventilation and light transmission are good, the lifespan is long, the yield is high, and the load capacity is large. It is suitable for growing in places with better conditions and for sparse planting with strong trunk tendency.

② Natural open-center form (without trunk form) generally has 2-4 main branches. Its characteristics are: rapid formation, early fruiting, easy shaping, and easy to master. This tree form is suitable for walnut varieties planted in areas with poor soil and unfavorable fertilizer and water conditions, and for early-fruiting varieties with an open tree posture.

Trunk determination method for late-fruiting walnuts: After sprouting in spring, select and retain 1 strong bud or robust branch above the trunk determination height as the first main branch, and prune away all branches and buds below it. If the young tree grows too vigorously and branching is delayed, in order to control the trunk height, cut back moderately at a suitable position above the required trunk height to promote the sprouting of the bud at the cut, and then select and retain the first main branch.

Trunk determination method for early-fruiting walnuts: After germination in the planting year, remove all lateral buds below the required trunk height. If the young tree has not reached the trunk determination height, the trunk can be determined the following year. If the terminal bud is necrotic, select and retain a robust bud close to the terminal bud to promote its upward growth, and determine the trunk after it reaches a certain height. When determining the trunk, the method of selecting and retaining main branches is the same as for late-fruiting walnuts.

3. Pruning and shaping

Walnut pruning differs with young trees, full-bearing trees and aging trees. At the same time, during the flowering and fruiting period, thin flowers and fruits appropriately.

Pruning of young trees varies with the different growth and development characteristics of each variety. Mainly prune away weak branches, crossing branches, overlapping branches, parallel branches and diseased branches, so as to cultivate trunk and branch frameworks at all levels and fruiting branch groups. The specific methods are: control secondary shoots; control water sprouts; handle vigorous vegetative branches well; thin out overly dense branches and handle downward-facing branches well.

Pruning of adult trees: For walnut trees just entering the adult stage, the tree form has basically formed and the yield gradually increases. The main pruning tasks for walnut trees in this period are: continue to cultivate main and lateral branches, make full use of auxiliary nutrient branches for early fruiting, actively cultivate fruiting branch groups, and expand the fruiting area as much as possible. The pruning principle is: remove the strong and retain the weak, release first and then contract, combining release with contraction, to prevent the fruiting area from moving outward.

Pruning of trees in the full bearing period: For large walnut trees in the full bearing period, most of the crown is approaching closure or has already closed, the number of peripheral branches gradually increases, and most of them become fruiting branches. Due to poor light, some small branches dry up, bare zones appear at the rear of the main branches, the fruiting area moves outward, and alternate-year bearing easily occurs. Therefore, the main pruning tasks in this period are: adjust the relationship between vegetative growth and reproductive growth, continuously improve the ventilation and light transmission conditions inside the crown, and continuously renew fruiting branches, so as to achieve the goal of high and stable yield.

Pruning of aging trees: When walnut trees enter the aging period, the peripheral branches droop, a large number of "scorched tips" appear, and at the same time a large number of water sprouts sprout, showing natural renewal, and the yield also drops significantly. In order to extend the fruiting years, renewal and rejuvenation can be carried out. The specific pruning methods are: ① Trunk renewal (major renewal): saw off all main branches so that they send out new branches again and form main branches. ② Main branch renewal (medium renewal): contract at an appropriate position on the main branch so that it forms new lateral branches. ③ Lateral branch renewal (minor renewal): contract the first-order lateral branches at an appropriate position so that they form new second-order lateral branches. Its advantages are: both the formation of a new crown and the increase in yield are faster.

4. Top grafting for variety improvement of walnuts

Top grafting for variety improvement of walnuts is an important way to improve varieties and realize the cultivarization of walnut cultivation. It can be divided into hardwood grafting and green shoot grafting.

① Hardwood grafting method: The commonly used one is the bark-insertion tongue grafting method. First, the scion should be collected 20-30 days before germination. The scion diameter should be about 1.5 cm, with small pith, plump branches, full buds, and no pests or diseases. After the scion is collected, it should be labeled by variety and specification and placed in a fruit cellar or ice cellar at 0-5°C, and taken as needed when grafting. The grafting time is from early April to early May. The grafting targets are generally about 5-year-old young trees with a trunk diameter above 1.5 cm and vigorous growth. For large trees over 10 years old, multi-head re-grafting can also be used. The grafting method is to first cut the scion into 10-15 cm branch sections, with more than 2 full buds on each section, and cut the branch section into a 5-8 cm long horse-ear-shaped cut surface in a tongue shape. Select a smooth and straight place on the stock tree, cut off the upper end, level the saw cut, and cut a 2-3 cm crescent-shaped incision at the place where the scion is to be inserted. Then, cut away the thick old bark of the stock below the incision to expose the phloem, with a shape and size slightly larger than the horse-ear-shaped cut surface of the scion. Insert the scion, then bind it with plastic rope for 5-7 turns, binding tightly from top to bottom. When binding, start from the interface; binding too low is unfavorable to survival after grafting. After binding, carry out heat preservation and shading treatment. Generally, use waste newspaper or a tube shape and then fill in fine moist soil, but it must not be too wet, and put a plastic bag over it.

② Green shoot grafting: Mainly square bud grafting, in June. The scion is taken and grafted on the spot, and the stock is the newly grown branch of the current year. For grafting on large trees, prune in January by first cutting back the old branches, and after new shoots sprout, keep the new shoots for grafting.

5. Grafting precautions

Whether hardwood grafting or green shoot grafting, post-grafting management is very important, mainly including:

① Remove sprouts promptly: Promptly remove the new buds sprouting on the stock.

② Ventilate at the right time: Ventilate 20-30 days after grafting. The first time, the opening is the size of a cigarette butt; the second time, the size of a five-fen coin; the third time, remove the bag and newspaper.

③ Fix with supports to prevent wind breakage: When the grafted tender shoots grow to 20 cm, fix supports promptly to prevent wind breakage.

④ Loosen the binding and remove the film.

⑤ Cut the scion and cut the stock.

⑥ Remove young fruits.

⑦ Fertilize and prune.

Soil and fertilizer management

1. Horizontal intercropping

Horizontal intercropping refers to intercropping with perennial crops, trees and fruit trees. When walnuts are intercropped, while the crops are plowed, loosened, weeded, fertilized and irrigated, the walnut trees are also tended, so the walnut trees grow robustly, pests and diseases are reduced, and the yield is high.

2. Three-dimensional intercropping

Three-dimensional intercropping refers to using the space and open ground under walnut trees to intercrop shorter crops and shrub species. The most commonly used method in most mountainous areas of Yiliang is intercropping with food crops, but the following points should be noted when intercropping:

① Because young walnut trees have small trunks and root plates, low-stalk crops such as wheat, millet, sweet potato and dwarf beans should be planted, and a tree plate about 1.6 m in diameter should be left around the young trees to facilitate fertilization and weeding and prevent competition for nutrients.

② After the walnut trees grow taller, corn, wheat, upland rice, beans, peanuts, strawberries, radishes, etc. can be planted; these are relatively ideal intercrops.

③ Walnut roots can secrete an organic chemical substance - juglone, which has an inhibitory effect on the growth of some plants. Therefore, walnut groves should not be intercropped with crops sensitive to juglone, such as apples, black strawberries, tomatoes, potatoes, alfalfa, etc.

④ Plowing the soil: Walnut trees without intercropping should not be left barren; barrenness will cause a large occurrence of pests and diseases, decline in growth vigor and yield, and even lead to tree death. Plow twice a year, the first time in spring and the second time in autumn. When plowing, plow deeper outside the crown and shallower near the tree plate to prevent root damage. Plowing the soil can achieve the goals of eliminating weeds, storing water and preserving moisture, improving the soil's physical and chemical properties, increasing soil fertility, and eliminating some overwintering pests and diseases.

⑤ Weeding: Carry out twice a year, once in May-June and once in August-September, to protect the normal growth of walnut trees and facilitate fruit harvesting.

3. Fertilization management

Fertilization is an important measure to ensure normal growth and development of walnut trees and achieve high and stable yield. It can not only directly supply nutrients, but also improve the mechanical composition and structure of the soil, and promote the root development, flower bud differentiation and earlier fruiting of young trees.

① Reasonable fertilization: In the process of growing, especially after entering the full bearing period, walnut trees need sufficient nutrient supply. Walnuts need many nutrients, among which the nutrient elements absorbed in larger amounts include nitrogen, phosphorus, potassium, calcium, magnesium, boron, iron, zinc, copper, manganese, etc. Some of these elements are abundant in the soil, but some are lacking in the soil and need to be supplemented by fertilization. Walnuts need many kinds and large amounts of nutrient elements, but it is not that the more fertilizer applied the better; fertilization must be reasonable. So-called reasonable means adapting to local conditions, applying fertilizer at the right time, in the right amount and scientifically, so as to both give play to the fertilizer effect and save fertilizer.

② Fertilization amount: The fertilization amount is determined according to soil fertility, walnut growth status and the nutrient demand of walnut trees at different periods. Generally speaking, young trees should be mainly fertilized with nitrogen, while adult trees should be fertilized with nitrogen while increasing phosphorus and potassium. Under medium soil fertility conditions, for 1-5 year-old non-fruiting trees, the annual fertilization amount per plant is: 100 g nitrogen fertilizer for 1-year-old trees, 30 g each of phosphorus and potassium fertilizer, and thereafter nitrogen fertilizer increases by 100 g per year of tree age, reaching 500 g at 5 years old, with phosphorus and potassium fertilizer increased appropriately, and 5 kg of farmyard manure added; after 6-8 years old when fruiting begins, the annual fertilization amount is 550 g nitrogen fertilizer, 400 g phosphorus fertilizer, 500 g potassium fertilizer, and 5 kg of farmyard manure added.

4. Fertilization time

① Base fertilizer: Generally applied in spring and autumn, with autumn being better. The base fertilizer is mainly slow-acting farmyard manure, such as stable manure, compost, green manure, straw manure, distiller's grain manure, mud manure, etc.

②Top dressing: Generally carried out 2-3 times per year. The first top dressing is applied before flowering or at the early stage of leaf expansion, mainly with quick-acting nitrogen, whose main purpose is to promote flowering, fruit setting and new shoot growth; the top dressing amount should account for 50% of the annual top dressing amount. The second top dressing is in June during the vigorous growth period, mainly with quick-acting nitrogen, whose main purpose is to meet the nutrient demands of the vigorous growth period, to promote fruit development and new shoot growth, reduce fruit drop, and benefit flower bud differentiation. The third top dressing is carried out in July during the nut hardening stage (for young trees that have not yet borne fruit, the third top dressing may be omitted), mainly with a nitrogen, phosphorus and potassium compound fertilizer, whose main purpose is to supply the nutrients needed for kernel development and ensure the nuts are plump and full.

5. Fertilization methods

The main fertilization methods for walnut trees include radial fertilization, ring fertilization, hole fertilization, strip fertilization, and broadcast application over the whole orchard. Adapt measures to local conditions and choose the method with good results.

①Radial fertilization With the tree canopy as the center, within the canopy projection area, dig 4-8 fertilization trenches in a radial pattern, with a trench width of 20-40 cm and a depth of about 30 cm (slightly deeper for base fertilizer, shallower for top dressing); the trench length is similar to the canopy radius, and the trench depth gradually increases from inside the canopy to outside the canopy. After the fertilization trenches are dug, thoroughly mix the fertilizer with the soil and fill it into the trenches, then cover with soil. The positions of the fertilization trenches should be changed every year, and gradually moved outward as the canopy continues to expand. This method is mainly used for trees with strong vigor and older tree age.

②Ring fertilization With the trunk as the center, along the outer edge of the canopy, dig a ring-shaped trench 30 cm deep and 20-40 cm wide, mix the fertilizer with the soil and fill it into the trench, then cover with soil. Bury base fertilizer deeper and top dressing shallower. The fertilization trench can be dug as a half ring or a full ring; for half rings, the trenches must be dug in rotation, one direction per year. This method is more suitable for young trees under 4 years old.

③Hole fertilization Within the canopy projection area, dig several small holes (the number and size depending on the canopy size) and bury the fertilizer in them. This method is generally used for top dressing.

④Strip fertilization Between walnut tree rows or between plants, on two opposite sides cut at the canopy edge, dig parallel fertilization trenches respectively; the width and depth of the trenches are the same as for the other methods, and the length is determined by the canopy size. The positions of the dug trenches are changed once a year. This method is mostly suitable for young trees and mature trees.

⑤Broadcast application over the whole orchard This is a commonly used method for fertilizing large trees. The specific procedure is: first spread the fertilizer evenly over the whole orchard, then shallowly till. This method is simple and easy to carry out, but its drawback is that the fertilizer is applied too shallowly, and frequent broadcast application will draw fine roots toward the soil surface.

When fertilizing, note that plant ash must not be mixed with decomposed human excrement and urine, because the main component of plant ash is potassium carbonate, whose aqueous solution is alkaline, while the nitrogen in decomposed human excrement and urine exists in the form of ammonium carbonate; when it encounters alkalinity, it volatilizes ammonia, thereby causing nitrogen loss and reducing fertilizer efficiency. For the above 5 methods, irrigation should be carried out immediately after fertilization to increase fertilizer efficiency. If there are no irrigation conditions, water conservation measures should be taken.

Harvesting and processing of walnut fruit

The mature harvesting of walnuts varies with altitude, climate, site conditions, variety and tree age. The same variety has different maturity periods due to different altitudes; under the same site conditions, old trees mature first and young trees mature later, wasteland matures first and cultivated land matures later, but most varieties mature around White Dew. It is very important to master the timing of harvesting and beating walnuts. If harvested and beaten too early, the seeds are not yet mature and not plump. This not only affects fruit quality, but also makes the fruit difficult to detach, and it is easy to damage flower buds, affecting the next year's fruiting. If harvested and beaten too late, the seeds are overripe and a large number drop off, causing losses.

The characteristics of walnut maturity are that the outer fruit skin changes from green to yellow-green and splits. The maturity of walnut fruits on the same tree is not uniform. When the outer fruit skin of the walnut tree splits and 1/3 of the fruits have split, they can be harvested. The method is to use a long bamboo pole to strike the small branches sideways, shaking the walnut fruits to the ground. When striking, care must be taken to protect the branch tips; do not strike hard with force, as breaking small branches and flower buds will affect the next year's fruiting.

Control of major diseases and insect pests

The main diseases and insect pests of walnut mainly include walnut bacterial blight and walnut anthracnose, trunk-boring pests - longhorn beetles and carpenter moths, and leaf-eating pests - scarab beetles, nettle moths, etc.

1. Walnut bacterial blight

Walnut bacterial blight damages fruits and also leaves and new shoots, causing fruit rot and early fruit drop, and reducing the kernel yield. It is a bacterial disease. Control methods:

①Breed and cultivate disease-resistant varieties.

②Maintain healthy and vigorous tree growth, enhance disease resistance, and promptly remove diseased fruits, diseased leaves and other sources of disease.

③Before germination, spray 3-5 degrees Baume lime sulfur mixture. From May to June, spray 1:2:200 Bordeaux mixture or 50% thiophanate-methyl wettable powder 500-800 times solution, once each before female flowering, after flowering, and at the young fruit stage.

2. Walnut anthracnose

It mainly damages fruits. It is a fungal disease and can mutually infect with the apple anthracnose pathogen. Control methods: before onset, spray 1:1:200 (copper sulfate: lime: water) Bordeaux mixture; during the onset period, spray 40% ziram wettable powder 800 times solution, or 50% carbendazim wettable powder 1000 times solution, 75% chlorothalonil 600 times solution, 70% or 50% thiophanate 800-1000 times solution, once every half month, 2-3 times; if an adhesive (0.03% hide glue, etc.) can be added, the effect is even better.

3. Walnut longhorn beetle

The walnut longhorn beetle mainly damages walnut branches and trunks, causing the death of some main branches and the central leader of walnut trees, and in some cases the death of the entire tree. It is a devastating pest on walnut trees. Control methods: during the larval activity period, use dichlorvos medicinal mud and plug the insect holes to kill the pests, or in late winter and early spring use carbofuran for root burial to control the pests.

4. Carpenter moth

The carpenter moth mainly damages walnut branches, causing the death of some branches of walnut trees. Control methods: during the larval activity period, use dichlorvos medicinal cotton and plug it into the insect holes to kill the larvae, or prune off the infested branches and burn them. When larvae are found damaging the root crown, pry open the bark and dig out the larvae; open the soil sealing the root crown, inject 40% dimethoate emulsifiable concentrate 20 times solution into the insect holes, then seal tightly with wet soil to kill the larvae; during the adult egg-laying period, spray 1-2 times 50% parathion emulsifiable concentrate 400 times solution from below 1.5 m on the trunk to the root crown to kill newly hatched larvae.

5. Scarab beetles and nettle moths

Adult scarab beetles and nettle moth larvae mainly feed on leaves, causing walnut trees to be stripped bare, thereby affecting tree growth. Control methods: when the infestation is severe, during the period of mass adult occurrence, use bonfires or black light lamps for trapping and killing; options include 90% trichlorfon 800 times solution, dichlorvos 800 times solution, isocarbophos 800 times solution, and parathion 2000 times solution, with a killing rate of over 90%.

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