Detailed Explanation of Strawberry Planting Techniques and Cultivation Management Points

Strawberry, also called red berry, foreign berry, ground berry, etc., is a red flower-fruit. Strawberry is the general term for plants of the genus Fragaria in the rose family (Rosaceae), and is a perennial herbaceous plant. The strawberry has a heart-shaped appearance, is bright red and tender, with juicy flesh and a special rich fruit aroma. Strawberries have high nutritional value and are rich in vitamin C, which helps digestion; at the same time, strawberries can also strengthen the gums, freshen the breath, and moisten the throat. In spring, people's liver fire tends to be relatively strong, and eating some strawberries can help suppress it.

In addition, strawberries are best eaten after a meal, because they contain a large amount of pectin and cellulose, which can promote gastrointestinal peristalsis, aid digestion, improve constipation, and prevent hemorrhoids and intestinal cancer. The nutritional ratio of strawberries is very reasonable; the vitamin C content is about 10 times that of an equal amount of watermelon, grapes, or apples. In addition, strawberries are rich in iron, fructose, glucose, citric acid, malic acid, etc. For the lung-heat cough, sore throat, and boils that easily appear in spring, the nutrients contained in strawberries can play a supporting therapeutic role. Also, because they contain iron, friends with anemia can also eat them often. However, doctors also remind us that although strawberries are a very good appetite-stimulating fruit, they are cooling in nature, so in early spring do not eat too many at one time; especially people with weak and cold spleen and stomach, those prone to diarrhea, and those with excessive stomach acid should control the amount even more when eating strawberries.

Production and Cultivation Overview

At present, most countries in the world cultivate strawberries. The United States has a strawberry cultivation area of 23,000 hectares, with an output of 567,000 tons, accounting for about 28% of world total production, with an average yield of 24.6 tons/hectare. Japan has a cultivation area of 11,000 hm2, with an output of 218,000 tons, accounting for 11% of world total production, with an average yield of 19.3 tons/hectare. Europe is the main strawberry producing area, accounting for about 50% of world production. Poland, Italy, Spain, the Netherlands, Belgium, Russia, Romania, and the United Kingdom have relatively large cultivation areas, with yields generally 9.5-18.3 tons/hectare. China is the country with the richest wild strawberry resources in the world, began using wild strawberries very early, and has continued this to the present day. Large-fruited strawberry cultivation in China began in 1915, but in the past it received little attention and developed slowly. Since the 1980s, strawberry production has developed rapidly. China currently has a strawberry production area of about 70,000 hm2, ranking first in the world in area. The main producing areas are distributed in eastern coastal regions such as Anhui, Liaoning, Hebei, Shandong, Jiangsu, Shanghai, and Zhejiang. In recent years, Sichuan, Anhui, **, Beijing, and other areas have also developed quickly. Key strawberry producing areas include Sihong in Jiangsu, Hefei in Anhui, Dandong in Liaoning, Baoding in Hebei, Yantai in Shandong, the suburbs of Shanghai, Shuangliu in Sichuan, and Lianyungang in Jiangsu, among others. Among them, Changfeng County in Hefei currently has a strawberry planting area of 145,000 mu, with an annual strawberry output of more than 200,000 tons and a total output value of more than 1 billion yuan. By 2012 it will expand to more than 200,000 mu, and the country's only national-level virus-free strawberry science and technology park has been built. Every year, promotion meetings are held at the Great Hall of the People in Beijing and the Diaoyutai State Guesthouse in Beijing, and matchmaking meetings between dealers and strawberry growers are held at the Beijing Xinfadi Market, Tianjin Hongqi Market, and Shenyang Fruit Wholesale Market. Its production scale has already risen from originally first in Anhui Province to become the largest strawberry county in the country, and Changfeng strawberry has become a well-known trademark in China.

Growth Conditions

Strawberries are suitable for planting in soil with plenty of sunlight and good drainage. The soil depth should be about 8-10 inches. For large strawberry plants, the row spacing should be 12 inches, and the plant spacing about 18 inches. The runners of the plants should be removed in time to favor fruiting. Strawberry yields are cyclical, so it is best to cultivate some new plants in the first few years of planting. If you do not like managing strawberries, you can plant one strawberry every 18-24 inches, so the strawberries can spread freely. Of course, it will look a bit messy, and the strawberries will not be large. If you want to avoid this situation, you can appropriately remove some runners. In autumn, spread a layer of soil over the plants to prevent frost. After the soil freezes, you can spread another 3-4 inches of dry grass over the plants. In the spring of the following year, when new leaves grow, remove the dry grass. After the weather turns warm and stable, remove the covering soil on the surface of the plants. But leave some dry grass between the rows to prevent weed growth and maintain soil moisture.

Planting Techniques

In world small berry production, strawberry ranks first. Strawberry is an economic crop with fast fruiting, early maturity, easy propagation, a short cycle, and high benefits.

1. Preparation of the Propagation Seedling Plot

1) Choose paddy field that drains and irrigates easily, is not prone to waterlogging, and has relatively high fertility, or vegetable garden soil (previous crop and soil blocks where chlorsulfuron herbicide has been used). Apply sufficient base fertilizer (cake fertilizer, farmyard manure, human excrement and urine, phosphate fertilizer), spread it after it has decomposed, and at the same time apply 1 jin of 50% phoxim or 3 jin of 3% carbofuran per mu, mix with 25 jin of fine soil, spread it, then turn the soil and make beds. The bed width is 1.5—1.8 m, turtle-back shaped to prevent water accumulation, and the soil should be crumbly.

2) Selection and planting of each plant. Choose plants with new leaves developing normally, symmetrical leaflets, dark green leaf color, thick petioles, large leaves, robust growth, and good yield potential, and remove diseased leaves and old leaves. In our city, planting in the propagation plot is generally done in April of the Gregorian calendar (daily average temperature above 12°C). Plant two rows per bed, planting 30 cm from the edge of the bed surface, with a plant spacing of 60—80 cm. After planting, water immediately to settle the roots.

3) Fertilizer and water management. The principle of fertilizing the seedling plot is: moderate nitrogen, heavy phosphorus and potassium. Per mu, use 200 jin of decomposed rapeseed cake plus 7—8 jin of urea, 50 jin of phosphate fertilizer, and 10 jin of potassium fertilizer; dissolve in water and irrigate once every 20 days. Human excrement and urine can also be used instead.

4) After each plant has survived planting (one week later), spray gibberellin (920). That is, each gram of “920” mixed with 40—50 jin of water (first dissolve the 920 in high-concentration white liquor in a clean bowl) and spray. Spray twice in succession, with an interval of one week to 10 days. In August, strictly control nitrogen fertilizer application and allow it to be appropriately dry, but not excessively.

2. Timely Transplanting and Preparation and Specifications of the Transplanting Site

1) Field preparation: choose fertile fields or soil that drain and irrigate easily as the field site. Strawberries have a relatively large fertilizer requirement, and in the later stage (fruit-picking period) fertilizer is generally applied less, so the base fertilizer must be sufficient, mainly organic fertilizer. Generally, per mu: 1,500 kg of organic fertilizer, 50 kg of cake fertilizer, 25-30 kg of compound fertilizer, 7.5 kg of urea, 40 kg of calcium superphosphate, and 10 kg of potassium fertilizer. Except for urea and compound fertilizer, mix the other fertilizers well and let them decompose, then mix evenly with urea and compound fertilizer, spread on the soil surface, and then turn the soil and make ridges. Generally the ridge height is 25—30 cm, the ridge bottom width is 90 cm, and the ridge surface is 60 cm. The ridge furrow width is 30 cm; the ridge bottom plus furrow width is about 100--120 cm, and the ridge surface has a certain slope down to the furrow bottom.

2) Planting period and method: facility cultivation in our city is generally transplanted from the end of September to the beginning of October. Planting density should be treated according to seedling condition and whether the land is fertile or poor; strong seedlings, dry seedlings, and fertile land are suitable for sparse planting. Otherwise, dense planting is suitable. Generally, 7—9 thousand plants are planted per mu. After the ridges are made, plant 5 cm inward from the ridge edge, with a plant spacing of 12—15 cm. The ridge length generally does not exceed 30 m.

When transplanting, note the following: First, directional transplanting: with the arched back facing outward, which helps the inflorescence emerge later. Second, double-row triangular (pin-shaped) planting, which helps ventilation, light penetration, and rooting. Third, grasp the depth, so that the roots are not exposed below and the seedling heart is not buried above, which helps tillering. Fourth, transplant with soil, which helps survival. Fifth, plant on sunny afternoons and all day on cloudy days. Sixth, strengthen water and fertilizer management; after planting, immediately water thoroughly to settle the roots, and when watering, add thiophanate-methyl at 800 times dilution. Seventh, check for and fill gaps in seedlings in time.

3. Field Management

1) Pre-winter management: after planting and survival until mid-to-late November, pay attention to three points: first, apply thin fertilizer frequently, mainly nitrogen fertilizer, preferably diluted manure water; second, keep it moist; third, weed, loosen the soil, and remove old leaves and diseased leaves.

2) Management before and after flowering: before flowering, at the young fruit stage, and at the fruit enlargement stage, promptly spray Caiguo Zhuangdiling to increase the cyclic fruit-setting rate of strawberries, promote fruit development, and at the same time use thiophanate-methyl, procymidone, dimethoate, etc., to control diseases and pests.

3) Overwintering management: before the cold winter arrives, water thoroughly to prevent cold damage.

4. Timely Film Covering

Covering with film can multiply yield and reduce fruit loss and prevent contamination. Film is divided into greenhouse film covering and plastic mulch. The time for covering film should be when the daily average temperature drops to about 8°C, then begin covering. Cover the greenhouse film first, then the plastic mulch. Before covering, first weed, cultivate, fertilize, and control diseases and pests. (Greenhouse construction and film purchase models) Due to limited space, these will not be introduced; those interested please contact the agricultural science institute. After covering, the temperature inside the greenhouse at night should be kept at 8°C, and around 20°C during the day; on sunny days at noon, the film should be lifted, and at 3 p.m. it should be covered again. If the temperature is too high, the pollen dies; if the temperature is too low, the pollen activity is insufficient, making pollination difficult.

5. Greenhouse Planting

Strawberries planted in greenhouses in early spring can flower and fruit.

6. Open-Field Cultivation Techniques

Open-field strawberry cultivation can use two methods: one planting per year or one planting for many years. The former rotates with other crops after harvest each year; under this system, strawberries have strong vitality, good fruit quality, early maturity, and few diseases and pests. However, the key technique is to cultivate strong seedlings with more than 3 leaves and a well-developed root system, and they can be appropriately densely planted. One planting, many years of harvest, transplant in autumn, harvest in May of the following year. After 3 years, renew once using runner seedlings

1) Land Preparation and Base Fertilizer Application

Strawberries have shallow roots and are suitable for growing in loam or sandy loam with good permeability and rich organic matter. The previous crop is preferably wheat, beans, melons, and vegetables. They can also be intercropped with tall-stalk crops. Deeply plow the land early, apply 3,000 kg per mu of fully decomposed manure as base fertilizer, and sun the soil. When preparing the land, apply 25 kg of diammonium phosphate and 10 kg of potassium chloride. Irrigate once with a small amount of water before planting.

2) Planting

Before transplanting, select seedlings with 5-6 compound leaves, robust plants, and intact root systems, and plant them in the field on cloudy days or in the evening. The planting density is (20-25) cm×(25-30) cm. Plant the seedlings so that they are shallow enough not to expose the roots and deep enough not to bury the heart. After planting, irrigate once thoroughly; after the water dries, check the seedlings in time, loosen the soil, earth up, or fill gaps. When planting, make the arched back of the seedling face toward the flat bed for easy management and fruit harvesting.

3) Field Management

After strawberry planting, water to settle the roots, then keep the field moist, lower the soil temperature, and irrigate timely and appropriately according to field humidity. When irrigating overwintering water, combine with applying 15-20 kg/mu of compound fertilizer to improve overwintering ability. The spring flowering and fruiting period is a water-sensitive period, and the soil should be kept moist. When irrigating, combine with applying nitrogen-phosphorus compound fertilizer or foliar fertilizer; do not use too much water, and drain accumulated water in time. At the same time, before flowering, at the young fruit stage, and at the fruit enlargement stage, promptly spray Caiguo Zhuangdiling to increase the cyclic fruit-setting rate of strawberries and promote fruit development. After strawberry transplanting and survival, cultivate frequently and weed. After fruit harvest, earth up in time. In winter, appropriately use ground cover to prevent cold, keep warm, and help strawberries overwinter smoothly. Now, plastic film mulching is mostly done from the end of January to the beginning of February, which can promote earlier strawberry maturity and extend the harvest period.

Strawberry Care

Once strawberries begin to fruit and turn red, be careful not to let birds peck at them, because birds easily notice red things. Put a net over the strawberries, or cover the strawberries with a wooden basket. But if you have a greenhouse at home, you can move the strawberries into the greenhouse, which is even better. Strawberries will also fruit more easily. After the strawberry fruiting period is over, you can move them out of the greenhouse and place them outdoors to overwinter.

From a certain perspective, if the strawberry plants experience some frost, it is more beneficial for increasing yield the following year. Strawberry is a plant that is very easy to cultivate and can be transplanted. Sometimes you may find that the plants have yellow leaves, but do not worry; just remove them. In winter, you can keep the yellow leaves until new leaves grow in the following spring, then remove the dead yellow leaves, and pay attention to watering, weeding, and pest control. You can also plant strawberries in plant bags, but be sure to water evenly, and prevent birds from pecking at the strawberries and prevent pests. The soil in plant bags easily dries out, so it needs to be checked frequently to ensure the soil stays moist. If planting on a small scale, try not to use pesticides; you can spray diluted dishwashing detergent, or place some melon rind, beer, etc., nearby to lure away snails and other soft-bodied crawling pests.

Disease Control

When growing strawberries, change or control the environmental conditions for their growth and development, overcome adverse factors, so that they flower and fruit normally, achieve early harvest, and supply the market out of season. Greenhouse cultivation has the characteristics of low investment, quick results, high yield, and good benefits, with 1,500 kg produced per mu, more than double that of open field; the output value is more than 10 times higher than open field. In order to extend the strawberry supply period and meet the demand for year-round supply, four cultivation forms are currently commonly used:

(1) Forcing cultivation (ripening and marketed from November to December in late autumn and early winter).

(2) Semi-forcing cultivation (ripening and marketed from February to March).

(3) Super-forcing cultivation.

(4) Inhibiting cultivation.

Although greenhouse production has many advantages, it also has shortcomings, because the greenhouse is hot and humid inside. It easily creates extremely favorable environmental conditions for the occurrence of diseases and pests. Strengthening integrated disease and pest control, “control early, control small, control thoroughly”, is especially important, and has become a key link in achieving high and stable yields of greenhouse strawberries.

1. Leaf Spot Disease

Also called snake-eye disease, it mainly damages leaves, petioles, fruit stalks, tender stems, and seeds. Dark purple small spots form on the leaves, and after expanding they form nearly round or oval lesions, with purple-red-brown edges and gray-white centers, slightly finely ringed, making the entire lesion look like a snake eye; no small black grains form on the lesions.

Control measures: promptly remove diseased leaves and old leaves. In the early stage of the disease, use 70% chlorothalonil wettable powder at 500-700 times dilution, and spray again after ten days. Or use 70% mancozeb wettable powder, 200 g per mu mixed with 75 kg of water for spraying.

2. Powdery Mildew

It mainly damages leaves, and also attacks flowers, fruits, fruit stalks, and petioles. Leaves curl upward into a spoon shape. Affected flower buds and petals turn purple-red, cannot bloom or bloom as complete flowers, and the fruit does not enlarge, becoming slender; young fruit loses its luster and hardens. Strawberries damaged near the ripening stage lose their commercial value.

Control measures: at the center of the disease and around it, focus on spraying 0.3 degrees Baume lime sulfur mixture. After harvest, cut all leaves in the whole orchard, and spray 70% thiophanate-methyl at 1000 times dilution or 50% thiram at 800 times dilution and 30% triflumizole at 5000 times dilution, etc.

3. Gray Mold

It is the main disease after flowering and can occur on flowers, petals, fruits, and leaves. On fruits during the enlargement period, brown spots form and gradually expand, densely covered with gray mold, causing the fruit to soften and rot, seriously affecting yield.

Control measures: from the bud stage to the flowering stage, spray 25% carbendazim wettable powder at 300 times dilution, 50% captan wettable powder at 800 times dilution, 50% iprodione at 500-700 times dilution, etc.

4. Root Rot

Starting from the lower leaves, the leaf margins turn red-brown and gradually wilt upward until they die. The support becomes dark brown and rots in the middle, and the central column of the root is red.

Control measures: before strawberry transplanting, use 40% asparagus green powder at 600 times dilution and pour it on the bed surface, then cover with soil, level and transplant, so as to effectively kill pathogens in the soil, lower the base number of inoculum in the field, and reduce chances of infection.

5. Verticillium Wilt

This disease is a soil disease. The main symptoms are deformed young leaves, yellowing leaves, and extremely rough leaf surfaces. Subsequently the leaf margins turn brown and wilt inward until they die.

Control measures: strictly introduce disease-free plants for planting; shorten the renewal period; use 13.5 liters to 20 liters of chloropicrin or solar film covering with irrigation for soil disinfection; pull out and burn affected plants.

Walnut High-Yield Planting Techniques and Cultivation Management Points

Cultivation of Walnut Seedlings

In order to ensure the quality of seedlings for walnut base afforestation and avoid quality variation caused by propagation and seedling raising from local walnut seedlings, efficient and rapid propagation and grafting techniques are used to cultivate grafted walnut seedlings, that is, using one-year-old iron walnut seedlings for in-place rootstock grafting or transplanted rootstock 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 realization of improved walnut varieties.

2. It can significantly increase yield and improve quality.

3. It can dwarf the plant and bear fruit earlier.

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

Walnut Planting

Walnut planting begins with the selection of the planting site. Choose flat land, terraced land, and gentle slope land as the walnut planting base, and carry out full or block land preparation. Planting should achieve large holes, spread roots, close root-soil contact, full backfilling of pond soil, sufficient watering, heat and moisture preservation, and sufficient nutrients, so as to ensure the survival of walnut planting and benefit the rapid growth of walnut trees. In order to master practical and feasible walnut planting techniques, the forestry department, after years of exploration, has 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, put in a load of farmyard manure, plant a strong seedling, water a bucket of clear water, cover a piece of plastic film”.

1. Plot Selection

Choose relatively concentrated and contiguous land such as flat land, terraced land, and gentle slope land with loose soil and good drainage as the walnut planting base. It grows best on slightly alkaline soil containing calcium. Walnut is a deep-rooted tree species, and the root system needs a deep soil layer of more than 1 m to maintain good growth and development. If the soil layer is too thin, it easily forms “little old man trees”, or the shoot tips wither year after year, and yield cannot be formed.

2. Land Preparation and Planting

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

① Land preparation: digging planting ponds in advance helps soil maturation and increases moisture in the planting ponds. Digging planting ponds can be done as early as summer. The pond specifications are length×width×depth of 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 groove to facilitate water accumulation. The backfilled pond is left until planting time. In places where conditions do not allow digging ponds in advance in summer, ponds can also be dug and planted immediately before planting. The pond is 100 cm long and wide, and 80—100 cm deep. When digging, pile the topsoil and subsoil (stone) in the pond separately. If the soil is clayey or the lower layer is gravel or impermeable, the planting pond should be enlarged and deepened, and guest 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 calcium superphosphate or 1.5 kg of fused calcium magnesium phosphate with topsoil and fill into the pond. If farmyard manure is lacking, leaves, weeds, turf soil, organic garbage, etc., can be used instead. The position of the ponds is generally arranged horizontally, that is, each row is on the same horizontal plane.

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. It is not suitable to plant during the vigorous summer growth period.

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

④ Planting density: 12—16 plants per mu is suitable. 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 row spacing is 6 m×7.5 m or 6 m×7 m, about 15—16 plants per mu. Usually, walnut plots intercropped with crops have better results, using cultivation instead of tending, and short-term crops to support long-term crops, achieving multiple benefits from walnuts above and grain below, so as to obtain high yield and high quality.

3. Planting Techniques

Planting techniques can be summarized as the eighteen-character formula: “place straight, orient, stand upright, bury 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 Bury soil: cover with nutrient soil mixed with fertilizer.

⑤ Lift gently: after the root system is completely buried, gently lift the seedling once so that the root system spreads out and closely combines 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, 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 a 1 m×1 m piece of agricultural plastic film, 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 film edges below the ground surface.

Walnut Management

Walnut management refers to the follow-up management after walnut planting, namely 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, with 25 kg per plant each time. Where conditions permit, irrigate 1—2 times each year before walnut flowering. Walnut trees are relatively sensitive to surface water accumulation and excessively high groundwater levels, and should be drained in time. In areas with relatively high groundwater levels, deep ditches can be dug to lower the water level. According to the growth depth of the walnut tree root system, drainage ditches 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 prevent 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 walnuts have grown to 80—100 cm after planting, determine the trunk, retaining 3—4 main branches in a sparse layered form or natural open-center form.

① Sparse layered form (with trunk form): generally has 6—7 main branches, arranged in 2—3 layers. Its characteristics are: the crown is semi-circular, ventilation and light penetration 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 trees with strong apical dominance.

② Natural open-center form (no 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 quality and poor fertilizer and water conditions, and for early-fruiting varieties with an open tree posture.

Trunk determination method for late-fruiting walnuts: after spring sprouting, select and retain 1 strong bud or robust branch above the trunk determination height as the first main branch, and cut off all branches and buds below it. If the young tree grows too vigorously and branching is delayed, in order to control the trunk height, shorten it at an appropriate position above the required trunk height to promote the bud at the cut to sprout, and then select and retain the first main branch.

Trunk determination method for early-fruiting walnuts: after sprouting in the year of planting, remove all lateral buds below the required trunk height. If the young tree has not reached the trunk determination height, trunk determination can be done the following year. If the terminal bud is necrotic, select and retain a robust bud close to the terminal bud, 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 for young trees, full-bearing trees, and aging trees. At the same time, during the flowering and fruiting period, appropriately thin flowers and fruits.

The pruning of young trees varies with the different growth and development characteristics of each variety; mainly cut off weak branches, crossing branches, overlapping branches, parallel branches, and diseased branches, so as to cultivate backbone branches at all levels and fruiting branch groups. The specific methods: control secondary shoots; control water sprouts; properly handle vigorous vegetative branches; thin out excessively dense branches and properly handle downward-growing branches.

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

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

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

4. Walnut Top Grafting for Variety Improvement

Walnut top grafting for variety improvement is an important way to improve varieties and realize the cultivarization of walnut cultivation. It can be divided into hardwood grafting and greenwood 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 sprouting. The scion thickness should be about 1.5 cm, with a small pith, plump branches, full buds, and no diseases or pests. After collection, the scions should be put into a fruit cellar or ice cellar at 0—5°C by variety and specification with labels attached, and taken as needed during grafting. The grafting time is from early April to early May. The grafting target is 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 regrafting can also be used. The grafting method is to first cut the scion into 10—15 cm branch segments, with more than 2 full buds on each segment, and cut the branch segment 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, smooth the saw cut, and cut a 2—3 cm crescent-shaped incision 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 5—7 turns with plastic rope, binding tightly from top to bottom. When binding, start from the graft union; if the binding position is too low, it is not conducive to survival after grafting. After binding, carry out heat preservation and shading treatment, generally using waste newspaper or a tube shape and then filling in fine moist soil, but it must not be too wet, and put a plastic bag over it.

② Greenwood grafting: mainly square bud grafting, in June. The scion is collected and grafted immediately, and the rootstock is the newly sprouted branch of the current year. For grafting on large trees, prune in January and first shorten the old branches, and after new shoots sprout, retain the new shoots used for grafting.

5. Grafting Precautions

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

① Remove sprouts in time: promptly remove new buds sprouting on the rootstock.

② Ventilate at the right time: ventilate 20—30 days after grafting. The first time, make an opening 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 supports to prevent wind breakage: when the grafted tender branch grows to 20 cm, promptly fix supports to prevent wind breakage.

④ Loosen the binding and remove the film.

⑤ Cut the scion and cut the rootstock.

⑥ Remove young fruit.

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, the plowing, loosening of soil, weeding, fertilizing and irrigation of the crops also serve to tend the walnut trees, so the walnut trees grow vigorously, pests and diseases are reduced, and yields are 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. In most mountainous areas of Yiliang, the most commonly used method is intercropping with food crops, but the following points should be noted when intercropping:

① Because young walnut trees have small trunks and root zones, low-stalk crops such as wheat, millet, sweet potato and dwarf beans should be planted, and a tree disc about 1.6 m in diameter should be left around the young trees to facilitate fertilizing 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 intercrop crops.

③ Walnut roots can secrete an organic chemical substance——juglone, which inhibits the growth of some plants. Therefore, walnut groves should avoid intercropping with crops sensitive to juglone, such as apples, blackberries, tomatoes, potatoes, alfalfa, etc.

④ Plowing the soil: Walnut trees that are not intercropped should not be left uncultivated; neglect will cause pests and diseases to break out in large numbers, reduce growth vigor and yield, and even lead to tree death. Plowing is carried out 2 times per year, the 1st in spring and the 2nd in autumn. When plowing, it should be deeper outside the canopy and shallower near the tree disc to prevent root damage. Plowing the soil can achieve the goals of eliminating weeds, storing water and preserving moisture, improving the physical and chemical properties of the soil, increasing soil fertility, and eliminating some overwintering pests and diseases.

⑤ Weeding: Carry out 2 times per year, once each in May—June and 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 to achieve high and stable yields. It can not only directly supply nutrients, but also improve the mechanical composition and structure of the soil, promote root development of young trees, flower bud differentiation and earlier fruiting.

① Rational fertilization: During the growth process of walnut trees, especially after entering the full fruiting period, they need a sufficient supply of nutrients. Walnuts require many nutrients, among which the nutrient elements absorbed in relatively large amounts include nitrogen, phosphorus, potassium, calcium, magnesium, boron, iron, zinc, copper, manganese, etc. Some of these elements exist in large amounts in the soil, but some are deficient in the soil and need to be supplemented by fertilization. Walnuts require many types and amounts of nutrient elements, but it is not that the more fertilizer applied the better; fertilization must be rational. So-called rational means adapting to local conditions and applying fertilizer at the right time, in the right amount and scientifically, so as to both give play to the effect of the fertilizer and save fertilizer.

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

4. Fertilization time

① Base fertilizer: Generally applied in spring and autumn, with autumn being better. The base fertilizer is mainly slow-release farmyard manure, such as barnyard manure, compost, green manure, straw manure, dregs manure, mud manure, etc.

② Topdressing: Generally carried out 2—3 times per year. The 1st topdressing is carried out before flowering or at the early stage of leaf expansion, mainly with quick-acting nitrogen, and its main role is to promote flowering and fruit setting and new shoot growth; the topdressing amount should account for 50% of the annual topdressing amount. The 2nd topdressing is in June during the vigorous growth period, mainly with quick-acting nitrogen, and its main role is to meet the nutrient demand during the vigorous growth period, so as to promote fruit development and new shoot growth, reduce fruit drop, and benefit flower bud differentiation. The 3rd topdressing is carried out in July during the nut hardening period (if the young trees have not yet fruited, the 3rd topdressing may be omitted), mainly with nitrogen, phosphorus and potassium compound fertilizer, and its main role 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. It is necessary to adapt to local conditions and choose methods with good effects.

① Radial fertilization  With the canopy as the center, within the canopy projection range, dig 4—8 fertilization ditches in a radial pattern, with a ditch width of 20—40 cm and a depth of about 30 cm (slightly deeper for base fertilizer and shallower for topdressing); the ditch length is similar to the canopy radius, and the ditch depth gradually deepens from inside the canopy to outside the canopy. After the fertilization ditches are dug, mix the fertilizer thoroughly with the soil and fill it into the ditches, then cover with soil. The position of the fertilization ditches should be changed each year, and gradually moved outward as the canopy continuously expands. This method is mainly used for trees with strong growth and older tree age.

② Ring fertilization  With the trunk as the center, along the outer edge of the canopy, dig a ring-shaped ditch 30 cm deep and 20—40 cm wide, mix the fertilizer with the soil and fill it into the ditch, then cover with soil. Base fertilizer should be buried deeper and topdressing shallower. The fertilization ditch can be dug as a half ring or a full ring; for half-ring digging, the digging should be rotated, one direction per year. This method is more suitable for young trees under 4 years old.

③ Hole fertilization Within the canopy projection range, 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 topdressing.

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

⑤ Broadcast application over the whole orchard This is a commonly used method for fertilizing large trees. The specific practice is: first spread the fertilizer evenly over the whole orchard, then shallow-plow. This method is simple and easy to carry out, but its disadvantage is that fertilization is too shallow, 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 urine and feces for application, because the main component of plant ash is potassium carbonate, whose aqueous solution is alkaline, while the nitrogen in decomposed human urine and feces 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-preserving measures should be taken well.

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 grasp the time for harvesting and knocking down walnuts. If harvested too early, the seeds are not yet mature and not plump. This not only affects fruit quality, but the fruit is also difficult to detach and easily damages flower buds when knocked, affecting the next year's fruiting. If harvested too late, the seeds are overripe and fall off in large amounts, causing losses.

The characteristic of walnut maturity is that the outer husk changes from green to yellow-green and splits. The maturity of walnut fruits on the same tree is not uniform; when the outer husk of walnut trees splits and 1/3 of the fruits have split, harvesting can begin. The method is to use a long bamboo pole to knock the small branches sideways, shaking the walnut fruits to the ground. When knocking, care should be taken to protect the branch tips; do not strike hard with force, which may break small branches and flower buds and affect the next year's fruiting.

Control of main pests and diseases

The main pests and diseases 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 caterpillars, etc.

1. Walnut bacterial blight

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

① Breed and cultivate disease-resistant varieties.

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

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

2. Walnut anthracnose

It mainly harms fruits. It is a fungal disease and can infect each other with the apple anthracnose pathogen. Control methods: before disease onset, spray 1:1:200 (copper sulfate:lime:water) Bordeaux mixture; during disease onset, spray 40% thiram wettable powder 800 times liquid, or 50% carbendazim wettable powder 1000 times liquid, 75% chlorothalonil 600 times liquid, 70% or 50% thiophanate 800—1000 times liquid, 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 harms walnut branches and trunks, causing the death of some main branches and the central leader of some walnut trees, and the death of some entire trees. It is a destructive 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 harms 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 cut off the infested branches and burn them. When larvae are found harming the root crown, pry open the bark and dig out the larvae; uncover the soil sealed at the root crown, inject 40% dimethoate emulsifiable concentrate 20 times liquid 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 liquid from below 1.5 m on the trunk to the root crown to kill newly hatched larvae.

5. Scarab beetles and nettle caterpillars

When adult scarab beetles and nettle caterpillar larvae mainly feed on leaves, they can eat walnut trees bare, thereby affecting tree growth. Control methods: when the outbreak is severe, during the period of massive adult occurrence, use bonfires or black light lamps to trap and kill them; 90% trichlorfon 800 times liquid, dichlorvos 800 times liquid, isocarbophos 800 times liquid, and parathion 2000 times liquid can be selected, with a killing rate of over 90%.

Key technical points for strawberry cultivation and management

  Strawberry (scientific name: Fragaria × ananassa Duch.) is a perennial herbaceous plant of the genus Fragaria in the family Rosaceae, 10-40 cm tall, with stems lower than or nearly equal to the leaves, trifoliate leaves, leaflets with short petiolules, obovate or rhombic, petioles 2-10 cm long, cymose inflorescences with 5-15 flowers, aggregate fruit large, up to 3 cm in diameter, flowering period April-May, fruiting period June-July.

  Strawberry is native to South America; it is cultivated throughout China and widely cultivated in Europe and other places.

  Strawberry has high nutritional value and is rich in vitamin C. Traditional Chinese medicine holds that strawberry is sweet in flavor and cool in nature, enters the spleen, stomach and lung meridians, and has the effects of moistening the lungs and promoting fluid production, strengthening the spleen and harmonizing the stomach, promoting diuresis and reducing swelling, and relieving fever and summerheat; it is suitable for lung-heat cough, poor appetite, scanty urine, summerheat thirst, etc.