Detailed Explanation of Cherry Planting, Cultivation Techniques and Management Methods
I. Variety Selection, Orchard Establishment and Planting Chinese cherries have weak cold resistance and prefer a warm and moist climate, making them suitable for cultivation in areas with an annual average temperature of 15-16°C. Sweet cherries prefer cool and dry conditions. The natural dormancy period of cherries is about 80-100 days. The chilling requirement for sweet cherries to complete dormancy is 1100-1300 hours below 7.2°C. Sour...
I. Variety Selection, Orchard Establishment and Planting
Chinese cherries have weak cold resistance and prefer a warm and moist climate, making them suitable for cultivation in areas with an annual average temperature of 15-16°C. Sweet cherries prefer cool and dry conditions. The natural dormancy period of cherries is about 80-100 days. The chilling requirement for sweet cherries to complete dormancy is 1100-1300 hours below 7.2°C. Sour cherries require 1200-2500 hours. Chinese cherries have a relatively short dormancy period and tend to sprout when temperatures warm up in late winter and early spring. If a "late spring cold snap" (frost or snow) occurs, the flower organs will be damaged, which can seriously affect yield or even result in total crop failure. Therefore, when developing an orchard, attention must be paid to whether the timing of local annual spring low-temperature cold waves coincides with the flowering period. Locations where unfavorable weather (frost, snow, strong winds) occurs during the cherry flowering period year after year should not be planted. Even in places where disastrous weather rarely occurs, suitable micro-topography should be selected when establishing an orchard.
The suitable annual rainfall for cherry growth is generally 700-1000 mm. In some southern regions, how to solve the "spring drought" problem should be fully considered when establishing an orchard. This is because drought in the early stage of fruit growth can cause severe fruit drop and affect fruit growth and development.
Cherries are a light-loving tree species. Chinese cherries are relatively shade-tolerant, but with good light, the fruit ripens earlier and colors well.
Cherries are suitable for cultivation in fertile, loose sandy soil with deep soil layers. The soil pH is generally 6.0-7.5.
The vertical distribution of Chinese cherry roots is generally concentrated in soil about 20 cm deep. Loose soil texture and good drainage and irrigation conditions are required. Heavy clay soil is not suitable for growing cherries. Since cherries do not tolerate transport well, orchards should be established in locations with convenient transportation.
Planting density should vary according to variety, rootstock and soil conditions. On fertile flat land, Chinese cherries using Y-shaped training and close planting can be spaced at 1 x 3 m, with 220 trees per mu. If natural clump form or natural open-center form is used, spacing can be 2-3 m x 3-4 m. In the juvenile period, density can be appropriately increased, and thinning measures can be taken after the orchard matures.
Planting time is generally divided into two periods: autumn and spring. In areas with cold, dry and windy winters, spring planting is preferable, and spring planting should be done before the seedlings bud. In warm winter areas, autumn planting can be used.
Before planting, the soil should be deeply plowed and aged, and large planting holes should be dug. Apply 25-50 kg of organic fertilizer per hole. Mix the fertilizer thoroughly with the soil, then plant the seedlings and immediately water to settle the roots.
II. Soil, Fertilizer and Water Management
Regarding soil management for cherries, based on our experimental observations, the management method of spring irrigation plus mulching and intertillage and weeding in other seasons is preferable. Mulching reduces the impact of spring drought on the plants and has a beneficial effect on fruit growth. After cherry harvest, remove or plow under the mulch. According to calculations, a mature orchard should generally be mulched with 2000-2500 kg of wheat straw per mu. Cherry trees should be fertilized 3-4 times a year, namely:
1. Fertilization after fruit harvest is mainly to restore tree vigor, promote flower bud differentiation and increase next year's yield. Immediately after harvest, apply barnyard manure, poultry and livestock manure and urine, and add an appropriate amount of chemical fertilizer. Apply 30-60 kg of poultry and livestock manure per tree depending on the amount of fruit produced.
2. Fertilization before sprouting and flowering
Apply quick-acting nitrogen fertilizer as the main fertilizer. Apply 15-20 kg of poultry and livestock manure water per tree, or 0.5 kg of urea.
3. Fertilization during rapid fruit growth After petal fall, the fruit enters development. For large fruiting trees, one application of quick-acting chemical fertilizer should be made, along with an appropriate amount of phosphorus and potassium fertilizer.
4. Applying basal fertilizer well Apply basal fertilizer before leaf fall in September-October (October-November in warm southern regions) in autumn to rejuvenate tree vigor and increase stored nutrient content in the plant. Since cherries take only just over 40 days from flowering to fruit maturity, the amount of stored nutrients largely affects fruit size and quality. Therefore, the application of basal fertilizer is very important and should account for 50-70% of the annual fertilization amount. Organic fertilizer should be the main component, such as compost, barnyard manure, chicken manure, decomposed soybean cake, etc., and an appropriate amount of superphosphate or calcium magnesium phosphate fertilizer should be added.
In addition to the above soil fertilization, from early flowering to full bloom, spray twice at 10-day intervals with 0.5% urea, or 600 times diluted potassium dihydrogen phosphate solution, or 0.3% borax solution, which helps increase the fruit-setting rate.
III. Training and Pruning
1. Training
a. Natural clump form is a commonly used tree form for Chinese cherries. Generally there are 5-6 main branches extending outward in all directions, and each main branch has 3-4 lateral branches. Fruiting branches are borne on the main and lateral branches. After the main branches age, suckers are used for renewal. This tree form has a relatively open angle, forms quickly and bears fruit early. However, the interior of the canopy is prone to becoming overcrowded.
b. Natural open-center form is mostly used for sweet cherries. Trunk height is 30-40 cm, and the whole tree has 3 main branches with a branching angle of 30 degrees. The central leader is initially retained, and after 4-5 years of planting, the central leader is removed to form an open center. This tree form is easy to train, requires little pruning, has an open canopy, good ventilation and light penetration, bears fruit early, has high yield and relatively good fruit quality.
c. Modified leader form Trunk height is 40-60 cm, with a central leader. There are 6-7 main branches distributed in 3-4 tiers alternately on the central leader. The first tier has 3 main branches with an opening angle of 50-60 degrees; the second tier has 2 main branches with an opening angle of about 45 degrees; the third and fourth tiers each have 1 main branch. The spacing between the first and second tiers is 60-80 cm, between the second and third tiers is 40-50 cm, and the spacing between upper tiers can be appropriately smaller. Each main branch is equipped with 2-4 lateral branches. At the same time, fruiting branch groups are developed on the main framework branches at all levels.
d. "Y" shape tree form This tree form has rows running north-south, with two main branches per tree symmetrically on both sides. During the training period, a support frame is needed for fixed tying. This tree form has good ventilation and light penetration, flowers and fruits easily, is suitable for close planting, is convenient to manage, and produces good fruit quality.
2. Pruning
a. Points to note in pruning Cherry branches are divided into two types: vegetative branches and fruiting branches. Young trees have more vegetative branches, whose terminal leaf buds extend and grow to expand the canopy, while lower axillary buds produce fruiting branches. After entering the fruiting stage, most one-year-old branches have terminal buds that are leaf buds, while axillary buds are mostly flower buds, and these are called fruiting branches. Fruiting branches are divided by length into long fruiting branches (15-20 cm), medium fruiting branches (5-15 cm), short fruiting branches (about 5 cm) and flower cluster fruiting branches (1-2 cm). In terms of fruiting ability, long fruiting branches have relatively poor fruit-setting ability, generally around 40%; the fruiting ability of medium fruiting branches varies by variety; short fruiting branches have a high fruit-setting rate and also good fruit quality; flower cluster fruiting branches are the main fruiting branches on vigorous trees during the full fruiting period, with a fruit-setting rate reaching about 80%. The fruit quality is the best, and they have a long lifespan, capable of bearing fruit continuously for 10-20 years. Fruiting branches and flower cluster fruiting branches are the basis for yield formation. Chinese cherries and sour cherries have a large proportion of long and medium fruiting branches in the early fruiting stage, while in the full fruiting stage, short fruiting branches and flower cluster fruiting branches predominate.
b. Pruning of young trees To encourage young trees to bear fruit early, on the basis of training, pruning of all types of branches should be light, mainly by pinching during the growing season. This controls vigorous shoot growth, increases branching and accelerates canopy expansion. Winter pruning time should be postponed until before bud break to avoid dehydration and drying of the pruning cuts. Apart from heading back the main branches and extension branches and appropriately thinning some overly dense and crossing branches, medium and small branches should be retained as much as possible.
c. Pruning of fruiting trees Summer pruning is often carried out after fruit harvest. Thinning is used to remove overly dense, overly vigorous perennial large branches that disrupt the canopy, adjust canopy structure and promote flower bud formation. When removing large branches, take care that the wounds are small and smooth to facilitate rapid healing. When removing one-year-old branches, they can first be cut above the basal axillary flower buds, and after fruiting and becoming bare, they can be removed. During winter pruning, attention should be paid to appropriately heading back the tips of framework branches and the 2-3 year old sections of short fruiting branches to stimulate vegetative growth and the continuous formation of new fruiting branches, and to prevent the fruiting zone from moving outward and the interior of the canopy from becoming bare.
d. Pruning of aging trees The main task is timely renewal and rejuvenation, using vigorous water sprouts to form a new canopy. For framework branches that have weakened first and lost fruiting ability, timely heading back should be done. When using latent buds for renewal by heading back, the latent buds of Chinese cherries have a lifespan of about 5-10 years. In order to head back with branches for renewal, it is best to have relatively normal small branches at the heading-back point, as this causes less damage to the tree. From the water sprouts produced after heading-back pruning, select branches with appropriate direction, position and vigor that grow outward to develop into new main branches and lateral branches. Excessive ones should be thinned, and the rest should be headed back to promote branching, then left unpruned to form fruiting branch groups. When renewing large branches, this should also be done after fruit harvest to avoid causing gumming at the wounds.
IV. Flower and Fruit Retention
Flower retention mainly requires attention to fertilizer and water management in spring to promote complete flower organ development and normal flowering. The purpose of fruit retention is to increase the fruit-setting rate of healthy fruits. Measures include: artificial supplementary pollination; using insects visiting flowers for pollination; spraying plant hormones such as gibberellin (GA3), PP333, Greenfenwei foliar fertilizer, etc.; to promote healthy fruit, flower and fruit thinning and prevention and reduction of fruit cracking are needed.