Practical experience shared on greenhouse cultivation of cherries

Editor's note: Recently, quite a few readers have consulted our newspaper's Science and Technology 110 hotline about greenhouse cherry cultivation. For this reason, the editorial department of this page has specially put together this page on greenhouse construction, temperature, humidity and water-fertilizer management, shaping and pruning, and pest and disease control in greenhouse cherry cultivation, for readers' reference.

Greenhouse structure and variety selection

1. Sunlight greenhouse structure. Choose a wind-sheltered, sunny spot with ample water, flat terrain, sandy loam or loam, and far from pollution sources to build a sunlight greenhouse. The span of the sunlight greenhouse is 7.5-9 m, the ridge height is 2.9-3.3 m, and the arch beams can be made of bamboo, wood or steel bars and other materials. The east and west gable walls and the back wall are all 50 cm thick double hollow brick wall structures, the back wall is 180 cm high, and the greenhouse is 50-80 m long. Its lighting, heat preservation and pressure resistance are all very good. The bamboo-wood structure has a lower cost, while the steel bar structure has a higher cost but good sturdiness, with a service life of more than 10 years, and is the development direction for the future.

2. Cherry variety selection. Cherries suitable for sunlight greenhouse cultivation are best early-maturing varieties, so that they can mature earlier and increase economic benefits. A variety that performs relatively well in cultivation is Red Light.

Shaping and pruning

1. Shaping. (1) Natural open-center form. Trunk height 20-40 cm, no central leader, the whole tree has 2-4 main branches, with an opening angle of about 40°, each main branch is equipped with 2-3 layers of side branches, with 30 cm between each layer, and the side branches bear various types of fruiting branch groups. (2) Natural spindle form. Trunk height 40-60 cm, the central leader is equipped with 6-10 single-axis extended main branches, on which a large number of fruiting branch groups are borne. When pruning, the head should be dropped and the center opened in time to control tree height. When shaping, in the year of planting, leave 50 cm to set the trunk; after setting the trunk, select from the elongating shoots those that are robust and well positioned as main branches, and pull them to a horizontal angle during the growing season. In winter pruning of the second year, leave 40-60 cm on the extension shoot of the central leader and cut it back. During winter pruning, competing branches and back branches should be removed or cut back, and the remaining slanting branches and moderate branches can be left unpruned or lightly pruned. In the third year, pinch the central leader at 50 cm, continue to open the angle during the growing season, pinch the back branches and vigorously growing branches in the inner canopy, and train them into fruiting branch groups.

2. Pruning. (1) Growing-season pruning. Mainly carried out during the new shoot growth period and after fruit harvest. The former mainly inhibits excessive new shoot growth and promotes branching, and can be done with multiple pinchings. Pruning after fruit harvest is mainly to thin out dense branches. Cut back two-year-old branches at the axillary buds, and after fruiting remove them from the base. (2) Dormant-season pruning. In the young tree stage, appropriate cutting back is suitable to promote branching and increase bouquet spurs and leafy shoots; after fruiting, appropriate retraction should be done to maintain tree vigor and improve fruiting capacity.

Pest and disease control

1. Shot hole disease. In the early stage, small purplish-brown spots appear on the leaves; later the lesions dry up and fall off, causing holes in the leaves, and in severe cases early defoliation. Strengthening fertilizer and water management, enhancing tree vigor, improving disease resistance, pruning out diseased branches and removing diseased leaves are fundamental to controlling this disease. From after flower drop to before harvest, spray 2-3 times with 65% mancozeb wettable powder at 500-600 times dilution, or 50% carbendazim wettable powder at 800 times dilution, or spray zinc sulfate lime solution for control. After fruit harvest, spray Bordeaux mixture for control.

2. Gummosis. It mainly occurs on branches and trunks, especially more severely at the forks. It generally begins to develop after harvest and worsens with increasing rainfall. It is often caused by freezing injury, insect damage and mechanical injury. Therefore, the most important thing in controlling this disease is to protect the tree body. Before winter, whitewash the trunk and branches to prevent freezing injury, control trunk-boring pests, and eliminate mechanical injuries, etc. For branches and trunks with gummosis, scrape and treat them promptly, and apply a wound dressing to prevent spread.

3. Red-necked longhorn beetle. This pest is an important pest damaging branches and trunks. Main control methods: (1) During the adult occurrence period, manually capture adults. (2) Before adults lay eggs, apply whitewash (made from 10 parts quicklime, 1 part sulfur, and 40 parts water) to the main trunk and main side branches to prevent egg laying. (3) When scraping the bark, if insect holes are found, insert a needle or wire to pierce to death or hook out the larvae damaging the phloem. (4) For larvae that have bored into the xylem, inject 100-times dichlorvos solution into the insect hole, or insert 1/4 of an aluminum phosphide tablet into the hole, then seal the hole tightly with plastic film or mud to fumigate the larvae in the hole to death.

Soil, fertilizer and water management

Cherry is a shallow-rooted tree species with vigorous root respiration, so the water, fertilizer, air and heat requirements for root growth should be met as much as possible. Each growing season requires 4-5 cultivations, with a cultivation depth of 5-10 cm as suitable. After harvest, shallow plowing should be carried out to promote root renewal and growth. Base fertilizer should be applied in late summer or early autumn, mainly organic fertilizer, with an appropriate amount of calcium, magnesium and phosphorus fertilizer added. During the growing season, additional fertilizer should be applied 2-3 times, before flowering and after flowering during the rapid fruit growth period, applying 0.5 kg urea or 0.5 kg ternary compound fertilizer per plant. After fruit harvest, each plant can be top-dressed with 0.5 kg urea or 1 kg superphosphate and 50 g borax, followed by watering, to promote flower bud formation and supplement nutrition; in addition, foliar fertilization should be carried out 2-3 times. In addition to watering once each in combination with autumn base fertilizer, pre-flowering and post-flowering topdressing, and the second post-harvest topdressing, also water once thoroughly during the fruit enlargement period, and water once with freezing water before the soil freezes.

Temperature and humidity regulation

1. Temperature regulation is mainly controlled by opening and closing ventilation windows, working doors, and uncovering and covering straw mats. Covering the greenhouse with plastic film can raise the ground temperature by 2°C-3°C. From film covering to before germination, keep the daytime temperature at 18°C-20°C and the nighttime temperature at 2°C-5°C; from germination to flowering, keep the daytime temperature at 18°C-20°C and the nighttime temperature at 6°C-7°C; at full flowering, keep the daytime temperature at 20°C-22°C, and it must absolutely not exceed 25°C; at flower drop, keep the daytime temperature at 20°C-22°C and the nighttime temperature at 7°C-8°C; during the fruit enlargement period, keep the daytime temperature at 22°C-25°C and the nighttime temperature at 10°C-12°C. After that, keep the daytime temperature at 22°C-25°C and the nighttime temperature at 12°C-15°C.

2. Humidity regulation. From film covering to before germination, control the relative air humidity at about 80%. If humidity is too low, flowering is uneven and it is prone to high-temperature damage; if humidity is too high, it is unfavorable for pollen and germination, and it is prone to disease. During flowering, keep the relative humidity at 40%-60%; if humidity is too low, the stigma is prone to drying out, affecting fruit set. During the fruit enlargement period, control humidity at 60%. From the coloring stage to the ripening stage, control humidity at about 50%. Soil humidity can be adjusted by irrigation. The fruit enlargement period requires more water, but at this stage small frequent irrigation is suitable, with each irrigation 10-15 mm deep. Before fruit ripening, the irrigation amount should be 5-7 mm deep as suitable.