Squatting Transformation Technology of aged Apple Orchard in Weibei Arid Plateau area of Shaanxi Province

Squatting Transformation Technology of aged Apple Orchard in Weibei Arid Plateau area of Shaanxi Province

The apple producing area of Weibei Arid Plateau in Shaanxi Province is the most suitable area for apple production, and the apple industry is the local leading industry, which has made a great contribution to the increase of farmers' income and the development of local rural economy. however, most of the orchards here were built in the 1980s and 1990s, the fruit trees showed weakening and aging, and some orchards showed poor efficiency, large investment in destroyed orchards and long cycle. The squat grafting technique mainly saws off the rotten tree body and inserts a new scion on the sawing end face, making full use of the strong root base of the original fruit tree, which can effectively eliminate the mutual repulsion caused by harmful substances in the re-establishment of the garden and overcome the obstacle of repeated crops. after grafting, the new plant balance relationship is established quickly, the germination ability is strong, the tree growth is prosperous, and then the newly inserted branches are grafted, which can quickly achieve the target tree shape and achieve preterm, high and stable yield. Make the fruit trees rejuvenate. In 2017, after the provincial old orchard transformation site meeting was held, we summed up the original local squatting technology in time and through practice, summed up the Weibei Qiaohua orchard squatting transformation technology, and achieved good economic benefits. it has been praised by the majority of fruit farmers and concerned by provincial and municipal leaders.

1 orchards suitable for squatting

For orchards with squatting reconstruction, the orchards with more than 20 years old, more branch diseases, weak trees, intact roots and stems and less than 2000 yuan per mu benefit are generally selected; for orchards with serious backwardness of some varieties and low economic benefits, squatting transformation can also be carried out (figure 1). Squatting transformation is not recommended for orchards with serious lack of plants, because the total number of plants is not enough, it is difficult to achieve the expected benefits after transformation.

Fig. 1 Orchard before transformation

2 preparatory work before the transformation

After the apple leaves fall before winter, remove the side branches of the fruit tree in time, smear the saw with shearing oil, then smear the wound with 43% tebuconazole diluted 30 times, or smear the wound with Guokangbao original solution, and take all sawed branches out of the orchard before squatting (figure 2). Avoid breaking the scion by pulling branches after squatting. If there are irrigation conditions, if the whole garden is watered with frozen water before winter, the survival rate of squatting will be higher in the coming year.

Fig. 2 remove the large side branches and clear the orchard before squatting

3. Collection and storage of scion

According to the local market conditions, scions with good market potential and excellent varieties should be selected to ensure that the transformed orchards achieve the expected economic benefits. Preliminary estimate the number of scions needed for squatting grafting, collect annual robust branches in winter, bundle them into a bundle every 100, and mark them. If the scions collected are not enough (especially when the selected scions are new varieties just approved and popularized, the scions are often very tight and the price is high), each tree can be budgeted according to 2 scions, and the rest can be supplemented by robust scions of local conventional varieties, but mark them well. Separate storage with wet sand, wet sand requires hands to hold into a ball, loose that is loose. The storage location is usually in the shade around the yard or orchard and checked regularly to prevent the scion from losing water caused by too dry sand.

4 squat pick-up

In Weibei area, the suitable squatting time is mid-April (before and after flowering), not too early, the bark and xylem are not separated, and the survival rate of squatting grafting is not high; it should not be too late, otherwise the temperature is too high and the water loss of scion is too fast after squatting graft. it also affects the survival rate.

Before squatting, first use a spade to dig a deep pit around the trunk with a diameter of 1 meter and a depth of about 20 centimeters. Because of the cold winter in Weibei area, the root neck is easy to be frozen, and there are often rot scars under the tree. About 10 centimeters under the tree, the bark is generally intact, smooth and easy to implement squatting. In order to facilitate the binding of scions, it is recommended that the depth of the pit is 20 centimeters.

Select the full buds in the middle of the scion, cut every 4 buds into segments, the upper part of each section is a little farther away from the bud, and the lower part is closer to the bud, soak the cut scion in clean water. According to the position of the uppermost bud (make sure that the position of the upper bud is facing the center of the trunk after squatting, so as to facilitate the second back grafting), the scion is cut into long and short sides, the corresponding side of the uppermost bud is longer (3 cm) and the back is shorter (1 cm). And gently scrape off the epidermis of about 2 cm to reveal green skin. Smooth and smooth the squatting surface (figure 3), gently pry open the bark with the tip of the knife, insert the scion (figure 4), gently tap with the knife handle to ensure that the scion has a whiteness of about 0.5 cm, and determine the number of scions to be inserted according to the thickness of the trunk. Usually insert a scion with a perimeter of 10 cm at intervals. If the number of scions of new varieties to be grafted is limited, the scions of two new varieties should be inserted in the opposite direction and marked, and the remaining positions that need to be inserted should be supplemented with spare scions. After all the scions are inserted, the bark is tightened with plastic paper or grass rope, and the ends of the plastic paper and rope are compacted with fresh soil, then the bark periphery is compacted with fresh soil, and then around the scion is compacted with fresh soil one by one. Finally, the whole tree stump and scion are covered with soil (figure 5), so that only the top buds are left on the scion. In order to prevent moisture evaporation, the fresh soil pile can be covered with film. Smear the top of the scion with shearing oil (figure 6). In order to prevent damage to the scion in the field, a branch with a length of about 1 meter can be inserted next to the scion to serve as a reminder and protection.

Fig. 3 trimming and smoothing the squatting joint

Fig. 4 insert scion

Fig. 5 bandaging the scion and compacting it with fresh soil

Fig. 6 cover with film and seal and cut oil with scion

5 Management after squatting

After the scion survives, wipe out other new buds other than the terminal bud in time, and the sprouting tillers of the original fruit trees can be selected and retained appropriately according to the degree of density. When the orchard is dry, water it in time. Take good care of the newly issued tender shoots in time to prevent cattle and sheep from eating. When the new shoot grows to 30cm to 40cm, tie the scion to the branch that is inserted in advance, and when the new shoot reaches 80cm, tie all the branches together. In order to improve the benefit of the old orchard after squatting transformation, watermelons can be planted among the tree rows to increase the benefit on the one hand, and on the other hand, when planting watermelons, observe the growth of new branches and take corresponding management measures, which can also prevent the ground from being exposed, keep orchard moisture, and avoid burning tender leaves at high temperature in summer.

6 secondary abutment

When the new tip is about 1 meter long (the Weibei area is usually in the first and middle of July), the docking will be implemented in time. Before joining, first choose the branch with the best growth as the central leader, and the other branches, choose the adjacent branches to connect with each other first, and finally rely on the central leadership. When leaning against the joint, we should first bring the two branches together and choose the place with a larger contact area to make the connection. According to the contact condition, the branch to be connected is cut short at the place where the contact is better, and the side of the branch that is to be grafted is cut to grow on one side, with a length of 2 cm to 3 cm, and the back to be cut into a short side, with a length of 0.5 cm, and the peeled position of the branch to be peeled is determined by leaning the branch against the grafted branch. The upper part of the resting position is cut obliquely up to the xylem, and then cut from the lower end of the abutting part to the upper notch, and then the two long cutting surfaces are leaned together, and the upper end of the cutting surface of the grafted branch is leaned against the wedge-shaped groove on the upper part of the grafted branch. Make sure the skin on one side of the two slices is aligned, and then wrap it with a clean plastic belt (figure 7). This process is best done in pairs, otherwise the branches are easy to deviate and affect the survival rate. Finally, the branches attached to each other are gently bound with a rope to further play a fixed role. In Weibei area, there are often strong winds and torrential rains in summer. in order to prevent the strong wind from blowing off the attached saplings, you can insert a bamboo pole or stick next to the trunk and gently tie the upper part of the squatting saplings to the bamboo pole (figure 8).

Fig. 7 epidermis aligned with bandaging and binding

Fig. 8 abutment forming

7 integrated management measures after connection

Summer drought is easy to occur in July and August in Weibei area, which is one of the main factors affecting the survival rate of secondary grafting. In the subsequent orchard, if there is high temperature and summer drought, the roots should be watered in time in the morning and evening to resist drought and preserve soil moisture.

For squatting orchards, emphasis should be placed on the prevention and control of aphids and apple leaf moths to prevent pests from eating leaves and affect plant nutrient accumulation.

For the lateral branches germinated in the later stage, the coring should be carried out in time to control the growth of the lateral branches to ensure the absolute superiority of the central leadership, and to reshape the lateral branches according to the target tree shape.