Key Points and Methods of Peach Tree Planting Technology Explained in Detail
I. Orchard Establishment
1. Site selection: relatively concentrated and contiguous, with suitable climatic and soil conditions, moderate altitude, slope and aspect. Peach trees like sunlight, so a south-facing site is best, with ample light. The slope should not be too steep, generally below 25 degrees is preferable. The hilltop is best left for afforestation; choose the foothill zone. Deep, fertile and loose soil is best, and soil depth is the most important factor. Fertility is relatively easy to improve. Existing forest land is best preserved, and clearing forest to plant fruit trees should be avoided as much as possible.
2. Comprehensive planning: integrated consideration of mountain, water, orchard, forest, roads, farming, forestry and animal husbandry, combining them wherever possible, such as combining forest with fruit, grass with fruit, and so on, adapting measures to local conditions to create a good ecosystem. On mountain land, the most important thing is soil and water conservation; if well integrated, the environment can be transformed and a virtuous cycle formed. In opening up a mountain to establish an orchard, the first consideration is to arrange roads, ditches, shelterbelts (patch forests and forest belts), as well as office buildings, dormitories, warehouses, work sheds, livestock and poultry houses and other buildings, some centralized and some dispersed, for convenience of work and life. The field also needs manure pits, water storage tanks, and so on.
3. Building and other high-standard terraces is the most important measure for bringing fruit trees onto mountain land and for soil and water conservation. The width of the terrace surface and the height of the terrace wall are most strongly related to slope: the steeper the slope, the higher the terrace wall and the smaller the terrace surface, so the slope cannot be too steep. On a single slope it is impossible for the gradient to be uniform, so the maximum slope should be taken as the baseline, which avoids the terrace surface being too small in places with individually steep gradients. The terrace wall should have a protective slope; when built with stone or grassed bricks, it should maintain a 70-degree incline, and earthen walls should be tamped firmly to prevent collapse. The terrace surface should be at least 3 m, kept as level as possible or slightly inward-sloping, with an earth ridge in front and a back ditch behind, for passage and for drainage and irrigation. When building terraces, work from the bottom upward, keeping the topsoil on the terrace surface as much as possible.
II. Planting
1. Digging planting holes or trenches. This is the first step in improving mountain soil. Mountain red soil generally has the drawbacks of being acidic, barren, sticky and drought-prone, and must be improved by digging holes or trenches and applying organic fertilizer. Where the subsoil is heavy and sticky with poor drainage, it is best to dig trenches. A hole or trench depth of 60-80 cm is sufficient; it need not reach 1 m, which saves labor and cost. Dead branches, fallen leaves, straw and so on filled into the bottom of the hole or trench can be coarser, then add some soil and some lime or human feces and urine to promote decomposition, then place finer material in layers, and finally return all the soil dug out back into the hole or trench. This is best done 1-2 months before planting.
2. Planting
(1) Timing: deciduous fruit trees are generally planted after leaf fall.
(2) Planting distance: generally about 40 peach trees per mu. For terraces with a 3 m surface, a plant spacing of 4 m allows planting of young trees. Stagger them higher and lower to increase light exposure.
(3) Method: planting stock should be graded by size and planted in batches, to avoid unevenness within one orchard. After marking the points according to plant and row spacing, dig a small hole within the originally opened large hole. If accurate positioning is desired, a planting board can be used. When planting, let the fibrous roots spread naturally, and when filling soil into the hole, make it fit closely against the roots without leaving gaps, then press firm. Note that the planting depth should be based on the original depth at the time of leaving the nursery; it should not be too deep or too shallow. If too shallow, the roots will be exposed and prone to drought; if too deep, growth will be slow or the tree may even fail to grow. After planting, water thoroughly to settle the roots. In windy places, set up stakes. At planting, apply some superphosphate, calcium magnesium phosphate, farmyard manure and so on. Mix them evenly with the soil to prevent fertilizer concentration from injuring the roots.
III. Management of Young Trees
Peach trees can come into production 2-3 years after planting, but the canopy continues to expand. In this period the main tasks are comprehensively improving the orchard site and developing a reasonable canopy. The main work is as follows:
1. Training: generally the natural open-center form is used, that is, after planting, cut and head the tree at about 50 cm above the ground. Below the cut there should be 6-8 plump buds. In spring, after buds sprout and shoots emerge, select 3-4 vigorous branches growing in different directions as main branches to train. The points of attachment of the main branches should be at a certain distance from one another, and their vigor can be controlled by changing the angle. Other branches that compete with the main branches should be removed, while weak ones can be retained as auxiliary branches. By May-June, when the main branches are growing vigorously and have reached 60-80 cm in length, they can be pinched to promote a second flush of growth, train secondary main branches and sub-main branches, and expand the canopy. The bud at the cut is generally left on the outer side, and additionally a lateral branch sprouting below is selected at a suitable position and vigorous growth as a sub-main branch. The sub-main branches retained on each main branch should be on the same side, to avoid emptiness or collision. In this way, secondary main branches can be trained in one year, and by retaining secondary branches a second time the canopy can be formed, coming into production by the third year.
2. Expanding soil improvement: continue to expand the scope of soil improvement by digging orchard ditches or strip ditches about 40 cm deep outward from the originally opened holes or trenches, and applying organic fertilizer just as when the holes were opened, in order to improve the soil. When expanding, the new area should connect with the original holes to prevent leaving a barrier layer. Expansion can be completed within 2-3 years after planting; autumn is the best time, though it can also be done in winter.
3. Fertilization: in addition to applying fertilizer as base fertilizer at planting and during expansion, quick-acting fertilizer can be applied as a top dressing before each growing season to promote branch growth. Urea and similar fertilizers can be used, 1-2 liang per tree.
4. Intercropping in the orchard: the gaps in a young orchard can be intercropped with various crops to increase income. Rice straw can be turned under as fertilizer or used as mulch. Planting legumes or a mix of legumes and grasses is most beneficial for building soil fertility, and can also provide feed. Grass species for slope protection can also be planted on the terrace walls. It is best to have the ground covered with green crops.
5. Drainage and water conservation: peach trees fear waterlogging most, so attention should be paid to drainage during the rainy season. Clogged back ditches should be cleared and opened up, and the silted soil should be banked onto the tree basin. In the dry season, the tree basin can be loosened and mulched to reduce water evaporation loss.
IV. Management of Mature Trees
1. Pruning: flower buds form very easily on peach trees, and fruiting is generally mainly on long and medium fruiting branches; some cultivars can bear fruit on long, medium and short fruiting branches. For trees just beginning to bear, the canopy continues to expand, with more long fruiting branches and water-sprout-type fruiting branches, so light pruning and long training are required; heavy pruning should be avoided to prevent excessive vegetative growth. Train third- and fourth-order main branches, while forming medium and long branch groups below to bear fruit. More upright branches can be spread apart in angle and appropriately pinched to control tree vigor. For mature trees, long fruiting branches can be renewed by the single-branch method, that is, cutting back the long fruiting branch at 8-10 plump buds, so that some flower buds bear fruit and fruiting branches grow to prepare for the next year's crop. As the bearing age increases, tree vigor gradually declines and the growth of long fruiting branches weakens, so pruning can be heavier, while as medium and short fruiting branches increase they can be appropriately cut or left uncut to bear fruit, and when too dense a portion should be thinned out. When long fruiting branches weaken and cannot be renewed to produce long fruiting branches by cutting back, the double-branch renewal method can be adopted, that is, within the same branch group, one long branch is lightly pruned to continue bearing fruit, and the other is heavily pruned leaving 2-3 years, so that it grows 2-3 long fruiting branches, with one branch bearing fruit the next year and the other heavily pruned and renewed in winter as above, maintaining branch vigor. Fruiting positions should be kept as close to the main branches as possible. If the fruiting position moves outward, it must be cut back to keep the canopy within a certain range.
During pruning, overly dense branches, crossing and overlapping branches, and diseased, pest-damaged and dead branches should be thinned out, so that the canopy has good ventilation and light penetration.
Pruning is generally done in winter after leaf fall, but pinching and bud removal during the growing season are also very important, as they can promptly deal with some undesirable branches and reduce nutrient consumption. Leaves close to the fruit should also be thinned, which can reduce pest damage.
2. Soil management
(1) Fertilization: base fertilizer should be applied in autumn, preferably farmyard manure; if green manure is grown, it can also be turned under. For mature trees, 50-100 kg per tree; where soil acidity is high, add some lime and superphosphate, 0.5-1 kg. Apply top dressing 2-3 times: once in February-March before bud break and flowering, once during the young fruit stage in April-May, and once after fruit harvest in June-July, using quick-acting fertilizers. Peach trees have a high demand for potassium fertilizer, so attention should be paid to increasing potassium application. Its N:P:K ratio is 1:0.5:1. To produce 100 kg of fruit, 1 kg of nitrogen, 0.5 kg of phosphorus and 1 kg of potassium are needed. Other elements such as calcium, magnesium, iron, boron, zinc and manganese are also very important.
(2) Tree basin cultivation and mulching: generally the tree basin should often be kept loose to facilitate soil aeration and reduce water evaporation. In the dry season, mulching can be used to retain moisture; mulch materials can include rice straw, mountain grass, green manure stems and leaves, and so on.
(3) Drainage: in the rainy spring and summer seasons, ditches should be cleared for drainage to prevent waterlogging damage.