Practical techniques for Root-burying and Seedling cultivation of improved varieties of Robinia pseudoacacia

Practical techniques for Root-burying and Seedling cultivation of improved varieties of Robinia pseudoacacia

Robinia pseudoacacia, also known as Robinia pseudoacacia, is a deciduous tree of Robinia pseudoacacia of butterfly family. It is not only a pioneer tree species for soil and water conservation, barren mountain afforestation and saline-alkali land afforestation in Liaoning area, but also an important urban and rural greening tree, nectar source tree and fertilizer tree. However, it is difficult to root by cutting seedlings of Robinia pseudoacacia, which is disadvantageous to the asexual propagation of improved varieties of Robinia pseudoacacia. In recent years, combined with my own work practice, the author has carried out repeated experiments on root-burying seedlings of Robinia pseudoacacia and achieved success. The key technical links are summarized as follows.

1 nursery site selection

Choose the land with convenient transportation and irrigation conditions, good drainage, leeward to the sun, flat terrain, and the soil should be slightly acidic to slightly alkaline loam, sandy loam or clay loam.

(2) soil preparation and fertilization

Land preparation includes ploughing, raking, leveling and suppression. Do deep ploughing and fine finishing, remove grass roots and stones, and ensure that the ground is broken. The depth of ploughing is 2530 cm in autumn and 2025 cm in season. Ploughing and raking should be leveled and suppressed in time.

Follow the principle of "giving priority to organic fertilizer, supplemented by chemical fertilizer, applying sufficient base fertilizer and proper topdressing". Before ploughing, 25 t/hm2 of mature organic fertilizer was sprinkled before ploughing, and 300 × 375 kg/hm2 of diammonium hydrogen phosphate was applied when making beds (beds and ridges), and mixed into the soil layer of 0: 15 cm. Disinfect and disinfect the soil in time. Before making bed (border, ridge) soil disinfection, spray 2%-3% ferrous sulfate water agent, for the control of soil-borne diseases, the dosage is 300 kg/hm2. To control soil-borne diseases, pentachloronitrobenzene powder can be used and mixed with soil before making bed (border, ridge), the dosage is 37.5 kg/hm2. For underground pests, methyl-mixed phosphorus powder was used to mix 50 times fine dry soil to make poisonous soil according to the standard of 40 kg/hm2, and mixed with soil when making bed (border, ridge).

3 make beds (beds, ridges)

When the soil is dry, fill the bottom water 3-5 days before making the bed. For the nursery with sufficient water source, good irrigation conditions and high groundwater level, bed or ridge cultivation is adopted, on the contrary, border cultivation or flat cultivation is adopted. Seedling bed, seedling ridge and seedling bed should be done well before cutting and transplanting, and the soil should be finely broken, the surface is flat and the edge is neat.

When making a bed, the bed surface is 10 cm higher than the trail, the bed width is 1.0 m 1.5 m, the bed length is 10 m 20 m, the mechanical operation can be longer, and the trail width is 30 cm wide. During border cultivation, the border surface is 10 ~ 15 cm lower than the trail, the width of the border is 1.0 ~ 1.5 m, and the width of the trail is 30 cm. The length of the seedling bed is determined according to the amount of seedlings, and a drainage ditch is left on one side of the seedling bed. In ridge cultivation, the width of the bottom of the ridge is 60 ~ 70 cm, and the width of the ridge is 30 ~ 35 cm. The length of the ridge depends on the topography. When flat cropping, strip operation is adopted, and 30-50 cm trails are left between belts. Big seedlings can be cultivated without trails.

4 burying root operation

4.1 Root segment collection and processing

The root collection should be carried out before the mother tree or seedling germinates in spring, or the lateral roots around the young and middle-aged trees can be cut off and trimmed by the seedlings in the nursery. Generally, one-to two-year-old seedlings are selected for seed roots, and the roots left after coming out of the nursery or pruned roots should be 0.3-1.2 cm thick.

4.2 Root segment shear

It is required to make the incision smooth, not to break the skin, not to split, not to hurt the bud. The root segment was pruned in time, and the length was 6-8 cm. After cutting, they were bundled according to the thickness and divided into three grades (0.3-0.6,0.6-0.9,0.9-1.2 cm), each with a bundle of 100 roots.

4.3 Sand storage treatment

Seed root should be taken along with seedling, root cutting and sand storage, so as to prevent water loss from root section. In the leeward direction, bury the root section in the sand and sprinkle a small amount of water to moisturize. After sand storage treatment for 7 days and 10 days, the incision can be healed, and then the sprouting can be removed.

4.4 burying the root

From late April to early May, when the soil surface temperature was more than 10 ℃, the roots were generally buried 300 roots / m ~ 2, and bed and border cultivation were mostly used. The method of closed warming, preserving soil moisture and accelerating seedling growth was adopted. Flat rake fine border (bed) surface, evenly sow roots (flat roots), cover the soil thickness to not expose the roots is appropriate, and then compacted and sprayed with water. Set up a bow-shaped scaffolding on the bed or border, covered with plastic film, pressed with soil on both sides and pressed with wood or masonry on both sides. The two ends can be opened freely, and the measures of ventilation and cooling, spraying and moisturizing can be taken. Cover straw curtain and other heat preservation at night, and the temperature is controlled between 24 and 30 ℃. Pay attention to spraying water to keep the relative humidity at about 65%. After sprouting and graded root insertion, the emergence of the whole seedling is guaranteed, and the whole seedling can be produced in 15-20 days.

5 later stage management

5.1 Transplant Management

After the emergence of the whole seedling, remove the plastic sheet and replace the non-woven cloth, paying attention to the proper tradeoff between ventilation and moisturizing. When the height of most of the seedlings reached more than 5 cm, the seedlings began to dry (seedling refining), and then transplanted after 3-5 days. Those who have not germinated continue to stay in the bed to accelerate germination and transplant in batches. Most of the transplanting operations are ridge or flat cropping. Transplanting is best carried out in cloudy days. If transplanting is clear, it should be done before 9:00 or after 16:00. The row spacing of transplanted plants was 35 cm × 70 cm. When transplanting, appropriate vertical wall deep planting, transplanting seedlings affixed to the vertical wall, covering soil and watering, and sealing soil to preserve soil moisture [4].

5.2 Water and fertilizer management

Watering the soil properly in the seedling stage to keep the soil moist; watering in the seedling stage takes a small amount of water for many times. Watering should be done on the bed (bed) surface without water storage. From the middle of July to the middle of August, after entering the fast-growing period, extra-root topdressing could be carried out and 200 kg/hm2 urea could be applied. After late August, 100 kg/hm2 potassium dihydrogen phosphate was applied to promote the Lignification of seedlings. Watering in the fast-growing period should take the method of more quantity and less times, and make sure that the internal water does not accumulate and the external water does not flood. After the first ten days of September, stop watering.

5.3 weeding and loosening the soil

According to the precipitation, loosen the soil in time, the depth is 2 ~ 3 cm, and pull out the weeds in time.

5.4 Plant setting and tiller removal

If there are many clusters of sprouts in cutting roots, redundant plants (buds) should be erased in time, and 2 or 3 strong seedlings should be selected when transplanting seedlings. After transplanting, one strong seedling was retained when the seedling height reached 20 cm. After seedling transfer, when the height growth of the seedling reached 10-15 cm, several sprouting tillers from one root were removed, and one strong bud was left for each plant to fix the seedling.

5.5 Disease and pest control

The seedling stage of Robinia pseudoacacia is mainly harmed by aphids. It can be sprayed with a flash sword to kill aphids in the first ten days of July, adding about 30 mL per spray pot (about 15 kg water). The control effect was investigated the next day and the insecticidal rate reached 100%. Flash Sword EC is a new type of pyridine insecticide, which has the effects of contact and stomach toxicity, strong internal absorption and conductivity, good quick effect, and a lasting period of about 20 days. It is suitable for controlling prickly sucking pests such as aphids, whitefly and thrips, low toxicity to humans and animals, little killing to natural enemies, and is a pollution-free pesticide. It is usually diluted by 2 500 to 3 500 times. It is the most ideal insecticide to control Robinia pseudoacacia pests, especially black locust mouthparts pests.

5.6 seedlings coming out of the nursery

The seedlings start after the seedlings stop growing in autumn and before the seedlings germinate in spring. It is necessary to classify the quality of seedlings out of the nursery, and at the same time do a good job of transportation, false planting and so on. At the same time, do a good job in technical archives in accordance with relevant regulations.