Nutrition Bowl "Double Covering" Cutting Propagation Technique for Llex cornuta var. fortunei S. Y. Hu

Xiaojiao YIN, Xing LI, Xuyou LI*

1. Hubei Ecology Vocational College, Wuhan 430200, China; 2. Xianning City Forestry Survey and Planning Institute, Xianning 437000, China

Abstract Llex cornuta var. fortunei S. Y. Hu is a good ornamental tree species for viewing fruits and leaves, and has a wide range of garden uses. Nutrition bowl cutting seedlings can improve the survival rate of L. cornuta var. fortunei S. Y. Hu transplanting and greening, and has the advantages of no time limit for planting and saving management costs. Based on this, this paper introduced the container seedling double-covering cutting technology for L. cornuta var. fortunei, to provide a reference for the propagation of L. cornuta var. fortunei.

Key words Llex cornuta var. fortunei S. Y. Hu, Nutrition bowl, Double covering cutting, Propagation technique

1 Introduction

Llexcornutavar.fortuneiS. Y. Hu is a natural variety of Ilex L. genus Aquifoliaceae family, an evergreen shrub or small tree[1]. It is naturally distributed in 10 provinces in the middle and lower reaches of the Yangtze River, including Jiangsu, Zhejiang, Jiangxi, Anhui, Hubei, Hunan and Guangxi, and it can tolerate a certain degree of low temperature[2]. It likes warm temperature, moist climate, shade tolerant, but also needs some sunlight. It is suitable for planting in fertile soil with good drainage and slightly acidic soil, but it can also grow in barren sandy soil. The leaf surface is dark green and shiny, leathery, oval, without serrations. The bark is smooth, the crown is round and there are fewer pests and diseases. It starts flowering in April and May. The fruit is spherical. It is green at first and matures in autumn. The branches are full of fruits. It is a good ornamental tree species for viewing fruits and leaves. It is often used as greening materials for squares, courtyards, roads, bonsais and rock gardens, so its gardening uses are very broad[3].L.cornutavar.fortuneiS. Y. Hu uses nutrition bowl cuttings to raise seedlings, which improves the survival rate of transplanting and greening, and speeds up the propagation.

2 Preparation before cutting

2.1 Nursery land selection and site preparationWhen choosing a nursery land for raising seedlings using nutrition bowls, it is necessary to choose a plot with flat terrain, convenient transportation, good irrigation and drainage systems, and good site conditions as the nursery. After the nursery land is selected, the nursery land should be leveled, too high area should be removed and too low area should be filled up, and the seedling bed should be set up in the north-south direction, the ridge width should be kept 1.2 m and slightly higher in the middle to prevent water accumulation, and the ditch should be 0.4 m wide. For large field nursery land, the surrounding drainage ditches must be dug to a depth of 60-70 cm, to ensure smooth drainage after heavy rain. Before filling the bowl, use lime-sulfur mixture or quicklime at the dose of 75-90 kg/ha to disinfect the seedbed.

2.2 Preparation of nutrient soil and bowl fillingThe mixing ratio of nutrient soil directly affects the later growth quality ofL.cornutavar.fortuneiS. Y. Hu cutting seedlings. The preparation method is 60% yellow soil+20% sawdust+20% fine river sand (with suitable and uniform particle size), or 70% yellow soil+30% sawdust, the yellow soil is crushed and mixed with sawdust and fine river sand and sieved with 80 mesh, and well stirred. Before filling up the bowl, expose the nutrient soil to the sun for 3-4 d for sun disinfection. Put the prepared and sun-exposed nutrient soil into a 9 cm × 13 cm non-woven nutrition bowl. The non-woven nutrition bowl completely solves the problem of the formation of entangled roots and crooked roots due to the difficulty of penetrating the container wall of the seedling roots in the plastic nutrition bowl, and it is easy to degrade and will not cause white pollution[4]. Fill the nutrition bowl with the nutrient soil to 95% of the height of the nutrient bowl for watering. First place the nutrition bowl flat and tightly on the ridge surface, and at the same time squeeze the gaps of the nutrition bowl, pour soil around the ridge surface to 2/3 of the height of the nutrition bowl.

3 Operation of cutting technique

3.1 Cutting timeGenerally,L.cornutavar.fortuneiS. Y. Hu double covering cuttings in southeastern Hubei is better carried out from March to October each year, and it can be carried out all year round in the south of Yangtze River.

3.2 Selection and treatment of excellent branch cuttingsGen-erally, good plants that grow robustly and are free of quarantine pests are selected as the mother trees for picking branches. For cutting slips, select semi-mature branches of the current year (cuttings from May to October) or autumn shoots of the previous year (cuttings from March to April). Generally, cutting slips should choose lignified branches with robust growth, full lateral buds, no pests and diseases, with one full bud and more than two healthy leaves[5]. When conducting the cutting operation, first sterilize the scissors with 75% alcohol, cut the cutting slips 6-10 cm long, cut the upper cut bud flat, and cut it at 0.6-1.0 cm above the node position; cut the lower cut bud into an oblique cut, 0.2 cm below the node position. Keep half or one leaf at the upper cut bud position. In order to promote rapid rooting of cutting slips, apply 0.5% Guoguang rooting powder in cutting slips for 30 s before cutting. Preparation method for rooting powder: add 0.5 kg water in 2.5 g per bag. The rooting powder should be prepared immediately before use, and the root dipping time should not be too long, otherwise it will inhibit rooting[6]. In order to prevent the production of weeds after cuttings (mainly annual gramineous weeds), spray the blocking herbicide 90% acetochlor before cuttings. Before cutting, it is necessary to spray water on the nutrition bowl, water it thoroughly and keep the relative humidity at 90% or higher.

3.3 CuttingAfter the treatment of roots of cutting slips, promptly conduct cutting. In this way, the survival rate is high. The cutting depth is generally 4-6 cm (about 2/3 of the cutting slips), and one cutting slip is sufficient for each nutrition bowl. When conducting cuttings, the cutting slips should be in close contact with the nutrient soil, and try not to leave gaps. In the process of operation, try to keep the leaf blades in the same direction to make them evenly receive light, which is favorable for wound healing and rooting. The picked branches should be kept in a cool place. For branches that cannot be cut that day, they should be covered with plastic film and kept fresh overnight for later use. In Hubei area, cutting can be carried out from March to October every year. In spring and autumn, cutting can be carried out all day; in summer, cutting cannot be carried out under sunlight (the operation should be carried out before 10:00 am or after 4:00 pm).

3.4 Setting up small arched sheds and large shade sheds(i) After completion of cutting of one ridge, spray water on the cuttings immediately, and keep the relative humidity higher than 90%, so that the cuttings will be in close contact with the nutrient soil, leaving no gaps, so as to facilitate the formation and rooting ofL.cornutavar.fortuneiS. Y. Hu. (ii) Insert small bamboo arc bow with a length of 1.85 m at an interval of 0.75 m on the ridge surface. Cover the bow surface with a polyethylene agricultural plastic film with a width of 2 m and a thickness of 0.014 mm. The surrounding soil is pressed and compacted to keep the cutting ridge in a closed state. (iii) Insert large bamboo bows with a length of 2.9 m at intervals of 1.5 m, and cover the large bamboo bows with shading nets. If the width of the shading net is 4 m, the two ridges will share a large shade shed, tighten the level the shed, fix the shading net on the large bamboo bow with thin iron wires. Note that both ends of the large shade shed should also be shaded to prevent direct sunlight entering the small arched shed. In summer, it is necessary to use shading nets with a shading rate of 75% for cuttings; in spring and autumn, use shading nets with a shading rate of 50%. Studies have shown that rooting ofL.cornutavar.fortuneiS. Y. Hu cuttings has higher requirements for shading than Photinia fraseri Dress and Loropetalum chinense var.rubrum. Appropriately increasing the density of shading nets is of great significance for improving the survival rate ofL.cornutavar.fortuneiS. Y. Hu cuttings[7].

4 Maintenance after cutting

4.1 Cultivation in small closed arched shedsL.cornutavar.fortuneiS. Y. Hu cutting slips take root and sprout in a closed state. At this stage, only the maintenance and management of the large shed is needed, and it is only necessary to protect the large sheds and the small arched sheds, without any other management operations[8].

4.2 Lifting off the plastic film and uncovering the netsAfter cutting, the wounds ofL.cornutavar.fortuneiS. Y. Hu are usually healed in 20 d in summer and generated callus. In spring and autumn, wounds are healed in 35 d and generated callus. In summer, new roots usually begin to produce about 30 d, and then produce leaves; in spring and autumn, new roots usually begin to produce about 50 d, and then leaves. The cutting slips basically need shading in the period after cutting to before sprouting (30-50 d after cutting). When it is observed that 80% of the cutting slips have produced new shoots, the plastic film of the small arched sheds can be lifted off. At this time, the cutting slips ofL.cornutavar.fortuneiS. Y. Hu have become rooted seedlings. First, lift off the plastic film of the small arched sheds, letL.cornutavar.fortuneiS. Y. Hu seedlings gradually grow for a period of time under the shade of the large shading sheds. When theL.cornutavar.fortuneiS. Y. Hu seedlings grow to 3 to 4 leaflets and the light and temperature are not very strong, the shading net of the large shading sheds can be uncovered gradually[9].

4.3 Management after lifting off the shedsForL.cornutavar.fortuneiS. Y. Hu, there are generally fewer diseases and insect pests, and the main insect is Ceroplastes rubens (Maskell), and the main disease is sooty mold. C. rubens generally occur one generation a year, and they can be controlled through spraying malathion and dichlorvos (DDVP) around the end of June, once every 7 days, and spray 3 times. In winter, it can be controlled through spraying high-concentration lime-sulphur-synthetic-solution (LSSS). Alternatively, use 800 times solution of carbendazim or 600 times solution of chlorothalonil every 10 d for foliar spraying to prevent pests and diseases.

After lifting off the sheds, the main operations including watering, fertilization, and weeding. Promptly remove the weeds on the cutting nursery, and mainly apply compound fertilizer on the leaf surface. The fertilization should be neither too much nor too frequent. Generally, apply the nitrogen-based nitrogen-phosphorus fertilizer in March in spring, and apply phosphorus-potassium-based fertilizer again in October. Water the seedlings in time according to the weather and temperature conditions. After lifting off the sheds, it is necessary to protect the cutting nursery from trampling and destruction of livestock and poultry, and carry out well management of the cutting nursery. In northern regions of China, such as Hubei Province, it is necessary to pay attention to preventing freezing in winter. After lifting off the sheds, keep the bamboo bow. In case of temperature drop or snow, cover the shading net again.

5 Precautions for cutting propagation

(i) In general, the wound healing and rooting time ofL.cornutavar.fortuneiS. Y. Hu cuttings are different. For cuttings in summer with higher temperature,L.cornutavar.fortuneiS. Y. Hu cuttings slips wounds heal and produce callus faster than that in spring and autumn, and the rooting time is shorter than that in spring and autumn.

(ii) If there are tall trees 30 m near the nursery, it may have an important impact on the survival rate ofL.cornutavar.fortuneiS. Y. Hu cutting seedlings. The well-developed roots of tall trees penetrate deep into the seedbed to absorb some of the water in the seedbed, causing part of the seedbed to lose water, which affects the survival rate ofL.cornutavar.fortuneiS. Y. Hu cutting seedlings. Therefore, it is necessary to ensure that there are no tall trees 30 m near the seedbed.

(iii) The natural factors such as temperature, light and humidity in large shading sheds and small arched sheds are a dynamic process of change. Therefore, it is necessary to check and observe frequently, and adjust the temperature, light and humidity in the small sheds in time to create a suitable rooting environment for theL.cornutavar.fortuneiS. Y. Hu cutting slips.

(iv) The wound healing and rooting ofL.cornutavar.fortuneiS. Y. Hu cutting seedlings have higher requirements for shading rate. Therefore, it is necessary to increase the density of shading net appropriately.

(v) Cutting matrix, cutting season, and the degree of lignification of cutting slips may be important factors affecting the survival rate ofL.cornutavar.fortuneiS. Y. Hu cutting seedlings. It is necessary to make active exploration in practice.