Is Eucalyptus toxic? Sapling prices, planting density and cultivation methods
Eucalyptus, also known as gum tree, white diesel tree (Chaoshan), mang tree (Nan'ao), youjiali (eucalyptus), large-leaved eucalyptus, etc., is the collective name for plants of the genus Eucalyptus in the family Myrtaceae. So is it toxic? How much does a sapling cost? How many to plant per mu? How to plant? According to the Suqian nursery base, eucalyptus saplings generally cost about 2-3 yuan.
Is eucalyptus toxic?
Legend says it is toxic, but in reality it is not. This was even specially covered on CCTV Channel 10. Eucalyptus grows in a wide range of areas and has strong vitality, and it can be planted in the Qiandongnan region of Guizhou. Moreover, eucalyptus is one of the world's three famous fast-growing tree species, with advantages such as strong adaptability, a short cultivation cycle, high timber yield and wide uses. It can be used for greening on both sides of roads; it is fast-growing, quick to show results and has a neat forest appearance, making it an excellent street tree. Its wood has good industrial properties and can be widely used for particleboard, blockboard, papermaking and pulping, edible fungi, furniture and other fields.
How many eucalyptus trees are planted per mu?
The planting density of eucalyptus has a very important effect on the final yield of eucalyptus, and digging the holes determines the final cultivation density. When digging holes, the spacing should be decided according to the planting years and variety growth characteristics of fast-growing eucalyptus, to ensure reasonable permeability during the growth of eucalyptus and also to avoid wasting soil fertility because the planting density is too low. Usually, the hole-digging density can be a row spacing of 3m×2m, with hole specifications of 1250px×1250px×1000px, arranged in a triangular pattern. In addition, it is also necessary to prevent soil erosion caused by digging holes, so first prepare the land and then dig the holes, and the depth of the hole bottom should be deeper than 1000px. Generally, about 111 trees can be planted per mu of land.
How to plant eucalyptus?
Planting density (plant and row spacing) of common eucalyptus species: Eucalyptus camaldulensis clone 1.5m×3m, 148 trees per mu; Eucalyptus dunnii and Eucalyptus saligna 2m×3m, 117 trees per mu, or 3m×3m, 89 trees per mu.
The best planting month for eucalyptus is February to June each year; eucalyptus planted during this period has a high survival rate and vigorous forest growth.
Eucalyptus fertilization techniques
The main nutrient elements absorbed by eucalyptus are nitrogen, phosphorus, potassium, calcium, magnesium, zinc, boron and others. According to research, each eucalyptus tree absorbs an average of 36 grams of nitrogen, 2.8 grams of phosphorus, 20 grams of potassium, 31 grams of calcium and 8.5 grams of magnesium per year, and the absorption ratio of nitrogen, phosphorus and potassium is about 13:1:8.
1. Fertilization principles: Eucalyptus fertilization must first meet the eucalyptus's demand for various nutrients; second, it should be done in the right amount, achieving the greatest economic benefit with the smallest fertilizer input; third, the fertilization method must be mastered to improve fertilizer use efficiency.
2. Base fertilizer: Apply together with organic fertilizer, 0.25-0.5 kg of special eucalyptus fertilizer per tree. Generally, 1-2 weeks before planting, apply it together with the backfilled topsoil when digging the holes.
3. Topdressing: Start topdressing 1 month after planting or after the young trees have grown 1 meter tall, applying 0.2-0.3 kg of compound fertilizer or special eucalyptus fertilizer per tree to promote early and rapid growth of eucalyptus. Apply topdressing once in March-April of the second year, 0.3-0.5 kg of compound fertilizer or special eucalyptus fertilizer per tree. Apply topdressing once each in the third and fourth years, 0.5-0.8 kg of compound fertilizer or special eucalyptus fertilizer per tree, to promote rapid timber formation of eucalyptus.
4. Fertilization method: 30 cm from the tree roots, on the uphill side of the roots, open a crescent-shaped fertilization trench or open one fertilization hole above and on the left and right sides of the roots, then cover with soil after application to prevent fertilizer loss.
5. Precautions: Before each topdressing, weeds must be removed to avoid weeds competing for fertilizer; it is best to fertilize after rain, as the fertilizer is easily absorbed; on ridge slopes, where the soil is thin and poor, more fertilizer should be applied, while by ditches and valleys, where the soil is thick and fertile, less fertilizer should be applied, adjusting measures to local conditions, using reasonable amounts, saving costs and improving benefits.
Pest and disease control of eucalyptus
1. Disease control
Blister blight, bacterial wilt, stem rot and gray mold are common diseases of fast-growing eucalyptus.
Blister blight mainly shows as grayish-green water-soaked areas at the boundary between healthy tissue and the lesions, with leaves quickly drying up and falling off. Bacterial wilt can occur throughout the entire growth cycle of fast-growing eucalyptus, mainly showing as some or all leaves wilting in a dehydrated manner, drying up and drooping, and the tree will die within a few days. Stem rot shows as white water-soaked lesions at the base of the plant stem, which then turn brown and black. Gray mold shows as fungal mold-like growth on the plant surface. For the control of fast-growing eucalyptus diseases, the policy of giving priority to prevention and combining prevention with control must be adhered to. First, thorough disinfection should be carried out during the planting process to prevent pathogens from being brought in with the saplings, and the drainage system in the planting area should be kept normal to cut off the transmission routes of pathogens. Reasonable fertilization should also be noted. In addition, chemical agents such as Bordeaux mixture, chlorothalonil and thiophanate-methyl can be used for sterilization.
2. Pest control
Soil-dwelling termites are a common pest of fast-growing eucalyptus, usually occurring in the young forest stage. Termites first damage the roots and stems of young plants, then move to the surface and above ground and peel along the topsoil to feed on the main roots and lateral roots, ultimately causing the seedlings to die because they cannot transport nutrients. Termite control should focus on prevention, using poisoned bait to lure and kill them. When afforesting, 3-4 g of carbofuran can be placed in the hole, mixed with the soil base fertilizer to fill the hole, using 0.35 kg of pesticide per 667 m2. After afforestation, 2 g of carbofuran can be placed 5 m away from the tree base, using 0.22 kg of pesticide per 667 mz; when applying the pesticide, care should be taken to avoid the powder contacting the saplings and causing phytotoxicity. Fast-growing eucalyptus is one of the fastest-growing tree species in the world, and reasonable cultivation techniques are of great significance for increasing eucalyptus yield. Every link in the planting and management of fast-growing eucalyptus will affect its final yield. By using scientific planting techniques and strengthening pest and disease control, the goal of rapid yield increase can surely be achieved.
3. Weed treatment
Manually lay 5-silk-thick 1 m2 black plastic film, and after laying it press the surrounding edges firmly with soil, so that it will not be blown open by the wind. Or use thinner agricultural plastic film (1×1 or 1.5×1.5); it is recommended to use 1.2-1.5 meter wide agricultural film laid in strips, which saves labor and time. According to estimates: 1 m2 of black plastic film (non-degradable) costs 0.35 yuan per tree; using agricultural plastic film (degradable) costs 0.16 yuan per tree, and its lifespan can generally reach 10-12 months. Using this agricultural film method means no weeding is needed within one year of use, and it also has very good effects in keeping warmth, retaining water and preventing pests.