Poplar is very fond of light. No matter in Tairan forest or artificial forest, poplar always forms the highest part of the upper crown. Attention should be paid to its light ecological characteristics in intensive cultivation. Populus deltoides and Populus euphratica in the south are the most phototropic types. It is generally believed that the minimum intensity of photosynthesis of poplar should not be less than 12000M candle. I-72 poplar I-69 poplar I-63 poplar is a southern poplar, which needs sunshine conditions in the south to grow well.
Second, the temperature conditions.
Poplar has great plasticity to temperature. The annual average temperature in the most productive areas in Europe and America is not less than 9.5 degrees, and the average temperature in the growing period is 16.5 degrees. The temperature required by Populus deltoides is higher than that of Populus deltoides.
The southern limit of poplar natural distribution 1 month average temperature is 8 degrees, and the average temperature in Taiwan Province province 1 month is about 10 degrees, which is within this range. The average temperature there in July is 20 degrees (it can withstand a high temperature of about 40 degrees in a short time), and Taiwan Province Province is about 20 degrees, which is also within this range. There are basically no poplars in areas where the average temperature in January is above 12 degrees.
Third, water conditions.
Poplar is in great need of water. Every time the dry weight of poplar plantation increases by 1g, it needs to absorb 6-7 cubic centimeters every day. From May to September, every 24 hours, the water absorbed by each gram of leaves (dry weight) reached 50.438 0 cubic centimeters.
Poplar likes water, but it is not water-resistant. The site conditions where the flowing water stays for more than 100 days in the growing period are not suitable for poplar planting. Cohesive soil with groundwater level not less than 50cm or 2 m is not suitable for planting.
Poplar has a great demand for water, so it should be watered 3 ~-4 times a year. Irrigation with green water before germination in late March; Irrigation from May to June promotes water growth and branches and leaves expansion; 1 1 month irrigate with antifreeze water to promote root growth. Water after fertilization in case of drought. Fertilization is divided into base fertilizer and topdressing. When planting trees, apply base fertilizer to human holes. Generally, plants are applied with organic fertilizer of 5 ~ 10 kg or calcium superphosphate of 250g, and the fertilizer is mixed with mature soil and backfilled in the active layer of root system of 30 ~ 60 cm. Topdressing is used to open a fertilization ditch under the crown edge. The ditch is 80 cm long, 20 cm wide and 20 ~ 30 cm deep, and 250 g urea is applied to each plant. If the mixed application of nitrogen and phosphorus is better, the ratio is n: 5, phosphorus oxide = 3: 1. Water and intertillage in time after fertilization.
Fourthly, PH value and salt content.
The suitable PH value of Populus deltoides and Populus euramericana is 6.5-7.5. When the pH value is less than 5-5.5 or more than 9, most poplars can't adapt.
The salt tolerance of poplar is complex, which is related to soil salt content and salinity, and the soil salt content is closely related to local precipitation, climate, temperature and evaporation.
The maximum salt tolerance of Populus deltoides is 0. 15% (soil layer is 0-20cm, and the salt content is mainly carbonate and sulfate).
Verb (abbreviation of verb) soil conditions
The effective soil layer can be planted at 40- 100 cm, the thicker the better, and the groundwater level is between1.5-2 m. If there is no drainage measure below 0.5 m for a long time, poplar should not be planted. If the groundwater level is slightly higher than two meters and the soil structure is good, poplars can be planted.
Six, poplar fertilization and weeding conditions
Loosening and weeding can improve the physical and chemical properties of soil. In the early stage, thinning can be combined to replace rolling, and intertillage weeding 1 time every year after enclosure is very effective in promoting forest growth. Judging from the geographical distribution and requirements for water and soil, Hunan is still suitable for poplar growth, but the requirements are relatively high. The above contents are for reference only, please consult professionals in detail before use.