Detailed Explanation of Seedling Raising Methods and Techniques for the Golden Tree Species Robinia pseudoacacia 'Idaho'

Robinia pseudoacacia 'Idaho' (RobiniapseudoacaciaCV.ldaho) is a variety of black locust, a deciduous tree of the legume family Papilionoideae, with a tree height of 5-8 m, a straight trunk, and two full blooming seasons per year. The first is in May, with a flowering period of about 20 d, and the second is in July-August, with a flowering period of 40 d. The flowering period is long, the number of flowers is large, the flowers are large, and the flower shape is beautiful. It is a landscaping tree species introduced to China in recent years. It has vigorous growth, a well-developed root system, and strong stress resistance. It grows noticeably better than black locust on dry mountain land, and Robinia pseudoacacia 'Idaho' has strong root sprouting ability. In the second year after planting, it can sprout a large number of new plants, and it can be planted in barren mountains and barren beach areas. Based on production practice experience, we have summarized the seedling raising techniques for Robinia pseudoacacia 'Idaho'.

1 Site selection and land preparation

In mid-to-late April, select cultivated land with deep sandy loam soil, a relatively low groundwater table, good drainage, no pests or diseases, convenient transportation, conditions for well irrigation, and flat terrain. Clear away debris and level the ground. Broadcast high-quality diammonium fertilizer, then plow and harrow by shallow plowing and deep loosening, and then use an animal-drawn plow to form ridges, with a ridge spacing of 70-80 cm and a ridge height of 15-20 cm.

2 Root digging and seed root storage

Because Robinia pseudoacacia 'Idaho' does not set seed, root burial propagation is generally used. For root burial propagation, select 1-2 year old main and lateral roots of Robinia pseudoacacia 'Idaho', with a diameter of 0.5-1.5 cm being suitable. There are generally two methods for digging roots: one method is not to move the tree. In spring, before Robinia pseudoacacia 'Idaho' begins growth, cut the lateral roots at 20-30 cm from the root crown, dig a ring ditch 30 cm deep and 100 cm wide around the root crown, and the amount of roots cut should not exceed half of the lateral roots. On the inner side of the double ring ditch, cut off root systems with a thickness greater than 4 mm, and dig out the cut roots. After digging the roots, apply sufficient fertilizer to each tree and promptly cover with soil and water. The other method is to dig out the tree together with the roots, leave 15-20 cm of roots, and cut off all the rest with scissors for storage. The tree can still be planted. The dug roots must be stored immediately. Choose a wind-sheltered, light-avoiding place and bury the seed roots mixed evenly with fine sand. The fine sand should first be screened clean, stones removed, and a certain humidity maintained.

3 Root cutting, treatment, and cutting propagation

From late April to early and mid-May, cut the root segments into 5-7 cm sections and soak them in an indolebutyric acid solution at a concentration of 40-50 mg/L for 12-24 h. At the same time, use a furrow opener to open a furrow along the exact center of the ridge surface, place the root cuttings flat in the furrow, preferably with the morphological upper ends all facing the same direction, with root segments 10-15 cm apart, cover with about 4 cm of soil, and press firm. After root cutting propagation, immediately irrigate or spray water on the ground so that the soil is thoroughly wet. Before buds emerge from the soil, soil moisture must be maintained continuously. Within several months after buds emerge from the soil, keep the soil moist.

4 Seedling transplanting

Transplanting is best carried out before spring growth. When transplanting, dig holes and apply sufficient base fertilizer. After the seedlings are planted, fill with soil, press firm, water thoroughly, and keep moist thereafter. Because Robinia pseudoacacia 'Idaho' has strong vitality, the seedlings do not need to be with soil, and the planting survival rate can reach more than 95%. To make the seedlings grow robustly, after transplanting, cut back at ground level, cut off the aboveground part, and retain one strong bud again from the base. After cutting back, Robinia pseudoacacia 'Idaho' not only has a high survival rate, but also has a good tree shape and grows quickly.

5 Tending and management

Because Robinia pseudoacacia 'Idaho' naturally grows with an open crown and a beautiful tree shape, pruning is not needed. However, weeds must be removed promptly throughout the entire growth process. In addition, pay attention to observing pests and diseases, achieve early treatment, treatment while small, and complete control, and at the same time ensure timely and appropriate watering, timely bud removal, and topdressing, so as to ensure that seedling growth is not affected.