Detailed Explanation of the Method for Sprouting and Raising Black Locust Seedlings from Root Segments

Black locust (Robinia pseudoacacia) is tolerant of drought and poor soil and grows quickly, making it a good tree species for rural landscaping around homes and for block planting. If the root-segment sprouting method is used for raising seedlings, it is not only low in cost and simple to carry out, but the seedlings are also of good quality.

1. Site selection and bed preparation Choose a nursery site that is sheltered from the wind, faces the sun, has level ground and good drainage as the hotbed. Before making the beds, apply 1000 kg of organic fertilizer per mu, and 50 kg each of ammonium bicarbonate and superphosphate; after plowing and harrowing level, scatter a 100:1 bait of bran and methamidophos on the bed surface to prevent damage from underground pests such as mole crickets. The beds should run north-south, 1.5 m wide and about 12 m long, with bed ridges 50 cm wide, and the bed surface level with the ground.

2. Cutting the roots and laying them out Select roots from superior varieties such as Luci 74068, using one-year-old seedling roots with a stem thickness of 0.2-0.5 cm, cut them into root segments 3-5 cm long, and divide the root segments into three groups by thickness; tie every one hundred roots into 1 bundle and store them in moist sand for later use, so that the root segments do not lose water and lose their ability to sprout; they can also be cut, graded and laid out as you go. In early March, lay the root segments evenly in the prepared hotbed beds, at 300-350 roots per square meter, without crossing or overlapping each other; after sowing, spray with plenty of water, cover with 1 cm of fine soil, then immediately set up arched frames and cover them well with plastic film, seal all around, and dig drainage ditches.

3. Sprouting in the hotbed After the roots are laid out and the film is covered, keep the bed surface temperature at 20-25°C to promote sprouting. Sprouting begins in about 15-20 days, and the seedlings emerge completely in about 30 days. In the early period, when the temperature is low, do not spray water in the beds; after late March, as the temperature gradually rises, when the bed temperature exceeds 30°C at noon, pay attention to proper ventilation and cooling, and strictly prevent sunscald of the young seedlings. After the seedlings emerge completely, spray water to keep them moist, and choose a sunny afternoon to soak them once. Pay attention to ventilation and air exchange, and regulate bed temperature and humidity to keep the seedlings growing normally. When the seedlings are more than 5 cm tall, air the beds and harden the seedlings; two days before transplanting, remove the film for the whole day so that the sprouted seedlings adapt to field conditions.

4. Transplanting the sprouted seedlings The seedling-raising site should have level ground and convenient drainage and irrigation. Before transplanting, apply 1000 kg of organic fertilizer per mu, and 50 kg each of ammonium bicarbonate and superphosphate; after comprehensive mechanical plowing and harrowing level, make small raised ridges running north-south, with ridges 60 cm wide, furrows 30 cm wide and 25 cm deep, and ridges about 25 m long. Transplant when the seedlings are 5-10 cm tall. Because root segments sprout unevenly, the sprouted seedlings should be transplanted in batches; small seedlings or root segments that have not yet sprouted can continue to be sprouted in the hotbed. Transplant from late April to early May. It is best to transplant on a cloudy day; on a sunny day, transplant after 3 p.m., avoiding the midday heat so that the sprouted seedlings do not lose water and their survival is not affected. When transplanting, first spray water in the bed, then use a small shovel to cut out soil blocks with the seedlings and put them into a basin; if the soil block breaks apart, plant the sprouted seedling immediately. When planting, use a small shovel to dig a small hole 5-8 cm deep with straight sides, place the sprouted seedling close against the straight side, cover with soil, and water immediately. Plant two rows per ridge, with 45 cm between rows and 30 cm between plants, planting about 4900 plants per mu.

5. Seedling-stage management After transplanting, water once a day for one week to ensure survival. After the seedlings survive in mid-May, apply about 15 kg of urea per mu as a top dressing and water once; in mid-June, apply another 15-20 kg of urea per mu and water. Loosen the soil and weed in good time to promote seedling growth. During the period when the sprouted seedlings turn green and become established, promptly spray 100-fold omethoate emulsion to prevent aphids from harming the young seedlings; spray once more during the vigorous growth period. In this way, the height of the seedlings when they leave the nursery can be ensured to be more than 2.5 m, and most seedlings can meet the needs of planting around homes and block planting.