Sowing and raising seedlings of Robinia pseudoacacia in mountainous area

Robinia pseudoacacia is one of the main tree species for afforestation in mountainous areas. it is not only an important source of wood such as pillars, sleepers, cars and boats, agricultural tools, but also a good source of honey.

First, nursery site selection and land preparation. The nursery land should choose the sandy loam land with flat terrain, good drainage, deep and fertile soil layer, and irrigation conditions. After the nursery land is selected, ploughing should be carried out in autumn, with a depth of 30 cm. The top of the early spring rake fine rake flat, while picking out the grass roots and stones. Combined with land preparation, 3000-5000 kg of rotten barnyard manure per mu. Poisonous soil made of 50% phoxim EC was applied during soil preparation to prevent underground pests.

Second, seed soaking and sprouting treatment. It is better to soak seeds to accelerate germination and sow seeds in batches by increasing temperature step by step. Put the seeds in a jar, pour 50-60 ℃ of hot water, pour water and stir until it is not hot. After soaking for 1 day and night, remove the floating chaff seeds, bad seeds and impurities, and use a fine-eyed sieve to separate the dilated seeds from the hard seeds. When the unswollen seeds were treated with 80-90 ℃ hot water for 1-2 times, most of the seeds could swell. Put the remaining small amount of hard grains into an iron sieve (1.5-2 kg per sieve), soak in boiling water for 10 seconds, and then soak in warm water for 1 day and night, the seeds can basically expand. Each time the selected water-absorbing swelling seeds should be promptly put into the mud basin or basket, covered with wet grass curtains or wet sacks, and placed in a warm place to sprout. In order to prevent the seeds from sticking and deteriorating, rinse the seeds with water twice a day, and then place them in a warm and ventilated place to promote germination. After about 4-5 days, the seeds can be taken out and sown when the white root tip is exposed. All the seedlings emerged 3-5 days after sowing.

Third, sow seeds. The sowing date was carried out when the average temperature reached 16 ℃ in late April. The seeding rate of ridge cultivation is 3-4 kg. The ridge distance is 70 cm, adopt wide strip sowing. First trench on the ridge, ditch width of 10-15 cm, trench bottom should be flat, depth should be consistent. Spread the seeds evenly into the sowing ditch, cover the soil 1-2 cm, and then gently press the seeds once so that the seeds are in close contact with the soil.

Fourth, nurturing and management at seedling stage. The first seedling was carried out when the seedling height was 3-4 cm, then 1-2 times, and the last time when the seedling height was 10-15 cm. About 10 seedlings should be preserved in the sowing ditch per meter, and 10,000 seedlings per mu should be kept. Irrigate in time after transplanting. It can be irrigated 4-6 times a year. Topdressing can be done twice from the first ten days of June to the middle of July. Each time 5 kg of urea or 7.5 kg of ammonium sulfate were applied per mu. Water should be irrigated after fertilization. Stop irrigation and topdressing after mid-August, and shovel frequently. 0.5-1% Bordeaux solution was used to control blight, and 80% wettable trichlorfon 800 times solution was used to control seed flies. When aphids occur from June to July, 2000 times of dimethoate EC can be used to kill insects.