(2) Layered sand storage, the process of seeds entering germination state after a series of physiological changes for a certain period of time under the influence of comprehensive conditions is called post-ripening. Deciduous fruit trees in the north have the characteristics of natural dormancy, while evergreen fruit trees in the south generally have no dormancy period, which is very short. In the process of dormancy, the embryo can not mature until it continues to develop, or the gas exchange is blocked because of the structural obstacle of seed coat or pericarp, such as hard, dense, waxy or leathery seed coat, or because the seed coat is covered with lignified and hard endocarp. However, most temperate deciduous fruit trees need to be treated for a period of time under the conditions of low temperature, ventilation and humidity, in order to strengthen the water absorption capacity of seeds, improve the permeability of protoplasm and the activity of enzymes, and the seeds can only germinate after being hydrolyzed by organic matter. This treatment method is called layered sand storage, and the sand storage temperature is 2 ~ 7℃, not lower than -5℃ and higher than 17℃. Walnut, hazelnut, apricot and pear for 60-80 days; Jujube, peach, peach, apricot and grape 80 ~ 100 days; Chinese plum 80 ~ 120 days, sweet cherry 100 days, chestnut 100 ~ 150 days, sour cherry180 days and hawthorn 200 ~ 300 days. When sand, a layer of sand and a layer of seeds are stored, the humidity of the sand is: hold the watermark with your fingers, and do not drip down or scatter when touching the ground. Cover the top with sand for 20-30 cm to prevent mildew and rodent damage, and the storage time is connected with the sowing date.
(3) Sowing: Sowing time can be divided into autumn sowing or spring sowing in temperate zone, and can be sowed in tropical and subtropical zones all year round. Generally, in areas with short but not too cold winter, good soil quality and suitable humidity, autumn sowing is better, with early emergence and long growth period, and Miao Zhuang. The Yangtze river basin is from early October to late February in 10, and the north China is from mid-June to mid-kloc-0/0. But sowing in autumn takes a long time in the field, and birds and mice are very harmful. Therefore, in places with cold, windy, dusty and sticky soil in winter, the sowing effect in spring is better. Spring sowing is carried out after the soil is thawed, from late February to late March in the Yangtze River basin and from mid-March to early April in North China and Northwest China. There are many evergreen fruit trees, such as loquat, litchi and longan, which should be planted with the harvest. Small seeds such as apples and pears are all drilled; Large seeds such as peaches, apricots, chestnuts and walnuts are usually planted on demand. When sowing, walnut seeds should be placed horizontally and chestnut seeds should be placed vertically, which is beneficial to the germination of embryos and the robust growth of seedlings. According to the seed size, soil properties and climatic conditions, the sowing depth is generally 1 ~ 4 times of the seed size. Strawberries and figs have the shallowest covering thickness, and no seeds can be seen; Within shanding 1 cm, begonia, pear, pearl plum, bitter orange, grape and Schizonepeta fruit1.5 ~ 2.5 cm; Jujube, cherry, plum, ginkgo and loquat are about 4 cm; Peach, peach, apricot, etc. 4 ~ 5 cm, walnut, chestnut 5 ~ 6 cm. The sowing amount per 667 square meters is: peach 1 ~ 1.5 kg, peach 30 ~ 50 kg, peach 20 ~ 40 kg, apricot 15 ~ 30 kg, jujube 4 ~ 6 kg, 7.5 ~ 65438+. Carya cathayensis 150 ~ 175 kg, Tetrandra tetrandra-5 ~ 10 kg, Fructus Aurantii 20 ~ 60 kg, Capparis spinosa 15 ~ 45 kg, Fructus Aurantii 35 ~ 60 kg and Longan 40 ~1.