营养土应就地取土,力求具有质轻、透水、保肥和良好的通气性,每亩需营土4000公斤左右。生产上常用的营养土是选择三年以上没有耕作过的林土或是生土,或用表土50-70%、土杂肥(腐熟)30-50%,过磷酸钙2%三者混合配制,然后粉碎过筛,最大颗粒直径不得大于1厘米,再进行土壤消毒,用40%的甲醛加50倍水,每立方米营养土用量20-40毫升,充分搅拌后,封闭覆盖24小时,然 Nutrient soil should be borrowed on the spot, and strive to have a light weight, water permeability, fertilizer and good ventilation, mud per acre to be about 4000 kg. Nutritional soil commonly used in production is the choice of more than three years without cultivation of forest soil or raw soil, or with topsoil 50-70%, Tuza Fei (decomposed) 30-50%, superphosphate 2% three mixed preparation , And then crushed and sieved, the maximum particle diameter of not more than 1 cm, and then soil disinfection, with 40% formaldehyde and 50 times the water, 20-40 ml of nutrition soil per cubic meter, stir, closed for 24 hours,