大苗营造农田防护林带,成林早,见效快。农田防护林带可采用2～4年生的小青杨、小叶杨、沙兰杨、小黑杨、旱柳等。西北风砂地区以及地势高燥的地方,宜采用5～10年生的樟子松、油松大苗。 杨柳大苗的根系较深,起苗时需带一部分侧根,不可从根颈处切断。苗挖出后要及时运输并假植,避免根部长时间暴露在外。挖松树大苗必须带土坨,用草袋或草绳将土坨捆紧(冬季挖冻坨移植,则不必捆绑)。5～7年生幼松需带直径1.0～1.5尺的土坨,8～10生年的需带直径2.0尺土坨。 按照定植点挖坑,2～3年生杨柳大苗栽植坑,直径和深度均为1.5尺。松树视土坨的大小挖坑,坑大土活, Big seedlings to create farmland shelterbelt, forest early, quick. Farmland shelterbelt with 2 to 4 years of young Populus, Populus, Sallam, Populus, Salix and so on. Northwest wind sand area and high terrain, should adopt 5 to 10 years of Pinus sylvestris, pine seedlings. Willow seedlings deep roots, when needed to take part of the lateral root, not cut off from the root neck. Miao dug out after the timely transport and fake plants, to avoid prolonged exposure to the roots. Digging pine seedlings must bring soil lumps, with grass bag or grass rope lump Tuo tight (winter frozen lump transplant, you do not have to bundle). 5 to 7-year-old pine need to bring the diameter of 1.0 to 1.5 feet of soil lumps, 8 to 10 years of age with 2.0-foot diameter soil Tuo. According to the planting site digging, 2 to 3-year-old willow seedlings planting pit diameter and depth are 1.5 feet. Pituasia pine depending on the size of the pit, pit big earth live,