杨树大苗是指插条培育出的二年根二年干(茎),或三年根二年干以上的带根苗。利用杨树大苗造林,可以增强对恶劣环境的抵抗能力,防止沙压,速生丰产,防护效益早,林相整齐美观,便于管理。杭锦后旗地处河套平原,降雨量多集中在七、八、九月份,土壤盐碱化严重,解冻期又长,引黄灌溉从5月中旬才开始。因此,春季用大苗大面积造林,由于不浇水或栽后浇水,或引黄灌溉的造林,成 Poplar big seedlings refers to two years of root bred nursery stems (stems), or three years more than two years rooted shoots with roots. The use of poplar seedlings afforestation, can enhance the resistance to harsh environments, to prevent sand pressure, fast-growing, protective benefits of early, neat forest phase, easy to manage. Hangjinhouqi is located in the Hetao plain. The rainfall is mostly concentrated in July, August and September. The soil is salinized severely and the thawing period is long. The irrigation of the Yellow River will not begin until mid-May. Therefore, large-scale afforestation with large seedlings in spring, due to not watering or transplanting watering, or irrigating the afforestation, into