国外容器苗质量调控技术研究进展

近年来,由于造林重点由宜林地向困难立地转移,对苗木质量的要求也随之增高.文章系统总结近年来国外容器苗的质量调控技术及其对于我国困难立地植被恢复的重要意义,从指数施肥、秋季施肥、底部灌溉、短日照处理和夏季造林、修根技术、容器规格、冻藏和解冻等研究进展进行了论述总结.指数施肥的每次施肥量与植物生长节律和养分需求同步,施肥效果较优.秋季施肥能避免苗木的养分稀释效应,已被应用于很多树种.实施底部灌溉的植物生长不亚于上部灌溉的植物,而底部灌溉用水量少,氮肥淋溶小.夏季造林时,将正处于速生期的苗木进行短日照处理,诱导顶芽形成,促进根系发育,能提高苗木抗性和造林效果.苗木冻藏可使空气中自由态的水凝固成结晶态的冰,苗木感染病菌几率降低,因此冻藏成为针叶树种贮藏的标准方法.在当前研究热点的基础上,论文就未来研究方向进行展望.

A Review on the Abroad Studies of Techniques in Regulating Quality of Container Seedling

In recent years, afforestation shifted from land suitable for afforestation to the harsh sites asks for a higher quality of seedlings to overcome the environment stress. It is essential to review the late decade abroad advances in intensive container seedlings culture for applying the techniques to forest restoration in stressful sites in China. This paper summarized current techniques such as exponential fertilization, fall fertilization, subirrigation, short-day treatments and hot-planting, root pruning, container size, as well as cold storage and thawing. Exponential fertilization has been approved to be more effective because fertilizer is raised progressively to match exponential growth and nutrient demand. Fall fertilization, applied in autumn, can avoid growth dilution of nutrients, which has been successfully applied in many tree species. Plants with subirrigation grow at least as well as their cohorts with overhead irrigation, besides, subirrigation needs less water inputs, and less nitrogen leaching. Field performance of a seedling can be improved by stopping shoot growth in summer with the seedling exposed to short-day treatments, by which the root system growth can be enhanced. Freezer storage of conifer seedlings has become a standard operating procedure for many commercial nurseries, because freezing converts all the free water to ice in the storage container, and thus the development of pathogenic fungi is retarded. This paper prospected future study trends on techniques to promote seedling quality.