红壤山地广泛分布在我国长江以南的地区,该地区高温多雨,有机质分解快,土壤结构不良。水分过多时,土粒吸水成糊状;干旱时水分容易蒸发散失,土块又易板结坚硬。砧木苗生长情况的好坏关系到嫁接能否进行,嫁接苗生长情况的好坏又关系到苗木能否及时或提前出圃。因此,在南方山地红? Red soil mountains are widely distributed in the area south of the Yangtze River in China. The area is hot and rainy with rapid decomposition of organic matter and poor soil structure. When the water is too much, the soil particles absorb water into a paste; when the water is dry, the water is easy to evaporate and lose, and the soil blocks are hard to be hardened. Rootstock seedling growth is related to the quality of graft can be carried out, the growth of grafted seedlings is related to the quality of seedlings can be timely or early nursery. Therefore, in the southern mountain red?