在美国东南沿海平原许多低洼地上,过量的土壤水分限制着松树的生长。常常采用开沟和垫土来调节地下水位。而施放磷肥也能促进火炬松和湿地松良好的生长,事实证明,施磷肥引起的生长增长比公认的排水法效果好。在灌溉或高度还原条件下天然矿质土壤中的可溶性磷比排水良好的好气性条件下的数量大些。但是,树种遗传因子的影响与磷的施用不同,更有可能在少量排水的条件下限制生长。因此实际情况恰相反,在潮湿的环境和少量排水的土壤上,火炬松和湿地松应经常获得磷肥才能达到最大生长量。这些自相矛盾的关系是由于根部通气不良降低了松树吸收营养元素的能力,而更高的土壤渗透浓度对于满足一些树木的 Excessive soil moisture limits the growth of pine trees in many low-lying lands in the southeast coastal plain of the United States. Ditches and paddy soil are often used to regulate groundwater levels. The application of phosphate fertilizer can also promote the good growth of Pinus taeda and Pinus elliotis. Facts have proved that the growth growth caused by phosphate fertilizer is better than the accepted drainage method. Under irrigated or highly reduced conditions, soluble phosphorus in natural mineral soils is larger than under well-drained aerobic conditions. However, the effect of tree genetic factors is different from that of phosphorus and is more likely to limit the growth with small amounts of drainage. Therefore, the actual situation is just the opposite. In the humid environment and in a small amount of drainage soil, it is necessary for Pinus taidis and Pinus elliottii to obtain phosphate fertilizer to achieve the maximum growth rate. These conflicting relationships are due to the poor ability of the pine tree to absorb nutrients as a result of poor root ventilation, and higher soil osmolality can be expected for some trees