由于缺乏某种营养元素,而使橡胶叶子非物候性过早变黄的现象,在河口垦区橡胶林地或多或少地发生。这些林地大多原有植被破坏较早,有的在植胶之前就是茅草或芒萁之类的植被,土壤瘠簿。植胶20多年来水土流失及施肥的不当也有很大关系。黄叶病发生的状况,一般山顶较重,凹地及下坡较轻,山脚则较为正常,这也显示出在同一山头土壤肥力分布的不同,反映在胶树生长上则上坡的胶树茎围小于下坡。 Due to the lack of a nutrient element, leaving rubber leaves prehistoric phenomenon of yellowing phenomenon, rubber plantation in estuarine more or less. Most of the original vegetation in these woodlands was destroyed earlier, and some plants, such as thatch or mangosteen, were planted before planting, and soil was barren. Planting more than 20 years of soil erosion and improper fertilization is also a great relationship. Yellow leaf disease occurs, the general peak heavier, concave and downhill lighter, more normal foot of the mountain, which also shows the distribution of soil fertility in the same hill different, reflected in the plastic growth of the gum tree is uphill Wai less than downhill.