柚子皮呈鐵灰色 - 農業知識入口網

我們家的柚子皮顏色呈現鐵灰色或者褐色，跟正常情況下的柚子皮顏色明顯不同，請問這是正常現象嗎?或是生了什麼病?亦或是缺乏什麼養分?
圖片如下
[IMG]http://img390.imageshack.us/img390/2011/dsc03955bz0.jpg[/IMG]
[IMG]http://img390.imageshack.us/img390/8282/dsc03955ci7.jpg[/IMG]
[IMG]http://img98.imageshack.us/img98/6338/dsc03954dq8.jpg[/IMG]
[IMG]http://img98.imageshack.us/img98/3370/dsc03953di6.jpg[/IMG]
[IMG]http://img511.imageshack.us/img511/8409/dsc03952ve8.jpg[/IMG]
[IMG]http://img150.imageshack.us/img150/4192/dsc03951xv0.jpg[/IMG]
[IMG]http://img209.imageshack.us/img209/3460/dsc03950zu3.jpg[/IMG]
[IMG]http://img209.imageshack.us/img209/3460/dsc03950zu3.jpg[/IMG]
[IMG]http://img164.imageshack.us/img164/287/dsc03949eu4.jpg[/IMG]

如果看不見
請用下列網址
http://img390.imageshack.us/img390/2011/dsc03955bz0.jpg
http://img390.imageshack.us/img390/8282/dsc03955ci7.jpg
http://img98.imageshack.us/img98/6338/dsc03954dq8.jpg
http://img98.imageshack.us/img98/3370/dsc03953di6.jpg
http://img511.imageshack.us/img511/8409/dsc03952ve8.jpg
http://img150.imageshack.us/img150/4192/dsc03951xv0.jpg
http://img209.imageshack.us/img209/3460/dsc03950zu3.jpg
http://img164.imageshack.us/img164/287/dsc03949eu4.jpg