Bark pine, leaves yellowing occur frequently because of ferrous sulfate deficiency and lack sunlight. These two factors would influent the growth of white?bark pine even death ,causing serious economic lost .Now, we summed up some common reasons of white?bark pine leaves yellowing and their prevention solution as bellow :
Firstly, yellowing for nitrogen deficiency. Apply base fertilizer and foliar fertilizer Nitrogen timely .The spraying concentration is 0.2% ~ 0.3% (urea).Once every six or seven days, continuous 3 or 5 times.
Secondly, improper sunshine. White?bark pine prefers shady condition thus corn crops could be planted sparsely within white pine fields. Practices prove this is a effective method.
Third, the poor soil quality may cause yellowing .Sticky soil that makes ventilation worse and saltilized soil would easy appear leaves yellowing. The ways to improve the situation method is increasing organic fertilizer, hoeing and turn soil more frequently with green manures and straw. When watering and hoeing, use and scatter salt improver when necessary.
Fourth, Water Improper. The concentration of inorganic nutrients would go up When fields in dry that may cause yellowing. Plants should be watered timely. Long time waterloging prevent the roots from exposuring to oxygen, even as water turn to freezing in winter. That also can cause yellowing. Pay attention to keep the drainage get through.
The last, the deficiency disease.Such as ferrous sulfate deficiency, we can scatter ferrous sulfate 30~50kg per area followed with once watering. As to magnesium, manganese deficiency, it also easily causes yellowing. It’s often applied to increase related micronutrient fertilizer, such as magnesium sulfate, manganese sulfate, etc.
