STUDIES ON THE CHLOROStS AETIOLOGICAL FACTORS OF CUNNINGHAMIA LANCEOLATA IN THE FOREST FARM OF HONGYA, SICHUAN Ⅰ. Leaf reacting with the determination and analysis of soil factors

On the basis of the distribution of disease regions and the samples from the disease regions, the experiment and studies were carried for the determination and analysis of the soil environmental factors and the descending axis activity. The result showed that in the sour soil with high water content the active iron content increased so that the descending axis became intoxicant, causing depauperation, and affected the uptake and utilization of manganese from soil, resulting in physiological disorder of Cunninahamia lanceolata, all the factors of which were directly related to the Chlorosis.