Manganese sulfate is one of essential nutrient elements, and takes up one to three ppms, and the content is high in seeds, green leaf and cortex of fruit. Manganese is also the main part of oxidation-reduction enzyme, taking part in the photosynthesis and cholorophyllous combination, too much manganese will cause roughbark.
In the early period, the leaves will lose green color from the middle leaves and extend to the top leaves and bottom. What’s seriously, veins will turn to yellow color; in the late stage, new leaves keep green. Mn content is 20ppm or below, it’s deficient of manganese.
Mn deficiency and roughbark disease have a relationship with the soil physicochemical property, and the soil in common gardens is alkali. Roughbark occurs when Mn is insoluble in drought spring, it’s hard for trees to absorb. Ph is 5 or below, and Mn content is 0.01% above.
Ways to cure the manganese deficiency
Improve the soil quality and apply organic fertilizer; in May to July, spray 0.2-0.3% manganese sulfate solution for 3-4 times, every 20 days a time; paint some on branches with 0.3% manganese sulfate solution to promote the new tips and leaves’ growth. 0.5-1.25kgs of manganese oxide or manganese chloride or 1-4kgs of manganese sulfate.