Trace elements deficiency will be bad for soybean growth, what’s the worst, it will make soybean mature lately or decrease the output if it is deficient of manganese sulfate.
Some symptoms are as follows:
Fe deficiency will make leaves and petiole be yellow, and the new leaves in branch will be easy to get sick, the leaf opex will be light green.
Manganese deficiency: superior leaf will lose green, and both sizes of leaf will occur the orange stain, in which there are 1-3 dark red dots like pinholes, and there are big or small dots on the back pulse, like tadpole. In the late time, the new leaves veins will occur black dots, and new leaves roll and become yellow, and then drop off. What’s the worst, terminal bud will wither and mature lately.
Zn deficiency, inferior leaves will lose green color or angulate, and plant is very thin, maturing lately.
How to prevent and cure?
Increase the organic fertilizer, apply 1000-2000kg of bubble compost or thoroughly decomposed organic fertilizer for every 667㎡ soil， which also can improve the output.
Keep the soil moisture in the flower phase, but do not fill fields with tornado to avoid nutrient prediction.
In some soybean area which is lack of organic fertilizer, supply chemical fertilizer and trace elements to prevent the element deficiency. 50kg 0.3-0.5% ferrous sulfate are needed for every 667㎡ soil, and 50kgs of 0.5% zinc sulfate and manganese sulfate will be needed too.