How is manganese sulfate used to promote plant growth?

Manganese sulfate (${\text{MnSO}}_4$) is a vital compound used in agriculture to promote healthy plant growth by addressing manganese deficiencies. It is commonly applied to soils or used as a plant spray to provide this essential [trace element], which is necessary for critical biological processes, including the assimilation of [nitrates].123

The application of manganese sulfate is particularly beneficial for certain crops, such as [citrus]. While manganese is naturally present in many soils, it can sometimes become chemically bound and unavailable to plants—for example, in alkaline soils where it may react with oxygen to form insoluble manganese dioxide, leading to deficiency diseases like "gray speck" in [oats]. By providing manganese in a soluble form, manganese sulfate ensures that plants can effectively absorb the nutrient required for their development and maturation.13

It is important to note that while manganese is essential, it must be managed carefully; an excess of this element can be toxic to plants.1