Take a deep breath – and then thank manganese. Without manganese, that breath of air might contain a little less oxygen for you. By accepting electrons from water molecules in plants, manganese helps release oxygen from photosynthesis into the air for us to breathe. Manganese (not to be confused with magnesium) is an essential nutrient for plants, too. It helps activate enzymes break down carbohydrates and aids in the production of chloroplasts.

Manganese likes to stay put. It tends to get chemically bound up in the soil, making it less available to plants. This problem is exacerbated in alkaline soil, where high pH makes the nutrient less available to plants. Soil compaction also prevents manganese uptake, as the aerobic soil microbes that typically move manganese around the soil find it more difficult to survive.

Once inside the plant, manganese doesn’t move, either. That’s one reason why foliar feeding of manganese is not effective; the nutrient needs to be taken in through the roots where it can be actively transported through the plant. A telltale sign of manganese deficiency is a yellowing of younger leaf tissues between the veins, which stay green.