Manganese is an essential plant mineral nutrient, playing a key role in several physiological processes, particularly photosynthesis.

Manganese deficiency is a widespread problem, most often occurring in sandy soils, organic soils with a pH above 6 and heavily weathered, tropical soils. It is typically worsened by cool and wet conditions.

Specific Benefits

Numerous crop species have been reported to show high susceptibility to manganese deficiency in soils, or a very positive response to manganese fertilization, including cereal crops (wheat, barley and oats), legumes (common beans, peas and soybean), stone fruits (apples, cherries and peaches), palm crops, citrus, potatoes, sugar beets and canola, among others. The impact of manganese deficiencies on these crops includes reduced dry matter production and yield, weaker structural resistance against pathogens and a reduced tolerance to drought and heat stress.

Manganese Deficiency

Manganese has a relatively low phloem mobility in plants, and as a result, typical leaf symptoms of manganese deficiency first develop in younger leaves. The critical concentration for manganese deficiency is generally below 20 ppm dry weight in fully expanded, young leaves. In the case of dicots, manganese deficiency first results in pale mottled leaves, followed by typical interveinal chlorosis.

Under severe manganese deficiency dicots may also develop a number of brownish spots. In cereals, manganese deficiency can cause pale green or yellow patches in younger leaves. This condition is known as gray speck, and is characterized by necrotic spots that form in older leaves