Manganese deficiency-Potatoes | Yara South Africa

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Nutrients

Potatoes - Chlorosis

Symptoms
Intercostal yellowing on entire leaflets usually starting on younger leaves. Necrosis at leaf edge may be due to severe deficiency but it occurs usually in spots along the line of the veins.

Reasons
Manganese deficiency Nightfrosts can cause similar symptoms. Magnesium deficiency is similar but here yellowing usually starts on older leaves. Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils, if the soil preparation has created a loose soil with high oxygen content.

Potatoes - Chlorosis

Symptoms
Symptoms start on younger leaves. Leaf veins first remain green, but black spots develop along the line of the veins. Leaves near shoot tip small and chlorotic/necrotic.

Reasons
Severe manganese deficiency. Could be confused with late blight (Phytophthera infestans) but manganese deficiency has no smell and necrosis of stem base. Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils, if the soil preparation has created a loose soil with high oxygen content.

Potatoes - Chlorosis

Symptoms
Symptoms start on younger leaves. Leaves turn pale green/yellow followed by black spots developing along the line of the veins.

Reasons
Manganese deficiency. Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils, if the soil preparation has created a loose soil with high oxygen content.

Potatoes - Deformation

Symptoms
Symptoms start on younger leaves. Leaf veins first remain green, but black spots develop along the line of the veins. Slight cupping of entire leaflets. Leaves near shoot tip small and chlorotic/necrotic.

Reasons
Severe manganese deficiency (back side of leaf) Could be confused with late blight (Phytophthera infestans) but manganese deficiency has no smell and necrosis of stem base. Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils if the soil preparation has created a loose soil with high oxygen content.

Potatoes - Chlorosis

Manganese deficiency made worse by

Organic soils
Sandy soils
High pH
Cold wet periods
Fluffy soils

Manganese is important for

Boosts bulking
Increases the yield of tubers
Improves disease resistance
Improves skin finish
Increases tuber dry matter content
Increases starch levels

Yara recommended fertilizers for Manganese

YaraTera CHELATE 1089

Potatoes: Apply 2 kg/ha before planting (can be coated on pre-plant fertilizers) Apply a further 1 kg/ha at 3, 5, 7 weeks after planting. Can also be applied as a foliar application: Up to 150 g/100L water.

YaraTera CHELATE 1090

YaraVita MANCOZIN

Potatoes: 1 l/ha at one week after 100% emergence and during tuber bulking. For moderate to severe deficiency repeat applications at 10 to 14 day intervals. Water rate: 200 l/ha.

YaraVita MANTRAC PRO

Potatoes: 1 to 2 l/ha at one week after 100% emergence. For moderate to severe deficiency, repeat applications at 10 to 14 day intervals. Also, 1 l/ha following petiole analysis during tuber bulking. Water rate: 30 to 200 l/ha.

YaraVita TRI-PHOLATE

Potatoes: Apply 2 kg/ha 1 week after 100% emergence. Apply a further 2 kg/ha at tuber initiation and a final 2 kg/ha at flowering. Water rate: 200 l/ha for tractor driven sprayer. 100,000 l/ha for application through irrigation system.