Potassium deficiency-Lettuce | Yara United States

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Nutrients

Lettuce - Deformation

Symptoms
Tips and margins of older leaves get chlorotic spots with increasing size which become necrotic later on. On account of scorched leaf margins leaves are deformed. With more severe deficiency the leaf color turns to mottled dark green and the plant appears wilted. Occasionally leaves are less crinkled than normal and shape of the leaves becomes more rounded. Growth of the plants is restricted, they do not form heads or the heads remain loose.

Reasons
Potassium deficiency Symptomes may be confused with high salt concentration of the growing substrate. In this case the veins of the leaves become brown in addition to dry leaf margins.

Lettuce - Discolouration

Symptoms
Potassium deficiency causes longer main roots than normal and only few secondary roots. They show yellowish color. Often roots are slimy .

Reasons
Potassium deficiency on roots

Lettuce - Deformation

Symptoms
Tips and margins of older leaves get chlorotic spots with increasing size which become necrotic later on. On account of scorched leaf margins leaves are deformed. With more severe deficiency the leaf color turns to mottled dark green and the plant appears wilted. Maybe leaves are less crinkled than normal and shape of the leaves becomes more rounded. Growth of the plants is restricted, they do not form heads or the heads remain loose. Potassium deficiency causes longer main roots than normal and only few secondary roots. Often roots are slimy and yellowish in color.

Reasons
Potassium deficiency on head and roots

Lettuce - Deformation

Symptoms
Tips and margins of older leaves get chlorotic spots with increasing size which become necrotic later on. On account of scorched leaf margins leaves are deformed. With more severe deficiency the leaf color turns to mottled dark green and the plant appears wilted. Maybe leaves are less crinkled than normal and shape of the leaves becomes more rounded. Growth of the plants is restricted, they do not form heads or the heads remain loose.

Reasons
Potassium deficiency (right) compared to optimum supply(left) Symptoms may be confused with high salt concentration of the growing substrate. In this case the veins of the leaves become brown in addition to dry leaf margins.

Lettuce - Necrosis

Symptoms
Symptoms of potassium deficiency start on older leaves. The leaf color turns to mottled dark green and the plant appears wilted. Tips and margins get chlorotic spots with increasing size which become necrotic later on. On account of scorched leaf margins leaves are deformed. On the photo necrotic areas appear along the main veins. More typical are scorched zones on the margins. Occasionally leaves are less crinkled than normal and shape of the leaves becomes more rounded.

Reasons
Potassium deficiency on leaves

Potassium deficiency made worse by

Acidic soils (low pH)
Sandy or light soils (leaching)
Drought conditions
High rainfall (leaching)
or heavy irrigation
Heavy clay (illite) soils
Soils with low K reserves
Magnesium rich soils

Potassium is important for

Internal water regulation
Vigorous growth and healthy foliage
Required in large amounts

Yara recommended fertilizers for Potassium

YaraMila® 15-15-15

Lettuce (field grown): Apply 400-1000 lbs YaraMila® 15-15-15/acre in split applications according to yield potential and soil test. Apply no more than 25% of product at planting. Apply the remainder in 2-3 side dress applications. Utilizing YaraMila® 15-15-15 provides a balanced nitrogen approach by supplying both nitrate and ammoniacal nitrogen along with fully available Phosphate, soluble Potassium and Sulfur in a homogenous prill. Consult with your agronomist for local recommendations. Consult with your agronomist for local recommendations.

YaraMila® 21-7-14

Lettuce (field grown): Apply 275-750 lbs YaraMila® 21-7-14 /acre in split applications according to yield potential and soil test.. Apply the remainder in 2-3 side dress applications. YaraMila® 21-7-14 provides fully available Phosphate along with Nitrogen, Potassium and Sulfur, in a homogenous prill. Consult with your agronomist for local recommendations.

NUTRA-PHOS Zn-K PLUS

Lettuce (field grown): 2 to 10 lb. per acre per application. Make several applications at intervals of 2 to 3 weeks starting at thinning period. Apply aerial applications in at least 5 gallons/acre and ground applications in at least 10 gallons/acre; however, when total application gallonage is 25 gallons per acre or less, DO NOT mix more than 1 lb. of this product per gallon of water.

SULFATE OF POTASH - GRANULAR 0-0-50

Lettuce (field grown): Apply up to 100-425 lbs Sulfate of Potash/acre according to soil analysis throughout the growing season. Utilizing Sulfate of Potash from Yara for part or all of your potassium needs provides your crop with water soluble potassium along with sulfate sulfur. Consult with your agronomist for local recommendations.

Read more about SULFATE OF POTASH - GRANULAR 0-0-50