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Nutrient Deficiency Doctor
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The Role of Potash in Plant NutritionThe effects of potash deficiency are
- A serious reduction in yield
- Lowered quality of crop produce
- Increased susceptibility to disease and adverse conditions [esp. drought]
- Reduced frost resistance
- Poorer resistance to lodging
- Inability to make full use of light
- Higher water consumption.
Recognising Potash Deficiency in Arable Crops- Insufficient plant-available potash in the soil often manifests itself first as a blue-green colouration of the leaf, as is often seen where nitrogen supply is excessive. Depending on the crop, as the deficiency becomes more acute, the leaf colour changes from dark-green to a typical violet, brownish-red or brown. These discoloured areas appear first at the leaf-margin and then spread in an irregular manner towards the centre. Finally these areas die.
- Potassium deficiency becomes first evident in older leaves. Typically, this results in premature leaf-fall. There are often morphological changes in leaves which may develop a crinkled upper surface and bend or roll inwards and appear dull. In clovers, white spots appear first at the leaf margin. Later the leaflet dies off.
- In fruit production, fewer and smaller fruits are produced… but in the interests of reproduction, the plant will attempt to maintain the potassium concentration of the seeds…even if the main plant becomes starved of potash.
Illlustrated Examples Acknowledgements & Source of Information:
The table below is reproduced from Potash Deficiency In Crops published by the Kali und Salz GmbH and Potash Limited, Sawbridgeworth, UK. 
 | Wheat [Triticum vulgare]Yellowish green to red-brown colouration of the margins and tips of older leaves. Leaves limp & drooping, wavy upper surface and leaf-tips twisted.
Potash Deficiency in Wheat |  | Maize [Zea mais]
Marked undulation of the upper leaf surface leaves pale green [chlorosis]. Brown leaf margins and tips which eventually dry-up Potash Deficiency in Maize |  | Sugar Beet [Beta vulgaris]
Yellow to reddish-brown colouration and finally death of older leaves, beginning at the margins. Leaves strongly crinkled and margins turning downwards. Brown flecks and strips on leaf stalks. Potash Deficiency in Sugar Beet |  | Potatoes [Solanum tuberosum]
Leaves blue-green between the veins. Leaf margins and tips turn reddish-brown. Leaf margin turned down. Leaves close together and finally die & fall Potash Deficiency in Potatoes | 
| Tomatoes [Solanum lycopersicum] Young er leaves dark green at first turning grey-green. Development of whitish-yellow necrotic spots starting at the margin, which later turn brown on older leaves first. Stems remain thin and in severe deficiency exhibit dark necrotic spots. The fruit has a pallid appearance and may show greenback Potash Deficiency in Tomatoes |  | Dwarf Beans [Phaseolus vulgaris]
Metallic-bronze leaf discoloration. Chorotic spots between the leaf margins beginning from the leaf edges. Later additionally necrotic leaf margins curling-up Potash Deficiency in Dwaft Beans |  | Apple [Malus domestica]
Brown discoloration of the leaf-margin, downward curling of the leaves, which after death remain attached for a long time. Fruit small and poorly coloured [appearing unripe]. Low acids content, shrivel quickly and rot easily. Cautionary note. Whilst potash is extremely important in apples, rates should be calculated with caution as an excess of this nutrient can affect storage quality. |  | Grapes [Vitis vinifera]
In the early stages the leaf margins curl inwards. Leaves turn yellow and die at the margin extending towards the middle. New shoots deformed rendering them unable to sustain ripening. Potash Deficiency in Grapes |  | White Clover [Trifolium repens]
White spotting at the leaf margins and death of leaflets. Potash Deficiency in White Clover |  | Oil Seed Rape [Brassica napus olefera]
In the early stages, dark green leaves followed by loss of colour at the margins and tip. Older leaves turn down, loose their gloss and die. Potash Deficiency in Oil Seed Rape |  | Strawberries [Fragaria moschata]
Leaves become blue-green around the mid-rib. Leaf margins of the older leaves turn red-brown to purple. The coloration and subsequent necrosis spreads until there remains only a green triangle at the leaf base. Death of leaves causing reduced production of runners and also fruits. The berries are small and tasteless. Potash Deficiency in Strawberries |
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