Identifying nutritional deficiencies in soil

Nutrient
Symptoms
Soil type
Remedies
Nitrogen
Plant turns pale green, then yellow. It begins at the tip of leaves at the bottom of plant especially older onesand works its way in the direction of the main stem. Yellowing gradually spreads up the plant to the top.
Can be normal during fruiting.
Very sandy soils or low in organic material. Excessively wet or leached soil. High or low pH. Also likely in fast growing crops. Alfalfa, blood, cottonseed, feather, fish, guano, seafood, urine. All manures
Regulates vital chemical reactions, needed in stem and leaf growth and induces rapid green growth.
Phosphorus
Early in the deficiency, plants look almost too healthy. Growth is normal but undersized. Plants become dark green frequently changing to purple, especially the undersides of leaves. Sometimes stems also take on this colour. Leaves then yellow in the final stages. Poor flowering and fruiting. Cold, wet or very acidic (below pH5). Soils in peat or sand; also very alkaline soils (above pH 7.3). Excess aluminium Bonemeal, bird manure, rock phosphate, vetch
Root formation, flowering, fruiting and ripening.
Potassium
Older leaves become mottled or spotted, edges become dry and scorched. Dead spots begin to appear, stems are weak, root systems are poor, fruit ripens unevenly. Reduced disease resistance, poor storage qualities. Sandy soils; acidic soil; soils high in peat. Excess calcium or magnesium. Kelp, wood ash, seaweed.
Important for the formation of flowers, fruit, leaves and growing tip. Helps photosynthesis at low light level and in internal water regulation. Improves flavour, fruit, vegetable and flower colour. Also linked to insect damage protection, disease and frost.
Magnesium
Because it moves freely within the plant, deficiency first shows up in the lower leaves discolouring the veins. They first turn yellow, then orange and finally brown. Leaves feel thin, brittle and sometimes cup upward. Wet, acid, high in peat or sand. Also soils given a high concentration of potash, fertilizers or calcium.
Vital for photosynthesis. Facilitates use of nitrogen, phosphorus and sulfur. It cleanses the plant of toxins that arise as a by-product of it’s own metabolism.. Needed in the formation of proteins.
Calcium
Since calcium doesn’t move freely within the plant, the symptoms first appear in new growth. Chlorosis begins first at leaf edges then moves in. Terminal buds become distorted. Young leaves turn yellow, then brown. Tomatoes develop “blossom end rot”, lettuce tip-burn. Acid soils, sandy soils. Soils that contain an excess of magnesium or potassium. Temporary problems may be due to drought or excess moisture. Eggshells, oystershells
Gives strenght to the plant.
Sulfur
Resembles to nitrogen deficiency. Plants turn pale green. Effects show up first in young growth. Leaves turn yellow but don’t dry out. Stems are weak. Legumes are most affected. Sandy or very wet soils, soils containing excessive amounts of nitrogen.
Together with nitrogen it makes protoplasm for plant cells.
Iron
Chlorosis begins at the top of the plant and works its way down. Leaves turn yellow but retain green veins. Shoots may die back and fruit may be discoloured. Alkaline soils. Excess phosphorus or alluminium.
Plays a role in the formation of chlorophyll and oxidation
Manganese
Very difficult to diagnose since it resembles to iron deficiency. Chlorosis is most severe at the top of the plant. Yellowing of the leaves appears first near leaf margins and develops in a V-shaped pattern. Leaves then develop a tan or gray spots that can easily be mistaken for air pollution damage. These spots are the major difference between manganese and iron deficiency. Lesions develop on pea and bean seeds. Alkaline soils high in humus or peaty soils with a pH of 6 or over.
Catalyst in the process of plant nutrition and encourages the growth and maturation of plants.
Boron
Corky spots develop on fruit. Rust-coloured cracks develop in stems and leafstalks, which later develop a corky edge. Leaves become thick, leathery, discoloured. Plants fail to bloom. Growing tips die. Any soil, especially those high in calcium or potassium.
Diverse use in plant functions including movement of sugar within the plant. Root, fruit and seed formation.
Molybdenum
Growing points die, leaves of young plants are chloritic, leaf margins yellow and curl. Older leaves become abnormally large, while young leaves remain very small. Brassicas are most affected. Acidic soils (soils with a pH of 5.2 and below). Excess sulfur or copper.
Essential for symbiotic nitrogen fixation and protein synthesis.
Copper
Young leaves become chloritc in a very strange way. Leaf centres yellow while veins and leaf margins remain green for a while. Shoots tips die, terminal leaves brown, leaves may fail to develop. Muck or peat soils; too much lime or phosphate applied. Excess phosphorus, zinc or nitrogen
Important in photosynthesis. Catalyst in plant respiration and iron utilization.
Zinc
Similar to nitrogen deficiency with rolled leaf margin. Chlorosis shows up first in young leaves, which are also reduced in size. Leaves are closely spaced, forming rosettes, and may be malformed. Poor nitrogen formation in legumes. Soils that are sandy and acidic or alkaline and rich in humus. Soils excessively high in phosphates, nitrogen, calcium, or aluminium.
Formation of growth hormone; protein synthesis; seed and grain production and maturation.