Foliage become light green in colour with reduced size
Shedding of leaves
Plant generally appears weak with stunted growth
Reduced plant height & uniform yellow chlorosis of leaf
Discolouration normally starts from leaf tip.
In extreme severity - reddening of leaf blade.
Management
For determining the severity of the deficiency, soil analysis has to be done
Application of quick releasing nitrogen fertilizer like urea, according to the results of the soil test.
Apply urea as a foliar spray (10 gram per litre of water) once every 15 days .
Frequent application of organic growth boosters is also beneficial.
Phosphorus (P)
Symptoms
Older leaves are affected which turns yellowish in colour with characteristic sign of grey green tissue along the leaf margin
In extreme conditions, root cap becomes dry
Growth is extremely stunted.
Reduction in boll number.
Management
Ensure that recommended amount of fertilizer is applied on regular time.
For determining the severity of the deficiency, soil analysis is to be done
Use fertilizers such as single superphosphate for quick correction or bone meal or rock phosphate for long-term correction.
In the pH range of 6.5-7.5, phosphorus is readily absorbed by the roots.
Addition of biofertilizers including phosphorus solubilizing bacteria along with organic manure helps to increase the availability of phosphorus
Potassium (K)
Symptoms
Deficiency first noticed in older and lower leaves.
Causes damage to leaves
During initial stage symptoms not seen in lower canopy & extend towards the plant
Balls are poorly developed
Reduced yield with poor quality fiber
Older leaves show interveinal chlorosis with beginning leaf scorch spreading from tip margin of area to centre
Deficiency can be noticed on pre blooming stage
Interveinal chlorosis leads to red/gold colour
Mottling between leaf veins progressing to yellowing & later browning, necrosis of leaf margins.
Delay in blooming and fruiting.
Sometimes leaves become smaller with purplish reddening.
Overall stunting of plant.
Balls will remain small & immature with poor retention.
Reduced yield
Premature leaf shedding
Many bolls fail to open altogether with inferior lint quality.
Management
In the pH range of above 6, Potassium is readily available.
Maintain pH by addition of lime/dolomite
Improve the soil fertility by adding organic matter and wood ash.
For determining the severity of the deficiency, soil analysis is to be done
Use Muriate of Potash (MOP) according to the results of the soil test. Split application is preferable.
Apply foliar sprays of sulphate of potash (SOP) (10 gm/litre of water) and wetting agents in the morning as an immediate remedy
Calcium (Ca)
Symptoms
Noticed in growing points, younger leaves and developing fruits.
Short internodes, stunted growth
Causes plants to weak, shortens resulting in toppling over
Fruit production is drastically reduced with crinkled leaves.
Leaves become upward curling of leaves (cup shape) with & poor root growth & sometimes leaves become brittle
Deficiency noticed in early stage of the crop.
Management
Analysis of pH in the soil
Check the pH of the soil. If the soil is extremely acidic (pH between 3.5 and 4.5), apply lime (3.4 kg/cent of 40 m2 in two split doses). And in areas of moderate acidity (pH between 5.5 and 6), apply lime (1 kg/cent of 40 m2).
High phosphorus levels leads to calcium deficiency
In alkaline soil application of Gypsum is preferable
Magnesium (Mg)
Symptoms
Deficiency may appear as purple red leaves with green veins on lower and older leaves.
Affected leaves show age prematurely and fall off
Early symptoms are noticed on mature leaves
Extreme deficiency develops whitish to brown spots followed by marginal necrosis
Sometimes plants may exhibit distinct reddish interveinal discolouration on middle & lower leaves
Plants may become stunted in appearance
Reduced yield
Management
Do the soil analysis and confirm the deficiency.
Addition of Magnesium sulphate (320 gram /cent or 32 kg/ acre) in bands near plants.
Long-term usage of dolomite will reduce magnesium deficiency
Magnesium and potassium fertilizers should not be applied together.
Sulphur(S)
Symptoms
Symptoms start on younger leaves which become pale green or yellow as the growth progresses while old leaves remain green.
At severe deficiency leaf size & general plant size are reduced with few vegetative branches
Balls are reduced in size
Veins develop green colour for a while but at severe deficiency they may chlorotic too
Sulphur deficient plants are small, spindly with slender stalks
Management
Application of sulphur-containing fertilisers, such as Factamfos, Ammonium sulphate, Single superphosphate, etc., reduces the deficiency.
In sulphur deficient soils, apply sulphur dust (100 gram per cent or 10 kilogrammes per acre).
Deficiency in alkaline soil can be reduced by application of gypsum
Addition of organic material improves sulphur availability in the soil.
Burning of organic waste leads to sulphur deficiency
Boron (B)
Symptoms
Young leaves show diffuse interveinal chlorosis
Subsequently necrotic sunken patches appear on margins
Petioles are shortened and thicker than healthy plants
Sometimes excessive stalk growth is noticed
Abortion of leaves & shedding of balls are noticed
Balls are malformed exhibiting flat-sided appearance is another symptom
Management
Analysis of soil to confirm the deficiency.
Application of borax (40 gram /cent or 4 kg/ acre) into the soil
Addition of borax (1 gram / litre of water) as foliar spray.
Avoid the combined application of Boron and calcium.
Application of borax with ammonium fertilizers should be avoided.
Copper (Cu)
Symptoms
Interveinal chlorosis
Subsequent necrosis starting from leaf margin
Leaves become narrow and brittle.
Management
Apply Bordeaux mixture (1%)
Iron (Fe)
Symptoms
Noticed on younger & medium aged leaves
At early stages pale yellow – green interveinal chlorosis later leads to complete yellowing of plant
Upper most leaves become chlorotic & bleached appearance
Leaf veins remains somewhat green in colour
At extreme conditions the entire plant may be light green in colour.
Management
Iron content in Kerala soils is often high. So, get a soil test to determine the reason for the problem
Low potassium levels leads to iron deficiency
Addition of Ferrous Sulphate (60 gram /cent or 6 kg/ acre) into the deficient soils.
Manganese (Mn)
Symptoms
Symptoms appear first on lower leaves new growth first
leaves to turn reddish grey except veins remain green.
Interveinal chlorosis developed on younger leaves
Show uniform yellowing with veins of leaves turn remain green
Leaves become puckered, mottled, and partially chlorotic and distorted in early stages
At maturity affected leaves become thickened and brittle.
Management
Soil Analysis
Application of Manganese Sulphate (5 gram per litre of water) as foliar spray
Zinc (Zn)
Symptoms
Deficiency symptoms first appear on newly produced & young leaves
Leaves develop interveinal chlorosis from leaf margin
Leaves appears thick, brittle leathery & upturned, during extreme deficiency Short internodes (rosetting)
Small & stunted leaf with bronzed appearance
Shedding of squares and flowers
Deficiency is seen in soils with high acidity.
Management
The optimal pH range for zinc availability is 5 to 7.5.
Confirm deficiencies by doing soil testing.
Avoid the application of Zinc and phosphate fertilizers at the same time
In severe cases, foliar spraying of Zinc sulphate (2 gram/litre of water) with Calcium carbonate (2.5 gram/litre of water) can be advocated in morning hours.
