Deficiency symptoms will be first noticed in older and lower leaves.
The initial symptoms will be pale green to light green colour change on leaves.
The deficient leaves are narrow, short, erect, and lemon yellowish.
The affected field will show stunted growth and general yellowing.
The size and yield of the grain are decreasing.
Management
Add organic matter to the soil at the time of planting.
Treat the planting materials with bio fertilizers like Azotobacter, Azospirillum etc.
Check whether the recommended quantity of fertilizers is applied in time.
Go for soil analysis and understand the extent of deficiency.
Apply quick release nitrogen fertilizers like urea as per soil test result in split doses.
As an immediate solution applies urea as foliar spray (10 gram /liter of water) once in 15 days till the deficiency is over.
Phosphorus(P)
Symptoms
The deficiency symptoms will be first noticed in older and lower leaves.
The affected leaves will first change to dark green colour.
The leaves also appear to be erect and leathery.
Leaf sheaths bend upward with red discoloration.
Roots turn purple or black and show poor development.
The affected plants will show stunted growth.
Plants with a severe deficiency of phosphorus frequently have thinner stems.
Management
Phosphorus is best absorbed by the roots in the pH range 6.5-7.5.
Add bio fertilizers containing phosphorous solubilizing bacteria along with organic manure to increase phosphorous availability.
An excess of Iron and Zinc may also cause the symptoms of phosphorus deficiency.
Apply fertilizers such as single superphosphate for immediate correction or bone meal or rock phosphate for long term correction as per the soil test report.
Potassium(K)
Symptoms
Deficiency symptoms first appear as pale to lemon-yellow margins on older leaves.
This is followed by browning and necrosis of leaf margins.
Purple spots may also appear on the leaf undersides.
The deficiency also influences tillering or branching of plant and size and weight of grain.
Management
Optimum availability of potassium is at soil pH above 6.0. So correct soil pH in acidic soils by adding lime/ dolomite.
Add organic matter and wood ash to the soil.
Add bio fertilizers containing potash mobilizing bacteria to release non exchangable potassium from soil.
Apply Muriate of Potash (MOP) as per soil test report.
Split application is more beneficial.
As an immediate solution apply Sulphate of Potash (SOP) as foliar spray (10 gm /liter of water) during morning hours along with wetting agents.
Calcium(Ca)
Symptoms
Calcium deficiency is seen mainly in growing points, younger leaves and developing fruits.
The intermodal length becomes shortened.
Youngest leaves remain rolled and joined together at their tips. The leaf edges become serrated and curl.
The appearance of the so‐called “bull‐whip” has been recognized as a calcium deficiency symptom.
Leaves become leathery and brittle.
Plant growth will be stunded.
Management
If the soil is extremely acidic (pH between 3.5 and 4.5), apply lime (3.4 kg/cent in two split doses).
And in areas of moderate acidity (pH between 5.5 and 6), apply lime (1 kg/cent).
High levels of phosphorous can also induce calcium deficiency.
In alkaline soil go for application of Gypsum.
Boron deficiency can also lead to calcium deficiency.
Magnesium(Mg)
Symptoms
The magnesium deficient leaves show advanced interveinal chlorosis, with necrosis developing in the highly chlorotic tissue.
Management
Go for soil analysis and confirm the deficiency.
Apply Magnesium sulphate (32 kg/acre) in bands near plants.
Application of dolomite will also reduce magnesium deficiency in long run.
However, magnesium and potassium fertilizers should not be used together.
Sulphur(S)
Symptoms
Deficiency symptoms first appear in the upper and younger leaves.
The symptoms are chlorosis followed by general yellowing.
An acute sulfur deficiency causes the entire plant to turn yellow.
The tips of the young leaves may show necrotic symptoms.
The affected plants show stunted growth.
Management
Apply organic matter to increase sulphur availability.
Avoid burning of organic wastes.
Application of fertilizers like Factamfos, Ammonium sulphate, Single superphosphate etc. that contain sulphur reduces the deficiency.
Apply sulfur dust (10 kg/acre) in the soil.
The application of gypsum will also correct the deficiency in alkaline soil.
Boron(B)
Symptoms
Boron deficiency is seen mainly in growing points, younger leaves and developing fruits.
Boron deficiency results in shortened internodal growth.
The affected leaves show a narrow white and transparent necrotic spots.
Acute boron deficiency will cause young leaves to become brittle, to twist and to produce wrinkled leaf tips.
The cobs will become smaller with less tightly packed kernels.
Kernel rows will appear highly irregular.
Management
Boron deficiency is seen more in dry soils.
High available phosphorous in soil also hinders boron absorption.
Apply Borax (4 kg/acre) into the soil.
For immediate result spray Borax (1 g/litre of water) as foliar spray. Excess concentration may result in toxicity.
Borax should not be applied with ammonium fertilizers.
Iron(Fe)
Symptoms
Deficiency symptoms appear on the new growth first.
The symptoms will be yellow leaves with dark green veins (interveinal chlorosis) with eventual bleaching of the new growth.
When severe, the entire plant may be light green in color.
Management
Good drainage and soil aeration favors iron availability.
Low levels of potassium can increase Iron deficiency.
In deficient soils, apply Ferrous Sulphate (6 kg/acre) into the soil.
Manganese(Mn)
Symptoms
The leaves develop interveinal chlorosis.
Cause streaky necroses on older and on younger leaves.
Cob development will be insufficient or irregular. And show empty tips or diverse kernel size, as well as bent cobs.
Management
Kerala soils in general have high levels of manganese.
High amount of iron may induce manganese deficiency.
So go for soil testing to understand the real reason for the problem.
In deficient soils, apply Manganese Sulphate (5 g/litre of water) as foliar spray.
Zinc(Zn)
Symptoms
Areas of leaf near the stalk may develop a general white to yellow discolouration (‘whitebud’).
The midrib and leaf margins remain green.
In cases of severe deficiency, the plants are stunted due to shortened internodes and the lower leaves show a reddish or yellowish streak about one third of the way from the leaf margin.
Management
The ideal pH range for zinc availability is 5 to 7.5.
Undertake soil testing to confirm deficiency. In deficient soils, apply Zinc sulphate (8 kg/acre) in the soil.
Zinc fertilizers and phosphate fertilizers should not be used simultaneously
In severe cases, foliar spraying of Zinc sulphate (2 g/litre of water) with Calcium carbonate (2.5 g/litre of water) can be advocated in morning hours.
