Deficiency symptoms will be first noticed in older and lower leaves
Yellowing of leaves starts from tips & margins.
Longer time to produce bulbs that i.e. delayed maturity
tissue above bulbs become soft at maturity
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
symptoms will be first noticed in older and lower leaves
Leaves become smaller & thinner
Some cases reddish tint noticed on leaf tips.
Stunted growth
older leaves gradually turn to yellow while the inner leaves remain dark green.
Fail to develop bulbs
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 6.2-7.0, 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
Yellowing of leaves starts from tips & margins
Late on spread to entire leaf surface & exhibits scorched appearance
Edge of leaves may curl & droop
Bolting is high at deficient situation
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 g/litre of water) and wetting agents in the morning as an immediate remedy
Calcium (Ca)
Symptoms
Development t of necrotic tissue at the tips & margins of leaf
Later this area become brown/black & spread inward
Reduced root growth
Delayed bud formation
Die back of tips causing the leaf to fall over & die
Management
Do the soil analysis
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 in two split doses). And in areas of moderate acidity (pH between 5.5 and 6), apply lime 1 kg/cent.
High phosphorus levels lead to calcium deficiency.
In alkaline soil application of Gypsum is preferable
Boron is needed for calcium utilization.
So, a boron deficiency can also lead to calcium deficiency.
Magnesium (Mg)
Symptoms
Deficiency are seen first in the bottom leaves.
Older leaves turn completely yellow
The leaf tips show white colour
Irregular elliptical shaped areas are noticed on leaves
Management
Do the soil analysis and confirm the deficiency.
Addition of Magnesium sulphate (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
Uniform yellowing on younger leaves
entire plant turns yellow
plants become thin, weak & spindly
delayed bulb formation & maturation
Management
Application of sulphur-containing fertilisers, such as Factamfos, Ammonium sulphate, Single superphosphate, etc., reduces the deficiency.
In sulphur deficient soils, apply sulphur dust (10 kg/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
Development of distorted & thickened leaves
Hollow or cracked stems
cessation of terminal bud growth.
Tips of fruits & shoots exhibits Necrosis & browning
Irregular bulbs with cracks or splitting
Management
Analysis of soil to confirm the deficiency.
Application of borax (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.
Iron (Fe)
Symptoms
Interveinal chlorosis of the youngest leaves,
Leaves show distinct patterns of green veins against yellow patterns
Affected leave become almost and pale & yellow
Under extreme deficiency totally bleached leaves are noticed
Smaller sized bulbs
Stunted growth
Management
Iron content in Kerala soils is often high. So, get a soil test to determine the reason for the problem
Low potassium levels lead to iron deficiency
Addition of Ferrous Sulphate (6 kg/ acre) into the deficient soils.
Manganese (Mn)
Symptoms
Leaf mottling and spotting with irregular patches of yellow or white appearing in leaf surface.
Interveinal chlorosis
Deficiency worse, brown/ necrotic appear on leaves & edges shows sign of scorching
Delayed bulb formation
Leaves show tip burn, and curling
Growth restricted
Management
Soil Analysis
Application of Manganese Sulphate (2 gram per litre of water) as foliar spray
Zinc (Zn)
Symptoms
Dwarfing, stunting growth with shorter & smaller leaves
Leaves distortion
Delayed bulb formation
Weaker & less developed root system
Interveinal chlorosis
Management
The optimal pH range for zinc availability is 5 to 7.5.
Confirm deficiencies by doing soil testing.
Apply zinc sulphate to deficient soils (8 kg/ acre)
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.
