In recent years soluble fertilizers otherwise known as foliar
fertilizers were introduced as Polyfeed and Multi K
Polyfeed contains 19 : 19 : 19 NPK with 6 micro-nutrients like
iron, manganese, boron, zinc, copper and molybdenum, while multi
K contains 13 : 0: 46 NPK.
These fertilizers provide nutrients to the plant by foliar application
as these fertilizers are completely soluble in water.
These fertilizers have no other impurities like sodium and chloride
and they are 100 % nutrients and these nutrients are easily absorbed
through the leaves.
In certain occasions the existence of prolonged drought there
is no scope to apply fertilizers to the soil for want of moisture.
Like wise in flooded conditions due to continuous rains fertilizers
could not be applied to the soil.
In such special circumstances these soluble fertilizers are
must to protect the crop against hunger and this forms a compulsory
act of crisis management.
In such circumstances the foliar application of Speciality fertilizers
play an important role in supplying the nutrients at critical
stages of flowering and fruit development.
The experiments conducted in different countries indicated that
these soluble fertilizers as supplement to soil application of
fertilizers enhances the production per unit area ranging from15-25%.
The trials conducted in Andhra Pradesh and Tamilnadu also indicated
that the use of Speciality fertilizers enhance the yields in several
crops like Paddy by 10%, Pulses, Chillies, Cotton, Groundnut by
20% and Cashew and mango by 20%
Types of Fertilizers
Multi K, 13% Nitrogen and 46% K
Polyfeed 19:!9:19 N: P:K and 6 micronutrients
Speciality fertilizers are to be applied at the
recommended concentrations.
These fertilizers are compatable with insecticides
and fungicides except sulphur
Character
Speciality Fertilizers
Other Fertilizers
Solubility
Fully water soluble. Dissolves rapidly in water and
remains in solution without impurities, (detrimental chloride and
sulphate).
Not water soluble and leaves soluble deposits with
impurities except urea.
Absorption
Plant nutrients are ionic form(chelated) and available
for plant absorption. Multi'K' K= (K) = N = ( No3) polyfeed
N = (No3)NH4) and P =(Po4) K =(K+)
and Fe , Mn, B , Zn, Cu,
Mo in PPm
Mostly in oxidized salt form. MOP MOP in K2O,
SOP in K2O, CSP in P2O5 , N fertilizers
mostly in salt conditions except urea.
Activity
Plays vital role in plant metabolic activities and
also plant food.
Utilized as plant nutrient (food)
Yield
Exploit fully yield potential in quality and quantity
by increasing 15 - 20% Yield at suggested dosage 1% - 2% spray
Increased yield if applied in balanced ratio ( proportion)
NPK ( 4 : 2 : 1
Application
Application is suggested at different critical
plant stages as nutritional foliar spray and fertilization. Eg:
Before reproductive stage and after grain setting at 1% spray
of multi K
Results
The experiments conducted at NARDI indicated
that foliar spray of 1 % either polyfeed or Multi K
at 45, 60 and 75 days after planting increased the rice yield
by about 10 % over unsprayed control.
Observation trials conducted by KVK (NFCL) indicated
that foliar application of Multi K at 1 % at the time
of maximum tillering and prior to panicle initiation resulted
in increased yield of 16.8 % over untreated control.
Polyfeed
Fertilizer Recovery
Recovery of top dressed fertilizer varies throughout the life
cycle( mainly as a function of root growth) in terms of N
recovered from fertilizer N applied (%)
Basal 15-30
At midtillering 30-50
At panicle initiation 45-75
At flowering 35-60
Phosphorous and Potassium
Efficient utilization of nutrient in the plant.
K can also be split and applied as 50% basal and 50% at PI but
this is mainly to improve pest resistance.
Nutrient Conversion Factors
Elemental to oxide
Conversion factor
P to P2O5
2.29
K to K2O
1.2
Oxide to Elemental
Conversion factor
P2O5 to P
0.437
K2O to K
0.830
Quantities of fertilizers required to provide a particular
quantity of nutrient.
Quantity of Nutrient Kgs (1 Kg)
Fert quantity in Kgs
N
2.2 Kgs of Urea
P
6.3 Kgs of Super phosphate
K
1.7 Kgs of Muriate of Potash
Benefits
Polyfeed
Readily taken up by plants, correct deficiencies of both
macro and micro nutrients.