Fertilizer use efficiency is determined by agronomic efficiency, physiological efficiency, and apparent recovery. Agronomic efficiency refers to additional crop yield from applied nutrients. Physiological efficiency is crop yield per unit of absorbed nutrient. Apparent recovery is the amount of applied nutrient uptake by the crop. Efficiency can be increased by applying optimal nutrient amounts, using appropriate fertilizer types and placements, proper application times, and integrated nutrient management. Residual effects vary by nutrient - nitrogen leaves little residue while phosphorus and organic fertilizers like FYM leave more for subsequent crops. Control of pests, diseases, weeds; use of soil amendments; and good crop management practices also impact fertilizer use efficiency.

1. AGR502- PRINCIPLES AND PRACTICES OF SOIL FERTILITY AND NUTRIENT
MANAGEMENT
Presented by
M.Jothi (2019502006)
COURSE TEACHERS
Dr.K.Ramamoorthy
Dr.R.Karthikeyan
TOPIC: RESIDUALEFFECTOF FERTILIZERANDFERTILIZERUSE
EFFICIENCY

2. Fertilizer use efficiency
 Efficiency - Efficiency in any system is an expression
of obtainable output with the addition of unit amount of
input.
 Fertilizer use efficiency is the output of any crop per
unit of the nutrient applied under a specified set of soil
and climatic conditions.
 Efficiency of fertilizer nutrient = recovery x
utilization

3. Need
 Continuous and steady increase in the use of fertilizer
 High cost of fertilizer
 Productive and profitable use of every unit of plant
nutrients is essential
Efficiency is determined by three ways
 agronomic efficiency
 physiological efficiency
 apparent recovery

4. Agronomic efficiency
• It refers to the additional produce obtained in kg per kg of an
applied nutrient
Yield from fertilized plot in kg –yield without fertilizer in kg
AE = ------------------------------------------------------------------------- x 100
Amount of fertilizer nutrient applied in kg
• It is like NR generally decreases with the increase in nutrient
supply.

5. Physiological efficiency
 kg of grain yield produced/ kg of nutrient absorbed.
 The AE and PE are related by % of NR
Apparent / Nutrient Recovery
 Nutrient Recovery (NR) refers to the actual amount of Nutrient taken up from the
fertilizers.
Nutrient uptake in fertilized plots - Nutrient uptake in unfertilized plots
NR= -------------------------------------------------------------------------------- x 100
Amount of nutrient added
 The NR exhibits a diminishing trend with the increasing amounts of nutrients.

6.  Example – nitrogen recovery varies with soil
properties; methods, amounts and timing of fertilizer
application and other management practices
 N recovery ranges 30-50%
 50 kg grain yield produced / kg of nitrogen
 Efficiency of fertilizer nitrogen - 15-25 kg rice yield/kg
of N
 P recovery is only 10-20% , most P fixed by clay
particle
 K ranges in between the N and P

7.  PPE is the amount of grain production per unit of
nitrogen absorbed at a particular growth stage
 Partial productive efficiency of nitrogen for grain
production = Y(n) – Y(n-1)
 Nitrogen absorbed at early stages is used to produce
more straw than grain
 Nitrogen absorbed at later stages is used to produce
more gain than straw
 Partial productive efficiency for both grain and straw is
higher when the nitrogen supply is lower

8.  There are two peaks for partial productive efficiency
for grain:
 The first around 20-25 DAP when the nitrogen
concentration in the culture solution is high and the
 second around 20-25 DBH when the nitrogen
concentration is moderate.
 When the nitrogen concentration is high, there is no
second peak.
 The most efficient time to supply nitrogen for grain
production varies with the level of nitrogen supply.

9. Losses of nutrient
 inevitable/evitable losses of nutrients that reduce the
efficiency.
 leaching,
 volatilization,
 immobilization,
 Chemical reaction between various components in the
mixture,
 change in capacity to supply nutrients,
 unfavourable effects associated with fertilizer
application.

10. Techniques of increasing fertilizer use
efficiency
 Amount of the fertilizer to be applied
 Type of fertilizer to be applied
 Time of application
 Method of application
 Placement of fertilizer
 Integrated nutrient management
 other considerations (cost, availability of fertilizer,
labour, ease of application, awareness on benefits of
fertilizer use, etc.)

11. Amount of fertilizer based on the field experiment
Type of fertilizer
 Choice of fertilizer is location specific and needs to
be found out by field experimentation.
 The choice is more with respect to N and P
fertilizers than for potassic.
 N – subjected to more leaching losses
 P - residual and cumulative effects are more

12. Time of application
 The objective of time of application is to get maximum
benefit from the fertilizer nutrient.
 Too earlier - lost in different ways or is absorbed more
than required.
 Late - either not absorbed or absorbed not utilized for
the purpose and only gets accumulated in plant parts.
 Some amendments need to be applied before
commencement – beneficial to the crop after
sowing/planting
 Example – application of press mud, other liming

13. Where to apply (placements)
 The objective of placement of fertilizer is to make the
nutrient available easily to the crop
 It should be near to the roots, surface broadcast, at
furrow bottom, top dressed and foliage
 This depends on type of crop, rooting pattern, feeding
area and ease of application
 The choice of method of application depends on soil-
crop-fertilizer interaction

14. Other considerations
 Proper control of pests and diseases
 Weeds, if not controlled on early stages (7-21 days) of
crop growth - 25 to 30 % of the applied plant nutrients to
be lossed
 For problem soil : alkali – gypsum,
acid – rock phosphat
 For rice crop - mix urea with available nitrification
inhibitors such as neem cake and karanj cake (1:5)-
reduce N losses from the soil

15.  Application of FYM and P should preferably be
made in wet and dry season, respectively
 Green manuring with daincha / sunhemp low land
paddy cultivation
 Ensure proper plant spacing
 Plant/sow the crop timely to get maximum benefit
from fertilizers
 Higher yielding varieties should be preferred over
local varieties

16. Residual Effect of fertilizers
 The application of fertilizer at rates that exceed crop
nutrient requirements can result in nutrient
accumulation in soil
 Residues left over in the soil depends on the type of
fertilizer used because of their mobility and solubility,

17.  Nitrogenous fertilizers leave no residues after the
crop is harvested. Only(1-2%) of N to following crop.
 Phosphatic fertilizers and farmyard manure leave
considerable residue in the soil which is useful for
subsequent crops.
 FYM applied to the previous crops: used only 50 % of
its nutrients and rest was available for subsequent
crops.
 The residues left by potassium fertilizers are
marginal.

18. REFFERENCE
 A Handbook of soil, fertilizer and manures by
P.k.Gupta – Fertilizer use efficiency (265-268).
 Residual effect of compost and fertilizer application on
nutrients in runoff by J.E Gilly, B.Eghball

19. THANK YOU