PIRACICABA

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Efficient use of N in conventional fertilizers
PIRACICABA
Antonio Enedi Boaretto CENA USP a.e.boaretto_at_cen
a.usp.br
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Efficient use of N in conventional fertilizers
1 REMARKS 2 N USE EFFICIENCY CONCEPTS 3 N
USE EFFICIENCY DATA 4 OPTMIZING N USE
EFFICIENCY 4-1 RIGHT RATE 4-2 RIGHT
TIME 4-3 RIGHT PLACE 4-4 RIGHT NUTRIENT
BALANCE 4-5 OTHERS FACTOR 5 FINAL COMMENTS
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Efficient use of N in conventional fertilizers
CONVENTIONAL FERTILIZERS (World/Brazil,)
. Urea (60/56) . Ammonium sulfate
(5/16) . Ammonium nitrate (15/9)
. monoammonium phosphate (2/9) .
Diammonium phosphate (7/-)
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Efficient use of N in conventional fertilizers 1
- REMARKS

• - N IS NECESSARY FOR ACTUAL
• AND FUTURE AGRICULTURE
• - HIGH YIELD AND EFFICIENT USE OF N

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Efficient use of N in conventional fertilizers 1
- REMARKS

• N IS NECESSARY FOR ACTUAL
• AND FUTURE AGRICULTURE

• RICE WHEAT MAIZE 60 of N
• 9,3 BILION PEOPLE (2050) 50 to 70 more
  grain
• CONSEQUENCE INCREASE N USE
• NECESSITY IMPROVE N EFFICIENT USE

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Efficient use of N in conventional fertilizers 1
- REMARKS
BRAZIL(2006) N share by crop ( of total)
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Efficient use of N in conventional fertilizers 1
- REMARKS

• - N IS NECESSARY FOR ACTUAL
• AND FUTURE AGRICULTURE
• - HIGH YIELD AND EFFICIENT USE OF N

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Efficient use of N in conventional fertilizers 1
- REMARKS
Yield response x N use efficiency
High yield Low N use efficiency
Low yield High N use efficiency
Spolidorio (1999)
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Efficient use of N in conventional fertilizers
THE INTERNATIONAL NITROGEN INITIATIVE (INI)
resulting from food and energy production
The overall goal of the INI
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• IE Internal utilization efficiency of a
  nutrient
• kg yield per kg N uptake
• PFP Partial factor productivity of applied
  nutrient
• kg harvested product per kg N applied
• PE Physiological efficiency of applied N
• kg yield increase per kg increase in N
  uptake from fertilizer
• AE Agronomic efficiency of applied nutrient
• kg yield increase per kg N applied,
• RE Apparent crop recovery efficiency of
  applied nutrient
• kg increase in N uptake per kg N applied,

(Dobermann, 2007)
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N RECOVERY EFFICIENCY (RE) REap ((U U0) /
RN).100
Wheat grain 4 t/ha
CONTROL
Spolidorio (1999)
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N RECOVERY EFFICIENCY (RE)
Calculation methods 1 - DIFFERENCE METHOD 2-
ISOTOPE METHOD (15N Labeled fertilizers) (more
detailed on the N fate in agro-systems)
Short-term assessment - Medium to long-term
assessment
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15N balance in soil-wheat system

(3060 kg/ha) 15N-urea
Grain 108 57 (65)
irrigated
Straw 38 15 (16)

Root 26 1
Soil (0-120cm) 15 (16)
Leached (gt50 cm) 1
Spolidorio, 1998
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N RECOVERY EFFICIENCY (RE)
N (urea) 90 kg/ha
STRAW
GRAIN
STRAWGRAIN
STRAWGRAIN ROOT
PLANT SOIL SYSTEM
Spolidorio (1999)
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N RECOVERY EFFICIENCY (RE)
1 Dobermann, 2005 (above ground part, 51) 2
Number of trials 3 Cantarella, 2007
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N RECOVERY EFFICIENCY (RE)
1 N in above ground part 2 Results from
short-term assessment (one cropping season) 3
Measurements mostly in trials plots 4 N
unaccounted for root system soil (20-40,
sugarcane, 24 coffee) 5 N mainly part is from
soil (80, sugarcane 30 60, wheat) System
level (plant soil) efficiency of N
applied Medium to long-term assessment
N LIFE CYCLE
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4-1 RIGHT RATE OVER or UNDER rate reduce the N
efficiency, losses in yield and crop quality,
possible environmental contamination
N rate (N required N soil) / RE
Soil N test no available Plant analysis (?)
Yield expected
Brazil, SP ? Historic of the site to be
fertilized ? Cerrado, RS / SC ?
SOM (soil analysis)
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4-1 RIGHT RATE (Maize)
Medium limed soil, after leguminous crop, no
tillage for 2 yr, or... High limed soil,
intensive cultivation of maize, or... Low no
tillage for years, after green manure, organic
manure, or...
Raij e Cantarella, 1997
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4-1 RIGHT RATE
Chlorophill meter
Leaf color chart
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4-1 RIGHT RATE (Coffee)
Raij e Cantarella, 1997
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4-2 RIGHT TIME
Ideal fertilization
N uptake
Barak Raban, 2007 (adapted)
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4-2 RIGHT TIME
Maize - rain gt 220 mm than evapotranspiration OM
S gt 5 g kg-1, 100 kg/ha (urea)
Sangoi et al., 2007
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4-3 RIGHT PLACE
N fertilization Where? Source?
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4-3 RIGHT PLACE
Vitti et al., 2007
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4-3 RIGHT PLACE
N sources
N Absorption from N volatilized
NH3 air concentration 2 mg m-3
Forest (15N) 8 19 (10 to 150 cm above
soil) Sugar cane 20 (plants, 80 cm
height) Coffee, Citrus (15N) 43 of NH3
volatilized Maize (15N) 23
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4-4 RIGHT NUTRIENT BALANCE
40 kg N/ha (cereal crops) 150 kg N/ha (sugarcane)
Roberts, 2006
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4-5 OTHERS FACTOR
N RESPONSE IS DEPENDENT OF WATER MANAGEMENT
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5 - FINAL COMMENTS
1 Nitrogen fertilization is very important for
increasing the food production for feeding a
global population increasing 2 To increase the
nutrient (N, P) use efficiency is a major
challenge for the world agriculture.
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Thanks!
PIRACICABA
a.e.boaretto_at_cena.usp.br