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Ricardo MelgarINTA Exp. ST. PergaminoArgentina
FLUID FERTILIZER FORUM Scottsdale, Feb 15-16, 2010
N soil - NO3-
N atmosphere N – NBF
Soybean - Bradyrhizobium
2N2 + 3H2Nitrogenase 2NH3
NH3 + R-COOH Proteins
Soybean - N uptake
0
100
200
300
400
0 20 40 60 80 100 120
Días después de la siembra
Re
qu
eri
mie
nto
de
N (
kg
/ha
)
Nodulada (5431 kg/ha)
Sin nodular (4400 kg/ha)
R3 - R6 maximum N assimilation. High supply by BNF
Critical stage of seting
nodules from the inoculant
Up to R1 minimum N requirements, soil supply
228194
35 3411
-183
10
-250
-200
-150
-100
-50
0
50
100
150
200
250
N Total NBF Soil Residue
- Top
Residue
-Roots
Exported N
Balance
N B
ala
nce in s
oybean c
rop
kg.h
a-1
Controversial Facts
Compete with BNF
Inhibits nodule formation & infestation
Inefficient – very low NUE
Grain yield is directly related to N total in plant
NBF Provides near 52 % of total N uptake
The proportion of fixed N decreased with increasing fertilizer-N additions
Controlled release fertilizers
Delays transformation of N of urea-compounds into soluble forms (NH4
+) Nitamin & Nitamin NFusion
(Georgia-Pacific)
Inhibitors of urease
Delays transformation of urea into NH4
+
Agrotain
Synchronization of N in soil with plant needs maximum uptake
∆ Yield with 30 kg N ha-1: 197 kgha-1
Six site-year experiments 2000-03 South Santa Fe-North Buenos Aires
2.00
3.00
4.00
5.00
Check N 200 -
Sowing
Inoculated Inoc.&Co+Mo N 30 - R3 N 30 - V4
Soybean g
rain
yie
ld M
g /
ha DLS 5%: 269 kg/ha
N fertilization in soybean in Pergamino
Previous works
To evaluate the effect of increasing late N availability by improving placement/product combinations of fluid N sources on soybean grain yields and N uptake
Four sites in 2008-091. Mercedes (Corrientes)
2. Crespo(Entre Rios)
3. Ocampo (N Buenos Aires)
4. Acevedo (N Buenos Aires)
Repeated in 2009-10
Product Placement
No N Fertilizer --
Ammonium Nitrate
Broadcast
Nitamin®
Knifed or Dribbled
Nitamin NFusion
Urea solution
Idem + 0.5% Agrotain
Nine 40 kg N ha-1treatments& Check (No N)
Total aboveground biomass at R5. Splitting leaves, stems and pods
N concentrations in leaves stems & pods
N uptake in aboveground biomass at R5
Grain yields
Total aboveground biomass at harvest
Grain protein
The country’s worst drought in 50 years has cut agriculture output almost 20%.
Disastrous consequences for the farmers, for the rural towns, the agribusiness chain and the whole country’s economy
Satellite imagery of vegetation of December 2008 relative to same month of 1996-2007 series
Site CheckMean All N
∆Yield
Kg ha -1
Mercedes 1825 2252 427
Crespo 1953 2270 317
Ocampo 1963 2069 106
Acevedo 1471 1219 -252
0
200
400
600
800
1000
1200
244
254
264
274
284
294
304
314
324
334
344
354
364 8
18
28
38
48
58
68
78
88
Acc
um
ula
ted
mm
Julian day
Pergamino
Precip ETP
0
200
400
600
800
1000
244
254
264
274
284
294
304
314
324
334
344
354
364 9
19
29
39
49
59
69
79
89
Acc
um
ula
ted
mm
Julian day
Crespo
Precip ETP
We were unable to find site factors that explain N response differences
1,000
1,200
1,400
1,600
1,800
2,000
2,200
2,400
2,600
2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000
Gra
in y
ield
kg/ha
Total aboveground biomass kg/ha
Grain vs. TDM yields
r= 0.74 **
1750
1800
1850
1900
1950
2000
2050
115 120 125 130 135
Soybean g
rain
yie
ld k
g/ha
Grain N uptake kg/ha
Treatment means overall
sites
Treatments Protein
Check 37.0 %
Control 37.8 %
All N Knifed 37.3 %
All N Dribbled 37.0 %
0
500
1,000
1,500
2,000
2,500
3,000
40 60 80 100 120 140
Gra
in Y
ield
kg/ha
N uptake in biomass at R5 (kg/ha)
Grain vs. N uptake at R5
3000
3500
4000
4500
1,500
1,625
1,750
1,875
2,000
2,125
2,250
Tota
l D
ry M
att
er
yie
ld k
g/ha
Soyb
ean g
rain
yie
ld k
g/ha
Grain TDM
LSD 5% Grain: 497 kg/ha - TDM: 919 kg/ha
Grains yield correlated to N uptake
We could not find site factors associated to N response differences
There were not differences among treatments
Final Considerations
The severe lack of rains during the critical periods of filling grains prevented the attain of a high yield that could stress the N symbiotic capacity to supply N to crops.
N was of ample abundance for the limited grain and biomass yields obtained.
We expect that a next season, with a different weather pattern, especially under a higher precipitation scenario, the treatment differences would allow reaching a more conclusive effect
We Acknowledge The Fluid Fertilizer Foundation for their support in this research
We thanks very much to our collaborators. Gabriel, Enrique and Francisco
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