density and n rate effects on nue in maize
DESCRIPTION
Density and N rate effects on maize yields and NUETRANSCRIPT
Can we improve the Nitrogen Use Efficiency in Maize Production?
Maize leaf area and N uptake at different plant densities and N rates
Ignacio A. CiampittiAGRY 596 – Professional Presentation
Purdue University - Department of AgronomySeptember 22, 2010
Introduction
Why NUE is important?
–Right N rate applied, both economically and environmentally important.
NUE, defined as the grain yield per unit of N available from the soil, including N fertilizer
Why Maize NUE is so low?
–Total loss of fertilizer N ranged from 20 to 50%, attributed to the combined effects of denitrification, volatilization and/or leaching.
Why N is important?• N uptake evolution follows the dry matter accumulation
Nitrogen in the Life of the Corn Plant100
80
60
40
20
0
Percen
t of to
tal N taken
up
by p
lant
N
Dry WeightSilking
Days after Planting (Mid-Season Corn Belt Hybrid)0 25 50 75 100 115
~100%
Highest Leaf Area
100
75
50
25
0
Per
cen
t o
f M
axim
um
Lea
f A
rea
~50%
Leaf Area
Nitrogen rate
Management factors
Plant density
Nitrogen rate
N uptake
NUE
Maize Yield
Environment
Understanding the leaf area and N uptake relationship
Presentation Question
Is the ratio of N uptake to leaf area constant when both are affected by plant density and N rate?
0.4 0.6 0.8 1.0
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Plant DensitySlice at V3 = 2
Nitr
ogen r
ate
Nitr
ogen
rat
e (k
g ha
-1)
Plant density (pl ha-1)54,000 79,000 104,000
0
165
33
0
Relationship
N uptake Leaf Area (g N/m2)
Optimum point??
Concluding remarks
•The strategy of the maize crop is to maintain the leaf area expansion even under N deficiency situations.
•The accumulation of N per unit of leaf area decreases as N rate decreases and plant density increases.
•The ratio of the N uptake to leaf area is not constant, and it varies with the N rate and plant density factors.
•More knowledge about maize physiology and N uptake dynamics will be needed to improve the NUE.
Thanks! Questions?