Inbred maize response to cover crops and fertilizer-N in the southern
semi-arid coast of Puerto Rico
David
1
Sotomayor-Ramirez* ,
1
Randy
2
Huckaba ,
Ricky
2
Barnes ,
Ronald
3
Dorcinvil ,
1
Espinosa
Jesus
College of Agricultural Sciences, University of Puerto Rico, Mayagüez
2
Dow AgroSciences LLC, Mycogen Seeds, Puerto Rico
3 North Dakota State University
*Contact author: david.sotomayor@upr.edu
ASA-CCSA-SSSA Annual Meeting, 2011
Poster # 310
This research was supported by the Univ of Puerto Rico, Agricultural Experiment Station and Dow AgroSciences LLC
•
•
Effect
Seed yield (kg/ha
Stover wt (kg/ha)
Ears/ha
Harvest index
Plant biomass (grain + stover) dry wt
Location was Mycogen Seeds Corp. research farm in Santa Isabel, Puerto Rico.
Soil series are Jacaguas (Loamy-skeletal, mixed, superactive, isohyperthermic
Fluventic Haplustolls) and Fraternidad (Fine smectitic, isohyperthermic Typic
Haplusterts)
(kg/ha)
Trial 1: Effects of two cover crops and five fertilizer-N levels on maize seed yield
response (2008-2009)
• Experimental design was a split-plot arrangement of a RCBD with previous
cover crop as the main plot and N level as sub-plot, with four replicates.
• Cover crop treatments of: fallow, velvetbean (Mucuna prurience) or cowpea
(Vigna unguiculata var Iron Clay), summer-fall 2008.
• After 140 days of growth, cover crops were sprayed with glyphosate and
incorporated via disking into the soil in late September 2008.
• Fertilizer-N levels of: 0, 112, 150, 186, and 228 kg N/ha; 50 kg N/ha pre-plant and
the remainder applied via fertigation, fall-winter 2008-2009.
• All subplots received 67, 112, and 28 kg/ha of P2O5, K2O and ME (minor element
mixture), respectively.
• Inbred maize line A1 was sown on 10 December 2008, grown to maturity and
harvested at about 91 DAP.
Trial 2: Effect of five fertilizer-N levels on maize seed yield (2009-2010)
• Experimental design was a RCBD with five treatments (N levels) and four
replications.
• Previous cropping was maize.
• Fertilizer-N levels of: 0, 84, 125, 168, 211 kg N/ha; 28 kg N/ha pre-plant and the
remainder applied via fertigation, winter 2010.
• Inbred maize line B1 was sown on February 2010, grown to maturity and
harvested at about 91 DAP.
• All plots received 63, 14, and 26 kg/ha of P2O5, K2O and ME (minor element
mixture), respectively.
1 - The inbred code is propietary information of Dow Agrosciences LLC
•
•
•
•
Irrigation was applied via drip irrigation following farm recommendations.
Soil preparation prior to maize planting included chisel plowing and disking.
Agronomic data gathered included: indicator leaf N concentration, SPAD
chlorophyll meter (Minolta Corp.), plant height, leaf area index, and leaf color index
(color chart with scale of 1 to 4).
Stover N (kg/ha)
Grain N concentration (%)
Grain N uptake (kg/ha)
Crop (stover + grain) N uptake (kg/ha)
SPAD chlorophyll reading (40 DAP)
SPAD chlorophyll reading (54 DAP)
SPAD chlorophyll reading (70 DAP)
Leaf color index (54 DAP)
LAI (40 DAP)
LAI (54 DAP)
LAI (70 DAP)
Plant height (cm), (40 DAP)
Plant height (cm), (54 DAP)
Plant height (cm), (70 DAP)
Effect
Seed yield (kg/ha
Stover wt (kg/ha)
Ears/ha
Harvest index
Plant biomass (grain + stover) dry wt (kg/ha)
Stover N (kg/ha)
Stover P (kg/ha)
Stover K (kg/ha)
Grain N concentration (%)
Grain N uptake (kg/ha)
Grain P uptake (kg/ha)
Grain K uptake (kg/ha)
Crop (stover + grain) N uptake (kg/ha)
Crop (stover + grain) P uptake (kg/ha)
Crop (stover + grain) K uptake (kg/ha)
SPAD chlorophyll reading (V5)
SPAD chlorophyll reading (R1)
Leaf color index (V5)
Leaf color index (R1)
Plant height (cm), (V5)
Plant height (cm), (R1)
Nutrient use efficiency indicators [balance method (BM)]
• PFP-BM = YGf/Na
• PBP-BM = NGf/ Na
• AE = NBYf /Na
Figure 2. Nitrogen budget for 2008-2009, Trial 1
50
0
0
-50
kg N/ha
kg N/ha
Explanation of terms
Crop = grain N + stover N
Immediate residual = crop N - fertilizer N
Potential residual 1 = crop N - (fertilizer N + stover N)
Potential residual 2 = crop N - (fertilizer N + stover N + soil N supply (estimated from
crop N uptake)
200
200
2010
2009
150
150
50
Grain
Stover
Crop
Inmediate residual
Potential residual 1
Potential residual 2
-100
-150
-200
-100
-150
-200
-250
-300
-300
0
50
100
150
Fertilizer-N applied
200
250
0
50
<0.001
<0.001
ns
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.26
0.21
9,346
107.9
39.7
149.3
50.6
53.4
54.3
4.2
1.05
1.71
1.64
33.8
59.5
64.2
0.01
151.2
1.9
1.5
2.8
0.4
0.4
0.2
0.1
0.02
0.03
0.03
0.4
0.8
1.1
7,474
83.0
25.7
110.4
43.1
50.7
52.6
3.3
0.82
1.47
1.40
26.4
48.0
59.9
0.01
294.1
3.8
Stover wt
Harvest index
Mean
Mean
Mean SE
Mean
SE
Pr > F
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
0.068
ns
ns
ns
ns
0.086
0.017
0.097
ns
ns
Contrast
between
control and
others (P =)
0.035
ns
ns
ns
ns
ns
ns
ns
ns
0.064
0.035
0.012
ns
ns
ns
ns
0.009
0.030
0.056
ns
ns
Mean
n/a
4,567
74,599
0.269
5,958
51.3
13.3
99.0
1.46
n/a
n/a
n/a
68.3
17.8
103.8
44.6
n/a
n/a
n/a
13
39
100
150
Fertilizer-N applied
200
250
SE
Mean SE
Mean SE
Mean SE
0
1,788
177.5 B 5,690
178.6 B
0.21
0.01
B
7,474
294.1
B
83.0
3.8
B
25.7
3.0
B
110.4 5.8
B
112
2,708
173.9 A 6,754
176.2 A
0.25
0.01
AB
9,462
288.6
A
108.3
3.7
A
39.2
3.0
A
149.3 5.6
A
149
2,592
173.7 A 6,488
174.9 A
0.25
0.01
AB
9,080
287.7
A
100.4
3.7
A
38.4
3.0
A
140.5 5.6
A
186
2,727
173.7 A 6,538
174.8 A
0.26
0.01
A
9,265
287.7
A
109.5
3.7
A
39.8
3.0
A
151.1 5.6
A
224
2,875
177.2 A 6,700
178.3 A
0.26
0.01
A
9,579
293.5
A
113.2
3.8
A
41.5
3.0
A
156.4 5.8
A
Figure 1:Scatter plots of the effect of fertilizer-N on N sufficiency indicators for
inbred maize during 2008-2009 (Trial 1).
56
4.6
54
4.4
52
50
48
40 DAP
54 DAP
70 DAP
46
4.2
4.0
3.8
3.4
42
3.2
50
100
150
200
54 DAP
3.6
44
0
250
0
50
Fertilizer-N (kg/ha)
100
150
200
250
200
250
Fertilizer-N (kg/ha)
2.0
70
1.8
1.6
1.4
1.2
1.0
0.8
0.6
60
50
40
30
20
0
50
100
150
200
250
0
50
Fertilizer-N (kg/ha)
100
150
Fertilizer-N (kg/ha)
Table 4. Treatment means of selected N indicator parameters of inbred
maize during 2009-2010. Means with different letters are significantly
different (P<0.05) (Trial 2).
N
level
SE
Seed yield
SPAD (R1)
Mean
SE
-----------------kg/ha------------
216.4
1,116
0.017
213.2
3.4
0.8
5.4
0.03
3.4
0.8
5.4
0.9
SE
Stover N
Crop (stover +
Grain N uptake grain) N uptake
--------------------------------------------------------------------------------------------kg/ha-----------------------------------------------------------------------------------------
3.0
5.8
0.7
0.5
0.5
0.1
0.04
0.05
0.06
0.7
1.1
1.3
0
84
125
168
211
Mean
Leaf color index (V5) Leaf color index (R1)
SE
Mean
SE
Mean
SE
B
1,181
101.8 B
49.0
0.6
3.1
0.1 C
3.3
0.1
AB
A
1,449
99.4
51.1
0.6
3.2
0.1 BC
3.4
0.1
AB
1,308
101.8 AB
50.8
0.6
3.2
0.1 BC
3.5
0.1
A
A
1,522
99.4
51.4
0.6
3.5
0.1 AB
3.7
0.1
A
A
1,495
98.6
51.3
0.5
3.7
0.1 A
3.6
0.1
---------------------------------------Mean of fertilized treatments -----------------------------------1,446
56.7
51.1
0.3
3.41
0.1
3.6
0.1
B
B
AB
A
AB
Table 5. Treatment means of selected N use efficiency indicator parameters of inbred
maize during 2008-2009 and 2009-2010. Means with different letters are significantly
different (P<0.05).
0.4
0.4
N budget
• Higher nutrient uptake in Trial 1 than Trial 2
• Crop N uptake was low, with grain N about 30% of
that in crop.
• Immediate residual N, is the fertilizer-N not taken
up by the crop, and is that which remains in soil
after harvest.
• Potential residual N 1, is the immediate residual N
plus that from stover N mineralization.
• Potential residual N 2, is the excess N in soil
considering stover N mineralization, soil profile N,
and soil N mineralization.
• Excess N increases with higher fertilizer-N.
-50
-250
ns
ns
ns
ns
ns
ns
ns
ns
0.009
0.008
ns
ns
ns
ns
ns
Unfertilized control)
Mean
SE
1,788
177.5
5,690
178.6
Trial 2
• Seed yield in the fertilizer-N range of 84 to 211 kg N/ha was 18% higher
than unfertilized maize.
• No significant treatment effects were observed for most agronomic
parameters (marked in red)
• The SPAD chlorophyll reading at R1 growth-stage adequately separated
out the control (mean of 49.0) from the fertilized plots (mean of 51.1).
• The leaf color index taken at both V5 and R1 growth-stage significantly
identified treatment differences between the control and the fertilized plots.
Where PFP is the Partial Factor Productivity; PBP is the Partial Balance Productivity; AE is
the Agronomic Efficiency; NGf is the grain N uptake in fertilized crop.
100
<.001
<.001
ns
0.006
<.001
<.001
<.001
0.030
<.001
<.001
<.001
0.012
<.001
<.001
0.002
Fertilizer N
Mean
SE
2,726
87.3
6,620
107.4
Seed yield
Crop (grain +
stover) dry wt
Table 3. ANOVA summary to examine the effect of fertilizer N levels on yields and
selected agronomic parameters of inbred maize during 2009-2010 (Trial 2)
Nutrient use efficiency indicators [difference method (DM)]
• AEY-DM = (YGf – YGu)/Na
• AEBY-DM = (BYf – BYu)/Na
• ARE-DM = (NBYf – NBYu)/Na
100
ns
ns
ns
0.080
ns
ns
0.361
0.009
ns
ns
ns
ns
<.001
ns
ns
N
level
Trial 1
• Maize yields (kg/ha) were highest following velvet bean (2,903) and cowpea
(2,522) and the latter was similar to fallow (2189). In general, the cover crops
positively influenced the agronomic indicators.
• Seed yield in the fertilizer-N range of 112 to 224 kg N/ha was 34% higher than
unfertilized maize.
• No significant difference was observed among fertilizer-N levels in the range of
112 to 224 kg/ha for stover weight, harvest index, plant biomass, stover N,
grain N uptake, crop N uptake, and these were higher than the control (no
fertilizer-N).
• The SPAD chlorophyll meter, leaf color index and leaf area index were suitable
indicators of N sufficiency.
Where AE is the Agronomic Efficiency; ARE is the Apparent Recovery Efficiency; Na is the
fertilizer-N applied; YGf and YGu is the grain yield in fertilized and unfertilized crop,
respectively; BYf and Byu is the biomass in fertilized and unfertilized crop,
respectively; NBYf , and NBYu are the whole plant biomass N in fertilized and
unfertilized plants, respectively.
•
Contrast
between
control
N
CC * N
and
CC
Level
Level
others
---------Significance level (P)------------0.016 <.001
ns
<0.001
ns
<.001
ns
<0.001
ns
ns
ns
ns
0.009 0.022
0.090
<0.001
Table 2. Effect of fertilizer N on selected agronomic parameters of inbred maize during
2008-2009 (Trial 1). Means with different letters are significantly different (P<0.05).
Leaf color index
•
•
MATERIALS AND METHODS
Table 1. ANOVA summary to examine treatment effects on yields and selected agronomic
parameters of inbred maize during 2008-2009 (Trial 1).
Plant heght (cm)
•
Determine optimum inbred maize seed yield response to antecedent
cover crop and fertilizer-N addition
Assess the effectiveness of agronomic predictors of crop nitrogen
(N) sufficiency status
Estimate potential N losses in the inbred maize production systems
SPAD units
•
RESULTS AND DISCUSSION
Leaf area index
•
OBJECTIVES
N
level
AEY-DM
AEBY-DM
ARE-DM
PFP-BM
PBP-BM
AE-BM
Mean SE
Mean SE
Mean SE
Mean SE
Mean
Mean SE
SE
--------------------------------------------------------------------2008-2009--------------------------------------------------------------------112
9.1
1.6
A
16.9
2.0
A
0.35
0.05
A
24.4
1.1
A
0.35 0.02
A
1.32
0.03
A
149
6.2
1.6
AB
10.5
2.0
AB
0.21
0.05
B
17.6
1.1
B
0.26 0.02
B
0.93
0.03
B
186
5.7
1.6
AB
9.3
2.0
B
0.22
0.05
AB
14.9
1.1
BC
0.22 0.02
BC
0.81
0.03
C
224
4.9
1.6
B
8.4
2.0
B
0.20
0.05
B
12.6
1.1
C
0.18 0.02
C
0.69
0.03
C
--------------------------------------------------------------------2009-2010----------------------------------------------------------------84
3.4
0.6
A
125
0.7
0.6
168
1.9
211
1.5
---1
17.5
0.6
A
0.21 0.01
A
0.81
0.07
A
B
10.2
0.6
B
0.13 0.01
B
0.53
0.07
B
0.6
AB
9.0
0.6
BC
0.11
BC
0.44
0.07
B
0.6
AB
7.1
0.6
C
0.09 0.01
C
0.36
0.07
B
mean of N levels (2010
only)
1.2
•
•
•
---1
2.3
0.05
0.01
0.03
CONCLUSIONS
Optimum crop response at fertilizer-N between 88 and 112 kg N/ha.
• Further refinement of these values should be done using varying
genetic materials (possibly classified as low- , medium-, and highyielders).
N-use efficiency and N balance data shows:
• Low fertilizer-N use efficiency, and harvest index
• Crop N extraction (63 to 75 kg/ha and 110 to 156 kg/ha)
• High immediate and potential residual soil N that increases
beyond critical fertilizer-N rate
Can use agronomic plant sufficiency diagnostic tools such as plant
height, indicator leaf N concentration, leaf color, SPAD chlorophyll
index, possibly pre-plant soil nitrate