EFFECT OF SEED DISTRIBUTION
AND POPULATION ON MAIZE
GRAIN YIELD
BEE KHIM CHIM
GRADUATE STUDENT
DEPARTMENT OF CROP, SOIL & ENVIRONMENTAL SCIENCES
EMAIL: BCHIM@VT.EDU
INTRODUCTION
Production of maize in World, U.S.A and Sub Saharan Africa.
World
United States of
America
Sub Saharan
Africa
7, 045, 483, 640*
314, 572, 078*
874, 841, 049†
Production (Mt)
840, 308, 214‡
327, 879, 500‡
63, 580, 236‡
Area Harvested
(Ha)
161, 765, 388‡
34, 163, 300‡
30, 910, 018‡
Yield (Mt/Ha)
5.20
9.60
2.06
Population
* From United States Census, 2012
† From World Bank, 2011
‡ From www.faostat.org , 2010
INTRODUCTION (CONT’D)
Developed Countries, maize planting
Developing Countries, maize planting
http://www.ia.nrcs.usda.gov/technical/JensenPhotos.html
http://nue.okstate.edu/Hand_Planter/img21.jpg
INTRODUCTION (CONT’D)
Maize area, ha (FAOSTAT, 2010)
Total
Sub Saharan Africa
Planted by hand (60%) *
ha
161, 765, 388 ha
30, 910, 018 ha
18, 546, 011
Potential yield increase (25%)*
(single seeds 14-17 cm apart)
15, 895, 059 Mg
Yield increase of 25% for 60% hand planted maize worth more
than 4.6 billion dollars/ year (corn price at $ 0.295/kg)
*From(http://nue.okstate.edu/Hand_Planter/summary_AGCO1.pdf )
LITERATURE REVIEW

Plant Spacing
•
Narrow: tall and weak steam plants, decreased yield due to lodging
(Rowland, 1993; Futuless et. al, 2010)
Wider: Encourage weed and pests infestation, influences maize yield
(Whiteman, 1981)
Increased row spacing from 0.35 to 1m will decrease grain yield
(Riahinia and Dehdashti, 2008)
•
•

Light Interception
•
Development of crop growth related to light interception (Gardner et
al., 1985)
Optimization of light interception increased grain yield (Stewart et
al., 2003)
Light interception can be increased by reduced row spacing
(Andrade et al., 2002)
•
•
OBJECTIVE

To determine the value of equadistant plant spacing
when compared to “hills”, placing 2-3 seeds per hill
MATERIALS AND METHODS





Locations: Lake Carl Blackwell research station and Efaw
research station
Cropping year: Summer 2011 and Summer 2012
10 treatments with 3 replications arranged in RCBD, middle
two rows planted by hand
Preplant N rate: 395.2 kg N ha-1 applied in the form of urea
(46-0-0)
Light Interception, LI-COR
MATERIALS AND METHODS (CONT’D)
Treatment structure
Treatment
Seeds Hill-1
Distance
Between Hills
Estimated Plant
Population
m
Plants ha-1
1
1
0.16
81,984
2
2
0.16
163,968
3
3
0.16
245,952
4
1
0.32
40,992
5
2
0.32
81,984
6
3
0.32
122,976
7
1
0.48
27,328
8
2
0.48
54,656
9
3
0.48
81,984
10
(Twin row)
0.32
81,984
MATERIALS AND METHODS (CONT’D)
Grain Yield, 2011
RESULTS
3500
SEDEFAW=638
3000
Grain Yield, kg ha-1
Grain yield versus seeds/hill in Lake
Carl Blackwell and Efaw research
station, Oklahoma, 2011-2012.
2500
0.16m EFAW
2000
0.32m EFAW
0.48m EFAW
SEDLCB=248
1500
0.16m LCB
1000
0.32m LCB
500
0.48m LCB
0
Grain Yield, 2012
1
2
Seeds per
14000
SEDEFAW=1327
Grain Yield, kg ha-1
12000
10000
0.16m EFAW
8000
0.32m EFAW
6000
0.48m EFAW
SEDLCB=1023
4000
0.16m LCB
0.32m LCB
2000
0.48m LCB
0
1
2
Seeds per
3
hill-1
3
hill-1
IPAR, 2011
RESULTS
SEDEFAW=8
100,0
SEDLCB=7
90,0
80,0
Intercepted photosynthetically active
radiation (IPAR) between treatments in
Lake Carl Blackwell and Efaw research
station, Oklahoma, 2011-2012.
IPAR, %
70,0
60,0
50,0
IPAR LCB
40,0
IPAR EFAW
30,0
20,0
10,0
0,0
1
2
3
4
5
6
Treatments
IPAR, 2012
SEDLCB=5
80,0
SEDEFAW=6
70,0
IPAR, %
60,0
50,0
40,0
IPAR LCB
30,0
IPAR EFAW
20,0
10,0
0,0
1
2
3
4
5
6
Treatments
7
8
9
10
7
8
9
10
2011
3500
RESULTS
y = -36,535x + 4384,7
R² = 0,2832
Intercepted photosynthetically active
radiation (IPAR) between treatments in
Lake Carl Blackwell and Efaw research
station, Oklahoma, 2011-2012.
Grain Yield, kg ha-1
3000
2500
2000
1500
1000
500
0
0,0
20,0
40,0
60,0
IPAR, %
2012
14000
y = 222,44x - 2090,8
R² = 0,7629
Grain Yield, kg ha-1
12000
10000
8000
6000
4000
2000
0
0,0
10,0
20,0
30,0
40,0
IPAR, %
50,0
60,0
70,0
80,0
80,0
100,0
POSSIBLE FACTORS?????
Arghh!!!!!
WEATHER
Total monthly rainfalls (mm), surface air temperature (°C) in Lake Carl Blackwell and Efaw research
station, Oklahoma, 2011-2012.
14
35
12
30
10
25
8
20
6
15
4
10
2
5
0
0
April
18
16
14
12
10
8
6
4
2
0
35
30
25
20
15
10
5
0
April
May
June
July
August
Month
LCB (Rainfall)
LCB (Temp)
June
July
August
Month
Stillwater (Rainfall)
Stillwater (Temp)
Temperature, °C
Rainfall, mm
Year 2012
May
LCB (Rainfall)
Stillwater (Rainfall)
LCB (Temp)
Stillwater (Temp)
Temperature, °C
Rainfall, mm
Year 2011
CONCLUSION
Trend for decreasing yields with increasing number of
seeds per hill (same population) range (200 to 1000
kg/ha) except Efaw research station, 2012.
 Trend for decreasing IPAR with increasing number of
seeds per hill (same population) range ( 6 to 17%) except
Efaw research station, 2012
 IPAR was correlated with final grain yield.
 Excessive heat lowered yield levels and decreased
the ability to decipher treatment differences

CURRENT AND FUTURE RESEARCH
http://nue.okstate.edu/Hand_Planter.htm
ACKNOWLEDGEMENT
Advisor at OSU: Dr. Bill Raun
 Advisor at VT:
Dr. Wade Thomason
 Soil fertility Graduate students at Oklahoma
State University( Jeremiah Mullock, Emily
Rutto, Guilherme Torres, Jacob Bushong,
Sulochana Dhital, Natasha Macnack, Candibyani
Fnu, Alex Cumbie, Michael Reinert, etc. )

Thank you so much for your attention~!!!