107 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
cropped large-seeded legumes on silage yield com- using the logx+1 transformation prior to analy-
sis. LER was calculated according to method ponents. Seedbed preparation and seeding were
the same as for the previous experiment. The described by Mead 1986.
treatments applied in the experiment are detailed in Table 4. When legumes were seeded in two rows
in intercrop plots an intercrop density of 250 000
3. Results and discussion
plants ha−1 was used in 1993, whereas a monocrop density of 500 000 plants ha−1 was used in
Any further discussion on yield will refer only to the intercrop treatments relative to the herbi-
intercrop plots in 1994. Also, before the delayed seeding of large-seeded legumes 3 weeks after corn
cide-treated corn, except where specifically stated. Large-seeded legumes will be referred to as
in 1994,
an additional
cultivation using
a Kongskilde VRC, Montreal, Canada cultivator
‘legumes’ throughout the rest of this paper. was added to improve monocotyledonous weed
control. 3.1. Experiment 1
All data were analysed using analysis of vari- ance with the GLM procedure of the Statistical
3.1.1. Corn Corn grain yield was not affected by any of the
Analysis System
SAS Institute,
1985. Probabilities equal to or less than 0.05 were consid-
treatments applied in this experiment Tables 5– 8. Other corn variables examined, such as HI,
ered significant. If analysis of variance indicated differences between treatment means a least sig-
HSW, and number of kernels per cob were also not affected by the various treatments. Corn plant
nificant difference LSD test was used to separate the treatment means. Data for grain and biomass
height was measured over the season and did not differ between monocrop and intercrop systems at
yield of large-seeded legumes were transformed
Table 5 Corn and legume grain production kg ha−1, HI, HSW g, legume pods per plant and legume seeds per pod for the intercrop and
monocrop treatments in experiment 1 at Macdonald in 1993 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 7994
0.56 27.4
– –
– –
– –
CS 7880
0.57 27.1
69 b 0.43 abc
18.1 3.1 c
1.7 c 1.09
CL 7424
0.56 27.1
0 c 0.00 d
0.0 d 0.0 d
0.0 d 1.00
Cann 7099
0.53 25.7
– –
– –
– 0.95
Cred 6966
0.51 26.2
– –
– –
– 0.98
Cper 7246
0.53 27.2
– –
– –
– 0.97
CSAnn 7442
0.57 26.7
67 b 0.40 abc
16.5 c 2.7 c
1.6 c 0.98
CSPer 7102
0.57 25.6
50 b 0.39 bc
17.0 c 2.8 c
1.8 c 1.04
CSRed 6947
0.54 26.5
60 b 0.38 c
16.0 c 3.3 c
1.6 c 0.90
CWeed 6356
0.58 24.3
– –
– –
– –
Chand 8235
0.55 27.6
– –
– –
– –
CLAnn 6227
0.53 25.8
0 c 0.00 d
0.0 d 0.0 d
0.0 d 0.91
CLPer 6078
0.54 25.7
0 c 0.00 d
0.0 d 0.0 d
0.0 d 0.95
CLRed 6674
0.51 27.2
0 c 0.00 d
0.0 d 0.0 d
0.0 d 0.96
Soybean –
– –
1662 a 0.47 a
21.1 b 11.7 a
2.6 b –
Lupin –
– –
1591 a 0.46 ab
33.2 a 8.8 b
3.3 a –
C.V. n.s.
n.s. n.s.
– Trt
23.1 9.6
6.8 11.9
21.9 12.6
30.3 10.8
– a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, PODS=number of pods per plant, SEEDS=
number of seeds per pod, LER=land equivalence ratio; n.s.=not significant at P0.05, =significant at P0.01. Values in the same column followed by the same letter are not different P0.05 according to a GLM protected LSD test.
108 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
either site in 1994 data not shown. A large from monocrop soybean except in the case of
CSMix at L’Assomption in 1994 and two treat- variation in the yield in 1994, especially at the
Macdonald site, was observed and might have ments CSPer and CSRed at Macdonald in 1993,
whereas HI in other intercrops was significantly been due to heavy precipitation resulting in flood-
ing in some areas. In this experiment, corn com- reduced Tables 5–8. The HSW and the number
of seeds per pod for intercropped soybean were peted well in the presence of other intercrop species
and, in general, its yield variables were not affected lower, only in 1993, than monocropped soybean;
once again, there were no differences among by intercropping. Several workers Mohta and
Ded, 1980; Chui and Shibles, 1984; Hikam et al., intercrop treatments. A decreased production of
pods per plant in intercrop soybean relative to 1992, have reported variable responses of corn as
a intercrop component, whereas in the present monocrop soybean was observed at both the sites
in 1993 but not in 1994. The height of intercropped study the yields of corn were not affected by
intercropping with legumes. soybean
was 15
to 20 cm
greater than
monocropped soybean at the end of both growing seasons data not shown.
3.1.2. Large-seeded legumes In general, soybean yield components i.e. grain
Hume et al. 1985 reported that, among yield components, the number of pods per plant is the
yield, HI, HSW, number of pods per plant, and number of seeds per pod were adversely affected
component most closely correlated with soybean yield and hence the factor most affected by compe-
by the presence of the taller corn component except at the Macdonald site in 1994, which may have
tition. Interestingly, the HSW and number of seeds per pod were affected only in 1993, a year with
been due to the heavy precipitation Tables 5–8. The HI for intercrop soybean was not different
less precipitation than 1994 Table 3. HI was not
Table 6 Corn and legume grain production kg ha−1, HI, HSW g, legume pods per plant and legume seeds per pod for the intercrop and
monocrop treatments in experiment 1 at L’Assomption in 1993 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 7892
0.45 25.5
– –
– –
– –
CS 8184
0.43 24.2
70 b 0.31 b
8.2 cd 2.8 c
1.6 c 1.11
CL 8486
0.44 24.4
0 c 0.00 c
0.0 e 0.0 d
0.0 d 1.18
Cann 8217
0.45 25.4
– –
– –
– 1.05
Cred 7691
0.43 23.6
– –
– –
– 1.02
Cper 7826
0.44 24.4
– –
– –
– 1.02
CSAnn 8029
0.46 24.6
115 b 0.47 a
13.5 c 2.7 c
1.6 c 1.01
CSPer 7555
0.40 23.4
123 b 0.38 ab
12.9 c 3.3 c
1.6 c 1.13
CSRed 8260
0.44 23.9
61 b 0.35 ab
3.9 de 2.8 c
1.4 c 1.02
CWeed 7661
0.46 25.0
0 c 0.00 c
0.0 e 0.0 d
0.0 d –
Chand 7913
0.44 24.7
0 c 0.00 c
0.0 e 0.0 d
0.0 d –
CLAnn 7585
0.42 24.8
0 c 0.00 c
0.0 e 0.0 d
0.0 d 0.99
CLPer 7171
0.43 24.2
– –
– –
– 1.10
CLRed 7260
0.40 25.1
– –
– –
– 1.08
Soybean –
– –
1769 a 0.34 ab
24.8 b 17.9 a
2.3 b –
Lupin –
– –
3257 a 0.38 ab
33.4 a 9.8 b
3.7 a –
C.V. 9.8
7.5 3.8
12.6 43.8
55.6 21.8
11.8 –
Trt n.s.
n.s. n.s.
– a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, LER= land equivalence ratio, PODS=number
of pods per plant, SEEDS=number of seeds per pod, LER=land equivalence ratio; n.s.=not significant at P0.05, =significant at P0.01. Values in the same column followed by the same letter are not different P0.05 according to a GLM protected LSD test.
109 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
Table 7 Corn and legume grain production kg ha−1, HI, HSW g, legume pods per plant and legume seeds per pod for the intercrop and
monocrop treatments in experiment 1 at Macdonald in 1994 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 6861
0.50 30.7
– –
– –
– –
CS 3749
0.52 26.5
1329.5 a 0.45 a
19.5 a 22.9 b
2.0 1.25
CL 2947
0.87 28.6
7.6 b 0.25 be
8.2 be 2.2 c
2.5 0.46
Cmix 4631
0.56 28.0
– –
– –
– 0.63
Cper 4906
0.68 29.1
– –
– –
– 0.63
Cred 4311
0.40 27.9
– –
– –
– 0.73
Csmix 5125
0.67 29.1
1144.5 a 0.48 a
19.6 ab 19.4 b
2.2 1.16
CSPer 2919
0.41 27.4
1421.3 a 0.50 a
10.2 abc 23.3 b
1.1 1.01
CSRed 5726
0.44 27.3
1395.4 a 0.45 a
19.6 ab 23.3 b
2.1 1.63
CLMix 2960
0.35 28.4
3.6 b 0.19 c
5.7 c 1.1 c
2.2 0.60
CLPer 5389
0.51 26.4
19.4 0.20 c
7.5 be 2.8 c
1.7 0.98
CLRed 4046
0.76 28.2
13.6 b 0.15 c
4.8 c 2.1 c
1.4 0.53
Cweed 5430
0.46 28.1
– –
– –
– –
Chand 6456
0.47 30.2
– –
– –
– –
Soybean –
– –
2059.6 a 0.43 ab
22.1 a 14.8 b
2.1 –
Lupin –
– –
664.3 a 0.33 abc
18.8 ab 33.4 a
1.1 –
C.V 40.5
48.0 5.9
30.8 22.6
51.0 32.7
62.1 –
Trt n.s.
n.s. n.s.
n.s. –
a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, LER=land equivalence ratio, PODS=number of pods per plant, SEEDS=number of seeds per pod; n.s.=not significant at P0.05, =significant at P0.01. Values in the same
column followed by the same letter are not different P0.05 according to a GLM protected LSD test.
affected by intercropping in 1993, indicating that were similar in intercrop and monocrop systems
at the Macdonald site, whereas intercropped lupin the overall partitioning of resources within the
soybean plant was not affected in this year. plants were 10 to 15 cm taller than monocropped
lupin at L’Assomption data not shown. However, the development of all other yield com-
ponents was affected. These differences between Overall, lupin appears to compete poorly with
corn, with intercropping resulting in no grain pro- the two years may be related to variation in
rainfall, the change in corn hybrid, or differences duction in 1993 and low grain production in 1994.
Lupin has been suggested as an effective replacement in weed pressure Carruthers et al., 1998.
In 1993 lupin produced no grain when inter- for soybean in silage Hill, 1977; Perez-Escamilla
et al., 1988 and may be more adaptable to northern cropped. This resulted in decreases in all yield
components of lupin grain yield, HI, HSW, climates Pate et al., 1985. However, this experiment
demonstrated that lupin is not a significant contrib- number of pods per plant, and number of seeds
per pod with no differences among the intercrop utor to silage when intercropped with corn and it
competes poorly with corn. Lupin responds to envi- treatments Table 6. In 1994, although there were
decreases in grain yield for intercropped lupin in ronmental stresses primarily by decreasing the
number of reproductive organs Herbert, 1977; comparison with monocrop yields, some yield
components were not affected. The HI and number Withers, 1979 and HSW Pate et al., 1985. The
results of the present experiment are in conformity of seeds per pod were not affected by any treat-
ment, whereas the HSW and the number of pods with the observations of the above workers. In the
present experiment the lupin HSW was much more per plant decreased. All components, except the
number of seeds per pod, were decreased at strongly reduced by intercropping than reported
earlier Pate et al., 1985. L’Assomption in 1994. Lupin heights, in 1994,
110 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
Table 8 Corn and legume grain production kg ha−1, HI, HSW g, legume pods per plant and legume seeds per pod for the intercrop and
monocrop treatments in experiment 1 at L’Assomption in 1994 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 8645
0.52 26.0
– –
– –
– –
CS 7267
0.55 24.3
465.7 b 0.44 ab
20.7 ab 15.7 bcd
2.0 1.00
CL 6733
0.52 23.8
43.2 c 0.20 d
14.4 bc 2.2 e
2.8 0.84
CMix 7631
0.54 24.8
– –
– –
– 0.86
CPer 7767
0.56 24.2
– –
– –
– 0.83
CRed 7748
0.55 24.2
– –
– –
– 0.85
CSmix 7592
0.55 23.7
483.2 b 0.42 b
20.8 ab 17.9 bc
1.9 1.03
CSPer 6213
0.46 23.8
597.4 b 0.47 ab
20.4 ab 20.0 b
2.0 1.06
CSRed 6482
0.59 23.1
452.9 b 0.47 ab
20.5 ab 13.4 cd
2.0 0.89
CLMix 8290
0.55 25.1
6.3 b 0.08 e
0.0 d 1.8 e
1.9 0.97
CLPer 6998
0.52 23.4
47.4 c 0.20 d
12.2 c 2.7 e
3.0 0.87
CLRed 8124
0.56 24.8
9.2 d 0.17 de
4.2 d 1.9 e
2.5 0.97
CWeed 7660
0.52 24.3
– –
– –
– –
CHand 8934
0.48 27.2
– –
– –
– –
Soybean –
– –
3161.3 a 0.53 a
20.1 ab 33.5 ab
2.2 –
Lupin –
– –
1223.6 ab 0.31 c
27.0 a 12.3 d
3.0 –
C.V 16.9
20.1 6.9
14.7 23.0
32.0 28.5
25 16.3
Trt n.s.
n.s. –
n.s. –
a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, LER=land equivalence ratio, PODS=number of pods per plant, SEEDS=number of seeds per pod; n.s.=not significant at P0.05, =significant at P0.01. Values in the same
column followed by the same letter are not different P0.05 according to a GLM protected LSD test.
3.1.3. LER 3.2. Experiment 2
All treatments utilizing soybean as an intercrop component had LERs equal to or greater than
3.2.1. Corn Corn grain yield was quite variable between
one, except for CSRed at Macdonald in 1993 and L’Assomption in 1994 Table 5–8. The LERs
sites during the two years. In 1993, most of the simultaneously seeded intercrop treatments had
ranged from 1 to 1.63, with CSRed at Macdonald in 1994 giving the best ratio. Corn–soybean
lower grain yields than monocropped corn; how- ever, there was no such reaction for the delay-
intercrops have frequently outyielded monocrop corn in many areas of the world Mohta and Ded,
seeded intercrops Tables 9 and 10. A three-way interaction, between legume type, seeding date and
1980; Chui and Shibles, 1984; Martin et al., 1990. Intercropping systems that consistently give LERs
number of legume rows, occurred for corn grain yield in 1993 due to an atypical decrease in one
greater than one are thought to be more efficient systems
from a
land use
perspective than
treatment CS1D at L’Assomption and an atypical increase in one treatment CS1S at Macdonald.
monocrops Willey 1979. Thus, corn–soybean intercrops are superior to corn–lupin intercrops in
Corn grain yield was not affected by any treatment applied at Macdonald or L’Assomption in 1994
this environment. At L’Assomption in 1993, all intercrop treatments except for CLAnn gave LERs
Tables 11 and 12. The HI of the corn crop was generally not affected by the treatments, with the
greater than one Table 6. Although not statistic- ally different, all intercrop corn had numerically
two exceptions being CS2S and CL1S, which decreased HI at Macdonald in 1993. These
higher biomass yields than the herbicide-weeded monocrop corn, leading to overyielding by the
decreases caused a three-way interaction similar to that seen for corn grain in 1993. The HSW
corn component alone data not shown.
111 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
Table 9 Corn and legume grain production kg ha−1, HI, HSW g, legume pods per plant and legume seeds per pod for the intercrop and
monocrop treatments in experiment 2 at Macdonald in 1993 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 8924 a
0.47 ab 28.2 ab
– –
– –
– –
Soybean –
– –
1379.4 a 0.42 ab
21.9 c 10.6 a
2.3 c –
Lupin –
– –
694.0 b 0.47 a
33.1 a 6.8 b
3.4 b –
CS1S 2902 d
0.43 be 21.6 d
336.5 cd 0.47 a
20.2 cd 6.1be
2.1 d 0.58
CS2S 2872 d
0.35 d 22.8 d
355.3 c 0.45 a
19.3 de 6.8 b
2.0 d 0.68
CS1D 7446 b
0.47 ab 27.0 b
39.0 f 0.18 d
17.5 e 2.3 e
1.3 e 0.94
CS2D 8249 ab
0.48 ab 28.6 a
63.1 e 0.20 d
18.6 de 3.3 de
1.4 e 1.01
CL1S 2846 d
0.39 cd 22.6 d
239.5 d 0.33 c
26.0 b 3.8 d
3.7 a 0.89
CL2S 4116 d
0.45 ab 23.0 d
394.8 c 0.39 be
24.1 b 5.2 c
3.8 a 1.17
CL1D 8687 ab
0.50 a 27.3 ab
0.0 g 0.00 e
0.0 f 0.0 f
0.0 f 0.93
CL2D 7919 ab
0.47 ab 27.5 ab
0.0 g 0.00 e
0.0 f 0.0 f
0.0 f 0.89
Cweed 6006 c
0.44 abc 25.1 c
– –
– –
– –
Chand 9034 a
0.47 ab 27.9 ab
– –
– –
– –
L n.s.
n.s. –
D –
R n.s.
n.s. n.s.
n.s. n.s.
n.s. –
L×D n.s.
n.s. n.s.
n.s. –
L×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
D×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
L×D×R n.s.
n.s. n.s.
n.s. n.s.
– a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, PODS=number of pods per plant, SEEDS=
number of seeds per pod, LER=land equivalence ratio. L=legume type soybean or lupin, D=seeding date simultaneous or delayed , R=number of rows of legume seeded 1 or 2; n.s.=not significant at P0.05, =significant at P0.05, =significant
at P0.01. Values in the same column followed by the same letter are not different P0.05 according to a GLM protected LSD test. Indications as to the significance of main effects and interactions refer to a factorial analysis that included only legume intercrop
treatments.
decreases ranged from 6.6 to 3.2 g relative to the component most often affected was HSW. The HI
of corn was not affected, suggesting that corn monocrop corn and reflected the decreases seen in
corn biomass, except at both sites in 1994 where reacted to competition by reducing the weight of
the grain to balance the loss of vegetative biomass, no effect was observed. At Macdonald in 1993,
simultaneous seeding of the intercrop components rather than altering its partitioning of resources.
decreased the HSW. At L’Assomption in 1993, a legume type by seeding date interaction occurred
3.2.2. Large-seeded legumes In general, soybean grain and biomass yields
because the HSW of corn in corn–soybean intercrops was not affected by delayed seeding
were decreased by all intercrop treatments,
although treatment CS2S at L’Assomption 1993 whereas that of simultaneously seeded plants was,
but the lupin intercrop
components caused yields were not different from monocrops Tables
9–12. The simultaneous seeding of soybean did decreases in corn HSW in simultaneously seeded
intercrops. As seen in the previous experiment, the not affect the HI of soybean, but delayed seeding
resulted in HI values lower than for monocropped height of the corn plants data not shown and the
number of kernels per cob 1994 were not affected soybean. Delayed seeding has been shown to result
in increased shading for soybean plants, reducing by any of the intercrop treatments. Delayed seed-
ing of the intercrops rarely affected corn variables, overall photosynthate production to a level where
soybean plants compensated by decreasing the whereas simultaneous seeding produced extremely
variable and often deleterious results. The yield amount of photosynthate allocated to grain pro-
112 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
Table 10 Corn and legume grain production kg ha−1, HI, HSW g, legume pods per plant and legume seeds per pod for the intercrop and
monocrop treatments in experiment 2 at L’Assomption in 1993 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 7474 a
0.41 24.0 a
– –
– –
– –
Soybean –
– –
838.5 a 0.34 ab
31.0 a 9.7 a
2.1 b –
Lupin –
– 813.7 ab
0.37 a 29.1 a
8.0 ab 3.3 a
– CS1S
7048 ab 0.39
24.1 a 226.0 bc
0.31 abc 19.9 b
5.2 bcd 1.6 bcd
1.07 CS2S
5401 cd 0.38
22.9 ab 392.6 ab
0.40 a 20.1 b
8.1 ab 1.7 bcd
1.40 CS1D
6729 abc 0.41
23.3 a 70.4 cd
0.29 abc 16.4 b
2.6 de 1.2 d
0.97 CS2D
6737 0.43
23.2 ab 79.0 cd
0.31 abc 17.3 b
3.6 cd 1.3 cd
0.95 CL1S
4621 d 0.38
20.6 bc 70.9 cd
0.26 be 16.0 b
2.9 cde 2.7 a
0.82 CL2S
5983 bcd 0.33
20.0 c 46.2 d
0.21 c 11.2 c
6.0 bc 1.9 bc
0.83 CL1D
6805 abc 0.43
23.9 a 0.0 e
0.00 d 0.0 d
0.0 e 0.0 e
0.91 CL2D
6823 abc 0.39
23.1 ab 0.0 e
0.00 d 0.0 d
0.0 e 0.0 e
0.97 Cweed
6315 abc 0.41
22.9 ab –
– –
– –
– Chand
7765 a 0.42
25.0 a –
– –
– –
– L
n.s. n.s.
n.s. n.s.
– D
n.s. n.s.
– R
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
– L×D
n.s. n.s.
n.s. –
L×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
D×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
L×D×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
– a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, PODS=number of pods per plant, SEEDS=
number of seeds per pod, LER=land equivalence ratio. L=legume type soybean or lupin, D=seeding date simultaneous or delayed , R=number of rows of legume seeded 1 or 2; n.s.=not significant at P0.05, =significant at P0.05, =significant
at P0.01. Values in the same column followed by the same letter are not different P0.05 according to a GLM protected LSD test. Indications as to the significance of main effects and interactions refer to a factorial analysis that included only legume intercrop
treatments.
duction Legere and Schreiber, 1989. It may also expect any gains in silage production from seeding
this late, as has been reported for similar experi- have been the case that the level of shading during
grain filling was higher than before grain filling, ments with corn and beans Francis et al., 1976,
and corn and cowpea Ofori and Stern, 1987b. resulting in drastic reductions in HI. As in the
previous experiment, the HSW and number of Other researchers have reported that simultaneous
seeding produced better, but variable, results with soybean seeds per pod decreased for all intercrop
treatments in 1993, but neither were affected in intercropped corn and bean Francis et al., 1982
or corn and peanut Misbahulmunir et al., 1989. 1994. The lack of intercropping effects on these
variables may have been due to higher levels of There was no difference between seeding one or
two rows of legume in intercrops for yield compo- precipitation in 1994 than 1993 Table 3. In most
cases the number of pods per plant decreased, with nent variables.
Lupin biomass and grain production were the only exceptions observed being for a few of
the simultaneously seeded treatments. Delay- decreased by all intercrop treatments. In the delay-
seeded treatments, lupin competed so poorly that seeded intercropped soybean was generally 20 to
30 cm shorter than simultaneously seeded soybean, it produced no grain in either year Tables 9–12.
Since no grain was produced by the delay-seeded and simultaneously seeded soybean was also taller
than monocrop soybean data not shown. In treatments and little was produced by the simulta-
neously seeded treatments, all of the yield compo- general, delayed seeding resulted in poorer soybean
growth than simultaneous seeding, insufficient to nents were greatly decreased when compared with
113 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
Table 11 Corn and legume grain production kg ha−1, HI, HSW g, legume pods per plant and legume seeds per pod for the intercrop and
monocrop treatments in experiment 2 at Macdonald in 1994 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 6470
0.60 30.9
– –
– –
– –
Soybean –
– –
3234.9 a 0.48 a
21.3 ab 26.8 a
2.3 –
Lupin –
– –
583.8 c 0.24 c
22.8 ab 12.5 c
2.9 –
CS1S 3365
0.43 29.7
1134.0 b 0.47 a
22.6 ab 24.5 a
2.0 1.19
CS2S 3498
0.61 28.4
1558.6 b 0.44 a
24.5 a 18.4 b
2.1 1.08
CS1D 3671
0.47 29.3
58.4 e 0.31 b
21.4 ab 5.5 d
1.6 0.71
CS2D 5490
0.71 29.4
30.3 f 0.32 b
15.1 c 3.6 d
1.6 0.75
CL1S 5195
0.79 29.4
52.6 e 0.20 c
20.8 ab 2.7 d
2.8 0.85
CL2S 4297
0.65 28.0
117.0 d 0.19 c
18.0 bc 5.3 d
2.7 1.03
CL1D 4638
0.49 29.8
0.2 g 0.00 d
0.0 d 0.5 d
1.5 0.89
CL2D 5894
0.71 29.3
0.5 g 0.00 d
0.0 d 0.5 d
0.8 0.88
Cweed 3555
0.41 28.7
– –
– –
– –
Chand 5998
0.39 30.2
– –
– –
– –
L n.s.
n.s. n.s.
n.s. –
D n.s.
n.s. n.s.
n.s. –
R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
L×D n.s.
n.s. n.s.
n.s. n.s.
– L×R
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
D×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
– L×D×R
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
– a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, LER=land equivalence ratio, PODS=number
of pods per plant, SEEDS=number of seeds per pod. L=legume type soybean or lupin, D=seeding date simultaneous or delayed , R=number of rows of legume seeded 1 or 2; n.s.=not significant at P0.05, =significant at P0.05, =significant at P0.01.
Values in the same column followed by the same letter are not different P0.05 according to a GLM protected LSD test. Indications as to the significance of main effects and interactions refer to a factorial analysis that included only legume intercrop treatments.
monocrop production. Also, delay-seeded lupin a value this close to one constitutes no real
improvement. LERs of 1.19 CS1S and 1.08 plants were much shorter than monocrop or simul-
taneously seeded plants data not shown. Most CS2S were the highest values recorded for simul-
taneously seeded soybean at the Macdonald site simultaneously seeded treatments resulted in
decreased HIs, HSWs, number of pods per plant in 1994, whereas at the 1994 L’Assomption site,
an LER of 1.02 CS2D for the delay-seeded and seeds per pod for lupin. However, some simul-
taneously seeded treatments did have values similar soybean was the highest value recorded Tables 7
and 8. Flooding at the L’Assomption site in 1994 to monocrop lupin for all of these variables Tables
10–12. Simultaneously seeded lupin was always affected corn growth so that over yielding of the
monocrop corn control was not seen for any corn– 10 to 15 cm taller than monocrop lupin data not
shown. The results of the present experiments soybean treatment. Higher soybean yields for
simultaneously seeded corn–soybean intercrops as suggests that lupin may not be a good intercrop
component with corn. opposed to delayed seeding of the soybean compo-
nent in this experiment are consistent with results from previous studies Allen and Obura 1983;
3.2.3. LER In 1993 at L’Assomption, the two simulta-
Herbert et al., 1984. Beneficial LERs were also recorded for lupin CL2S at the 1994 and 1993
neously seeded soybean intercrop treatments gave LERs greater than one CS2S=1.40, CS1S=1.07
Macdonald sites due to some lupin growth in this system, accompanied by no reduction in corn
Table 6. An LER of 1.01 for CS2D was obtained in 1993 for the Macdonald site Table 5, although
growth.
114 K. Carruthers et al. European Journal of Agronomy 12 2000 103–115
Table 12 Corn and legume grain production kg ha−1, HI, HSW g, number of kernels per cob, legume pods per plant and legume seeds
per pod for the intercrop and monocrop treatments in experiment 2 at L’Assomption in 1994 a
Treatment CG
CHI CHSW
LG LHI
LHSW LPODS
LSEEDS LER
Corn 7855
0.46 24.1
– –
– –
Soybean –
– –
1761 a 0.49 a
15.7 bc 27.3 a
2.2 ab –
Lupin –
– –
572 ab 0.30 bcd
24.6 a 9.0 b
2.9 a –
CS1S 4103
0.35 20.7
158 cd 0.35 abc
18.4 abc 7.9 b
1.9 b 0.84
CS2S 4135
0.36 20.9
437 bc 0.40 ab
19.2 ab 9.3 b
1.9 b 0.99
CS1D 5340
0.44 21.6
31 d 0.22 cde
10.9 cd 3.0 b
1.6 b 0.75
CS2D 5174
0.33 22.2
62 de 0.18 de
16.5 bc 2.8 c
1.5 b 1.02
CL1S 3531
0.37 20.5
0 g 0.00 f
0.0 e 0.0 c
0.0 c 0.57
CL2S 3 f
0.08 ef 4.4 de
1.4 c 1.6 b
0.64 CL1D
4282 0.40
20.6 0 g
0.00 f 0.0 e
0.0 c 0.0 c
0.87 CL2D
4635 0.37
21.2 0 g
0.00 f 0.0 e
0.0 c 0.0 c
– Cweed
6836 0.47
23.5 –
– –
– –
– Chand
6716 0.45
24.0 –
– –
– –
– L
n.s. n.s.
n.s. –
D n.s.
n.s. n.s.
– R
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
– L×D
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
L×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
– D×R
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
L×D×R n.s.
n.s. n.s.
n.s. n.s.
n.s. n.s.
n.s. –
a C=corn, L=legume, G=grain, HI=harvest index, HSW=hundred seed weight, LER=land equivalence ratio, PODS=number of pods per plant, SEEDS=number of seeds per pod. L=legume type soybean or lupin, D=seeding date simultaneous or delayed ,
R=number of rows of legume seeded 1 or 2; n.s.=not significant at P0.05, =significant at P0.05, =significant at P0.01. Values in the same column followed by the same letter are not different P0.05 according to a GLM protected LSD test. Indications
as to the significance of main effects and interactions refer to a factorial analysis that included only legume intercrop treatments.
4. Conclusions seeds per pod in 1993, and altering HI in 1994,
