Maize (Zea mays) Intercropping with
Legumes Enhances
Growth, Dry Matter and its Forage Yield under Deficit Irrigation
Muhammad Aslam1*†, Muhammad Naeem1†, Abdul Rehman2,3, Muhammad
Mubashar Zafar4, Rashid Iqbal1, Muhammad Ayaz Shahzad1,
Rana Muhammad Ikram Khan1 and Javed Iqbal1
1Department
of Agronomy, Faculty of Agriculture and Environment, The Islamia University of
Bahawalpur, 63100, Pakistan
2Zhengzhou
Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University,
Zhengzhou 450000, China
3Institute
of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000,
China
4State
Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic
Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research,
Chinese Academy of Agricultural Science, Anyang, 455000, Henan, China
*For correspondence: aslam1302@gmail.com; aslam1302@yahoo.com
†Contributed
equally to this work and are co-first authors
Received 25 July 2020; Accepted 04 September 2020;
Published 10 December 2020
Abstract
Climate change is one of the serious threats to
agriculture and livestock. Climate change induced and reduced water shortage
lowers production of food and fodder crops. In order to investigate the effects
of deficit irrigation on forage yield of maize (Zea mays L.), cowpea (Vigna unguiculata L.), and guar
(Cyamopsis tetragonoloba L.) grown as
sole or intercropping of maize with cowpea and guar, the fields experiments
were conducted during spring 2016 and 2017 in randomized complete block design
(RCBD) with split plot arrangement. These crops were further exposed to water
deficit by skipping irrigation at crop stages following maize growth scale at
15 days (V4), 30 days (V6), 45 days (V9), and 60 days (V12) after sowing along
with normal irrigation. Maize intercropped with guar had maximum leaf area,
plant height land equivalent ratio and monetary advantage index at normal
irrigation but did not differ significantly under deficit irrigation. Thus,
maize intercropped with guar was found more productive and beneficial with
respect to sole under deficit irrigation. © 2021 Friends Science Publishers
Key words: Cowpea; Forage; Guar; Intercropping; Maize; Yield
Introduction
Sustainable agriculture based on the provision of food
security, enhanced quantity and quality of agriculture produces to satisfy the
demand of increasing population (Eskandari 2012). Livestock though the mainstay
of agriculture sector has remained a neglected sector for years. Various
factors are responsible for low productivity of dairy animals regarding milk
and meat production. The non-provision of quality forages is the single main
factor that squelches the animal’s productivity (Iqbal et al. 1999). Moreover, the availability of quality fodder to the
livestock is contributed to sustainable milk and meat production (Ginwal et al. 2019). Therefore, in order to
keep the livestock’s productivity up, it is much needed to increase supply of
quality forage/fodder (Iqbal and Iqbal 2015).
Forages are considered most reliable and
nutritious source of animal feed resource. The term forage represents all the
plant materials in succulent and green form while the term fodder represents
the dried form of feed such as silage and hay. Cereals forages such as millet (Panicum
miliaceum L.), maize (Zea mays
L.), and sorghum (Sorghum bicolor
L.), are important source of animals feed but have less protein contents.
Compared to the cereals, legume forages such as soybean (Glycine max L.), cow pea (Vigna
unguniculata L.), cluster bean (Cyamopsis
tetragonoloba L.) are more protenious but their yield per unit area is a
matter of concern (Bhagmal et al.
2009). Growing of legumes with cereals crops is productive and evolves as
profitable cropping system over solitary cropping (Evans et al. 2001). Growing of mixed crop would enhance the production on
the given area, and economic resources utilization (Marer et al. 2007). Legumes fix the atmospheric nitrogen, improve soil
fertility, and are also a good source of nitrogen for cereal crops (Manna et al. 2003). Growing of cereals with
legumes is best way for the availability of nitrogen to the neighbor crop
(Connolly et al. 2001). When legumes are intercropped with cereals, it
improves the utilization of available resource for maximizing yield (Khonde et
al. 2018).
Water is a limiting factor in dry areas. Deficit
irrigation has been evolved a way not only to save the water but an important
tool to get optimum yield. The effect of deficit irrigation is non-significant
if applied on less sensitive growth stages of the crop (Moutonnet 2002). When
maize crop receives three irrigations with the depth of 150 mm for each at
vegetative, tasseling and grain filling stages, it would produce higher yield (Fentawa 2006). Maize
can be intercropped with legumes to feed the animals at any stage without risk
of any ingredient i.e., prussic acid and oxalic acid (Dahmardeh et al.
2009).
When cereals
like wheat and barley (Hordeum vulgare L.) are intercropped with legumes like fababean (Vicia faba L.), and rapeseed (Brassica napus L.) under deficit
irrigation, the yield of the cereals is not affected (Amanullah et al. 2020). When maize is intercropped
with legumes under deficit irrigation, the yield of maize is also not
significantly affected (Sani et al. 2014).
Various
studies have been conducted to explore yield/economic advantages of the
intercropping but to find a suitable combination of cereal and legumes to get
optimum yield and forage quality under deficit irrigation has not been explored
to its full potential. Therefore, to explore this area of research, three
spring fodders viz., maize, cowpea,
and guar were grown as sole crops and intercropping of maize with cow pea and
guar under deficit irrigation and the impact of deficit irrigation was
evaluated on the forage yield of the crops.
Materials and
Methods
Experiment was carried out at experimental area
Department of Agronomy, Faculty of Agriculture and Environment, The Islamia
University of Bahawalpur, Pakistan (Latitude, 29° 23ʹ 60.00” N, Longitude, 71° 40ʹ 59.99” E). The soil of experimental area was analyzed
before sowing the crops. The soil was found to be sandy loam type. The soil
samples were taken from 0-15 cm and 16-30 cm depth. The soil physico-chemical
properties of experimental area were analyzed at Soil and Water Testing
Laboratory Regional Agriculture Research Institute Bahawalpur, Pakistan during
2016 and 2017 are given in Table 1.
The seeds of three spring fodders i.e. maize variety
‘Neelam’, local variety of guar ‘desi’, and local variety of cowpea ‘rawaan’
were collected from Ayub Agricultural Research Institute, Faisalabad, Pakistan
and sown on February 15, 2016 and 2017, as sole maize, cowpea, and guar and
intercropping of maize with cowpea and guar respectively, maintaining seed
ratio of 70:30 for each combination (Azim et
al. 2000).
The sole crops and their combinations were subjected to
four water deficit irrigation regimes along with control applied at different
interval days in the following manners: Normal Irrigation, V4= Four leaves
development stage (15 days after sowing), V6= Six leaves development stage (30
days after sowing), V9= Nine leaves development stage (45 days after sowing),
and V12=Twelve leaves development stage (60 days after sowing). The treatments
were replicated three times using randomized complete block design (RCBD) under
split plot design with net plot size of 3 m × 6 m. A fine seed bed was prepared
by four ploughing followed by planking. Seeds were sown through hand drill on
ridges maintaining row to row distance of 30 cm and legumes intercropped in
alternate rows of maize. Fertilizer was applied at 112.50 kg N and 50 kg P2O5
ha-1 in each plot. The ½ of the nitrogen and whole phosphorous
was applied as basal dose and remaining nitrogen was applied at succeeding
irrigation. Seed rate for maize, cowpea and guar was used at the rate of 100,
30, and 50 kg ha-1 respectively. Maize crop was harvested at heading
stage approximately 75 days after sowing (at least 35% dry matter) for green
fodder. Legume fodders were harvested at early pod formation stage (8 weeks
after sowing) (Azim et al. 2000;
Iqbal et al. 2006).
Data regarding average environmental temperature and
rainfall during field experiment in 2016 and 2017 was recorded respectively
(Table 2).
Leaf area (cm) per plant was measured with the help of formula; LA= LW × A. Where LA is leaf area, L is leaf maximum length, and
W is leaf maximum width and A is constant respectively. The value of the
constant (A) is 0.75 (Montgomery
1911). A quadrant
with dimension 1 m × 1 m was used
while taking the sample from each plot. Number of plants (stand density; m-2)
was calculated in area (Khan et al.
2014). Height of harvested
plants (cm) of each crop was measured at maturity by taking five plants from each
plot selected randomly with the help of meter rod (Khan et al. 2014). The randomly selected plants in the given area were
separated and counted number of leaves per plant (Khan et al. 2014).
Competition indices
Land equivalent
ration was measured with following formula: LER:
(LER maize + LER legume). Where LER maize: (Yml /Ym) and LER legume: Ylm / Yl. Where Ym was yield of
sole maize crop and Yl was yields of sole legumes crops, respectively. Yml was
yield of maize intercrop and Ylm was yield of legumes intercrops respectively (Machet et al. 1997). The value of relative crowding coefficient (K) was
calculated with following formula: K: (Kmaize × Klegume), Where Kmaize: Yml × Zlm/
(Ym - Yml) × Zml), and Klegume: Ylm × Zml / (Yl - Ylm) × Zlm). Where Zml and Zlm are the proportions of maize and
legume in the mixture respectively (Dhima et
al. 2007). Aggressivity (A) was measured as: Amaize
Table 1: Physico-chemical analysis of
experimental soil
Description |
2016 |
2017 |
||||
Values |
Status |
Values |
Status |
|||
Depth |
0-15 cm |
16-30 cm |
0-15 cm |
16-30 cm |
||
Texture |
sandy loam |
Sandy loam |
||||
Sand percentage |
41 |
38 |
39 |
37 |
||
Silt percentage |
35 |
36 |
36 |
37 |
||
Clay percentage |
24 |
26 |
25 |
26 |
||
Chemical analysis |
0-15 cm |
16-30 cm |
0-15 cm |
16-30 cm |
||
EC |
1.30 dS m-1 |
1.28 dS m-1 |
Normal |
1.34 dS m-1 |
1.29 dS m-1 |
Normal |
pH |
8.7 |
8.9 |
Alkaline |
8.6 |
8.4 |
Alkaline |
Organic matter |
0.93% |
0.91% |
Deficient |
0.98% |
0.95% |
Deficient |
P |
16.90 mg kg-1 |
16.71 mg kg-1 |
Deficient |
17.12 mg kg-1 |
17.09 mg kg-1 |
Deficient |
N |
0.016 mg kg-1 |
0.017 mg kg-1 |
Deficient |
0.017 mg kg-1 |
0.018 mg kg-1 |
Deficient |
K |
125 mg kg-1 |
126 mg kg-1 |
Sufficient |
126 mg kg-1 |
127 mg kg-1 |
Medium |
EC: Electric conductivity; P: Phosphorous; N: Nitrogen; K: Potassium
Table 2: Average monthly temperature and rainfall during experimental duration
(2016 and 2017)
Years |
Months |
Temperature (0C) |
Rainfall
(mm) |
2016 |
February |
20 |
12.2 |
March |
25 |
14.1 |
|
April |
30 |
16.5 |
|
May |
32 |
18.1 |
|
2017 |
February |
12 |
4.2 |
March |
20 |
12.3 |
|
April |
25 |
10.3 |
|
May |
16 |
8.5 |
(Source: Arid Zone Research Institute,
Bahawalpur, Pakistan)
= (Yml / Ym × Zml) –
(Ylm / Yl × Zlm) and Alegume = (Ylm / Yl × Zlm) – (Yml / Ym × Zml) (Dhima et al. 2007). Competitive ratio (CR) was calculated with formula:
CRmaize = (LERmaize / LERlegume) (Zlegume-maize / Zmaize-legume), and CRlegume = (LERlegume
/ LERmaize) (Zmaize-legume / Zlegume-maize) (Tsubo et al. 2005). Actual yield loss index (AYLI) was calculated as: AYL =
AYLmaize + AYLlegume. Where AYL maize={(Yml /Zml) (Ym/ Zm)}−1 and AYL legume={(Ylm/ Zlm) (Yl /Zl)}−1 (Banik and Sharma 2009). Monetary
advantage index (MAI) describes
economic advantages of intercropping. It can be calculated by using following
formula: MAI: (value of combined intercrops) (LER-1) /
LER. Higher value of MAI results in profitable intercropping (Ghosh 2004). Intercropping advantage (IA) describes economic feasibility of intercropping and measured
as:
IAmazie: AYLmazie × Pmaize where IAlegume: AYLlegume × Plegume. Commercial values of legumes and maize are
denoted by Pmaize and Plegume respectively (Banik et al. 2000). After harvesting plants from every plot with the help
of sickle, their (t ha-1) weight was measured by spring balance
(Iqbal et al. 2006). The dry matter
yield was calculated with the help of formula; Dry matter (%): Dry weight/Fresh
weight x 100 and Dry matter yield: Forage yield of related crop × dry matter (%) of that crop (Iqbal et al. 2006).
Data were analyzed statistically by using Fisher’s
analysis of variance techniques using STATISTIX software and the differences
among the treatment means were compared according to Least Significant
Difference (LSD) at 5% probability (Steel et
al. 1997).
Growth and
yield parameters
Leaf area per plant, stand density, green forage and dry
matter yield of sole maize and intercrops were affected significantly by
different levels of irrigation during both years respectively. Maximum leaf
area per plant was exhibited by maize intercropped with guar at normal irrigation
during both years while minimum leaf area per plant was exhibited by sole maize
for irrigation skipped 45 and 60 days after sowing, respectively.
Sole maize achieved maximum stand density, green forage and dry matter yield at
normal irrigation with respects to its intercrop (Table 3).
Leaf area per plant, plant height, stand density, green
forage and dry matter yield of cowpea grown as sole and intercropped with maize
were affected significantly at each irrigation level during both years
respectively. Maximum leaf area per plant was achieved by cowpea intercropped
with maize at normal irrigation while sole cowpea resulted in minimum leaf area
per plant at same level of irrigation. Maximum plant height was exhibited by
sole cowpea at normal irrigation and
Table 3: Effect of different irrigation regimes on growth and yield parameters of
maize grown as sole and intercropped with cowpea and guar
Leaf area (cm2) per plant |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Maize |
585.30d |
551.23de |
604.35cd |
517.18e |
598.24d |
606.40e |
623.25de |
633.45c-e |
626.54de |
612.35e |
Maize + cowpea |
676.33ab |
685.41ab |
704.88ab |
704.00ab |
664.78bc |
754.52ab |
705.65ab |
706.80ab |
696.45bc |
707.25ab |
Maize + guar |
729.81a |
723.41ab |
720.24ab |
704.23ab |
684.33ab |
773.22a |
733.68ab |
689.12b-d |
708.20ab |
707.88ab |
LSD
value at 5% |
64.16 |
56.76 |
||||||||
Plant height (cm) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Maize |
215.89a |
208.70ab |
210.00ab |
199.90ab |
219.56a |
249.80a |
217.41b |
205.37bc |
216.38b |
215.22b |
Maize + cowpea |
196.41ab |
205.05ab |
212.53ab |
193.43ab |
197.49ab |
213.63b |
215.78b |
210.38b |
209.50bc |
211.23b |
Maize + guar |
199.20ab |
207.00ab |
183.44ab |
205.48ab |
208.31ab |
208.04bc |
208.73bc |
181.98c |
208.20ab |
213.74b |
LSD
value at 5% |
31.93 |
27.27 |
||||||||
Number of leaves per plant |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Maize |
15a |
13ab |
12ab |
12ab |
13ab |
16a |
14ab |
13ab |
12b |
14ab |
Maize + cowpea |
14ab |
13ab |
11b |
12ab |
14ab |
15ab |
13ab |
14ab |
13ab |
13ab |
Maize + guar |
13ab |
12ab |
12ab |
13ab |
13ab |
12b |
13ab |
13ab |
15ab |
15ab |
LSD
value at 5% |
3.53 |
3.45 |
||||||||
Stand density ( plants m-2) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Maize |
26a |
21b-e |
22a-c |
23ab |
22a-c |
30a |
24ab |
23b |
22b-d |
23b |
Maize + cowpea |
18b-f |
17c-f |
16d-f |
15ef |
16ef |
18c-e |
16d-e |
15e |
16e |
15e |
Maize + guar |
15f |
15f |
14f |
16ef |
19b-f |
15e |
14e |
16e |
15e |
15e |
LSD
value at 5% |
4.85 |
4.87 |
||||||||
Green forage yield ( t ha-1) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Maize |
40.63a |
34.257bc |
33.83bc |
34.45b |
33.95bc |
40.39a |
31.63bc |
33.027b |
31.29bc |
30.78b-d |
Maize + cowpea |
32.28bc |
29.84d-e |
31.16bc |
28.73e |
28.60d-e |
29.90b-e |
26.67d-f |
28.49c-e |
23.75f |
26.06ef |
Maize + guar |
32.79b-d |
30.80b-e |
30.50c-e |
32.24b-e |
28.76e |
29.38b-e |
28.94b-e |
29.61b-e |
27.35d-f |
27.47c-f |
LSD
value at 5% |
3.85 |
3.78 |
||||||||
Dry
matter yield ( t ha -1) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Maize |
13.15a |
10.20b |
8.98bc |
8.83bd |
8.27c-e |
12.16a |
8.92bc |
7.93cd |
8.25bc |
9.45b |
Maize + cowpea |
7.24d-e |
7.38c-e |
7.01e |
8.04c-e |
6.82e |
6.36e |
5.03f |
5.89ef |
5.72ef |
6.55e |
Maize + guar |
8.01c-e |
7.190de |
6.87e |
6.80e |
6.60e |
6.71de |
6.70de |
6.87de |
6.80de |
6.47e |
LSD
value at 5% |
1.79 |
1.18 |
Where I1, I2, I3, and I4
indicate numbers of irrigation skipped after 15, 30, 45, and 60 days after
sowing keeping I0 normal irrigation with no skipping. Values sharing
same letters differ non-significantly (P
> 0.05)
minimum plant height was achieved by cowpea intercrop
for irrigation skipped 15 and 30 days after sowing, respectively. Maximum stand
density, green forage and dry matter yield were exhibited by sole cowpea at
normal irrigation while minimum for irrigation skipped 15 and 30 days after
sowing while minimum green forage yield for irrigation skipped 30 and 60 days
after sowing and dry matter yield for irrigation skipped 45 days after sowing
by cowpea intercropped with maize respectively (Table 4).
Leaf area per plant, plant height, stand density, green
forage and dry matter yield of sole guar and intercrop were affected
significantly by all irrigation levels during both years, respectively. Maximum
leaf area per plant and plant height were achieved by guar intercrop and sole
at normal irrigation while minimum leaf area per plant for irrigation skipped
15 and 30 days after sowing and minimum plant height for irrigation skipped 60
and 45 days after sowing was achieved by sole guar respectively. Sole guar had
stand density, green forage and dry matter yield at normal irrigation. The
lowest stand density for irrigation skipped 45 and 30 days after sowing and
lowest green forage and dry matter yield for irrigation skipped 60 days after
sowing were achieved by guar intercrop. Maximum number of leaves per plant was
achieved by sole guar at normal irrigation and minimum number of leaves per
plant was exhibited by guar intercrop for irrigation
skipped 15 and 45 days after sowing respectively (Table 5).
Competition indices
Table 4: Effect of different irrigation regimes on growth and yield parameters
of cowpea grown as sole and intercropped with maize
Leaf area (cm2) per plant |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Cowpea |
597.1d |
554.95d |
685.57a-c |
624.67b-d |
611.39cd |
623.00d |
642.39cd |
717.48ab |
676.30b-d |
618.90d |
Cowpea + maize |
719.54a |
722.67a |
707.47ab |
704.19ab |
685.49a-c |
755.44a |
710.74a-c |
707.47 a-c |
695.49 a-c |
707.46 a-c |
LSD
value at 5% |
57.30 |
79.99 |
||||||||
Plant height (cm) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Cowpea |
162.00a |
137.20c |
137.02c |
141.24bc |
159.76ab |
162.18a |
137.20a-c |
135.29a-c |
153.01a-c |
158.14ab |
Cowpea + maize |
135.58c |
130.39c |
146.30a-c |
128.68d |
133.39cd |
128.42c |
135.75a-c |
132.48bc |
135.76 a-c |
140.43 a-c |
LSD
value at 5% |
16.04 |
26.88 |
||||||||
Number of leaves per plant |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Cowpea |
80a |
57bc |
60bc |
64bc |
70ab |
77a |
61bc |
73ab |
66a-c |
75ab |
Cowpea + maize |
68ab |
65b |
61bc |
67ab |
52c |
69ab |
67a-c |
64 a-c |
71ab |
53c |
LSD
value at 5% |
13.60
|
17.85 |
||||||||
Stand density (plants m-2 ) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Cowpea |
65a |
59a |
57a |
60a |
61a |
60a |
52a |
54a |
53a |
51a |
Cowpea + maize |
41b |
30b |
38b |
38b |
40b |
36b |
32b |
31b |
34b |
35b |
LSD
value at 5% |
10.54 |
10.01 |
||||||||
Green forage yield (t ha -1) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Cowpea |
15.24a |
12.58ab |
12.96a |
12.10a |
13.54ab |
16.14a |
14.02ab |
15.51ab |
13.42b |
14.47ab |
Cowpea + maize |
6.20bc |
5.80c |
5.30c |
6.01bc |
5.90c |
7.10bc |
6.80c |
6.40c |
5.98c |
6.10c |
LSD
value at 5% |
2.54 |
2.38 |
||||||||
Dry matter yield (t ha -1) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Cowpea |
4.01a |
3.17a-c |
3.13a-c |
3.05a-c |
3.50ab |
5.12a |
3.60b-d |
3.91bc |
3.58b-d |
3.85bc |
Cowpea + maize |
2.68bc |
2.37cd |
2.17c |
2.01d |
2.05d |
2.85c-e |
2.19e |
2.13e |
2.10e |
2.30c |
LSD
value at 5% |
0.83 |
1.05 |
Where I1, I2, I3, and I4
indicate numbers of irrigation skipped after 15, 30, 45, and 60 days after
sowing keeping I0 normal irrigation with no skipping. Values sharing
same letters differ non-significantly (P
> 0.05)
Maize showed dominance in maize: cowpea and maize: guar
intercropping combinations as it showed higher values of land equivalent ratio
(LER), relative crowding co-efficient (K), aggressivity (A), competition ratio
(CR), actual yield loss index (AYLI), intercropping advantage (IA) at each
irrigation level than cowpea and guar intercrops during both years
respectively. The highest values of LER were recorded for maize-guar
intercropping with guar at normal irrigation and minimum
land equivalent ratio (LER) were recorded for irrigation skipped 30 and 15 days
after sowing for maize-cowpea intercropping, respectively. It showed the
economic advantages of maize-guar intercropping over maize-cowpea
intercropping. Moreover, LER values of maize-guar intercropping did not differ
significantly to each other at each irrigation level. Higher values of relative
crowding co-efficient (K) for maize: guar intercropping were observed at normal
irrigation while maize-cowpea resulted in minimum K values for irrigation
skipped 15 days after sowing respectively that showed better performance over
maize-cowpea intercropping. Different values of aggressivity (A) indicate that
companion crops did not show equal competition and maize showed higher value to
dominate over other intercrops. Higher values of A of maize-cowpea intercropping
were recorded at normal irrigation as compared to A values of maize-guar
intercropping that achieved minimum for irrigation skipped 15 and 45 days after
sowing, respectively. Maximum values of competition ratio (CR) of maize were
recorded at normal irrigation that showed its dominance over intercrops.
Moreover maize-cowpea intercropping achieved higher values of CR at normal
irrigation while minimum CR values of maize-guar intercropping were observed
for irrigation skipped 30 and 60 days after sowing, respectively. Higher
positive values of actual yield loss index (AYLI) of maize were observed at
each irrigation level as compared to negative AYLI values of intercrops while
maize-guar intercropping showed maximum values of AYLI at normal irrigation as
compared to the minimum AYLI values of maize-cowpea intercropping for
irrigation skipped 15 and 30 days after sowing respectively. Overall all
positive values of AYLI indicate the economic advantages of intercropping. Likewise,
maize resulted in to higher positive values of intercropping advantage (IA) at
all irrigation levels as compared to negative IA values of intercrops and
maize-guar intercropping resulted in to higher values of IA at normal
irrigation as compared to the minimum IA values of maize-cowpea for irrigation
skipped 30 and 45 days after sowing respectively. Over all positive values of
IA showed the beneficial effects of intercropping. Maize-guar intercropping
Table
5: Effect of different
irrigation regimes on growth and yield parameters of
guar grown as sole and intercropped with maize
Leaf area (cm2) per plant |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Guar |
703.20ab |
563.19cd |
616.43c |
569.99cd |
621.73c |
735.67a |
670.38cd |
607.79e |
607.80e |
708.34a-c |
Guar + maize |
719.54a |
690.67ab |
707.47ab |
704.19ab |
685.49a-c |
711.01ab |
680.87bc |
628.00e |
633.22de |
710.15 a-c |
LSD
value at 5% |
48.04 |
32.75 |
||||||||
Plant
height (cm) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Guar |
178.46a |
164.29bc |
168.88a-c |
160.07bc |
156.73c |
184.67a |
172.67ab |
166.43ab |
164.33b |
173.33ab |
Guar + maize |
174.37a-c |
166.50bc |
170.96bc |
172.34bc |
169.80bc |
185.21a |
177.33ab |
175.33ab |
178.67ab |
183.00ab |
LSD
value at 5% |
20.31 |
20.47 |
||||||||
Number of leaves per plant |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Guar |
319.33a |
313.33ab |
304.67ab |
292.67ab |
288.00ab |
317.00a |
315.33ab |
310.67ab |
297.67ab |
294.67ab |
Guar + maize |
286.00ab |
263.00b |
284.0ab |
289.33ab |
279.67ab |
285.67ab |
280.67ab |
284.00ab |
278.33ab |
283.67ab |
LSD
value at 5% |
55.99 |
44.56 |
||||||||
Stand density (plants m-2) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Guar |
38a |
29b |
28bc |
28bc |
26bc |
45a |
35b |
32bc |
33bc |
34b |
Guar + maize |
21bc |
18c |
19bc |
17c |
19bc |
24cd |
21cd |
20d |
22cd |
23cd |
LSD
value at 5% |
9.89 |
7.10 |
||||||||
Green forage yield (t ha -1) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
Guar |
21.48a |
16.79b |
16.92b |
15.80b |
15.05b |
22.62a |
19.86b |
17.64c |
17.80bc |
16.35c |
Guar + maize |
9.35c |
7.90c |
7.80c |
7.63c |
7.05c |
9.15de |
9.00de |
8.90e |
8.16e |
7.92e |
LSD value at 5% |
2.02 |
1.92 |
||||||||
Dry matter yield (t ha -1) |
||||||||||
|
2016 |
2017 |
||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|
|
|
|
|
|
|
|
|
|
|
|
Guar |
5.50a |
5.10a |
5.01b |
4.84ab |
4.53a-c |
6.65a |
5.57a |
5.87a |
5.86a |
5.36a |
Guar + maize |
3.74b-d |
3.65b-d |
2.55b-d |
3.50c-d |
3.16d |
3.01b |
2.97b |
2.99b |
2.84b |
2.73b |
LSD
value at 5% |
1.33 |
1.54 |
Where I1, I2, I3, and I4
indicate numbers of irrigation skipped after 15, 30, 45, and 60 days after
sowing keeping I0 normal irrigation with no skipping. Values sharing
same letters differ non-significantly (P
> 0.05)
resulted in the highest values of monetary advantage
index (MAI) at normal irrigation while minimum MAI values of
maize-cowpea intercropping were achieved for irrigation skipping 15 days after
sowing respectively that resulted in higher economic advantages with respect to
maize-cowpea intercropping. Moreover, the values of MAI did not significantly
affect at each irrigation level and resulted in the economic advantages of intercropping
under deficit irrigation (Table 6).
Discussion
Leaf area per plant, stand density, green forage and dry
matter yield of sole maize and intercrops were significantly affected during
both years (Table 3).
Table
6: Effect of different
irrigation regimes on competition indices of maize intercropped
with cowpea and guar
Land equivalent ratio (LER) |
||||||||||||
2016 |
2017 |
|||||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|||
Maize |
0.81c |
0.80c |
0.82c |
0.81c |
0.82c |
0.81c |
0.80c |
0.77c |
0.78c |
0.79c |
||
Cowpea |
0.48d |
0.50d |
0.46de |
0.39e |
0.51d |
0.59d |
0.48e |
0.53e |
0.53e |
0.52e |
||
Guar |
0.64d |
0.58de |
0.54de |
0.58de |
0.50e |
0.58c |
0.57c |
0.54c |
0.59c |
0.54c |
||
Maiz + Cowpea |
1.29b |
1.30b |
1.28b |
1.20b |
1.33ab |
1.40a |
1.28b |
1.30b |
1.31b |
1.31b |
||
Maize + Guar |
1.45a |
1.38ab |
1.36ab |
1.39ab |
1.32ab |
1.39a |
1.37a |
1.31ab |
1.37a |
1.34ab |
||
LSD
at 5% |
0.06 |
0.05 |
||||||||||
Relative crowding co-efficient (K) |
||||||||||||
|
2016 |
2017 |
||||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|||
Maize |
0.90a |
0.92a |
0.91a |
0.86a |
0.94a |
0.93a |
0.86a |
0.88a |
0.86a |
0.90a |
||
Cowpea |
0.19c-e |
0.13de |
0.22c |
0.20c-e |
0.21cd |
0.15f-h |
0.13g |
0.23b |
0.18e |
0.17e |
||
Guar |
0.57b |
0.36bc |
0.34bc |
0.38bc |
0.51bc |
0.30b |
0.29b |
0.25b |
0.30b |
0.31b |
||
Maiz + Cowpea |
0.17c-e |
0.12e |
0.20cd |
0.17c-e |
0.19c-e |
0.14g |
0.11h |
0.21d |
0.16e-h |
0.15f-h |
||
Maize + Guar |
0.51bc |
0.33bc |
0.31bc |
0.33bc |
0.47bc |
0.28b |
0.25b |
0.22c |
0.26b |
0.28b |
||
LSD
at 5% |
0.07 |
0.06 |
||||||||||
Aggressivity
(A) |
||||||||||||
|
2016 |
2017 |
||||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|||
Maize |
0.57a |
0.56a |
0.57a |
0.57a |
0.57a |
0.57a |
0.57a |
0.56a |
0.56a |
0.57a |
||
Cowpea |
0.21c |
0.15d-e |
0.14e |
0.14e |
0.16d |
0.14e |
0.14e |
0.13e |
0.16d |
0.16d |
||
Guar |
0.18c |
0.21c |
0.22c |
0.19c |
0.18c |
0.17c |
0.17c |
0.18cd |
0.18cd |
0.18cd |
||
Maiz + Cowpea |
0.45b |
0.41b |
0.43b |
0.43b |
0.42b |
0.45d |
0.42b |
0.42b |
0.41b |
0.40b |
||
Maize + Guar |
0.39b |
0.37b |
0.35b |
0.37b |
0.39b |
0.40b |
0.40b |
0.39b |
0.38b |
0.39b |
||
LSD
at 5% |
0.04 |
0.05 |
||||||||||
Competition ratio (CR) |
||||||||||||
|
2016 |
2017 |
||||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|||
Maize |
0.82ab |
0.80b |
0.81ab |
0.81ab |
0.82a |
0.82a |
0.81ab |
0.81ab |
0.80ab |
0.81ab |
||
Cowpea |
0.39i |
0.50f |
0.46h |
0.48gh |
0.51f |
0.48hi |
0.46hi |
0.42i |
0.50h |
0.51g |
||
Guar |
0.60e |
0.69b-d |
0.71a-c |
0.64d |
0.67c |
0.63d |
0.57ef |
0.58ef |
0.55f |
0.59ef |
||
Maiz + Cowpea |
0.70a-c |
0.68cd |
0.76bc |
0.74bc |
0.69cd |
0.59g |
0.74b-e |
0.72c-e |
0.69c |
0.68c |
||
Maize + Guar |
0.61e |
0.51f |
0.49f |
0.53d |
0.57f |
0.65c-e |
0.62d |
0.60e |
0.61d |
0.59ef |
||
LSD
at 5% |
0.11 |
0.14 |
||||||||||
Actual yield loss index (AYLI) |
||||||||||||
|
2016 |
2017 |
||||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|||
Maize |
0.82ab |
0.88ab |
0.92a |
0.81ab |
0.96a |
0.93a |
0.73bc |
0.87ab |
0.88ab |
0.94a |
||
Cowpea |
-0.43f |
-0.52f |
-0.37e |
-0.42f |
-0.37e |
-0.38k |
-0.42l |
-0.50e |
-0.37k |
-0.24j |
||
Guar |
-0.12d |
-0.26e |
-0.15d |
-0.20d |
-0.24d |
-0.26j |
-0.29j |
-0.28d |
-0.27j-l |
-0.32k |
||
Maiz + Cowpea |
0.50de |
0.35d |
0.55cd |
0.39de |
0.59cd |
0.55d |
0.31h |
0.28i |
0.51e |
0.70b |
||
Maize + Guar |
0.77bc |
0.61c |
0.73bc |
0.61c |
0.72bc |
0.67c |
0.44g-i |
0.48f |
0.61c |
0.62c-e |
||
LSD
at 5% |
0.10 |
0.12 |
||||||||||
Intercropping advantage (IA) |
||||||||||||
|
2016 |
2017 |
||||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|||
Maize |
1167.30a |
910.50bc |
1090.40ab |
1103.80ab |
1159.20a |
1197.80a |
1020.30ab |
1032.50ab |
1094.70ab |
1144.30a |
||
Cowpea |
-539.40g |
-459.20g |
-651.70h |
-515.70g |
-467.70g |
-470.10f |
-463.50f |
-249.30f |
-561.00h |
-499.50g |
||
Guar |
-144.80f |
-192.60f |
-324.20fh |
-249.90f |
-307.20g-i |
-334.70e |
-334.10e |
-407.60ef |
-350.20e |
-370.70e |
||
Maiz + Cowpea |
627.90d |
451.30e |
438.70e |
558.10de |
691.40cd |
727.70cd |
556.80de |
783.20c |
533.70d |
644.80de |
||
Maize + Guar |
1022.50ab |
717.90bc |
766.20c |
853.90b |
852.00b |
863.10b |
686.20c |
624.90e |
744.50c |
773.60c |
||
LSD
at 5% |
195.87 |
158.86 |
||||||||||
Monetary advantage index (MAI) |
||||||||||||
|
2016 |
2017 |
||||||||||
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
I₀ |
I₁ |
I₂ |
I₃ |
I₄ |
|||
Maiz + Cowpea |
10860d |
12410cd |
15516ab |
12691b-d |
11971cd |
12925b-d |
9548d |
11869cd |
11900cd |
12329cd |
||
Maize + Guar |
16307a |
15581a |
14402a-c |
14569a-c |
14412a-c |
15589a |
12728c |
15152a-c |
15911a-c |
16640ab |
||
LSD
at 5% |
3305.6 |
4145.6 |
||||||||||
Where I1, I2, I3, and I4
indicate numbers of irrigation skipped after 15, 30, 45, and 60 days after
sowing keeping I0 normal irrigation with no skipping. Values sharing
same letters differ non-significantly (P
> 0.05)
The higher values of leaf area per plant were recorded
for maize-guar intercropping at normal irrigation. The higher leaf area is due
to the beneficial effects of legumes intercrop over the companion crops as the
former help to fix atmospheric nitrogen, increases over all productivity of the
intercrops and higher leaf area contributed to maximum interception of light,
utilized in photosynthesis which resulted in maximum forage yield (Nasrollahzadeh and Koohi 2014; Ginwal et al. 2019). The maximum stand density, green forage and dry matter yield
were achieved by the sole maize during the same years at same irrigation level
that might be due to the higher seed rate used for sole maize as compared to
low seed rate with 70:30 for maize and cowpea intercrop respectively. This
resulted in higher plant population, green forage and dry matter yield for sole
maize as compared to maize intercrop (Khan et
al. 2012). The leaf area per plant and plant height obtained under normal
irrigation were not significantly differed as compared to under deficit
irrigation. Sole cowpea and guar achieved maximum values of leaf area per
plant, stand density, green forage and dry matter yield during both
years as compared to intercrops. The higher leaf area of cowpea and guar was
achieved due to non-competing effect of the intercrops (Abate and Alemayehu 2018; Yang
et al. 2018). While higher stand
density, green forage and dry matter yield was due to higher seed rate used for
sole cowpea and guar as compared to the seed rate with 70:30 in intercropping
with maize as higher seed rate contributed to maximum plant population and
biological yield for sole cowpea and guar as compared to intercrops (Khan
et al. 2012) (Table 3 and 4).
Land
equivalent ratio (LER) measure the effectiveness of
intercropping over mono-cropping to utilize environmental resources and its
value greater than one, equal to one or less than one indicate more yield, same
or less yield respectively (Khonde et al. 2018). The maize-guar
intercropping resulted in maximum LER during both years and showed its
advantages over maize-cowpea intercropping that might be due to effective and
efficient utilization of natural resources like land and light (Yang et al.
2018). The relative
dominance of one species over the other in a mixture is known as relative
crowding co-efficient (K) and crop with higher value of K, the more dominant
effect it would have over companion crop (Takim 2012). The results revealed
that the partial K values of maize were greater than the
partial K values of cowpea and guar during both years which showed competitive
advantage of the maize over intercrops and maize intercropped with guar resulted in maximum K values as compared to its intercropping with
cowpea (Khonde et al. 2018). The relative competitive ability of one crop as compared
to other when cultivated in combination with that crop can be described with
the help of aggressivity (A). If the value of A is either zero (0), or positive
(above zero), and/or negative (less than zero) then both crops would be equally
competitive, or one crop is dominant or weak in competition respectively (Jan et al. 2016). During both years of the experiment, the partial values of A of maize
were greater than intercrops that showed the dominance of maize over cowpea and guar
(Imran et al.
2011). It is clearly shown from the experiment that partial values of CR of
maize were greater than intercrops during both years which resulted in
competitive advantage of maize over cowpea and guar showing higher ability to
utilize environmental resources efficiently (Javanmard et al. 2014). The proportionate yield advantage (gain) or
disadvantage (loss) of intercrops as compared to sole crops is described as actual
yield loss index (AYLI). It is derived from the experiment maize showed partial
positive values of AYLI that resulted in yield advantages while partial values
of AYLI of intercrops were negative that showed the yield disadvantages.
Maize-guar resulted in maximum values of AYLI during both years of the
experiment as compared to maize-cowpea intercropping (Takim 2012). The economic feasibility of intercropping is termed
as intercropping advantage (IA). It is observed from the experiment that maize
showed positive values of IA as compared to intercrops which showed negative
values. However, over all positive IA values were recorded which showed the
advantages of intercropping over solitary cultivation. Maize intercropped with
guar resulted in maximum values of IA during experimental duration that
resulted in to more feasible option of intercropping as compared to guar (Takim 2012). Monetary advantage index (MAI) describes economic advantages of intercropping. Maize-guar
intercropping resulted in maximum values of MAI as compared to MAI values of
maize-cowpea intercropping that showed its higher economic advantage over
maize-cowpea intercropping under deficit irrigation during both years (Tofa et
al. 2017) (Table 6).
Conclusion
This research study concludes that maize intercropped
with cowpea and guar reduced the yield as compared to their sole cultivation
but overall productivity in terms of leaf area, plant height, land equivalent
ratio, and monetary advantage index were recorded in maize: guar intercropping
under deficit irrigation and it did not differ significantly with respect to
normal irrigation. So, maize: guar intercropping was found a suitable cropping
combination under hot climate where farmer face scarcity of irrigation water.
Author Contributions
MA and MN planned, conduct, and write the initial
results/draft of the experiment, AR and MMZ reviewed the results, RI, MAS, RMIK
and JI statistically analyzed the data and made illustrations.
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