*3.1.1 Higher yield and greater resource utilization*

Yield is the basic consideration for assessing benefits of intercropping. In maize-legume intercropping maize is treated as based crop without much variation in plant stand of cereal component. In additive series of intercropping, legumes add plant population per unit area and benefits are achieved as total yield of crops, namely maize and legume yields. Further, in a combination of legume and nonlegume, generally non-legume component is benefited by sharing atmospheric nitrogen fixed by legumes. In assessing efficiency of an intercropping system, some competition functions are considered. Of which land equivalent ratio (LER) is a very common index used to measure productivity of intercropping system. Willey and Osiru [14] proposed the concept of the LER and it is defined as the proportionate land area required under pure stand of crop to produce the same productivity as obtained in an intercropping at the same management level. Actually, LER is the summation of ratios of the yield of each crop species involved in intercropping system to its corresponding pure stand yield. Experiments carried out in different countries clearly exhibited higher LER values in maize-legume intercropping system (**Table 1**).

The LER indicates the advantage of an intercropping with efficient resource utilization compared to pure stands of respective crops. The value of LER greater than unity (1.0) is indicative of the advantages in intercropping system [2].

The LER indicates on efficiency of using land area, but time factor is not considered for which the crop occupies the land area. To rectify the limitation of the LER, the concept of area time equivalent ratio (ATER) has been developed considering the occupancy of land by the crops for certain periods [23]. Like the LER, values of the ATER more than unity also indicate advantage of intercropping. Different researchers noted beneficial ATER values with maize-legume intercropping systems (**Table 2**).

However, researchers comment that the LER overestimates and the ATER underestimates the land-use efficiency [27].

Crop equivalent yield is another expression for evaluating the efficiency of intercropping system [25]. Actually, in maize-legume intercropping system, total

**107**

**Table 3.**

researchers in experiments.

**Intercropping system**

Maize + black cowpea

**Table 1.**

**Table 2.**

ping combination was noted than pure stands [29].

*Maize-equivalent yield (MEY) in maize-legume intercropping systems.*

*Potential and Advantages of Maize-Legume Intercropping System*

*Land equivalent ratio (LER) in maize-legume intercropping systems.*

*Area time equivalent ratio (ATER) in maize-legume intercropping systems.*

**Intercropping system Ratio/proportion LER Country References** Maize + bean 2:1 2.60 Kenya [15] Maize + cowpea 1:1 1.72 Turkey [16] Maize + French bean 1:2 1.66 India [17] Maize + soybean 1:1 1.54 Nigeria [18] Maize + groundnut 2:2 1.42 Ghana [19] Maize + garden pea 1:2 1.56 Bangladesh [20] Maize + soybean 100% + 75% 1.60 Turkey [21] Maize + groundnut 2:2 1.82 India [7] Maize + soybean 2:2 1.90 China [22]

yields are converted in the form of base crop (maize) equivalent yield by considering the intercrop yield and market price of maize (base crop) and associated intercrops. In maize-legume intercropping system it is termed as maize equivalent yield (MEY) and expressed in kg<sup>−</sup>ha. If the base crop equivalent yield is obtained higher in intercropping combinations than base crop yield, then intercropping is considered advantageous. **Table 3** indicates advantageous MEYs as obtained by the

**Intercropping system Ratio ATER Country References** Maize + black gram 1:2 1.37 India [24] Maize + black gram 1:2 1.47 India [17] Maize + soybean 2:6 1.32 India [25] Maize + black cowpea 2:2 1.51 India [26]

The greater yields in intercropping is recorded when the component crops show complementary effects amongst themselves and use natural resources efficiently than raised as sole crops [28]. The crops with inherent capability can only utilize natural resources efficiently and complementarity plays important role in resource utilization [2]. Further, higher yield of both the crops in maize-cowpea intercrop-

In soils with low nitrogen content, maize legume intercropping performed well [30]. Yield advantage in intercropping is expressed by crops because of greater use of growth resources like light, water, and nutrients and this efficient use is

Maize + soybean 2:6 9470 7092 5450 [25]

Maize + garden pea 1:2 20,220 8200 6450 [20]

**yield (kg<sup>−</sup>ha)**

2:2 7699 5062 4785 [26]

**Sole legume yield (kg<sup>−</sup>ha)** **References**

**Ratio MEY (kg<sup>−</sup>ha) Sole maize** 

*DOI: http://dx.doi.org/10.5772/intechopen.91722*

#### *Potential and Advantages of Maize-Legume Intercropping System DOI: http://dx.doi.org/10.5772/intechopen.91722*


#### **Table 1.**

*Maize - Production and Use*

system productivity.

**3. Advantages of intercropping**

ping is restoration of soil fertility.

*3.1.1 Higher yield and greater resource utilization*

quality of forage in terms of dietary value. Moreover, maize has higher potential for accumulation of carbohydrate, a source of energy as fodder, from unit area on daily basis. However, legumes can be planted in maize at the same time can also register

Maize and legume intercropping system has advantages in many ways and so preferred by small and marginal farmers. Experimental results showed that maizelegume intercropping can assure higher yield, soil restoration and greater impact of

In Intercropping, more crops are grown simultaneously in unit area which results not only greater productivity but also utilizes natural resources more efficiently. Management of pests, diseases and weeds is easier because of less incidence which leads to greater yield. Another important aspect of maize-legume intercrop-

Yield is the basic consideration for assessing benefits of intercropping. In maize-legume intercropping maize is treated as based crop without much variation in plant stand of cereal component. In additive series of intercropping, legumes add plant population per unit area and benefits are achieved as total yield of crops, namely maize and legume yields. Further, in a combination of legume and nonlegume, generally non-legume component is benefited by sharing atmospheric nitrogen fixed by legumes. In assessing efficiency of an intercropping system, some competition functions are considered. Of which land equivalent ratio (LER) is a very common index used to measure productivity of intercropping system. Willey and Osiru [14] proposed the concept of the LER and it is defined as the proportionate land area required under pure stand of crop to produce the same productivity as obtained in an intercropping at the same management level. Actually, LER is the summation of ratios of the yield of each crop species involved in intercropping system to its corresponding pure stand yield. Experiments carried out in different countries clearly exhibited higher LER values in maize-legume intercropping

The LER indicates the advantage of an intercropping with efficient resource utilization compared to pure stands of respective crops. The value of LER greater than unity (1.0) is indicative of the advantages in intercropping system [2].

The LER indicates on efficiency of using land area, but time factor is not considered for which the crop occupies the land area. To rectify the limitation of the LER, the concept of area time equivalent ratio (ATER) has been developed considering the occupancy of land by the crops for certain periods [23]. Like the LER, values of the ATER more than unity also indicate advantage of intercropping. Different researchers noted beneficial ATER values with maize-legume intercropping systems

However, researchers comment that the LER overestimates and the ATER under-

Crop equivalent yield is another expression for evaluating the efficiency of intercropping system [25]. Actually, in maize-legume intercropping system, total

higher growth attributes because of wider spacing of maize as grain crop.

**3.1 Advantage in improving productivity and soil fertility**

**106**

(**Table 2**).

estimates the land-use efficiency [27].

system (**Table 1**).

*Land equivalent ratio (LER) in maize-legume intercropping systems.*


#### **Table 2.**

*Area time equivalent ratio (ATER) in maize-legume intercropping systems.*

yields are converted in the form of base crop (maize) equivalent yield by considering the intercrop yield and market price of maize (base crop) and associated intercrops. In maize-legume intercropping system it is termed as maize equivalent yield (MEY) and expressed in kg<sup>−</sup>ha. If the base crop equivalent yield is obtained higher in intercropping combinations than base crop yield, then intercropping is considered advantageous. **Table 3** indicates advantageous MEYs as obtained by the researchers in experiments.

The greater yields in intercropping is recorded when the component crops show complementary effects amongst themselves and use natural resources efficiently than raised as sole crops [28]. The crops with inherent capability can only utilize natural resources efficiently and complementarity plays important role in resource utilization [2]. Further, higher yield of both the crops in maize-cowpea intercropping combination was noted than pure stands [29].

In soils with low nitrogen content, maize legume intercropping performed well [30]. Yield advantage in intercropping is expressed by crops because of greater use of growth resources like light, water, and nutrients and this efficient use is


#### **Table 3.**

*Maize-equivalent yield (MEY) in maize-legume intercropping systems.*

converted into biomass [2, 31]. The combination of maize-cowpea intercropping can assure greater light interception and check evaporation loss of soil moisture than pure stand of maize [32].

Maize and legumes are morphologically dissimilar and their time of peak demand and requirement of light, nutrients and water are different. Therefore, complementary effect between component crops is very common. Jiao et al. [33] noted that maize used strong light and groundnut preferred weak light (because maize provided partial shade) in maize-groundnut intercropping system and the system registered yield advantage. Further, soybean-maize intercropping has been known for efficient utilization of light, nutrients and available soil moisture [2, 34]. Soil moisture or water availability to plants is a determining factor in intercropping systems and efficient water use leads to use of other resources. Cereal-legume combination is known to use available water resources more efficiently than pure stands of crops. Scientific investigations showed that maize-legume combination registered greater water use efficiency than that of sole crops and under water stress conditions, it could be one of the best options [35] as soybean as a deep rooted crop having efficiency to use soil moisture from deeper layer (below 1 m) of the soil [36].

#### *3.1.2 Weed management*

Intercropping is an effective practice for weed management because enough of ground area is covered by crops which suppress weed growth. Combination of maize and legumes in intercropping is known to reduce weed population and weed biomass compared to pure stands of maize. Research evidences clearly show benefits of intercropping as it provides competitive effect against weeds both spatially and temporally than pure stands of maize. Reduced weed growth in maize-cowpea intercropping system than sole cropping of maize. Chalka and Nepalia [37] mentioned that in maize-legume intercropping systems, maize + cowpea and maize + soybean reduced NPK removal through weeds by 37.4 and 38.0% respectively and the two intercropping combinations registered higher biological yield of maize. Rahimi et al. [38] reported that maize-black gram intercropping combination of either 1:1 or 2:2 recorded lower densities of total weeds compared to pure stand of maize. Shah et al. [39] opined that weed smothering efficiency was higher in intercropping of maize with soybean than the combination of maize with green gram and it was due to the lower availability of space and light leads to reduce the weeds population with maize-soybean intercropping system. Weed biomass is reduced in intercropping as reported by researchers for maize–legume combinations [40, 41]. In studies it has been claimed that enhancement of diversity of crop species in intercropping system maintains a highly asymmetric competition over weeds resulting in less weed biomass [42, 43]. Weeds compete with crops for available resources and less weed occurrence assures ultimately higher productivity.

#### *3.1.3 Pest and disease management*

Intercropping systems can influence the pest and pathogen population dynamics. The population of beneficial insects such as parasites and predators are enhanced in polyculture due to diversity of crops [2] and presence of harmful pests may remain below the economic threshold level. Thus, plant protection becomes easy and use of chemicals for crop protection comes down which ultimately reduces the chemical pollution to agricultural ecology, however, monoculture of maize requires more chemical pesticides [44]. In intercropping system, two or more crop species are cultivated which creates complexity in food and habitat of pests. Further, intercropping of maize with legumes is known to increase population of beneficial

**109**

*3.1.5 Erosion control*

caused by wind [45].

*Potential and Advantages of Maize-Legume Intercropping System*

and thus minimizes the chance of pollution in crop ecology.

*3.1.4 N-fixation by legumes and transfer to associated non-legume*

to increase productivity of maize–soybean intercropping system [22].

**3.2 Advantage in enhancement of system productivity**

*3.2.1 Insurance against crop failure to small holders*

Intercropping is advantageous in terms of erosion control because of coverage of more ground area than monocropping of cereals. The striking actions of rain drops can erode the bare or uncovered soil, but the coverage of soil by legumes can check it. In maize-cowpea intercropping combination, ground area is mostly covered, thus soil erosion is reduced [54]. Taller crop like maize also plays a vital role as wind break and protects the crops with shorter canopy (like legumes) as well as erosion

Intercropping is a common practice of small and marginal farmers in developing countries of Asia and Africa and in risky and fragile ecological conditions which is known as a suitable practice to provide natural insurance and thus provides a profitable shape to farm economy. Under moisture stress conditions, more of ground area is covered under maize-legume intercropping than sole cropping of maize which

insects and decrease the population of bud worm, corn borer, leaf hopper and maize stalk borer [1, 45]. The intercropping system has also an impact against disease management, because in mixture of crops functional diversity is created that checks population increase of pathogen. Some diseases of legume crops like angular leaf spot (*Phaeoisariopsis griseola*) of beans and ascochyta blight (*Mycosphaerella pinodes*) were observed with less severity when these were intercropped with maize [46, 47] than pure stand of legumes. Reduction of pest-disease incidence not only saves the crop loss and better yield but also assures less use of chemicals for plant protection

Legumes are known to fix atmospheric nitrogen biologically. The biological nitrogen fixation (BNF) is a process where some bacteria convert atmospheric N2 into ammonia (NH3) and making it available to plants. In maize-legume intercropping system, both the crops acquire N from the common soil pool and compete and thus deficit of mineral N may occur in the rhizosphere which promotes legume to fix atmospheric N [48, 49]. Maize is an exhaustive crop and legumes are soil replenishing crops and decomposition of legumes residue improves soil fertility. In the soils with poor available nitrogen status, the biologically fixed nitrogen plays an important role. Under the situation of limited supply of nitrogenous fertilizer also intercropping legume and non-legume may a suitable option of nutrient management. Further, chemical N fertilizers are responsible for degradation of ecosystem in the form of nitrate pollution and legumes grown as intercrops help in environmental sustainability [50]. In maize-soybean intercropping system, soybean supplements nitrogen to cereal component [51]. Maize grown as forage in intercropping with legumes is known to improve quality parameters of forage like higher crude protein and mineral content and digestibility [48, 52]. Biologically fixed N by pigeon pea was transferred to associated maize and N content and uptake by maize was improved in maize-pigeon pea intercropping system [53]. The associated non-legume crop (maize) gets benefit of fixed N by legumes [1]. Thus, maize-legume intercropping system is beneficial in terms of N economy too. Leaf defoliation of legumes is known

*DOI: http://dx.doi.org/10.5772/intechopen.91722*

### *Potential and Advantages of Maize-Legume Intercropping System DOI: http://dx.doi.org/10.5772/intechopen.91722*

*Maize - Production and Use*

*3.1.2 Weed management*

than pure stand of maize [32].

converted into biomass [2, 31]. The combination of maize-cowpea intercropping can assure greater light interception and check evaporation loss of soil moisture

Maize and legumes are morphologically dissimilar and their time of peak demand and requirement of light, nutrients and water are different. Therefore, complementary effect between component crops is very common. Jiao et al. [33] noted that maize used strong light and groundnut preferred weak light (because maize provided partial shade) in maize-groundnut intercropping system and the system registered yield advantage. Further, soybean-maize intercropping has been known for efficient utilization of light, nutrients and available soil moisture [2, 34]. Soil moisture or water availability to plants is a determining factor in intercropping systems and efficient water use leads to use of other resources. Cereal-legume combination is known to use available water resources more efficiently than pure stands of crops. Scientific investigations showed that maize-legume combination registered greater water use efficiency than that of sole crops and under water stress conditions, it could be one of the best options [35] as soybean as a deep rooted crop having efficiency to use soil moisture from deeper layer (below 1 m) of the soil [36].

Intercropping is an effective practice for weed management because enough of ground area is covered by crops which suppress weed growth. Combination of maize and legumes in intercropping is known to reduce weed population and weed biomass compared to pure stands of maize. Research evidences clearly show benefits of intercropping as it provides competitive effect against weeds both spatially and temporally than pure stands of maize. Reduced weed growth in maize-cowpea intercropping system than sole cropping of maize. Chalka and Nepalia [37] mentioned that in maize-legume intercropping systems, maize + cowpea and maize + soybean reduced NPK removal through weeds by 37.4 and 38.0% respectively and the two intercropping combinations registered higher biological yield of maize. Rahimi et al. [38] reported that maize-black gram intercropping combination of either 1:1 or 2:2 recorded lower densities of total weeds compared to pure stand of maize. Shah et al. [39] opined that weed smothering efficiency was higher in intercropping of maize with soybean than the combination of maize with green gram and it was due to the lower availability of space and light leads to reduce the weeds population with maize-soybean intercropping system. Weed biomass is reduced in intercropping as reported by researchers for maize–legume combinations [40, 41]. In studies it has been claimed that enhancement of diversity of crop species in intercropping system maintains a highly asymmetric competition over weeds resulting in less weed biomass [42, 43]. Weeds compete with crops for available resources and

Intercropping systems can influence the pest and pathogen population dynam-

enhanced in polyculture due to diversity of crops [2] and presence of harmful pests may remain below the economic threshold level. Thus, plant protection becomes easy and use of chemicals for crop protection comes down which ultimately reduces the chemical pollution to agricultural ecology, however, monoculture of maize requires more chemical pesticides [44]. In intercropping system, two or more crop species are cultivated which creates complexity in food and habitat of pests. Further, intercropping of maize with legumes is known to increase population of beneficial

ics. The population of beneficial insects such as parasites and predators are

less weed occurrence assures ultimately higher productivity.

*3.1.3 Pest and disease management*

**108**

insects and decrease the population of bud worm, corn borer, leaf hopper and maize stalk borer [1, 45]. The intercropping system has also an impact against disease management, because in mixture of crops functional diversity is created that checks population increase of pathogen. Some diseases of legume crops like angular leaf spot (*Phaeoisariopsis griseola*) of beans and ascochyta blight (*Mycosphaerella pinodes*) were observed with less severity when these were intercropped with maize [46, 47] than pure stand of legumes. Reduction of pest-disease incidence not only saves the crop loss and better yield but also assures less use of chemicals for plant protection and thus minimizes the chance of pollution in crop ecology.
