**2. Considerations for choosing intercropping system**

The success of intercropping depends on different considerations before and during cultivation as because crops grown in mixture may compete spatially and temporally amongst species for available resources. An efficient intercropping system in terms of economic benefits depends on adaptation of planting geometry and choice of compatible and suitable crops. The features of an intercropping system differ with soil and climatic conditions, economic situation and preferences of the farmers. In cereal-legume intercropping system, choice of crop species, density of planting, planting geometry, time of planting and maturity of crops are the key considerations and the success of the system largely depends on these factors.

## **2.1 Choice of crops**

Choice of crops is important in intercropping, because severe competition in mixed culture may not be beneficial and even harmful if proper plant species are not chosen. In this way competition amongst plants can be minimized and better utilization of available resources can be assured. The combination of cereal and legume is considered an ideal because cereals can utilize a portion of biologically fixed nitrogen by legumes. In maize based intercropping system, groundnut is chosen as intercrop maize in South East Asia and Africa [5]. Maize can provide shade to associated legumes and the legume species should be to some extent tolerant to shade. Legume species like black gram (*Vigna mungo*), cowpea (*Vigna unguiculata*), groundnut (*Arachis hypogea*) and green gram (*Vigna radiata*) have much less effect on maize and these are tolerant to maize shade [6, 7]. Cereal-legume intercropping is very common in the continents of Asia, Africa and South America [8], however, in tropical countries, maize based intercropping is practiced with a preference to cowpea [9]. In Central and South America and parts of East Africa intercropping of maize and bean is widely practiced [10]. Maize and dwarf red gram intercropping combination is known as a suitable option in managing cereal component [11].

#### **2.2 Maturity of crop**

Maturity of crop is another important consideration in adoption of intercropping. Generally, crops grown in intercropping should have different peak period of growth, otherwise there will be competition amongst the crop species for available resources. The complementary effects benefit the system and these are reflected into yield advantage when the component species in intercropping have different

**105**

**2.4 Time of planting**

*Potential and Advantages of Maize-Legume Intercropping System*

growing period for major demands on available resources. Therefore crops with different duration maturity are chosen to get complementary effects. Maize has been recognized as a common crop in cereal-based intercropping and treated as base crop in additive series and dissimilar legumes are preferably considered as intercrop. In maize-based intercropping system choosing short duration legumes as intercrops is an ideal option. For example, in maize + green gram intercropping system, initial growth of maize is slow and it reaches at knee-height stage after 6–7 weeks and peak light demand starts from 55 to 60 days after sowing and by this period green gram sown at the same time will be in reproductive stage or in close to harvest. In this way green gram completes its major growth period and maize starts the same and thus

Optimum plant stand is synonymous to optimum yield. But in intercropping system two or more crops are accommodated in the same land at the same time and thus there may be reduction in population of crops compared to pure stand of individual species. On the basis of plant density, intercropping may be categorized into two groups, namely, additive series and replacement series. The additive series is comprised of addition of intercrop within fullest population of base crop. Another crop known as intercrop and it is sown into the base crop population by adjusting row spacing or changing planting geometry. Sometimes, paired row planting of maize is done to accommodate greater space for intercrops. But in replacement series of intercropping, there is not the concept of base crop and the crops (two or more) considered are termed as component crops or intercrops. In such type of intercropping, introduction of a component crop is made by replacing another and none of the component crops are sown with 100% population as recommended in their pure stands. It is very clear that certain proportion of population of one crop component is sacrificed and another component is introduced in that place. In many intercropping situations with replacement series, yield advantages are maximized by increasing population density in excess than their recommended population in the sole cropping. Here, the competition is relatively lesser in between component crops as compared to additive series. As maize is widely spaced crop and generally row spacing ranges between 60 to 90 cm and intercrops can easily be raised in uniform rows of planting. The planting geometry, particularly, paired row planting of maize may enhance the efficiency of growth parameters as well as yield of maize and associated legumes by efficient accommodation of crops. Prasad and Brook [12] observed an enhanced LAI per unit area with increase in plant population of maize in maize-soybean intercropping system. Under the major demand for resources at different times of system duration, the long duration cereal crop maize can recover its resource needs in combination with short duration legumes during remaining

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

high level of complementarity is observed.

**2.3 Plant density and maturity of component crops**

phase of growth that is after harvest of legumes [13].

Maize is recognized as a very common crop in intercropping system in which legumes can be sown easily. Generally, in maize based intercropping systems, as maize has slower initial growth rate up to knee height stage (6–7 weeks of sowing), if short duration legumes are sown simultaneously can reach into their reproductive stage can start their reproductive period and hence competition for common natural resources do not appear at the same period. Maize has diverse use and if maize is considered as fodder in intercropping, competition does not come into figure because of enhance biomass yield and mixture of grass-legume combination enhances the

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

*Maize - Production and Use*

**2.1 Choice of crops**

**2.2 Maturity of crop**

as considerations, advantages and limitations.

**2. Considerations for choosing intercropping system**

Maize (*Zea mays* L.), also termed as 'corn' and 'queen of cereals', is the third most important cereal of the world, ranks at third position amongst the cereals after rice and wheat and it is a member of Poaceae family. The very cereal has been a staple food for many people in Mexico, Central and South America and parts of Africa. In Europe and rest of the North America, maize is grown mostly as animal feed. Maize is widely cultivated throughout the world having a production of 1147 million tonnes [4]. In various cropping systems as well as in intercropping maize can be fit due to its wider adaptability in different seasons and agro-climatic conditions. Maize is a widely spaced crop and offers ample scope for adoption of intercropping and combination of maize legume in intercropping benefits the agricultural production system by many ways with enhancement of productivity from unit area [2]. This chapter focuses on different aspects of maize based intercropping system, such

The success of intercropping depends on different considerations before and during cultivation as because crops grown in mixture may compete spatially and temporally amongst species for available resources. An efficient intercropping system in terms of economic benefits depends on adaptation of planting geometry and choice of compatible and suitable crops. The features of an intercropping system differ with soil and climatic conditions, economic situation and preferences of the farmers. In cereal-legume intercropping system, choice of crop species, density of planting, planting geometry, time of planting and maturity of crops are the key considerations and the success of the system largely depends on these factors.

Choice of crops is important in intercropping, because severe competition in mixed culture may not be beneficial and even harmful if proper plant species are not chosen. In this way competition amongst plants can be minimized and better utilization of available resources can be assured. The combination of cereal and legume is considered an ideal because cereals can utilize a portion of biologically fixed nitrogen by legumes. In maize based intercropping system, groundnut is chosen as intercrop maize in South East Asia and Africa [5]. Maize can provide shade to associated legumes and the legume species should be to some extent tolerant to shade. Legume species like black gram (*Vigna mungo*), cowpea (*Vigna unguiculata*), groundnut (*Arachis hypogea*) and green gram (*Vigna radiata*) have much less effect on maize and these are tolerant to maize shade [6, 7]. Cereal-legume intercropping is very common in the continents of Asia, Africa and South America [8], however, in tropical countries, maize based intercropping is practiced with a preference to cowpea [9]. In Central and South America and parts of East Africa intercropping of maize and bean is widely practiced [10]. Maize and dwarf red gram intercropping combination is known as a suitable option in managing cereal component [11].

Maturity of crop is another important consideration in adoption of intercropping. Generally, crops grown in intercropping should have different peak period of growth, otherwise there will be competition amongst the crop species for available resources. The complementary effects benefit the system and these are reflected into yield advantage when the component species in intercropping have different

**104**

growing period for major demands on available resources. Therefore crops with different duration maturity are chosen to get complementary effects. Maize has been recognized as a common crop in cereal-based intercropping and treated as base crop in additive series and dissimilar legumes are preferably considered as intercrop. In maize-based intercropping system choosing short duration legumes as intercrops is an ideal option. For example, in maize + green gram intercropping system, initial growth of maize is slow and it reaches at knee-height stage after 6–7 weeks and peak light demand starts from 55 to 60 days after sowing and by this period green gram sown at the same time will be in reproductive stage or in close to harvest. In this way green gram completes its major growth period and maize starts the same and thus high level of complementarity is observed.

## **2.3 Plant density and maturity of component crops**

Optimum plant stand is synonymous to optimum yield. But in intercropping system two or more crops are accommodated in the same land at the same time and thus there may be reduction in population of crops compared to pure stand of individual species. On the basis of plant density, intercropping may be categorized into two groups, namely, additive series and replacement series. The additive series is comprised of addition of intercrop within fullest population of base crop. Another crop known as intercrop and it is sown into the base crop population by adjusting row spacing or changing planting geometry. Sometimes, paired row planting of maize is done to accommodate greater space for intercrops. But in replacement series of intercropping, there is not the concept of base crop and the crops (two or more) considered are termed as component crops or intercrops. In such type of intercropping, introduction of a component crop is made by replacing another and none of the component crops are sown with 100% population as recommended in their pure stands. It is very clear that certain proportion of population of one crop component is sacrificed and another component is introduced in that place. In many intercropping situations with replacement series, yield advantages are maximized by increasing population density in excess than their recommended population in the sole cropping. Here, the competition is relatively lesser in between component crops as compared to additive series. As maize is widely spaced crop and generally row spacing ranges between 60 to 90 cm and intercrops can easily be raised in uniform rows of planting. The planting geometry, particularly, paired row planting of maize may enhance the efficiency of growth parameters as well as yield of maize and associated legumes by efficient accommodation of crops. Prasad and Brook [12] observed an enhanced LAI per unit area with increase in plant population of maize in maize-soybean intercropping system. Under the major demand for resources at different times of system duration, the long duration cereal crop maize can recover its resource needs in combination with short duration legumes during remaining phase of growth that is after harvest of legumes [13].

#### **2.4 Time of planting**

Maize is recognized as a very common crop in intercropping system in which legumes can be sown easily. Generally, in maize based intercropping systems, as maize has slower initial growth rate up to knee height stage (6–7 weeks of sowing), if short duration legumes are sown simultaneously can reach into their reproductive stage can start their reproductive period and hence competition for common natural resources do not appear at the same period. Maize has diverse use and if maize is considered as fodder in intercropping, competition does not come into figure because of enhance biomass yield and mixture of grass-legume combination enhances the

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