CROPPING SYSTEM CROPPING SYSTEM INTERACTION COMPETITIVE – INTERACTION COMPETITIVE –

COMPLEMENTRY – COMPLEMENTRY – ALLELOPATHY ALLELOPATHY

CROPPING SYSTEM- INTERACTION

In intensive cropping, when crops are grown in association (intercropping or (sequential cropping) interaction between different component crop species occurs, which is essentially a response of one species to the environment as modified by the presence of another species (commonly referred to as interference or interaction).

Concept of competition in cropping systems

• Interaction The effect of presence of one plant on the

other plants environment Types Removal reactions - competition Additive reaction - Allelopathy and Symbiosis

Competition in cropping systems

Inter cropping• Solar radiation• Water and

nutrients• Allelopathy

Sequential cropping• Change in soil

condition• Shift in weed flora• Incidence of pest

and diseases

The interaction may be

CompetitiveNon-competitive Complementary

COMPETITIVE INTERACTION 

• One species may have greater ability to use the limiting factor and will gain at the expense of the other and this is called as competitive interaction or interference.

The concept of competition The struggle between the individuals

within a population for available resources

Competition function

Any function or formulae that

represents the manner in which the

maximum plan yield is reduced by

increasing competition

Competition functions

• Intra-Specific competition Competition occurs between the same species

• Inter-Specific competition occurs between the different species

• Parabolic function

• Asymptotic function

Competitive relationship

1.Competition for growth resources

2.Mechanism of plant population stress

3.Effect of plant population on crop

4.Competition in intercropping and sequential cropping

1. Competition for growth resources

Competition for nutrients Depends upon the root spacing of dominated and aggressive

crops

Competition for light The growth duration of the component crops play a major role

Competition for water Depends on the Method of irrigation, RGR, Earliness of

water demand, Root extension-Lateral and vertical growth

       

2. Mechanisms of plant population stress

• Yield per plant linearly correlated with the available space

• In close planting leaf surface per plant and unit area is reduced

• Effect of rapid growth of weeds on plant population-injurious

• The theory of injurious substances of the rhizosphere

3. Effect of plant population on growth

• Widely spaced crops have a circular root distribution beneficial to crops

• Closely planted crops have un uniform root spread

• Increased lodging in high plant density• High plant density lead to seedling mortality• Build up and spread of pest and diseases

more in HPD with out proper management

4.Factors deciding optimum plant density

• Plant size• Tillering • Lodging

Competition in intercropping and sequential cropping

Important requirements for Successful intercropping Different periods of peak nutrient demand Minimum competition for light The difference in maturity of component

crops should be at least 30 days

way of increase the light use efficiency

• Proper choice of crops • Proper choice of Genotypes• Adjustment of population density• Proportion of each component in the mixture • Planting pattern

Nutrient uptake kg/ha of maize and cow pea

Nutrient

Sole crop Inter crop TotalMaize

cowpea

Maize

cowpea

N 185.0 101.0 163.0 40.0 203.0

P 3.97 1.55 3.89 1.30 4.93

K 176.0 54.20 156.0 37.0 193.0

S 157.0 89.0 142.0 62.40 205.0

(Singh et al.,2009)

• Roots of sunflower              Sunflower is not recommended for cropping system approach especially in sequential cropping

• Removal of sorghum stubbles with high C/N ratio plays a major role in cropping system productivity 

                                             (Reddy etal.,-2010)

• Solar energy use efficiency under rice based cropping system, the

efficiency ranged from 1.58 to 2.02 per cent in UP.

• Efficiency of solar energy use in cotton based cropping system at

Coimbatore from 0.82 to 1.77 per cent of PAR for the whole year,

• indicating that by proper choice of crops, the efficiency is doubled.

(Venugopal et al., 2005)

Non-competitive

• If the crops are grown in association and the growth of either of the concerned species is not affected, such type of interaction is called non-competitive interaction or interference.

• Or if these resources (growth factors) are present in adequate quantities as a result of which the growth of either of the concerned species is not affected, then it is non-competitive interaction or interference.

Complementary interaction • If one species is able to help the other it is

known as complementary interaction. Or if the component species are able to exploit to supply of growth factors in different ways (temporal or spatial) or if one species is able to help the other in supply of factor.

• complementary interaction between space and time called is annidations.

• legumes supplying part of N fixed by symbiosis to non-legumes)

Eg. Maize intercrop with pulse

Annidations in Space

Certain crops require less light intensity and high relative humidity . Such an altered micro climate is provided when such crops are grown in between tall growing components in an intercropping system.Eg. Turmeric/ Ginger / Black pepper in coconut gardens.

Annidation in time

• When two crops of widely varying duration are planted, their peak demands for light and nutrients are likely to occur at different periods, thus reducing competition.

• When early maturing crop is harvested it become favorable for late maturing crop

• Eg. Sorghum+ Redgram, Groundnut+Redgram and maize + greengram

Other Complementary Effect in Intercropping Systems

• Presence of rhizosphere microflora and mycorhiza associated with one of the crops may lead to mobilization and availability of nutrients which may benefit the associated crop also.

• Similarly provision of physical support by a tall crop to a climbing type of intercrop is another example of complementary effect.

Eg. Coconut + Pepper, Sorghum + Lablab, Maize+ Climbing Beans.

• The taller component acts as wind barrier protecting the short crop as in maize+ groundnut, onion + castor, turmeric + castor

Allelopathy effect

• Allelopathy is referred as any direct or indirect harmful effect that one plant has on another through the relates of chemical substances or toxins into the root environment.

• Some crops may be unsuitable as intercrops because they secrete toxins into the soil which will adversely affect the associated crops.

• Eg.Roots  of  cucumber,  leaves  of  Eucalyptus globules,  decomposing  residues  of  sunflower are  known  to  produce  allelo  chemicals, affecting  the  growth  of  other  crops.  Such crops must be avoided.

Types• Allo inhibition : The chemical released by one species may inhibit species of plants other than the one releasing it

• Auto inhibition :inhibit more strongly plants of the producer species itself 

• Functional allelopathic :Toxic substances may be converted into active substances by some micro- organisms 

For success in intercropping, the component crops must

Differ in duration : a duration difference of 25% is preferable,  other  evidences  indicate  that  a difference at least 32-40 days is necessary.

Differ in rooting pattern-peak nutrient and water demand periods should occur at different times

should lead to more complementary effects.should not leave any allelopathic effectshould not encourage the increased incidence of any particular pest, disease or weed.

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