Cropping system interactions

Regarding cropping system interactions, allelopathy in cropping system and it includes multiple cropping system and legume interactions.

1. CROPPING SYSTEM INTERACTION COMPETITIVE – COMPLEMENTRY – ALLELOPATHY Thimmaiah M 1 St Ph.D Department of Agronomy UAHS, Shivamogga 1/12/2018 1

2. 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). 1/12/2018 2

3. 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 1/12/2018 3

4. Phyllosphere and Rhizosphere Interactions 1/12/2018 4

5. 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 1/12/2018 5

6. Kinds of Interactions 1. Competitive interaction 2. Non-competitive 3. Complementary Competitive interactions : One species may have greater ability to use factor and will gain at the expense of the other and the limiting this is called as competitive interaction or interference. In mixed crop communities, if the associated species are to share their growth from a limited pool of recourses such as light, water or nutrients, then it is non-competitive interaction or interference 1/12/2018 6

7. The concept of competition The struggle between the individuals within a population for available resources Competition function A ny f u n c t ion or f o r m u l a e t hat represents the manner in which the maximum crop yield is reduced by increasing competition. 1/12/2018 7

8. Competition functions Intra-Specific competition Competition occurs between the same species Inter-Specific competition occurs between the different species Parabolic function Asymptotic function 1/12/2018 8

9. Response of asymptotic and Parabolic curves 1/12/2018 9

10. Competitive relationship Competition for growth resources Mechanism of plant population stress Effect of plant population on crop Competition in intercropping and sequential cropping 1/12/2018 10

11. 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 1/12/2018 11

12. 2. Mechanisms of plant population stress Yi e ld p e r p la n t l i n ear l y c orre la te d with t h e available space I n c lose pl a nti n g l ea f su rfac e p e r p la n t a nd unit area is reduced Eff e ct of r a p i d g r ow t h of w e e ds on pl a nt population-injurious T he t h eo ry of i n j u r i o us s u bst a n ce s of the rhizosphere 1/12/2018 12

13. Intercropping v/s Monoculture 1/12/2018 13

14. 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 effect. Should not encourage the increased incidence of any particular pest, disease or weed. 1/12/2018 14

15. Interaction in Inter-Cropping Competition between the associated crops in mixed crop communities has been discussed by Donald (1963), Trenbath (1976) and Willey (1979). Competition for Solar Radiation: The taller crop in the intercropping systems intercepts most of the solar radiation while shorter component suffers. In Groundnut + Red gram intercropping system, light interception is prolonged as red gram starts growing after harvesting of groundnut. If the component crops have different growth durations the peak demand for light occurs at different times. In maize + green grams intercropping system, green gram flowers in 35 days after sowing and is harvested 65 days after sowing, peak light demand for maize occurs at 60 days after sowing when green gram is ready for harvest 1/12/2018 15

16. The inclination of leaves greatly influences the amount of light intercepted by the taller component and the amount that is available to shorter components. For example, one unit of LAI of prostrate-leaved perennial rye grass ( Trfolium ripens) absorbed 50% of the incoming light where as the some LAI of erect leaved perennial rye grass ( Lolium pereme ) absorbed only 26% ( Breugham , 1958). 1/12/2018 16

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18. Table1.Biological characters of maize in monocropping and intercropping 1/12/2018 18 Maize+ Soybean China Hanming et al, 2015

19. Light interception in a sorghum ( Sorghum bicolor ) based intercropping system was studied by Selvaraj (1978). Light was measured in flux units from 45th-90th day after sowing sorghum at 15 day interval. Light interception was expressed as percentages of light on the top of the canopy of each crop. The red gram/sorghum intercropping system makes better use of growth resources, particularly light, was brought out by Willey et al. (1981). Under intercropping situations, the component crops are grown in such a way that competition for light is minimized ( Okigbo , 1981); this can be achieved by proper choice of crops and genotypes, the shorter components being harvested sufficiently early so that the later harvested component is not greatly affected. 1/12/2018 19

20. Moisture and nutrients: Competition for moisture and nutrients may result in two types of effects on the less successful components. A) the roots to this component may grow less on the sides towards plants of aggressive component. B) plants affected by competition for soil factors may have increased root/shoot ratio. Among intercrops, sorghum and pearl millet are more competitive in extracting nutrients. Generally the intercrop stands remove greater amount of nutrients than sole crop stands. 1/12/2018 20

21. Interactions on Insect pest 1/12/2018 21

22. Table 1. Seed yield of main crop and intercrops in castor-based intercropping systems (kg ha-1) Tamil nadu Thanunathan et al ,2008 1/12/2018 22

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24. Advantages of multi-storied cropping system Better use of growth resources including sunlight, nutrient and water. Yield stability (suppress the growth of weeds). Ecological stability i.e. improved soil health and agro-ecosystem. Flow of income during cropping periods. Other miscellaneous benefits like distribution of labour, physical support of one crop to another and home gardening leading to more food supply. 1/12/2018 24

25. Considering market price (per kg) of bitter gourd = Rs. 10, ridge gourd = Rs. 6, bottle gourd = Rs. 5, Elephant foot yam = 15 Treatments Yield (q/ha) Main Crop Yield (q/ha) Companion Crop 2014-15 2015-16 Mean 2014-15 2015-16 Mean Sole Elephant Foot Yam (cv. Gajendra) 373.55 378.60 376.07 - - - - Elephant Foot Yam + Bitter gourd (cv. Hybrid US6214) 372.00 376.50 374.25 138.80 137.50 138.15 Elephant foot yam + Ridge gourd (cv. local) 362.00 362.65 362.32 147.30 147.97 147.64 Elephant foot yam + Bottle gourd (cv. Hybrid Mahima) 327.40 333.10 330.25 251.60 247.90 249.75 - Table 2 : Yield of elephant foot yam and companion crops under multi-layer vegetable cropping system

26. NET INCOME TOTAL EFY 554000 --164765 389235 EFY+BITTER GAURD 699000 --(164765+28000) 506235 EFY+RIDGE GAURD 631200 --(164765+28000) 438435 EFY+BOTTLE GAURD 619500 --(164765+28000) 426735

27. Mechanism of yield advantage in intercropping The most important index of biological advantage is the Relative yield total (RYT) : De wit and Land van Den Bergh (1965). Land equivalent ratio by Willey (1979). The mixture yield of a component crop expressed as a portion of its yields as a sole crop from the same replacement series is the relative yields of the crop and sum of relative yields of component crop is called Relative yield total ( RYT). The total land area required under sole cropping to give the same yields obtained in the intercropping is called Land equivalent ratio (LER). Both the expressions (RYT and LER) are similar. 1/12/2018 27

28. Land Equivalent Ratio (LER) This is the most frequently used efficient indicator. LER can be defined as the relative land area under sole crop that would be required to produce the equivalent yield under a mixed or an intercropping system at the same level of management. Where, La and Lb are LER of crop a and crop b, respectively; Yab = yield of crop an in intercropping, Yba = yield of crop b in intercropping, Yaa = yield of crop an in pure stand and Ybb = yield of crop b in pure stand. 1/12/2018 28

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30. Example: Let the yields of groundnut and red gram grown, as pure crops are 1,200 and 1,000 kg/ha, respectively. Let yields of these cops when grown, as intercrop be 1,000 and 600 kg/ha, respectively. The land equivalent ratio of groundnut + red gram intercropping system is LER of 1.43 indicates that a 43 percent yields advantage is obtained when grown as intercrop compared to growing as sole crops. In other words the sole crops have to be grown in 1.43 ha to get the same yields level that is obtained from 1.00 ha of intercropping. 1/12/2018 30

31. Relative Yields Total (RYT) The mixture yields of a component crop expressed as a portion of its yields as a sole crop from the same replacement series is the relative yield of crop and sum of the relative yields of component crop is called Relative Yields Total (RYT). Where , Yaa = yields of component a as sole crop Ybb = yields of component b is a sole crop Yab = yields of component a as intercrop in b Yba = Yield of component b as intercrop in a. 1/12/2018 31

32. Example: in pasture mixture, Stylo and anjan grown in 1:1 ratio with 50% sole crop population of both crops. In I/C, mixture yield (50%) for Stylo and anjan is 6 and 4 tons/ha of fodder, respectively. The yield of these crops in sole stand with 100% plant population is 10 and 8 tons/ ha of green fodder, respectively. RYT = 12+8/10+8 = 20/18 = 1.11. So RYT 1.11 indicates 11% extra fodder yields obtained by mixture. 1/12/2018 32

33. Relative Crowding Coefficient (K or RCC) It is proposed by de Wit (1960). It is used in replacement series of intercropping. It indicates whether a species or crop when grown in mixed population has produced more or less yield than expected in pure stand. In 50 : 50 mixture Relative crowding coefficient can be defined as But when population differ from 50: 50 then, 1/12/2018 33

34. Where, K = coefficient of each crop species Yaa = Yield of pure stand of a Ybb = Yield of pure stand of b Yab = Mixture yield of a in combination with b Yba = Mixture yield of b in combination with a Zab = Sown proportion of a in mixture with b Zba = Sown proportion of b in mixture with a Kab = Values indicate the following conclusions: K>1 = there is yield disadvantage K= 1 = there is no difference K< 1 = there is yield advantage in mixing 1/12/2018 34

35. Crowding coefficient and LER give the yield advantage but only LER give the magnitude of advantage. Therefore LER is preferred to assess the competition effects and yield advantage in intercropping situations. The two main indices of dominance are the aggressivity and competition index . Aggressivity is proposed by Mc Gihrist (1965). It gives a simple measure of how much the relative yield increase in species A is greater than that for species B. It is an index of dominance. An aggressivity value Zero indicates that the component species are equally competitive . A positive sign indicates the dominant species and a negative sign the dominated. 1/12/2018 35

36. competition index: It is proposed by Donald (1963). The basic process in the competition index is the calculation of two equivalence factors. one each component species. It is the product of two equivalent factors, one for each component species. It is a measure to find out the yield of various crops when grown together as well as separately. It indicates the yield per plant of different crops in mixture and their respective pure stand on an unit area basis. If the yield of any crop grown together is less than its respective yield in pure stand then it is harmful association but an increased yield means positive benefit. 1/12/2018 36

37. 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. 1/12/2018 37

38. 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 pulses 1/12/2018 38

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40. Annidation 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 1/12/2018 40

41. 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. E g . C o c on u t + P e p p er , S o r g h um + L a b l a b, Maize+ Climbing Beans. The taller component acts as wind barrier protecting the short crop. Eg . maize+ groundnut, onion + castor, turmeric + castor 1/12/2018 41

42. Overall Effects of Competition Three broad categories of competition can be recognized: Actual yield of each species is less than expected. This is called mutual inhibition . This is rare. 2. The yield of each species is greater than expected. This is called mutual co-operation . This cannot unusual. 3. One species yield is less and the other is more than expected. This can be termed compensation 1/12/2018 42

43. 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. E g . Ro ot s of cu c umb er, l e a ves o f E u c a ly p t us g l o b u le s , de c o m posin g r es i d u es o f sunflo wer are known to produce allelo chemicals, affecting the growth of other crops. Such crops must be avoided 1/12/2018 43

44. T y p es 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 allelopathy : Toxic substances may be converted into active substances by some micro- organisms 1/12/2018 44

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46. Allelochemical produced from the leaves of Eucalyptus globules drastically reduced the germination of mustard ( Brassica spp.) seed sown underneath ( Trenbath , 1976). Many plants exude organic substances from their roots and some of these roots exudates act as allelochemicals inhibiting the growth of the neighboring species. Living roots of walnut ( Juggles nigra ), cucumber ( Curcumas sativa ) and peach (Prunes persia ) are known to exude toxic substances which inhibit the growth of the plants growing near them. 1/12/2018 46

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