Productivity and economic viability of a palmarosa pigeonpea intercropping system in the subtropical climate of north India

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1 Journal of Agricultural Science, Cambridge (1998), 130, Cambridge University Press Printed in the United Kingdom 149 Productivity and economic viability of a palmarosa pigeonpea intercropping system in the subtropical climate of north India A. SINGH*, M. SINGH AND K. SINGH Central Institute of Medicinal and Aromatic Plants, PO CIMAP, Lucknow , India (Revised MS received 5 August 1997) SUMMARY The poor viability of the perennial aromatic grass, palmarosa (Cymbopogon martinii Stapf. var. motia), in the first of planting, restricts its popularity among farmers in India. Two pigeonpea cultivars, Bahar (late maturing), and UPAS 120 (early maturing) were intercropped at different row spacings with palmarosa at a row spacing of 60 cm, in the subtropical climate of Lucknow, north India in and Intercropping with the late maturing at 300 cm row spacing produced 1 26 t ha grain (2- mean) without affecting the growth and yield of the palmarosa. Intercropping improved land-use efficiency by 47%, relative net return by 58% and net economic return by Rs ha over a sole palmarosa crop. The grain, stalk and total dry matter yield per plant of pigeonpea was considerably improved when grown at the wider row spacing in the intercropped system than when grown as a sole crop. This indicates that the competition between pigeonpea plants was not reduced when palmarosa was present. Palmarosa tiller production and herb and oil yield were significantly reduced when the distance between rows of pigeonpea was narrowed, demonstrating both the greater susceptibility of palmarosa to lack of light, and also that in palmarosa pigeonpea intercropping systems, competition exists mainly for light rather than for nutrients and moisture, possibly because the two crop components acquire their nutrients and moisture from different soil layers. Intercropping with the high yielding, late maturing pigeonpea cultivar, Bahar, at 300 cm row distance is recommended to make palmarosa cultivation economically viable in the first of planting. The selection of high yielding, late maturing pigeonpea cultivars with an upright growth habit is suggested as a further way of improving the economic benefits of a palmarosa pigeonpea intercropping system. INTRODUCTION Palmarosa (Cymbopogon martinii Stapf. var. motia), is an important perennial aromatic grass, which is cultivated in India, Brazil, Paraguay, Madagascar, Guatemala and Indonesia for its essential oil, which is used world-wide in the soap, perfumery and cosmetic industries. India accounts for c. 70% of the total annual world production of palmarosa oil (Lawrence 1985) and is a major supplier to the world market. Because of its rose-like aroma, palmarosa oil and its isolate, geraniol, are much in demand in domestic as well as world markets. However, the production of palmarosa oil in India has remained constant at tonnes annually for several s. Its popularity among farmers in India is restricted by a poor * root cimap.sirnetd.ernet.in financial return from palmarosa in the planting ; this is mainly due to poor plant growth and yield, and the high cost of cultivation because the plants have to be raised in a nursery, resulting in increased land preparation, planting and weed control costs (Singh et al. 1995). In India, palmarosa is cultivated in a wide range of agroclimatic conditions, both as an irrigated and a non-irrigated crop. It grows to a height of m. In the first harvest (planting ) the plant produces only 60 70% of the tillers that it produces in subsequent harvest s, with a similar reduction in the herb and oil yields. Due to the limited plant growth made in the planting, the available growth resources such as light, space, moisture and nutrients are insufficiently well utilized. This offers an opportunity for palmarosa growers to cultivate another species as an intercrop to make palmarosa

2 150 A. SINGH, M. SINGH AND K. SINGH Table 1. Tiller production, herb and oil yields of palmarosa and grain and straw stalk yields of pigeonpea under sole and intercropping systems (2- mean) Palmarosa yield* Treatments Intercrop row spacing (cm) No. of tillers plant Planting Second harvest Fresh herb weight (t ha) Planting Second harvest Planting Oil yield (kg ha) Second harvest Pigeonpea yield (t ha) Grain Straw stalk Palmarosa sole Pigeonpea sole Pigeonpea sole Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea S.E D.F. (12) (12) (12) (12) (12) (12) (14) (14) * Planting and ; second harvest and growing economically viable in the first of plantation. However, information on intercropping with palmarosa in the sub-tropical climate of north India is scarce. In the tropical climate of south India (Bangalore), Prakash Rao et al. (1994) reported an increase in land-use efficiency by 15 and 24%, respectively, with one or two successive intercrops of blackgram (Vigna mungo L.). However, in the subtropical climate of north India, A. Singh, M. Singh & K. Singh (unpublished) did not find blackgram to be a suitable intercrop because of low grain production resulting from the high incidence of fungal diseases. High soil moisture and humidity in the sub-tropical climate of north India during the rainy season probably increases the incidence of fungal diseases. Disease virulence is further increased when blackgram is intercropped with tall-growing palmarosa. Pigeonpea is one of the most popular crop species for intercropping and is widely cultivated in mixtures with tall-growing crops such as millet, sorghum and maize, both in tropical and sub-tropical regions of India (Rao & Willey 1983). Our objective was to achieve a full yield of palmarosa and some additional yield of pigeonpea and to study the behaviour of the two crops when competing with each other. MATERIALS AND METHODS In two separate field experiments conducted at the research farm of the Central Institute of Medicinal and Aromatic Plants, Lucknow (26 5 N, 80 5 E, 120 m altitude), pigeonpea (Cajanus cajan) was intercropped with the perennial aromatic grass, palmarosa (Cymbopogon martinii Stapf. var. motia) during the planting s (first harvest, July June) in and The residual effects of intercropping in the first and second experiments were also studied in the second harvest s of and , respectively. The soil of the experimental plots (ph 7 8) was sandy loam in texture and had an organic C content of %, available N kg, available P kg and exchangeable K kg ha. The experiment consisted of nine treatments: sole palmarosa, sole pigeonpea and, intercropping of at 180, 240 and 300 cm inter-row spacing and at 120, 180 and 240 cm inter-row spacing. Pigeonpeas were grown between the lines of palmarosa, planted at a uniform row spacing of 60 cm and at a plant-to-plant distance of 30 cm within the rows. The experiment was

3 Palmarosa pigeonpea intercropping in subtropical India 151 conducted in a randomized block design with three replicates and individual plots measuring 9 4 m in each. Pigeonpea is a late maturing ( days), tall, highly branched and high yielding cultivar while is short duration ( days), medium tall, less branched and medium yielding. 40-day-old seedlings of palmarosa were planted in the first week of July in 1988 and Three days after planting the palmarosa, seeds of the pigeonpea cultivars were drilled in furrows between the rows of palmarosa at 2 g m row length. Pure crops of cvs Bahar and UPAS 120 were also sown on the same day at the same seed rate as that used for intercropping. The pure crop of was sown with 90 cm inter-row spacing while for UPAS 120, the distance between rows was 60 cm. Pigeonpea plants were thinned days after sowing to obtain a final population of 30 and 50 plants 10 m row length of cv. Bahar and, respectively. Sole as well as intercropped palmarosa received a uniform application of 150 kg N, 22 kg P and 42 kg K ha per. One third of the N and all the P and K were mixed into the soil before planting. The remaining N was top-dressed in two equal splits, after the first and second harvests. Both cultivars of pigeonpea under sole cropping received 25 kg N and 22 kg P ha in both experimental s. Palmarosa was harvested manually three times a in October, December and June in both the first (planting ) and second harvest s. Pigeonpea was harvested in the first week of April and UPAS 120 in the first week of December in both and Palmarosa tiller numbers per plant were recorded at each harvest and mean values were estimated. Fresh herb yield of palmarosa of each harvest was estimated and the values were added together to give the total herb yield for each. Oil yield was calculated by multiplying the herb yield by the oil content and a constant factor of 0 9, the specific gravity of palmarosa oil. Oil content (%) in fresh palmarosa was estimated by the hydro-distillation method, using Clavenger s apparatus (Longenau 1948). Since the yields of palmarosa and pigeonpea and the responses to intercropping were similar during both experimental s, mean values of the various characters are presented. To assess the advantages from intercropping, landequivalent ratio (LER) and relative net return (RNR) were calculated. Aggressivity (A) was used to measure the competitive ability of (a) palmarosa related to pigeonpea and (b) vice versa. The aggressivity of palmarosa related to pigeonpea and that of pigeonpea to palmarosa is denoted by Aab and Aba, respectively. Positive values indicate that the species is dominant and negative values indicate the subordinate species in the mixture. LER, RNR and A were estimated for planting only and the values given in Table 2 are the average of planting s and These were calculated as follows: LER Yia Yib Yma Ymb Aab Yia Yma Zia Yib Ymb Zib Aba Yib Ymb Zib Yia Yma Zia RNR [(Pa Yia Pb Yib) Dab](Pa Yma) where Yia and Yib are yields of crops a and b when intercropped and Yma and Ymb are the yields of the corresponding crops in monocultures; Zia and Zib are sown proportions of crop a and b; Pa and Pb are the prices of crops a and b; Dab is the differential cost of cultivation of crop combination ab, compared with the monocrop a. Net return of treatments was calculated taking into consideration the current prices of various inputs and produce. For calculating the return from intercrops, the cost of pigeonpea stalk was also added to the return of pigeonpea, as it is a valuable source of fuel in rural areas, and is also used for fencing fields and for making baskets. RESULTS AND DISCUSSION Tiller production, fresh herb weight and oil production of palmarosa and grain and straw stalk yield of pigeonpea in the two experiments in the planting were in good agreement with each other. Also, the residual effects of intercropping on the production of palmarosa in the second harvest in the two experiments were similar. Therefore, the statistical analysis of various growth and yield characters of palmarosa and pigeonpea (Table 1) was done on 2- mean basis. Palmarosa tiller production Tiller production per plant of palmarosa in the planting was severely reduced (P 0 01) by pigeonpea intercropping, except at the 240 cm row spacing with the early maturing cultivar UPAS 120. As the distance between the pigeonpea rows was reduced, the greater the reduction in tiller number. The maximum number of tillers plant (39) was recorded under sole palmarosa. At the narrow row spacing of pigeonpea cvs Bahar (180 cm) and UPAS 120 (120 cm), numbers of tillers were reduced to 25 5 and 23 8 per plant, respectively. The reduction in tiller production was presumably due to the shade created by tall-growing pigeonpea, especially during the

4 152 A. SINGH, M. SINGH AND K. SINGH Table 2. Land equivalent ratio (LER), aggressivity, relative net return (RNR) and net economic return of sole and intercropped palmarosa and pigeonpea (2- mean) Intercrop Agressivity row LER Net economic spacing Palmarosa Pigeonpea return Treatments (cm) Palmarosa Pigeonpea Total (Aab) (Aba) RNR (,000 Rs ha) Palmarosa sole Pigeonpea sole Pigeonpea sole Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea Palmarosa Pigeonpea Yield (g/plant) Row spacing (cm) Sole Intercropped () Sole Intercropped (cv. UPAS-120) Fig. 1. Grain ( ) and straw stalk ( ) yields of two pigeonpea cultivars under sole and intercropping systems in India. second harvest period, when the pigeonpea had attained its full growth. These results confirm the findings of Verma & Yadav (1988), who noted that tiller number in sugarcane was reduced by intercropping with wheat. Herb and oil yield of palmarosa Intercropping with the late maturing at 180 and 240 cm row spacing and the early maturing cv. UPAS 120 at 120 and 180 cm row spacing caused significant (P 0 01) reductions in palmarosa herb and oil yields over the sole crop. Reductions in herb and oil yield with ranged from 19 to 28% and with early maturing UPAS 120 from 11 to 24%. The late maturing at 300 cm and the early maturing at 240 cm row spacing produced a palmarosa yield equal to that of the sole crop. Upadhyay et al. (1990), working on different combinations of sorghum and pigeonpea, observed that a 100% population of sorghum plus 50% of pigeonpea was the most appropriate and any further increase in the pigeonpea population decreased the yield of both components. The yield of intercropped palmarosa at the wider row spacing of pigeonpea compared with sole palmarosa indicates that the available growth resources; light, moisture and nutrients, were sufficient to meet the combined demands of both crops and that under the intercropping system there had been a more efficient utilization of various resources than by sole palmarosa. Under intercropping, nutrients could have been a limiting factor but it seems that pigeonpea, being a deeper rooting crop, utilized nutrients and water from lower soil layers and did not compete for these resources with the shallow rooted palmarosa. Abbas et al. (1995) reached similar conclusions while working on maize pigeonpea intercropping. Significant reductions in palmarosa yield at closer row

5 Palmarosa pigeonpea intercropping in subtropical India 153 spacings with both cultivars of pigeonpea indicate that tall-growing pigeonpeas competed vigorously for light and that, in palmarosa pigeonpea intercropping, light is the major component of competition. The growth of melon was markedly reduced due to shading by intercropped maize but the reduction was less when the row spacing of maize was increased (Olasantan 1988). Of the two pigeonpea cultivars, Bahar was more competitive with palmarosa than was UPAS 120; for example at 180 cm row spacing, caused 17% more reduction in palmarosa yield than UPAS 120 did. The greater competitiveness of compared with UPAS 120 was due to more vegetative growth and later maturity (120 days more than UPAS 120). In a maize cocoyam (Xanthosoma sagittifolium) intercropping system, late maturing maize cultivars with spreading leaves caused a greater yield reduction in cocoyam than early maturing and erect-leaved maize cultivars (Ayuk- Takem & Chhedda 1985). Intercropping of pigeonpea during the first harvest did not affect palmarosa herb and oil yields during the second harvest. This shows that palmarosa plants are capable of recovering normal growth and development after setbacks in the early period of growth. Pigeonpea grain, stalk and total dry matter production Of the two pigeonpea cultivars, the late maturing Bahar outyielded early maturing UPAS 120 and produced three times as much grain when grown alone. On reduction of the plant population by 50, 62 5 and 70% in the intercropping system, the reductions in grain yield of were 20, 24 and 50%, respectively, compared with that of the sole crop. Similarly, with 50, 66 and 75% reductions in plant population in UPAS 120, the reductions in grain yields were 15, 44 and 55%, respectively, over the sole crop. Thus, the reductions in grain yield did not correspond directly with reductions in plant population. This showed that yield compensation occurred, with individual plants taking up more light and nutrients, becoming larger and yielding more than the plants of the dense sole crop. Pigeonpea intercropped with maize at 50% population of sole crop produced a grain yield equal to 84% of the sole crop (Abbas et al. 1995). Per plant grain, stalk and dry matter production of under intercropping was , and g plant against 67 5, and g plant in the sole crop, respectively. The grain, stalk and total dry matter production by the early maturing under intercropping was 18 19, and g plant against 10 7, 51 6 and 62 3 g plant as a sole crop, respectively (Fig. 1). These observations show that competition occurred strongly within pigeonpea plants but not between palmarosa and pigeonpea. Land equivalent ratio (LER) Increasing the row distance of pigeonpeas increased the LER of palmarosa and decreased that of pigeonpea (Table 2). Total LER as well as the LERs of pigeonpea cultivars were maximum when pigeonpea plants were intercropped at their closest row spacing. Increase in row distance caused a marginal decrease in total LER. Total LER across all row distances and pigeonpea cultivars ranged from 1 43 to Intercropping pigeonpea with sorghum (Upadhyay et al. 1990) and maize (Abbas et al. 1995) has been found to improve land-use efficiency by 44 49%. Aggressivity Aggressivity values of pigeonpea in relation to palmarosa (Aba) were always positive and that of palmarosa in relation to pigeonpea (Aab) always negative (Table 2). This shows that pigeonpea was a stronger competitor and that palmarosa remained the subordinate species in the mixture. Aggressivity of pigeonpea increased with decrease in the row spacing. Pigeonpea was more aggressive than UPAS 120. Abbas et al. (1995) also found pigeonpea to be the dominant component in maize pigeonpea intercropping systems, and this aggressivity increased with increases in the proportion of pigeonpea. Relative net return (RNR) and net economic return RNR and net economic return of palmarosa was greatly improved by intercropping with pigeonpea (Table 2). RNR values with late maturing pigeonpea at different row spacings ranged from 1 47 to 1 56, whereas with early maturing UPAS 120 it was The early maturing gave a considerably lower RNR and at the lowest row spacing (120 cm) the value was 1 00, which indicates a lower return than sole palmarosa. Lower RNR by the early maturing UPAS 120 was mainly due to its poor yield potential, compared to, while the effect of both cultivars on palmarosa was not very different, because during the period of greatest growth for (December March), palmarosa was dormant from December to February, and by March the pigeonpea had reached maturity and did not then compete for growth resources, especially light. Intercropping improved the net economic return of palmarosa considerably, compared to sole cropping. Intercropping pigeonpea at 300 cm row spacing gave an additional net return of Rs ha over sole palmarosa. Improvement in net economic return with the early maturing UPAS 120 was marginal.

6 154 A. SINGH, M. SINGH AND K. SINGH The results of the present investigation suggest that in the palmarosa pigeonpea intercropping system, under the sub-tropical climate of north India, the land-equivalent ratio (LER) is not a reliable measurement with which to judge the advantage of intercropping, particularly when there is a wide difference in the maturity periods and yield potentials of the pigeonpea cultivars. Intercropping the late maturing, high yielding pigeonpea at 300 cm row spacing is recommended in order to make palmarosa an economically viable crop in the first of planting. The selection of high yielding, late maturing pigeonpea cultivars with an upright growth habit is suggested to maximize the economic advantages from palmarosa pigeonpea intercropping. The authors are grateful to the Director, Central Institute of Medicinal and Aromatic Plants, Lucknow, for providing facilities. This paper is CIMAP Publication No J. ABBAS, M., TOMAR, S. S.&NIGAM, K. B. (1995). Maize (Zea mays) based cropping system with pulse under rainfed conditions. Indian Journal of Agricultural Sciences 65, AYUK-TAKEM, J. A.& CHHEDDA, H. R. (1985). Grain yield potential of some diverse maize (Zea mays L.) morphotypes intercropped with cocoyam (Xanthosoma sagittifolium). Experimental Agriculture 21, LAWRENCE, B. M. (1985). A review of the world production of essential oils (1984). Perfumer and Flavorist 10, LONGENAU, E. E. (1948). Determination of essential oil content of plant materials and oleoresins. In The Essential Oils, Vol I (Ed. E. Guenther), pp Princeton, NJ: Van Nostrand. OLASANTAN, F. O. (1988). The effects on soil temperature and moisture content and crop growth and yield of intercropping maize with melon (Colocynthis vulgaris). Experimental Agriculture 24, REFERENCES PRAKASH RAO, E. V. S., SINGH, M.& RAO GANESH, R. S. (1994). Performance of intercropping systems based on palmarosa (Cymbopogon martinii var. motia). Indian Journal of Agricultural Sciences 64, RAO, M. R.& WILLEY, R. W. (1983). Effects of genotype in cereal pigeonpea intercropping on the alfisols of the semiarid tropics of India. Experimental Agriculture 19, SINGH, APARBAL, SINGH, M. & SINGH, D. V. (1995). Continuous use of organic mulch (distillation waste) and herbicides in palmarosa. I. Weed competition, crop growth and yield. Indian Perfumer 39, UPADHYAY, M. S., SHARMA, R. A., YADAV, S., GUPTA,R.K. & BILLORES, S. (1990). Studies on population densities of component crops in sorghum pigeonpea intercropping. Indian Journal of Agronomy 35, VERMA, R. S. & YADAV, R. L. (1988). Minimizing yield losses of sugarcane when grown with a wheat companion crop by fertilizer and water management. Experimental Agriculture 24,