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Water requirement and productivity of palmarosa on sandy loam soil under a sub-tropical climate
Agricultuml watermanagement EI-SEVIER
Agricultural Water Management 35 (1997) 1- 10
Water requirement and productivity of palmarosa on sandy loam soil under a sub-tropical climate S. Singh *, M. Ram, D. Ram, S. Sharma, D.V. Singh Central Institute
ofMedicinal and Aromatic Plants, P.O. CIMAP, Lucknow-
015, India
Accepted 30 July 1997
Abstract
Water requirement, productivity and water use efficiency of a perennial aromatic grass, palmarosa (Cymbopogon martinii stapf cv motia), were studied under different levels of irrigation (0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3 and 1.5 1W:CPE ratio) for three years (July-June) during 1990 to 1993, on sandy loam soils under subtropical climate of Lucknow. Growth, herb and essential oil yield increased significantly up to 0.5 IW:CPE ratio. At 0.5 1W:CPE ratio palmarosa produced 47.3 tons of fresh herb and 227.3 kg of essential oil ha-’ yr- I. Further increase in irrigation levels caused an adverse effect on growth and yield of palmarosa. Irrigation levels did not affect the quality of oil in terms of its geraniol and geranyl acetate contents. Water requirement of palmarosa was worked out to be 89.1 cm. The highest water use efficiency of 2.97 kg oil ha-’ cm-’ was recorded at 0.1 1W:CPE ratio, at 0.5 IW:CPE ratio (optimum) it was 2.55 kg oil ha-’ cm-‘. Irrigation scheduled at 0.5 1W:CPE ratio gave the highest net return of Rs 51963 ha-’ yr-‘. 0 1997 Elsevier Science B.V. Keywords: Palmarosa; Cymbopogon martinii stapf cv motia; IW:CPE ratio; Herb and oil yield; Geraniol and geranyl acetate; Water requirement; Water use efficiency; Net profit
1. Introduction Palmarosa (Cymbopogon marfinii (L.) Stapf cv motia) is a multicut perennial aromatic grass. On hydrodistillation, leaves and flowering tops of palmarosa yields essential oil, rich in geraniol (70 to 90%), which finds extensive use in perfumery, flavouring and cosmetic industries the world over. India ranks first among the countries
* Corresponding author. 0378-3774/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO378-3774(97)00038-3
2
S. Singh et al. /Agricultural
Water Management 35 (1997) I-10
producing palmarosa oil (Singh et al., 1993) and is the major supplier to the world market. Palmarosa cultivation in India is spread over different agroclimatic zones and is cultivated as rainfed (Maheshwari et al., 1992) as well as irrigated crop. In subtropical climate of north India it is cultivated as irrigated crop (Ram and Singh, 1995). For irrigated palmarosa, about 10 irrigations are recommended for the cultivation in subtropical climate of North India (Virmani et al., 1992). However, these recommendations are based on the experiences gained over the years of cultivation. There is wide variation in the yield and quality of oil of palmarosa cultivated in different parts in subtropical climate. Variation in soil moisture during the period of growth and at harvest may be the possible reasons for a wide variation in yield and quality of essential oil of palmarosa in North India. The informations on the water requirement and optimum time of irrigation are scarce. Our objectives on present studies were to know the water requirement and water use efficiency, to assess the effect of levels of irrigation on oil biosynthesis and its quality and to develop optimum irrigation schedule.
2. Material and methods A field study was carried out at the experimental farm of Central Institute of Medicinal and Aromatic Plants, Lucknow (north India) (26.5”N, 88.5”E and 120 m altitude) for three years (July-June), 1990 to 1993. The treatments consisted of eight irrigation levels (0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3 and 1.5 1W:CPE ratio). IW refers to the depth of irrigation water for each irrigation which was 50 mm in the present investigation and was based on the moisture holding capacity of the experimental plot. CPE refers to the cumulative pan evaporation and it was computed as sum of the daily evaporation from standard U.S. weather bureau class- A open- pan installed nearby the plot. For 1W:CPE ratio 0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3 and 1.5, 50 mm irrigation was applied when the CPE reached to 500, 167, 100, 71, 55, 45, 38 and 33 mm, respectively. These were tested, in randomized block design with three replications and individual plot size 3.6 X 3.0 M. The depth of irrigation water was 50 mm. The experimental soil (pH 8.2) was sandy loam in texture (72.5% sand, 17.25% silt, and 10.25% clay) with bulk density of 1.48 g/cc. The moisture release curve for different depths (O-15, 15-30 and 30-45 cm) was developed using pressure plate/membrane apparatus and is presented in Fig. 1. The organic carbon, available N, P and exchangeable K in O-30 cm soil profile were 0.25%, 150 mg, 11 mg and 50 mg/kg, respectively. The mean monthly maximum and minimum temperatures, relative humidity, pan evaporation and the total rainfall received during the period of experimentation are presented in Fig. 2. The crop received a uniform dose of 120 kg N, 60 kg each of P205 and K,O ha-’ yr-‘. Full amount of P20, and K,O and l/3 of N was mixed in the soil before the planting in first year and before hoeing in the month of June in subsequent years of harvest. Rest of the N was top dressed in two equal splits after first and second harvests, each year.
S. Singh et al./Agricultural
Water Management
3
35 (1997) I-10
300 250 200 150 100 50 0
JUL AUG -
SEP
Min. Temp Total
OCT
( C)
Rainfall
(mm)
DEC
NO17
JAN FEB MAR
+
Max Temp
G+
Mean RH (X)
Y?+
( C)
Fig. 1. Moisture release curve of experimental
APR Total
MAY
JUN
Pan Eva
(mm)
plot.
MOISTURE CONTENT ('Z) 25
+
O-15
cm
+
1530
cm
#
15
.40
30-45
cm
20
15
10
5
0 .Ol
.02
.03
.04
.05
.06
ATMOSPHERIC
TENSION
Fig. 2. Weather parameters
.60
(MPa)
(average of 3 years).
1.00
1.50
1.80
4
S. Singh et al. /Agricultural
Water Management 35 f 1997) I-10
Thirty-day old seedlings of palmarosa were planted on 3 July 1990, in rows 60 cm apart, with plant to plant distance of 30 cm, using two seedlings per hill. The crop received three common irrigations in each year. In first harvest year, one irrigation was applied immediately after planting, and the remaining two after first and second harvest. While in second and third years, one irrigation was applied after each harvest. Common irrigations were applied to ensure proper establishment of seedlings after planting and regeneration of crop after each harvest. The remaining irrigations were applied as per treatments. The irrigation water was applied by receiving the water from the tubewell having uniform discharge of water. For measuring volume of water required for individual plot, Parshall flume was fixed before 20 m of the experimental plot and the discharge of water in the Parshall flume was measured. Water from Parshall flume was drained to the nearby plot for about 5-10 min before applying the water to each bed, for having constant head. The time required for irrigating each plot was worked out by taking in the consideration the volume of total water required for each plot and the discharge of water from the Parshall flume. The data on plant height and number of tillers per clump were recorded before each harvest. Three harvests were taken during the fourth week of October, February, and June each year. The crop was harvested at flowering stage 10 cm above the ground and fresh herb yield was recorded. The oil content in the fresh herb was estimated using clevanger’s apparatus. The oil yield (w/w> was calculated by multiplying the fresh herb yield with oil content and a constant factor of 0.90 (the approximate specific gravity of oil). The water requirement was calculated by adding the total water applied through irrigation and the effective rainfall, for each treatment. Thus the data on water requirement includes total water gift, received to the different level of irrigation at constant depth of irrigation. Neither losses of water through deep percolation etc. nor water gain from the deeper soil layers were considered in present study. For calculating effective rainfall, method given by Mishra and Ahmed (1987) was followed. Under this method each day values of open pan evaporation, amount of rainfall and maximum water holding capacity of root zone were taken into consideration. The actual soil moisture depletion from crop field was considered as 60% of open pan evaporation. Therefore the rainfall excess of 60% of the pan evaporation, between two rainy period assured to be ineffective. The water use efficiency (WUE) was calculated with the formulae given below. Essential oil yield (kg/ha) Water use efficiency
=
water applied
where: water applied = [( no. of irrigation
X depth at each irrigation,
5 cm)]
+ effective rainfall Two of the most important chemical constituents of palmarosa oil, geraniol and geranyl acetate, were determined using Perkin Elmer model 3920 GC equipped with 2 m X l/8 in. stainless steel column packed with 10% carbowax, 20 m on 100/120 mesh chromosorb, WAW TC detector and the flow rate of carrying gas H, was 30 ml/min, the column oven temperature was 130°C.
S. Singh et al./Agricultural
Water Management
35 (1997) I-IO
5
The net return of each treatment was worked out, taking into consideration the current prices of various inputs and the produce, palmarosa oil. Since response of treatments was similar in each harvest year, data of all the three years were pooled harvest-wise and year-wise, and analysed statistically using the method described by Panse and Sukhatme (1978).
3. Results and discussion 3.1. Crop growth Plant height and number of tiller/clump were significantly increased with increase in irrigation levels up to 0.5 IW:CPE ratio (Table 1). Further increase in irrigation levels did not bring any significant improvement in crop growth. The response of irrigation levels was more pronounced during winter and summer harvests. During rainy season harvest, though the number of tillers/clump varied significantly due to irrigation treatments, the height was not. Increase in irrigation levels beyond 0.5 1W:CPE ratio did not influence the plant height and tiller production rather irrigation levels beyond 1.3 IW:CPE ratio caused significant reduction in plant height and tiller number. The adverse effect of irrigations beyond 1.1 or 1.3 1W:CPE ratio on crop growth was possibly due to the aeration stress caused by the excessive water application and/or loss of nutrients through leaching. Palmarosa is a highly susceptible crop to water logging therefore its cultivation is recommended on well-drained soils (Virmani et al., 1992). Ram et al. (1988) reported that frequent irrigations in Japanese mint on light textured soil caused poor N recovery of applied N.
Table 1 Growth parameters Irrigation levels based on WCPE ratio 0.1
0.3 0.5 0.7 0.9 1.1 1.3 1.5 LSD tP = 0.5)
of palmarosa
as influenced
Plant height (cm)
by different
levels of irrigation
(pooled data of three years)
Number of tillers clump-’
Oil content (% v/w
Third harvest (summer season)
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
23.7a 23.8a 36.7d 35.7cd 34.7bcd 32.0bc 31.0b 25.7a 4.0
0.46 0.45 0.43 0.43 0.43 0.39 0.40 0.39 NS
0.65d 0.64d 0.57c 0.56bc 0.54abc OS2abc 0.50ab 0.48a 0.06
0.52~ 0.51c 0.46ab 0.45ab 0.43ab 0.43ab 0.41ab 0.40a 0.05
First harvest (rainy season)
Second harvest (winter season)
Third harvest summer season)
First harvest (rainy season)
217.6 210.6 207.3 207.3 213.3 210.6 206.3 212.0 NS
9.0a 77.6b 96.6d 96.6d 96.6d 95.4d 93.6d 86.3~ 4.9
90.7a 97.0b 104.0cd 106.0d 107.3d 106.0d 101.3bcd 97.7bc 6.3
29.3ab 4O.Oab 33.7cde 61.0d 71.3e 35.7e 34.7de 60.0d 3 1.3abcd 63.0d 34.0cde 52.7~ 32.7bcde 42.0b 30.3abc 39.7ab 3.8 4.0
Second harvest (winter season)
aMean values within a column followed by the same letter are not significantly NS, Non-significant; v/w, volume/weight.
different
basis)
on LSD (P = 0.05).
6
S. Singh et al./Agricultural
Water Management 35 (1997) l-10
Data on oil content in fresh herb of palmarosa, estimated at each harvest, indicated that the oil percentage, irrespective of treatment, was the maximum during winter season harvest, followed by summer and rainy seasons. Irrigation treatments could affect the oil content in fresh herb during winter and summer harvest only. During these seasons The highest oil contents in herb were recorded when the crop received irrigation at 0.1 or 0.3 1W:CPE ratio. Further increase in levels of irrigation caused significant decline in oil content. The oil content at 0.1 1W:CPE ratio during winter and summer season harvests were 0.65% and 0.52%, respectively. At the highest irrigation level (1.5 1W:CPE ratio) the oil content dropped to 0.48% in winter and 0.40% in summer season harvest. There are two important factors that determines the oil content in aromatic grasses (i) there is a negative correlation between the herb yield and oil content and (ii) aromatic plants under partial stress conditions accumulate the greater amount of essential oil than those growing under normal conditions. In the present experiment, the above phenomenon holds true. Sangwan et al. (1993) also reported increase in oil content in palmarosa herb, grown under partial moisture stress conditions. 3.2. Herb and essential oil yield The herb and oil yield of palmarosa were greatly influenced by the season of harvest (Table 2). The crop produced lowest herb and oil during winter season harvest. Low herb and oil yield in winter season harvest was due to the poor plant growth, specially the plant height owing to unfavourable environmental conditions, low temperature and relative humidity (Fig. 1). Irrigation levels could cause significant variation in herb and oil yield during winter and summer season and not in rainy season harvest. Due to
Table 2 Fresh herbage and essential oil yield of palmarosa, of three yeamY Irrigation level based on 1W:CPE ratio 0. I 0.3 0.5 0.7 0.9 1.1
1.3 1.5 LSD (P = 0.05)
Fresh herbage yield (t ha-
as influenced
’)
by different
levels of irrigation
(pooled data
Essential oil yield (kg ha- ‘I
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
16.4 17.1 18.0 18.1 17.6 17.5 18.1 17.4 NS
6.la 8.la 10.4c 9.7bc 9.6bc 9.5bc 9.7bc 9.0bc 1.6
11.5a 13.6a 19.7c 18.0bc 17.5bc 17.7bc 17.7bc 16.9b 2.4
34.2a 38.8b 47.3d 45.9d 45.5cd 44.7cd 45.4cd 42.2bc 3.5
15.4 76.9 77.4 71.8 75.1 68.2 12.4 67.9 NS
39.6a 50.7c 59.3d 54.3cd 5 1.8cd 49.4bc 48.5bc 43.2ab 8.5
59.8a 69.4ab 90.6~ 8 1 .Obc 75.2b 76.lb 72.6ab 67.6ab 14.3
174.8a 197.7bc 221.3d 213.lcd 202.7~ 193.7abc 193.5abc 178.7ab 20.6
“Mean values within a column followed NS, Non-significant.
by the same letter are not significantly
different on LSD (P = 0.05).
S. Singh et al. /Agricultural Table 3 Schedule of irrigation
for palmarosa
Water Management
Number of irrigations/month October
November
December
January
0.1 0.3 0.5 0.7 0.9 1.1
1 1 1 1 1 1 1 1
-
_
1 1 1 1
1 _ 1 1 1
1.5
7
during winter and summer seasons
Irrigation level based on lW:CPE ratio
1.3
35 (19971 I-10
February
March
-
-
1
11-l
_
1 1 1 1 2 2 2
1
2 3 3 5 5 5 7
1 1 1 1 1 2
3 3 3 4 5 5
April
May
June
July
Total
2 2 3 4 6 6 7
1 2 2 3 3 4 5
1 1 1 1 1 1 1
5 9 14 16 20 25 21 32
sufficient rainfall during rainy season, harvest irrigation levels could not be maintained and crop received almost equal amount of rain water in all irrigation levels maintained during preceding summer and winter seasons. These observations are inducting the facts that the palmarosa crop is capable of reviving the physiological and metabolic process after its exposer from moisture stress conditions to the optimum moisture conditions. Herb and oil yield increased with increasing levels of irrigation up to 0.5 IW:CPE ratio during both the winter and summer season harvests and tended to decline with further increase in IW:CPE ratio. Response of irrigation levels on total herb and oil yield was similar to these witnessed during in winter and summer season harvests. The total herb and oil yield at 0.5 IW:CPE ratio was respectively 38.30 and 30.0% higher over 0.1 1W:CPE ratio; the increase over 0.3 1W:CPE ratio was 21.90 and 14.97%, respectively. The decrease in herb and oil yield with increase in irrigation level beyond 0.5 IW:CPE ratio was due to decrease in the number of tillers/clump and plant height, the reason for which has already been explained. The results are in conformity with those reported by Pareek et al. (1991). Irrigation schedule given in Table 3 suggest that for optimum harvest of palmarosa the crop requires a total 14 irrigations (including common irrigation), mainly between March to June.
3.3. Quality of essential oil
Quality of oil as assessed by geraniol and geranyl acetate content, the major constituents of palmarosa oil, was unaffected due to irrigation levels irrespective of the season of harvest. However, the quality parameters were greatly influenced by the season of harvest. The geraniol content was highest (80.8 to 85.9%) in rainy season harvest followed by summer (78.3% to 81.4%) and winter (72.7 to 77.8%). The reverse was true for geranyl acetate content (Fig. 3). The hot and humid weather conditions prevailing during rainy season considered congenial for palmarosa seems to favour the biosynthesis of geraniol rather than the geranyl acetate.
8
S. Singh et al./Agricultural
Water Management 35 (1997) l-10
levels GERANIOL
100
CONTENT
,’ GERANYL
ACETATE
r
80
60
-
40
0 0
.l
.3 IRRIGATION
Fig. 3. Quality
of essential
3.4. Water requirement
.5 LEVEL
7
9
BASED
of palmarosa
1.1 ON IW CPE
as influenced
1.3
(1st
Har)
G acet.at&q
+
GeranlolS,
f3
C acetate%(Znd
Har)
Geramol%
Har)
++
20
GeramolZ
4
1st
Har)
(2nd
Ha)
(3rd
+
G acetateZ(3rd
4%
GeramolZ
+
G.acetate%(Average)
Har)
(Average)
1.5
RATIO
by different
levels of irrigation
(average
of 3 years).
and water use efjciency
During the rainy season, harvest water requirement of palmarosa did not differ due to irrigation levels as these could not be maintained on account of sufficient rainfall during the period of harvest. However, during winter and summer harvests, it increased with increase in the levels of irrigation (Table 3). Water use efficiency during rainy season harvest was the same irrespective of irrigation levels. It was due to the availability of sufficient and equal amount of water to each treatment (Tables 2 and 4). The irrigation levels 0.1 IW:CPE was found to be the best in terms of WUE during winter and summer harvest. WUE across the harvests was the maximum 2.97 kg oil/ha-cm of water at 0.1 1W:CPE ratio, followed by 2.70 kg oil/ha-cm at 0.5 1W:CPE ratio. 3.5. Economics Palmarosa gave the highest net return of Rs 51963 ha-’ yr-’ with irrigation scheduled at 0.5 1W:CPE ratio (Table 5). Increasing the levels of irrigation beyond 0.5 1W:CPE ratio resulted in a less net return. The profit of Rs 2.70 with per rupee investment from palmarosa cultivation was also highest at 0.5 1W:CPE ratio. It was due to the optimum crop growth coupled with relatively better water use efficiency. The
S. Singh et al./Agricultural Table 4 Water requirement and water use efficiency data of three years)
Water Management 35 (1997) I-IO
of palmarosa
as influenced
(cm)
9
by different levels of irrigation
(Pooled
Irrigation level based on IW:CPE ratio
Water requirement First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 LSD (P = 0.05)
25.8 25.8 25.5 24.4 23.5 25.0 24.9 24.9 -
11.0 16.0 19.0 22.6 27.6 32.6 36.0 43.0 -
22.2 31.2 44.6 68.9 82.2 97.2 110.5 130.5 _
58.9 73.0 89.1 115.9 133.3 154.8 171.4 198.4 _
2.92 2.98 3.04 3.18 3.22 2.73 2.90 2.73 NS
3.6Oe 3.16e 3.12e 2.40d 1.87~ 1S2bc 1.35ab 1.OOa 0.49
2.69e 2.22d 2.03d 1.17c 0.91bc 0.78ab 0.66ab 0.52a 0.34
2.97f 2.70e 2.55e 1.84d 1.52~ 1.25b 1.13b 0.90a 0.22
“Mean values within a column followed NS, Non-significant.
Table 5 Economics
of palmarosa
cultivation
Water use efficiency (kg oil ha- ’cm- ’ water)
by the same letter are not significantly
as influenced
by different levels of irrigation
different at LSD (P = 0.05).
(Pooled data of three years)
Irrigation level based on IWCPE ratio
Gross return (Rs ha-’ )
Net return (Rs ha- ‘1
Profit (Rs Re-
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5
69 920 76 680 90920 85 240 81080 77480 77400 71480
40 802 45 865 51963 49557 48 305 46 126 43 867 41936
2.60 2.60 2.70 2.60 2.60 2.40 2.40 2.20
’invested)
Price of palmarosa oil is taken at Rs 400 kg-‘. Price of water = 0.50 Re/M3. 1 US$ = 36.0 Rs.
reason for decline in output:input ratio at higher level of irrigation was on account of increased cost on irrigation with no improvement in oil yield beyond 0.5 IW:CPE ratio. 4. Conclusion It may be concluded from this study that for obtaining optimum yield potential of essential oil bearing palmarosa under subtropical climate of north India, crop should be irrigated at 0.5 IW:CPE, which necessitates application of 14 irrigations (each of 50-mm
IO
S. Singh et al. /Agricultural
Water Management
35 (1997) l-10
depth) during each harvest year. With this irrigation schedule a net return of Rs 51963 ha-’ yr-’ can be obtained. Future studies on economic feasibility of commercial cultivation of palmarosa under limited availability of irrigation water need to be undertaken.
Acknowledgements The authors are grateful to the Director, Central Institute of Medicinal and Aromatic Plants, Lucknow for providing facilities and Mr. A.A. Naqvi, senior scientist, CIMAP for gas chromatography of essential oil samples.
References Maheshwari, S.K., Chauhan, G.S., Trivedi, K.C., 1992. Response of palmarosa oil grass to irrigated and unirrigated sward and harvesting stage. Indian Perfumer 36 (11, 54-56. Mishra, R.D., Ahmed, M., 1987. Practical Manual of Irrigation, 1st edn. Oxford and IBH, New Delhi, 207 pp. Panse, V.G., Sukhatme, P.V., 1978. Statistical Method for Agricultural Workers, 2nd edn. ICAR, New Delhi, 359 pp. Pareek, S.K., Maheshwari, M.L., Gupta, R., 1991. Chemical weed control and water management in periwinkle, vetiver, and palmarosa oil grass. Recent Adv. Med. Aromatic and Spices Crops 1, 167-170. Ram, M., Chatterjee, B.N., Yadav, R.L., Singh, D.V., 1988. Minimizing volatilization and leaching losses of nitrogen by different nitrogen carriers in Japanese mint (Mentha arcensis L.) J. Agric. Sci. Camb. 110, 415-418. Ram, M., Singh, D.V., 1995. Intercrop potato with palmarosa. Indian Horti. 40 (2), 19. Sangwan, R.S., Farooqui, A.H.A., Bansal, R.P., Sangwan, N.S., 1993. Interspecific variation in physiological and metabolic responses of five species of cymbopogon to water stress. J. Plant Physiol. 142, 618-622. Singh, A., Singh, M., Singh, D.V., 1993. Effect of age of seedlings and nursery bed nutrient management on plant establishment, growth, herb and oil yield of palmarosa. Indian Perfumer 37 (2), 155-160. Virmani, O.P., Srivastava, G.N., Singh, D.V., 1992. Palmarosa and its cultivation in India, Farm Bulletin No. 7. Central Institute of Medicinal and Aromatic Plants, Lucknow, 14 pp.
Agricultural Water Management 35 (1997) 1- 10
Water requirement and productivity of palmarosa on sandy loam soil under a sub-tropical climate S. Singh *, M. Ram, D. Ram, S. Sharma, D.V. Singh Central Institute
ofMedicinal and Aromatic Plants, P.O. CIMAP, Lucknow-
015, India
Accepted 30 July 1997
Abstract
Water requirement, productivity and water use efficiency of a perennial aromatic grass, palmarosa (Cymbopogon martinii stapf cv motia), were studied under different levels of irrigation (0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3 and 1.5 1W:CPE ratio) for three years (July-June) during 1990 to 1993, on sandy loam soils under subtropical climate of Lucknow. Growth, herb and essential oil yield increased significantly up to 0.5 IW:CPE ratio. At 0.5 1W:CPE ratio palmarosa produced 47.3 tons of fresh herb and 227.3 kg of essential oil ha-’ yr- I. Further increase in irrigation levels caused an adverse effect on growth and yield of palmarosa. Irrigation levels did not affect the quality of oil in terms of its geraniol and geranyl acetate contents. Water requirement of palmarosa was worked out to be 89.1 cm. The highest water use efficiency of 2.97 kg oil ha-’ cm-’ was recorded at 0.1 1W:CPE ratio, at 0.5 IW:CPE ratio (optimum) it was 2.55 kg oil ha-’ cm-‘. Irrigation scheduled at 0.5 1W:CPE ratio gave the highest net return of Rs 51963 ha-’ yr-‘. 0 1997 Elsevier Science B.V. Keywords: Palmarosa; Cymbopogon martinii stapf cv motia; IW:CPE ratio; Herb and oil yield; Geraniol and geranyl acetate; Water requirement; Water use efficiency; Net profit
1. Introduction Palmarosa (Cymbopogon marfinii (L.) Stapf cv motia) is a multicut perennial aromatic grass. On hydrodistillation, leaves and flowering tops of palmarosa yields essential oil, rich in geraniol (70 to 90%), which finds extensive use in perfumery, flavouring and cosmetic industries the world over. India ranks first among the countries
* Corresponding author. 0378-3774/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO378-3774(97)00038-3
2
S. Singh et al. /Agricultural
Water Management 35 (1997) I-10
producing palmarosa oil (Singh et al., 1993) and is the major supplier to the world market. Palmarosa cultivation in India is spread over different agroclimatic zones and is cultivated as rainfed (Maheshwari et al., 1992) as well as irrigated crop. In subtropical climate of north India it is cultivated as irrigated crop (Ram and Singh, 1995). For irrigated palmarosa, about 10 irrigations are recommended for the cultivation in subtropical climate of North India (Virmani et al., 1992). However, these recommendations are based on the experiences gained over the years of cultivation. There is wide variation in the yield and quality of oil of palmarosa cultivated in different parts in subtropical climate. Variation in soil moisture during the period of growth and at harvest may be the possible reasons for a wide variation in yield and quality of essential oil of palmarosa in North India. The informations on the water requirement and optimum time of irrigation are scarce. Our objectives on present studies were to know the water requirement and water use efficiency, to assess the effect of levels of irrigation on oil biosynthesis and its quality and to develop optimum irrigation schedule.
2. Material and methods A field study was carried out at the experimental farm of Central Institute of Medicinal and Aromatic Plants, Lucknow (north India) (26.5”N, 88.5”E and 120 m altitude) for three years (July-June), 1990 to 1993. The treatments consisted of eight irrigation levels (0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3 and 1.5 1W:CPE ratio). IW refers to the depth of irrigation water for each irrigation which was 50 mm in the present investigation and was based on the moisture holding capacity of the experimental plot. CPE refers to the cumulative pan evaporation and it was computed as sum of the daily evaporation from standard U.S. weather bureau class- A open- pan installed nearby the plot. For 1W:CPE ratio 0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3 and 1.5, 50 mm irrigation was applied when the CPE reached to 500, 167, 100, 71, 55, 45, 38 and 33 mm, respectively. These were tested, in randomized block design with three replications and individual plot size 3.6 X 3.0 M. The depth of irrigation water was 50 mm. The experimental soil (pH 8.2) was sandy loam in texture (72.5% sand, 17.25% silt, and 10.25% clay) with bulk density of 1.48 g/cc. The moisture release curve for different depths (O-15, 15-30 and 30-45 cm) was developed using pressure plate/membrane apparatus and is presented in Fig. 1. The organic carbon, available N, P and exchangeable K in O-30 cm soil profile were 0.25%, 150 mg, 11 mg and 50 mg/kg, respectively. The mean monthly maximum and minimum temperatures, relative humidity, pan evaporation and the total rainfall received during the period of experimentation are presented in Fig. 2. The crop received a uniform dose of 120 kg N, 60 kg each of P205 and K,O ha-’ yr-‘. Full amount of P20, and K,O and l/3 of N was mixed in the soil before the planting in first year and before hoeing in the month of June in subsequent years of harvest. Rest of the N was top dressed in two equal splits after first and second harvests, each year.
S. Singh et al./Agricultural
Water Management
3
35 (1997) I-10
300 250 200 150 100 50 0
JUL AUG -
SEP
Min. Temp Total
OCT
( C)
Rainfall
(mm)
DEC
NO17
JAN FEB MAR
+
Max Temp
G+
Mean RH (X)
Y?+
( C)
Fig. 1. Moisture release curve of experimental
APR Total
MAY
JUN
Pan Eva
(mm)
plot.
MOISTURE CONTENT ('Z) 25
+
O-15
cm
+
1530
cm
#
15
.40
30-45
cm
20
15
10
5
0 .Ol
.02
.03
.04
.05
.06
ATMOSPHERIC
TENSION
Fig. 2. Weather parameters
.60
(MPa)
(average of 3 years).
1.00
1.50
1.80
4
S. Singh et al. /Agricultural
Water Management 35 f 1997) I-10
Thirty-day old seedlings of palmarosa were planted on 3 July 1990, in rows 60 cm apart, with plant to plant distance of 30 cm, using two seedlings per hill. The crop received three common irrigations in each year. In first harvest year, one irrigation was applied immediately after planting, and the remaining two after first and second harvest. While in second and third years, one irrigation was applied after each harvest. Common irrigations were applied to ensure proper establishment of seedlings after planting and regeneration of crop after each harvest. The remaining irrigations were applied as per treatments. The irrigation water was applied by receiving the water from the tubewell having uniform discharge of water. For measuring volume of water required for individual plot, Parshall flume was fixed before 20 m of the experimental plot and the discharge of water in the Parshall flume was measured. Water from Parshall flume was drained to the nearby plot for about 5-10 min before applying the water to each bed, for having constant head. The time required for irrigating each plot was worked out by taking in the consideration the volume of total water required for each plot and the discharge of water from the Parshall flume. The data on plant height and number of tillers per clump were recorded before each harvest. Three harvests were taken during the fourth week of October, February, and June each year. The crop was harvested at flowering stage 10 cm above the ground and fresh herb yield was recorded. The oil content in the fresh herb was estimated using clevanger’s apparatus. The oil yield (w/w> was calculated by multiplying the fresh herb yield with oil content and a constant factor of 0.90 (the approximate specific gravity of oil). The water requirement was calculated by adding the total water applied through irrigation and the effective rainfall, for each treatment. Thus the data on water requirement includes total water gift, received to the different level of irrigation at constant depth of irrigation. Neither losses of water through deep percolation etc. nor water gain from the deeper soil layers were considered in present study. For calculating effective rainfall, method given by Mishra and Ahmed (1987) was followed. Under this method each day values of open pan evaporation, amount of rainfall and maximum water holding capacity of root zone were taken into consideration. The actual soil moisture depletion from crop field was considered as 60% of open pan evaporation. Therefore the rainfall excess of 60% of the pan evaporation, between two rainy period assured to be ineffective. The water use efficiency (WUE) was calculated with the formulae given below. Essential oil yield (kg/ha) Water use efficiency
=
water applied
where: water applied = [( no. of irrigation
X depth at each irrigation,
5 cm)]
+ effective rainfall Two of the most important chemical constituents of palmarosa oil, geraniol and geranyl acetate, were determined using Perkin Elmer model 3920 GC equipped with 2 m X l/8 in. stainless steel column packed with 10% carbowax, 20 m on 100/120 mesh chromosorb, WAW TC detector and the flow rate of carrying gas H, was 30 ml/min, the column oven temperature was 130°C.
S. Singh et al./Agricultural
Water Management
35 (1997) I-IO
5
The net return of each treatment was worked out, taking into consideration the current prices of various inputs and the produce, palmarosa oil. Since response of treatments was similar in each harvest year, data of all the three years were pooled harvest-wise and year-wise, and analysed statistically using the method described by Panse and Sukhatme (1978).
3. Results and discussion 3.1. Crop growth Plant height and number of tiller/clump were significantly increased with increase in irrigation levels up to 0.5 IW:CPE ratio (Table 1). Further increase in irrigation levels did not bring any significant improvement in crop growth. The response of irrigation levels was more pronounced during winter and summer harvests. During rainy season harvest, though the number of tillers/clump varied significantly due to irrigation treatments, the height was not. Increase in irrigation levels beyond 0.5 1W:CPE ratio did not influence the plant height and tiller production rather irrigation levels beyond 1.3 IW:CPE ratio caused significant reduction in plant height and tiller number. The adverse effect of irrigations beyond 1.1 or 1.3 1W:CPE ratio on crop growth was possibly due to the aeration stress caused by the excessive water application and/or loss of nutrients through leaching. Palmarosa is a highly susceptible crop to water logging therefore its cultivation is recommended on well-drained soils (Virmani et al., 1992). Ram et al. (1988) reported that frequent irrigations in Japanese mint on light textured soil caused poor N recovery of applied N.
Table 1 Growth parameters Irrigation levels based on WCPE ratio 0.1
0.3 0.5 0.7 0.9 1.1 1.3 1.5 LSD tP = 0.5)
of palmarosa
as influenced
Plant height (cm)
by different
levels of irrigation
(pooled data of three years)
Number of tillers clump-’
Oil content (% v/w
Third harvest (summer season)
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
23.7a 23.8a 36.7d 35.7cd 34.7bcd 32.0bc 31.0b 25.7a 4.0
0.46 0.45 0.43 0.43 0.43 0.39 0.40 0.39 NS
0.65d 0.64d 0.57c 0.56bc 0.54abc OS2abc 0.50ab 0.48a 0.06
0.52~ 0.51c 0.46ab 0.45ab 0.43ab 0.43ab 0.41ab 0.40a 0.05
First harvest (rainy season)
Second harvest (winter season)
Third harvest summer season)
First harvest (rainy season)
217.6 210.6 207.3 207.3 213.3 210.6 206.3 212.0 NS
9.0a 77.6b 96.6d 96.6d 96.6d 95.4d 93.6d 86.3~ 4.9
90.7a 97.0b 104.0cd 106.0d 107.3d 106.0d 101.3bcd 97.7bc 6.3
29.3ab 4O.Oab 33.7cde 61.0d 71.3e 35.7e 34.7de 60.0d 3 1.3abcd 63.0d 34.0cde 52.7~ 32.7bcde 42.0b 30.3abc 39.7ab 3.8 4.0
Second harvest (winter season)
aMean values within a column followed by the same letter are not significantly NS, Non-significant; v/w, volume/weight.
different
basis)
on LSD (P = 0.05).
6
S. Singh et al./Agricultural
Water Management 35 (1997) l-10
Data on oil content in fresh herb of palmarosa, estimated at each harvest, indicated that the oil percentage, irrespective of treatment, was the maximum during winter season harvest, followed by summer and rainy seasons. Irrigation treatments could affect the oil content in fresh herb during winter and summer harvest only. During these seasons The highest oil contents in herb were recorded when the crop received irrigation at 0.1 or 0.3 1W:CPE ratio. Further increase in levels of irrigation caused significant decline in oil content. The oil content at 0.1 1W:CPE ratio during winter and summer season harvests were 0.65% and 0.52%, respectively. At the highest irrigation level (1.5 1W:CPE ratio) the oil content dropped to 0.48% in winter and 0.40% in summer season harvest. There are two important factors that determines the oil content in aromatic grasses (i) there is a negative correlation between the herb yield and oil content and (ii) aromatic plants under partial stress conditions accumulate the greater amount of essential oil than those growing under normal conditions. In the present experiment, the above phenomenon holds true. Sangwan et al. (1993) also reported increase in oil content in palmarosa herb, grown under partial moisture stress conditions. 3.2. Herb and essential oil yield The herb and oil yield of palmarosa were greatly influenced by the season of harvest (Table 2). The crop produced lowest herb and oil during winter season harvest. Low herb and oil yield in winter season harvest was due to the poor plant growth, specially the plant height owing to unfavourable environmental conditions, low temperature and relative humidity (Fig. 1). Irrigation levels could cause significant variation in herb and oil yield during winter and summer season and not in rainy season harvest. Due to
Table 2 Fresh herbage and essential oil yield of palmarosa, of three yeamY Irrigation level based on 1W:CPE ratio 0. I 0.3 0.5 0.7 0.9 1.1
1.3 1.5 LSD (P = 0.05)
Fresh herbage yield (t ha-
as influenced
’)
by different
levels of irrigation
(pooled data
Essential oil yield (kg ha- ‘I
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
16.4 17.1 18.0 18.1 17.6 17.5 18.1 17.4 NS
6.la 8.la 10.4c 9.7bc 9.6bc 9.5bc 9.7bc 9.0bc 1.6
11.5a 13.6a 19.7c 18.0bc 17.5bc 17.7bc 17.7bc 16.9b 2.4
34.2a 38.8b 47.3d 45.9d 45.5cd 44.7cd 45.4cd 42.2bc 3.5
15.4 76.9 77.4 71.8 75.1 68.2 12.4 67.9 NS
39.6a 50.7c 59.3d 54.3cd 5 1.8cd 49.4bc 48.5bc 43.2ab 8.5
59.8a 69.4ab 90.6~ 8 1 .Obc 75.2b 76.lb 72.6ab 67.6ab 14.3
174.8a 197.7bc 221.3d 213.lcd 202.7~ 193.7abc 193.5abc 178.7ab 20.6
“Mean values within a column followed NS, Non-significant.
by the same letter are not significantly
different on LSD (P = 0.05).
S. Singh et al. /Agricultural Table 3 Schedule of irrigation
for palmarosa
Water Management
Number of irrigations/month October
November
December
January
0.1 0.3 0.5 0.7 0.9 1.1
1 1 1 1 1 1 1 1
-
_
1 1 1 1
1 _ 1 1 1
1.5
7
during winter and summer seasons
Irrigation level based on lW:CPE ratio
1.3
35 (19971 I-10
February
March
-
-
1
11-l
_
1 1 1 1 2 2 2
1
2 3 3 5 5 5 7
1 1 1 1 1 2
3 3 3 4 5 5
April
May
June
July
Total
2 2 3 4 6 6 7
1 2 2 3 3 4 5
1 1 1 1 1 1 1
5 9 14 16 20 25 21 32
sufficient rainfall during rainy season, harvest irrigation levels could not be maintained and crop received almost equal amount of rain water in all irrigation levels maintained during preceding summer and winter seasons. These observations are inducting the facts that the palmarosa crop is capable of reviving the physiological and metabolic process after its exposer from moisture stress conditions to the optimum moisture conditions. Herb and oil yield increased with increasing levels of irrigation up to 0.5 IW:CPE ratio during both the winter and summer season harvests and tended to decline with further increase in IW:CPE ratio. Response of irrigation levels on total herb and oil yield was similar to these witnessed during in winter and summer season harvests. The total herb and oil yield at 0.5 IW:CPE ratio was respectively 38.30 and 30.0% higher over 0.1 1W:CPE ratio; the increase over 0.3 1W:CPE ratio was 21.90 and 14.97%, respectively. The decrease in herb and oil yield with increase in irrigation level beyond 0.5 IW:CPE ratio was due to decrease in the number of tillers/clump and plant height, the reason for which has already been explained. The results are in conformity with those reported by Pareek et al. (1991). Irrigation schedule given in Table 3 suggest that for optimum harvest of palmarosa the crop requires a total 14 irrigations (including common irrigation), mainly between March to June.
3.3. Quality of essential oil
Quality of oil as assessed by geraniol and geranyl acetate content, the major constituents of palmarosa oil, was unaffected due to irrigation levels irrespective of the season of harvest. However, the quality parameters were greatly influenced by the season of harvest. The geraniol content was highest (80.8 to 85.9%) in rainy season harvest followed by summer (78.3% to 81.4%) and winter (72.7 to 77.8%). The reverse was true for geranyl acetate content (Fig. 3). The hot and humid weather conditions prevailing during rainy season considered congenial for palmarosa seems to favour the biosynthesis of geraniol rather than the geranyl acetate.
8
S. Singh et al./Agricultural
Water Management 35 (1997) l-10
levels GERANIOL
100
CONTENT
,’ GERANYL
ACETATE
r
80
60
-
40
0 0
.l
.3 IRRIGATION
Fig. 3. Quality
of essential
3.4. Water requirement
.5 LEVEL
7
9
BASED
of palmarosa
1.1 ON IW CPE
as influenced
1.3
(1st
Har)
G acet.at&q
+
GeranlolS,
f3
C acetate%(Znd
Har)
Geramol%
Har)
++
20
GeramolZ
4
1st
Har)
(2nd
Ha)
(3rd
+
G acetateZ(3rd
4%
GeramolZ
+
G.acetate%(Average)
Har)
(Average)
1.5
RATIO
by different
levels of irrigation
(average
of 3 years).
and water use efjciency
During the rainy season, harvest water requirement of palmarosa did not differ due to irrigation levels as these could not be maintained on account of sufficient rainfall during the period of harvest. However, during winter and summer harvests, it increased with increase in the levels of irrigation (Table 3). Water use efficiency during rainy season harvest was the same irrespective of irrigation levels. It was due to the availability of sufficient and equal amount of water to each treatment (Tables 2 and 4). The irrigation levels 0.1 IW:CPE was found to be the best in terms of WUE during winter and summer harvest. WUE across the harvests was the maximum 2.97 kg oil/ha-cm of water at 0.1 1W:CPE ratio, followed by 2.70 kg oil/ha-cm at 0.5 1W:CPE ratio. 3.5. Economics Palmarosa gave the highest net return of Rs 51963 ha-’ yr-’ with irrigation scheduled at 0.5 1W:CPE ratio (Table 5). Increasing the levels of irrigation beyond 0.5 1W:CPE ratio resulted in a less net return. The profit of Rs 2.70 with per rupee investment from palmarosa cultivation was also highest at 0.5 1W:CPE ratio. It was due to the optimum crop growth coupled with relatively better water use efficiency. The
S. Singh et al./Agricultural Table 4 Water requirement and water use efficiency data of three years)
Water Management 35 (1997) I-IO
of palmarosa
as influenced
(cm)
9
by different levels of irrigation
(Pooled
Irrigation level based on IW:CPE ratio
Water requirement First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
First harvest (rainy season)
Second harvest (winter season)
Third harvest (summer season)
Total
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 LSD (P = 0.05)
25.8 25.8 25.5 24.4 23.5 25.0 24.9 24.9 -
11.0 16.0 19.0 22.6 27.6 32.6 36.0 43.0 -
22.2 31.2 44.6 68.9 82.2 97.2 110.5 130.5 _
58.9 73.0 89.1 115.9 133.3 154.8 171.4 198.4 _
2.92 2.98 3.04 3.18 3.22 2.73 2.90 2.73 NS
3.6Oe 3.16e 3.12e 2.40d 1.87~ 1S2bc 1.35ab 1.OOa 0.49
2.69e 2.22d 2.03d 1.17c 0.91bc 0.78ab 0.66ab 0.52a 0.34
2.97f 2.70e 2.55e 1.84d 1.52~ 1.25b 1.13b 0.90a 0.22
“Mean values within a column followed NS, Non-significant.
Table 5 Economics
of palmarosa
cultivation
Water use efficiency (kg oil ha- ’cm- ’ water)
by the same letter are not significantly
as influenced
by different levels of irrigation
different at LSD (P = 0.05).
(Pooled data of three years)
Irrigation level based on IWCPE ratio
Gross return (Rs ha-’ )
Net return (Rs ha- ‘1
Profit (Rs Re-
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5
69 920 76 680 90920 85 240 81080 77480 77400 71480
40 802 45 865 51963 49557 48 305 46 126 43 867 41936
2.60 2.60 2.70 2.60 2.60 2.40 2.40 2.20
’invested)
Price of palmarosa oil is taken at Rs 400 kg-‘. Price of water = 0.50 Re/M3. 1 US$ = 36.0 Rs.
reason for decline in output:input ratio at higher level of irrigation was on account of increased cost on irrigation with no improvement in oil yield beyond 0.5 IW:CPE ratio. 4. Conclusion It may be concluded from this study that for obtaining optimum yield potential of essential oil bearing palmarosa under subtropical climate of north India, crop should be irrigated at 0.5 IW:CPE, which necessitates application of 14 irrigations (each of 50-mm
IO
S. Singh et al. /Agricultural
Water Management
35 (1997) l-10
depth) during each harvest year. With this irrigation schedule a net return of Rs 51963 ha-’ yr-’ can be obtained. Future studies on economic feasibility of commercial cultivation of palmarosa under limited availability of irrigation water need to be undertaken.
Acknowledgements The authors are grateful to the Director, Central Institute of Medicinal and Aromatic Plants, Lucknow for providing facilities and Mr. A.A. Naqvi, senior scientist, CIMAP for gas chromatography of essential oil samples.
References Maheshwari, S.K., Chauhan, G.S., Trivedi, K.C., 1992. Response of palmarosa oil grass to irrigated and unirrigated sward and harvesting stage. Indian Perfumer 36 (11, 54-56. Mishra, R.D., Ahmed, M., 1987. Practical Manual of Irrigation, 1st edn. Oxford and IBH, New Delhi, 207 pp. Panse, V.G., Sukhatme, P.V., 1978. Statistical Method for Agricultural Workers, 2nd edn. ICAR, New Delhi, 359 pp. Pareek, S.K., Maheshwari, M.L., Gupta, R., 1991. Chemical weed control and water management in periwinkle, vetiver, and palmarosa oil grass. Recent Adv. Med. Aromatic and Spices Crops 1, 167-170. Ram, M., Chatterjee, B.N., Yadav, R.L., Singh, D.V., 1988. Minimizing volatilization and leaching losses of nitrogen by different nitrogen carriers in Japanese mint (Mentha arcensis L.) J. Agric. Sci. Camb. 110, 415-418. Ram, M., Singh, D.V., 1995. Intercrop potato with palmarosa. Indian Horti. 40 (2), 19. Sangwan, R.S., Farooqui, A.H.A., Bansal, R.P., Sangwan, N.S., 1993. Interspecific variation in physiological and metabolic responses of five species of cymbopogon to water stress. J. Plant Physiol. 142, 618-622. Singh, A., Singh, M., Singh, D.V., 1993. Effect of age of seedlings and nursery bed nutrient management on plant establishment, growth, herb and oil yield of palmarosa. Indian Perfumer 37 (2), 155-160. Virmani, O.P., Srivastava, G.N., Singh, D.V., 1992. Palmarosa and its cultivation in India, Farm Bulletin No. 7. Central Institute of Medicinal and Aromatic Plants, Lucknow, 14 pp.