Subscribe Now Subscribe Today
Research Article
 

Volatiles of Artemisia annua L. as Influenced by Soil Application of Organic Residues



A.A. Malik, J. Ahmad, S. Suryapani, M.Z. Abdin, S.R. Mir and Mohammed Ali
 
Facebook Twitter Digg Reddit Linkedin StumbleUpon E-mail
ABSTRACT

India with its copiousness of exuberant flora is one of the richest countries as regards the genetic resources of medicinal plants and occupies unquestionably a premier position in the use of herbal drugs but in this era of high-tech wizardry, urbanization and industrialization has created needless disturbance in the vulnerably delicate ecosystems due to the accretion of large quantities of municipal wastes and industrial residues. On the other hand, continued applications of chemical fertilizers resulted in the contamination of surface and ground waters and have adversely affected the biological, physical and chemical properties of soil. It was therefore, suggested to find and evaluate methods which can help solve serious environmental and plant nutritional problems. An experiment was conducted in this regard at the research field of Jamia Hamdard, New Delhi, India to assess the impact of sewage sludge biosolid, composted sugarcane pressmud and farmyard manure on volatile oil content and composition of Artemisia annua Linn., an important aromatic-antibacterial herb. The oil is quite useful pharmaceutically and is used in perfumery, cosmetics, aromatherapy and dermatology as an antimicrobial agent having fungicidal properties. We undertook the present study with a view to maintain the ecosystems of the soil and mitigate environmental pollution. The principal findings revealed significant variations in the oil content and percentage occurrence of different constituents therefore, paving the way for enhanced production of volatiles in this industrial crop as well as emerging as an alternative control measure for mitigation of environmental pollution.

Services
Related Articles in ASCI
Search in Google Scholar
View Citation
Report Citation

 
  How to cite this article:

A.A. Malik, J. Ahmad, S. Suryapani, M.Z. Abdin, S.R. Mir and Mohammed Ali, 2012. Volatiles of Artemisia annua L. as Influenced by Soil Application of Organic Residues. Research Journal of Medicinal Plants, 6: 433-440.

DOI: 10.3923/rjmp.2012.433.440

URL: https://scialert.net/abstract/?doi=rjmp.2012.433.440
 
Received: October 30, 2011; Accepted: January 02, 2012; Published: March 15, 2012



INTRODUCTION

Due to rapid urban development and industrial boom, large quantities of municipal wastes and unexploited organic by-products or residues from various industries are produced. To avoid environmental and economic costs of disposal and taking up space in landfills, their use in the agricultural sector has been suggested. On the other hand, unbalanced application of chemical fertilizers coupled with inadequate land management practices posed a serious threat to soil heath in terms of decline in soil organic matter (Saha et al., 2007; Qazi et al., 2009). Due to rapid increase in the prices of chemical fertilizers and also with a view to maintain the ecosystem of soils, it has become, necessary to minimize the use of chemical fertilizers (Kumar et al., 2009). Addition of soil organic matter with different origins to the soil is one of the most common rehabilitation practices to improve soil properties (Darwish et al., 1995; Mbah et al., 2007).

An alternative source of organic matter is Sewage Sludge Biosolid (SSB). SSBs are the stabilized organic residues from domestic and industrial wastewater treatment (Bright and Healey, 2003). They consist of multi element organic wastes that are used commonly as manures (Otobbang et al., 1997). SSB can substitute for commercial fertilizers and organic matter if applied in the right amounts to soil (Yamur et al., 2005). SSBs are rich in N, P, macro-and micro-nutrients and organic matter, thus making them suitable for land applications where it is expected to increase the soil organic content and improve soil properties like soil stability, porosity and water filtration rates (Asagi et al., 2007; Hussein, 2009) and promote recycling of nutrients (Gilani and Bahmanyar, 2008). In addition, sewage biosolid decreases soil acidification if applied to soil in the right amounts (Bengston and Cornette, 1973) and increases beneficial soil organisms, improving soil physical and biological properties. Plant nutrient uptake also improves (Kavitha and Subramanian, 2007). All these effects are advantageous for plant health (Pinamonti and Zorzi, 1996).

During the manufacture of white sugar, pressmud and molasses are produced as by-products. These waste products cause disposal and pollution problems. Pressmud is rich in potassium with considerable quantity of other nutrients and could be converted into nutrient rich organic manure or composted sugarcane pressmud (CPM). Conversion of waste products into rich organic manures not only solves the problems of disposal and pollution but also reduces the fertilizer cost (Rakkiyappan et al., 2001) besides improving soil properties and crop yield (Kalaivanan and Omar Hattab, 2008).

Farmyard manure (FYM) is a potential source of organic fertilizer. Use of FYM is important for improving soil quality and crop yield (Ashiono et al., 2006). Organic fertilizers, in addition to supplying nutrients and increasing yield, improve the physico-chemical condition of soils, enhance nutrient cycling and build the soil organic-matter capital (Palm, 1995; Reeves, 1997; Nakhro and Dkhar, 2010). Organic fertilizers have been reported to improve growth characteristics and yield in both medicinal as well as field crops (Abd El-Lattief, 2011; Abdelhamid et al., 2011; Affendy et al., 2011; Aslam et al., 2011).

Artemisia annua Linn. (annual wormwood) is a vigorous growing annual and aromatic herb, belonging to family Asteraceae. Chinese physicians used the plant for hundreds of years (Perazzo et al., 2003) externally for nosebleeds, bleeding rashes and sores and internally to treat heat stroke and malarial fever symptoms (Hsu, 2006). The plant produces a range of secondary compounds consisting volatile and non-volatile constituents (Simon et al., 1990), including terpenes. It produces an aromatic essential oil upon hydrodistillation which is used in ointments and is rich in monoterpenes (Charles et al., 1991; Ahmad and Misra, 1994). The oil is quite useful pharmaceutically because of its dermatological and fungicidal properties. It is used in perfumery, cosmetics, aromatherapy and dermatology as an antimicrobial agent (Woerdenbag et al., 1992; Laughlin, 1994). The essential oil is produced in its trichomes present on leaves and flowers (Duke and Paul, 1993). Significant variations in the percentage occurrence of different constituents have been reported in our earlier reports (Ali and Siddiqui, 2000; Mukhtar et al., 2007; Malik et al., 2009). We undertook the present study with a view to maintain the ecosystems of the soil and mitigate environmental pollution as well as solve the nutrition requirements of the very important medicinal and aromatic crop, A. annua.

MATERIALS AND METHODS

Plant material and field experiments: Seeds of A. annua, obtained from the Herbal Garden, Jamia Hamdard, New Delhi, were sown in 1x1 m nursery beds in the middle of December 2007. Two-month old seedlings were transplanted to the main field in a randomized block design. Sixteen plants were transplanted in each block of 2x2 m size with plant to plant and row to row spacing of 50 cm. The soil of the experimental field was sandy loam with neutral pH. The organic carbon content of the soil was 0.29% (w/w). The soil had 127 kg ha-1 available N, 24 kg ha-1 available P and 119 kg ha-1 available K. At the time of transplantation, the treatments were applied. Each treatment was replicated three times. Three treatments consisting of SSB, CPM and FYM each at the rate of 20 tons ha-1, were applied. The crop without any treatment was taken as control. The crop was irrigated on alternate days for the first ten days and then throughout the whole process of growth and development, irrigation was carried out at times dependent upon the rainfall. In the case of long-term drought, watering was carried out.

Isolation of essential oil: For the isolation of essential oil of aerial parts, the plants were harvested at full bloom stage of development as recommended by Gupta et al. (2002). Aerial parts of each sample (500 g) was collected and subjected to hydro-distillation in a Clevenger-type apparatus (Clevenger, 1928) for 4 h. The oil after extraction was collected in screw capped glass vials and dried over anhydrous Na2SO4. The oil collected from the three replicates of a sample was pooled (composite sample) and analyzed by GC and GC/MS.

Instrumentation and analysis of oil: GC analyses were carried out on a Shimadzu-17A gas chromatograph equipped with a Flame Ionization Detector (FID) and a DB-5 capillary column packed with 5% phenyl polysiloxane (30 m, 0.25 mm i.d.; 0.25 μm film thickness). The oven temperature was held at 90°C for 1 min then programmed to rise at 7°C min-1 to 230°C, held for 20 min. Other operating conditions were as follows: carrier gas, helium at a flow rate of 30 mL min-1; oxidant, oxygen at a flow rate of 300 mL min-1; fuel, hydrogen at a flow rate of 30 mL min-1; injector temperature, 240°C; detector temperature, 260°C, injection volume was 0.1 μL.

GC/MS analyses were performed on a HP-6890 GC system coupled with a 5973 network mass selective detector and equipped with a HP5-MS capillary column packed with fused silica (60 m, 0.25 mm i.d.; 0.25 μm film thickness). The oven temperature program was initiated at 40°C, held for 1 min then raised at 3°C min-1 to 250°C, held for 20 min. Other operating conditions were as follows: carrier gas, helium at a flow rate of 1 mL min-1; injector temperature, 250°C; split ratio, 1:50; injection volume was 0.1 μL. Mass spectra were recorded at 70 eV. Mass range was from m/z 20 to 500 amu.

Identification of essential oil constituents: The components of the essential oils were identified by comparing their retention indices and mass spectra fragmentation patterns with the literature values (Andersen and Falcone, 1969; Jennings and Shibamoto, 1980; Swigar and Silverstein, 1981; Libey, 1991; Ali, 2001; Adams, 2007).

RESULTS

The relative abundance of volatile components in the aerial parts of A. annua after treatment of the plots with organic residues was analyzed by GC and GC/MS. Hydro-distillation of untreated (control) plants yielded 0.28±0.05% essential oil on fresh weight basis. The predominant components in the essential oil were camphor (32.66%), o-cymol (13.76%), caryophyllene (13.38%), germacrene D (10.03%), camphene (5.48%), α-pinene (4.22%) and artemisia ketone (2.82%). The essential oil distilled from SSB treated A. annua amounted to 0.36±0.03% of fresh weight and consisted mainly of camphor (32.95%), α-pinene (25.43%), caryophyllene (10.62%), germacrene D (6.49%), artemisia ketone (5.95%), o-cymol (3.66%) and camphene (3.30%). The hydrodistillation of CPM treated A. annua yielded 0.31±0.04% essential oil on fresh weight basis. The predominant components in its essential oil consisted of germacrene D (21.76%), α-pinene (15.95%), camphor (13.49%), caryophyllene (12.99%), o-cymol (11.67%), germacrene B (6.13%), camphene (5.24%) and artemisia ketone (2.95%). Essential oil obtained from plants treated with FYM amounted to 0.33±0.03% of fresh weight and consisted mainly of camphor (37.20%), o-cymol (13.18%), germacrene D (11.09%), caryophyllene (8.46%), artemisia ketone (7.57%), α-pinene (5.91%) and camphene (4.42%) (Table 1).

Table 1: Comparative statement of the volatile oil composition of A. annua treated with different organic wastes
Image for - Volatiles of Artemisia annua L. as Influenced by Soil Application of Organic Residues
RI: Retention index, SSB: Sewage sludge biosolid, CPM: Composted sugarcane pressmud, FYM: Farmyard manure

DISCUSSION

All organic soil amendments substantially raised essential oil production, represented by increase in oil percentage and fresh weight of leaves of A. annua as compared to the control (unfertilized treatment). In all cases, the total yield of leaves on fresh weight basis increased as compared to the control variant. The hydrodistillation of aerial parts of untreated, SSB treated, CPM treated and FYM treated A. annua produced 0.28, 0.36, 0.31 and 0.33% essential oil, respectively, calculated on fresh weight basis. Presnt results established that SSB, CPM and FYM treated A. annua showed enhanced oil percentage. This result may be due to the effect of nutrients present in the manures in accelerating the metabolism reactions as well as stimulating enzymes. The quality and yield of essential oils have also been reported previously to be influenced by environmental factors (Malik et al., 2011; Nadim et al., 2011) including drying temperatures (Khangholi and Rezaeinodehi, 2008), fertilizer application (Sangwan et al., 2001) and the pH of soils (Alvarez-Castellanos and Pascual-Villalobos, 2003). Fertilizers have been found to increase the yield of essential oil from other crops like Matricaria recutita (Upadhyay and Patra, 2011), Rosmarinus officinalis (Abdelaziz et al., 2007) and Valeriana officinalis (Letchamo et al., 2004).

Gas-chromatographic analyses of the composition of these essential oils revealed little variation of active constituents. In A. annua, nineteen components were characterized in the essential oil from untreated plants; twenty-two components were identified in the essential oil from SSB treated plants; twenty constituents were identified in the essential oil from plants treated with CPM and twenty components were identified in the essential oil from FYM treated plants. Camphor was the major component present in all the four samples. Artemisia ketone was found in considerable quantity in all samples. Artemisinin was not found among the chromatographic profiles of any of the essential oils. It has long been reported that artemisinin undergoes decomposition under the steam distillation conditions and that its decomposition products are not steam distillable (Tellez et al., 1999). It is noteworthy to mention here that organic residues did not result in complete absence of sesquiterpenes in any of the oils as mentioned in our earlier report (Malik et al., 2009). It is well established that the glandular trichomes possess the biosynthenic machinery to produce secondary metabolites including isoprenoids (Guo et al., 1994; Clark et al., 1997). The results presented here suggest that different organic amendments increased the glandular trichome density in A. annua, observed by the increase in essential oil content. However, anatomical study is required to establish that organic treatments indeed favour the induction of trichomes in the leaves of A. annua.

CONCLUSION

Oil percentage and oil constituents were lower in plants cultivated in unamended soil compared to the SSB, FYM and CPM amended soil. The addition of organic matter rich in nutrients to the soil is thus a positive factor in essential oil production for A. annua. Therefore, greater attention needs to be paid for encouraging use of municipal wastes, organic industrial by-products and other locally available organic materials for improving the productivity of medicinal and aromatic plants whose secondary metabolites are directly influenced by the nutritional treatments. So, the agricultural recovery of municipal wastes and industrial organic by-products is a way to protect human health besides, solving serious environmental and plant nutritional problems.

ACKNOWLEDGMENTS

Hamdard National Foundation (HNF), New Delhi, India, is acknowledged for granting the research fellowship to Afaq Ahmad Malik.

REFERENCES

1:  Abd El-Lattief, E.A., 2011. Growth and fodder yield of forage pearl millet in newly cultivated land as affected by date of planting and integrated use of mineral and organic fertilizers. Asian J. Crop Sci., 3: 35-42.
CrossRef  |  Direct Link  |  

2:  Abdelaziz, M.E., R. Pokluda and M.M. Abdelwahab, 2007. Influence of compost, microorganisms and NPK fertilizer upon growth, chemical composition and essential oil production of Rosmarinus officinalis L. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 35: 86-90.
Direct Link  |  

3:  Abdelhamid, M.T., E.M. Selim and A.M. EL-Ghamry, 2011. Integrated effects of bio and mineral fertilizers and humic substances on growth, yield and nutrient contents of fertigated cowpea (Vigna unguiculata L.) grown on sandy soils. J. Agron., 10: 34-39.
CrossRef  |  

4:  Adams, R.P., 2007. Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry. 4th Edn., Allured Publishing Co., Carol Stream, IL., USA, ISBN-13: 9781932633214, Pages: 804

5:  Affendy, H., M. Aminuddin, M. Azmy, M.A. Amizi, K. Assis and A.T. Tamer, 2011. Effect of organic fertilizers application to the growth of Orthosiphon stamineus Benth. Intercropped with Hevea brasiliensis Willd. and Durio zibethinus Murr. Int. J. Agric. Res., 6: 180-187.
CrossRef  |  Direct Link  |  

6:  Ahmad, A. and L.N. Misra, 1994. Terpenoids from Artemisia annua and constituents of its essential oil. Phytochemistry, 37: 183-186.
CrossRef  |  Direct Link  |  

7:  Ali, M. and N.A. Siddiqui, 2000. Volatile oil of Artemisia annua leaves. J. Med. Aromat. Plant Sci., 22: 568-571.

8:  Ali, M., 2001. Techniques in Terpenoid Identification. Birla Publication, Delhi, India

9:  Alvarez-Castellanos, P.P. and M.J. Pascual-Villalobos, 2003. Effect of fertilizer on yield and composition of flowerhead essential oil of Chrysanthemum coronarium (Asteraceae) cultivated in Spain. Ind. Crop Prod., 17: 77-81.
Direct Link  |  

10:  Andersen, N.H. and M.S. Falcone, 1969. The identification of sesquiterpene hydrocarbons from gas-liquid chromatography retention data. J. Chromatogr. A, 44: 52-59.
CrossRef  |  

11:  Asagi, N., H. Ueno and A. Ebid, 2007. Effects of sewage sludge application on rice growth, soil properties and N fate in low fertile soil. Int. J. Soil Sci., 2: 171-181.
CrossRef  |  Direct Link  |  

12:  Ashiono, G.B., J.P. Ouma and S.W. Gatwiku, 2006. Farmyard manure as alternative nutrient source in production of cold tolerant sorghum in the dry highlands of Kenya. J. Agron., 5: 201-204.
CrossRef  |  Direct Link  |  

13:  Aslam, M., M.A. Khan, I.U. Awan, E.A. Khan, A.A. Khan and G. Jilani, 2011. Effect of single and combined use of various organic amendments on wheat grown over green manured soil: I. growth and yield attributes. Pak. J. Nutr., 10: 640-646.
CrossRef  |  Direct Link  |  

14:  Bengston, G.W. and J.J. Cornette, 1973. Disposal of composted municipal waste in a plantation of young slash pine: Effects on soil and trees. J. Environ. Qual., 2: 441-444.
CrossRef  |  Direct Link  |  

15:  Bright, D.A. and N. Healey, 2003. Contaminant risks from biosolids land application: Contemporary organic contaminant levels in digested sewage sludge from five treatment plants in Greater Vancouver, British Columbia. Environ. Pollut., 126: 39-49.
CrossRef  |  

16:  Charles, D.J., E. Cebert and J.E. Simon, 1991. Characterization of the essential oils of Artemisia annua L. J. Essent. Oil Res., 3: 33-39.

17:  Clark, L.J., J.G.C. Hamilton, J.V. Chapman and D.L. Hallahan, 1997. Analysis of monoterpenoids in glandular trichomes of catmint Nepeta racemosa. The Plant J., 11: 1387-1393.
CrossRef  |  Direct Link  |  

18:  Clevenger, J.F., 1928. Apparatus for the determination of volatile oil. J. Am. Pharm. Assoc., 17: 345-349.
CrossRef  |  Direct Link  |  

19:  Darwish, O.H., N. Persaud and D.C. Martens, 1995. Effect of long-term application of animal manure on physical properties of three soils. Plant Soil, 176: 289-295.
CrossRef  |  Direct Link  |  

20:  Duke, S.O. and R.N. Paul, 1993. Development and fine structure of the glandular trichomes of Artemisia annua L. Int. J. Plant Sci., 154: 107-118.
Direct Link  |  

21:  Gilani, S.S. and M.A. Bahmanyar, 2008. Impact of organic amendments with and without mineral fertilizers on soil microbial respiration. J. Applied Sci., 8: 642-647.
CrossRef  |  Direct Link  |  

22:  Guo, Z., R.F. Severson and G.J. Wagner, 1994. Biosynthesis of the diterpene cis-abienol in cell-free extracts of tobacco trichomes. Arch. Biochem. Biophys., 308: 103-108.
PubMed  |  

23:  Gupta, S.K., P. Singh, P. Bajpai, G. Ram and D. Singh et al., 2002. Morphogenetic variation for artemisinin and volatile oil in Artemisia annua. Ind. Crops Prod., 16: 217-224.
Direct Link  |  

24:  Hsu, E., 2006. Reflections on the discovery of the antimalarial qinghao. Br. J. Clin. Pharmacol., 61: 666-670.
CrossRef  |  

25:  Hussein, A.H.A., 2009. Impact of sewage sludge as organic manure on some soil properties, growth, yield and nutrient contents of cucumber crop. J. Applied Sci., 9: 1401-1411.
CrossRef  |  Direct Link  |  

26:  Jennings, W. and T. Shibamoto, 1980. Qualitative Analysis of Flavour and Fragrance Volatiles by Glass Capillary Column Gas Chromatography. Academic Press, New York, USA

27:  Kalaivanan, D. and K.O. Hattab, 2008. Influence of enriched pressmud compost on soil chemical properties and yield of rice. Res. J. Microbiol., 3: 254-261.
CrossRef  |  Direct Link  |  

28:  Kavitha, R. and P. Subramanian, 2007. Effect of enriched municipal solid waste compost application on growth, plant nutrient uptake and yield of rice. J. Agron., 6: 586-592.
CrossRef  |  Direct Link  |  

29:  Khangholi, S. and A. Rezaeinodehi, 2008. Effect of drying temperature on essential oil content and composition of sweet wormwood (Artemisia annua) growing wild in Iran. Pak. J. Biol. Sci., 11: 934-937.
CrossRef  |  PubMed  |  Direct Link  |  

30:  Laughlin, J.C., 1994. Agricultural production of artemisinin-a review. Trans. R. Soc. Trop. Med. Hyg., 88: 21-22.
CrossRef  |  Direct Link  |  

31:  Letchamo, W., W. Ward, B. Heard and D. Heard, 2004. Essential oil of Valeriana officinalis L. cultivars and their antimicrobial activity as influenced by harvesting time under commercial organic cultivation. J. Agric. Food Chem., 52: 3915-3919.
CrossRef  |  PubMed  |  

32:  Libey, L.M., 1991. A paradox of GC/MS data on components of essential oils and other volatiles. J. Essent. Oil Res., 3: 193-194.

33:  Malik, A.A., J. Ahmad, S.R. Mir, M. Ali and M.Z. Abdin, 2009. Influence of chemical and biological treatments on volatile oil composition of Artemisia annua Linn. Ind. Crops Prod., 30: 380-383.
CrossRef  |  Direct Link  |  

34:  Malik, A.A., S. Suryapani and J. Ahmad, 2011. Chemical vs. organic cultivation of medicinal and aromatic plants: The choice is clear. Int. J. Med. Arom. Plants, 1: 5-13.
Direct Link  |  

35:  Mbah, C.N., M.A.N. Anikwe, E.U. Onweremadu and J.S.C. Mbagwu, 2007. Soil organic matter and carbohydrate contents of a dystric leptosol under organic waste management and their role in structural stability of soil aggregates. Int. J. Soil Sci., 2: 268-277.
CrossRef  |  Direct Link  |  

36:  Mukhtar, H.M., S.H. Ansari, M. Ali, S.R. Mir, M.Z. Abdin and P. Singh, 2007. GC-MS analysis of volatile oil of aerial parts of Artemisia annua Linn. J. Essent. Oil Bear. Plants, 10: 168-171.

37:  Nadim, M.M., A.A. Malik, J. Ahmad and S.K. Bakshi, 2011. The essential oil composition of Achillea millefolium L. cultivated under tropical condition in India. World J. Agric. Sci., 7: 561-565.
Direct Link  |  

38:  Nakhro, N. and M.S. Dkhar, 2010. Impact of organic and inorganic fertilizers on microbial populations and biomass carbon in paddy field soil. J. Agron., 9: 102-110.
CrossRef  |  Direct Link  |  

39:  Otobbang, E., L. Sadovnikova, O. Lakimenko, I. Nilsson and J. Persson, 1997. Sewage sludge: Soil conditioner and nutrient source. II. Availability of Cu, Zn, Pb and Cd to barley in a pot experiment. Acta Agric. Scand. Soil Plant Sci., 47: 65-70.
CrossRef  |  Direct Link  |  

40:  Perazzo, F.F., J.C.T. Carvalho, J.E. Carvalho and V.L.G. Rehder, 2003. Central properties of the essential oil and the crude ethanol extract from aerial parts of Artemisia annua. J. Pharmacol. Res., 48: 497-502.
CrossRef  |  

41:  Pinamonti, F. and G. Zorzi, 1996. Experiences of Compost Use in Agriculture and in Land Reclamation Projects. In: The Science of Composting, De Bertoldi, M., P. Sequi, B. Lemmes and T. Papi (Eds.). Blackie Academic and Professional, London, pp: 515-527

42:  Qazi, M.A., M. Akram, N. Ahmad, J.F. Artiola and M. Tuller, 2009. Economical and environmental implications of solid waste compost applications to agricultural fields in Punjab, Pakistan. Waste Manage., 29: 2437-2445.
CrossRef  |  PubMed  |  

43:  Rakkiyappan, P., S. Thangavelu, R. Malathi and R. Radhamani, 2001. Effect of biocompost and enriched pressmud on sugarcane yield and quality. Sugar Tech, 3: 92-96.
CrossRef  |  

44:  Reeves, D.W., 1997. The role of soil organic matter in maintaining soil quality in continuous cropping systems. Soil Tillage Res., 43: 131-167.
CrossRef  |  

45:  Saha, P.K., M. Ishaque, M.A. Saleque, M.A.M. Miah, G.M. Panaullah and N.I. Bhuiyan, 2007. Long-term integrated nutrient management for rice-based cropping pattern: Effect on growth, yield, nutrient uptake, nutrient balance sheet and soil fertility. Commun. Soil Sci. Plant Anal., 38: 579-610.
CrossRef  |  

46:  Sangwan, N.S., A.H.A. Farooqi, F. Shabih and R.S. Sangwan, 2001. Regulation of essential oil production in plants. Plant Growth Regul., 34: 3-21.
CrossRef  |  Direct Link  |  

47:  Kumar, T.S., V. Swaminathan and S. Kumar, 2009. Influence of nitrogen, phosphorus and biofertilizers on growth, yield and essential oil constituents in ratoon crop of davana (Artemisia pallens Wall.). EJEAF Chem., 8: 86-95.
Direct Link  |  

48:  Simon, J.E., N. Charles, E. Cebert, L. Grant, J. Janick and A. Whipkey, 1990. Artemisia annua L.: A Promising Aromatic and Medicinal. In: Advances in New Crops, Janick, J. and J.E. Simon (Eds.). Timber Press, Portland, Oregon, pp: 522-526

49:  Swigar, A.A. and R.M. Silverstein, 1981. Monoterpenes: Infrared, Mass, 1H NMR and 13C NMR Spectra and Kovats Indices. Aldrich Chemical Co., Milwaukee, WI., USA., Pages: 130

50:  Tellez, M.R., C. Canel, A.M. Rimando and S.O. Duke, 1999. Differential accumulation of isoprenoids in glanded and glandless Artemisia annua L. Phytochemistry. Phytochemistry, 52: 1035-1040.

51:  Upadhyay, R.K. and D.D. Patra, 2011. Influence of secondary plant nutrients (Ca and Mg) on growth and yield of chamomile (Matricaria recutita L.). Asian J. Crop Sci., 3: 151-157.
CrossRef  |  Direct Link  |  

52:  Woerdenbag, H.J., N. Pras, W. Van Uden, A. De Boer, S. Batterman, J.F. Visser and T.M. Malingre, 1992. High peroxidase activity in cell cultures of artemisia annua with minute artemisinin contents. Nat. Prod. Lett., 1: 121-128.
CrossRef  |  

53:  Yamur, M., D. Kaydan and O. Arvas, 2005. Effects of sewage biosolid application on seed protein ratios, seed NP contents, some morphological and yield characters in lentil (Lens culinaris Medic.). Res. J. Agric. Biol. Sci., 1: 308-314.

54:  Palm, C.A., 1995. Contributions of Agroforestry trees to nutrient requirements of inter cropped plants. Agrofor. Syst., 30: 105-124.
CrossRef  |  Direct Link  |  

©  2021 Science Alert. All Rights Reserved