Wetland Rice Cultivation: A Major Cause of Global Warming

Sanjeet

sanjeet.biotech@gmail.com

Emerging Science, 2011, 3(10): 15-18.

Abstract

In this paper, author presented the results of literature on the relation between global warming and wetland rice cultivation, their effect and future plan to reduce methane emission from wetland rice cultivation to protect our climate.

Key  words: Rice cultivation, Methane emission, Modelling of emission, Global warming.

Introduction

Global warming and climate change are one of the most critical global challenges for our country. People concern about global warming mostly focuses on greenhouse gases and methane is the one of major component, which is increasing at the rate of 1 % per year, is likely to contribute more to future climatic change. (Cicerone & Oremland 1998).Wetland rice fields have been identified as a source of atmospheric methane and the emission estimates from paddies range from 29 to 61 Tg per year(IPCC 2002).Rice cultivation is an important agricultural priority worldwide, because rice is the major cereal crop feeding two-third of the global population, which continue to increase by  ̴ 80 million people per year(Cohen 2003), and is expected to continue to feed large numbers of the ever-growing populations(Babu et al., 2005), so it has been estimated that global rice production must almost double by the year 2020 in order to meet the growing demand(Li C et al., 2002), and this may increase methane fluxes by up to 50%(Bouwman 1991).Contribution of methane to the green house effect is ̴ 1.7 wm² and 20% total methane emission comes from paddy field(Purkit et al. 2007).In India measurement of methane emission from rice paddies were initiated by Saha et al., &  Parashar et al., estimated methane emission from India’s paddy at 3 Tg/yr, based on a limited number  of field measurements. Recently, Bhutia et al., used IPCC default flux values for the base year 1994-1995 to estimate methane emissions from all agricultural fields in India to arrive at figure of 2.9 Tg/yr(Babu et al., 2005).According to Purkit et al., 2007 the total harvested rice area of India is nearly 42.23 Mha and total methane emission is nearly 4 Tg per year.

How Methane is Produce in Wetland Rice Cultivation.

In wetland rice cultivation, methane is produced due to the anaerobic decomposition of organic materials in flooded rice paddy soil. Methane is produced as the last step of the anaerobic breakdown of organic matter in wetland rice soils with the help of methanogenic bacteria by transmethylation. The level of methane emission from rice paddy is related to various factors that control the activity of the methenogen and methane-oxidizing bacteria such as temperature, pH, soil redox potential & substrate availability, soil type, rice variety, tillage, water management & fertilization (Conard 2002).Mitra et al., have recently reported that the methane emission is related to also concentration of organic carbon. According to Purkait et al., 2007, methane from paddy field is released into the atmosphere by:-

·        Diffusion from the interfaces following the concentration gradient.

·        Forming gas bubbles and escaping into the atmosphere by ebullition or burst.

·        Diffusion into the root and aerenchyma of the plant. It implies that in addition to the normal process of methane emission.

·        Emission in the form of ebullition occurs during moderate and high emission periods.

Modelling for methane emission

There are many types of models available to predicate the rate of methane emission from wetland rice field. Some models tried to use the least number of input parameters and more empirical equations to capture basic pattern of gas fluxes, these models are :-( Sources –Babu et al., 2005)

·        DNDC

·        Expert-N

·        CASA

·        CENTURY

·        NLOOS

·        MERES

·        MEM

·        DAYCENT

·        INFOCROP.

Among above model the DNDC model was developed for the predication of C and N biogeochemical cycles in both upland and wetland ecosystems (Li et al.,1992, Li et al.,1994 & Babu et al.,2005.).It is powerful assessment tool because it can predict crop grain and shoot yield, gaseous methane, nitrous oxide, ammonia emissions, soil C balance and N leaching below the root zone.  DNDC was also developed for predicting carbon sequestration and trace gas emission for non-flooded agricultural lands, simulating the fundamental process controlling the interaction among ecological drivers, soil environment factors and relevant biochemical or geochemical reactions, which collectively determine the rates of trace gas production and consumption in agricultural ecosystems (Li et al.,1994, Li et al.,1996 & Babu et al.,2005).

                      Using MEM model, Cao et al., estimated methane emission from rice fields in China and Matthews et al. estimated Methane emission from rice fields in China, India, Indonesia, the Philippiness and Thailand( Matthews et al.,2000 ).

Factors for Methane emission

In wetland rice cultivation, there are many factors for appropriate methane emission, which control the activity of the methanogens and methane-oxidizing bacteria, such as temperature, pH, soil redox potential and substrate availability, soil type, water management etc are major. Rice plant influence methane production by enhancing anaerobic conditions due to root respiration, and by provide substrate for methanogens such as root exudates (Neue,1997).  The plant can also affect methane oxidation by enxymatic oxidation and diffusion of oxygen through aerenchyma into the rhizosphere(Epp & Chanton, 1993k ).N fertilization also stimulates the methane oxidizing bacteria(Bodelier et al.,2000).

Table No. : - Values of soil parameters (sources –Purkait et al.,2007).

Parameters	Kharif	Rabi
pH	7.6	7.8
C/N ratio	21.25	10.25
Cation exchange capacity	9.7	5.5
Sand %	12.6	12.8
Clay %	42.6	45.6

Reduction of methane emission

Significant decrease of methane emission from wetland rice field could be achieved using:-

·        Zero tillage and mulching reduce methane emission from wetland rice cultivation.

·        Change of cultivation practices, such as a shift from transplanting to direct seeding and appropriate water management can also contribute water management can also contribute decreasing of methane emissions.

·        Reducing the time during which the fields are flooded, can reduce GHG emissions by about 50 %(Cole et al.,1997).

·        Intermittent drainage is the most effective methane emission mitigation practice for irrigated rice paddies(Majumadar,2003).

·        Improved rice cultivator's have been estimated to reduce GHG emissions by up to 20%(Sass et al. 1992).

·        Fertilization with iron (Conrad 2002),or increased ferric iron content in the rhizosphere seems to suppress methane formation (Watanabe 1999k),

·        Also sulphate inhibits methane production (Denier et al 2001).

·        Rabi cultivation is encouraged to reduce methane emission (Purkait et al., 2007).

Conclusion

Wetland rice cultivation contributes a significant proportion of methane emission, & it is predicated to increase as the global population depends on wetland rice particularly in India and other Asian country. By using different approaches which described above, can reduce the emission of methane and  check the climate change and  global warming due to wetland rice cultivation, also need the global research and policy support.

References:

Cicerone, R. J., and R. S. Oremland. 1988. Biogeochemical aspects of atmospheric methane. Global Biochem. Cycles 2: 299-327.

Denier van der Gon, H.A., van Bodegom, P.M., Wassmann, R., Lantin, R.S. and Metra-Corton, T.M., 2001. Sulfate-containing amendments to reduce methane emissions from rice fi elds: mechanisms, eff ectiveness and costs. Mitigation and Adaptation Strategies for Global Change 6 (1),71-89.

Sass, R.L., Fisher, F.M., Wang, Y.B., Turner, F.T. and Jud, M.F., 1992. Methane emission from rice fi elds: the eff ect of fl oodwater management. Global Biogeochemical Cycles 6, 249–262.

Epp, M. and Chanton, A.J.P., 1993. Rhizospheric methane oxidation determined via the methyl fl uoride inhibition technique. Journal of Geophysical Resources 98, 18422–18423.

IPCC, Special report on Emission Scenarios , Cambridge University Press, Cambridge, UK 2002.

Watanabe, A. and Kimura, M., 1999. Infl uence of chemical properties of soils on methane emission from rice paddies. Communications in Soil Science and Plant Analysis 30, 2449–2463.

Takai, Y. 1970. The mechanism of methane fermentation in flooded soils. Soil Sci. Plant Nutr. 16: 238

Cicerone, R. J., and J. D. Shetter.1981. Sources of atmospheric methane: measurements in rice paddies and a discussion. J. Geophys. Res. 86: 7203-7209.

Conrad, R., 2002. Control of microbial methane production in wetland rice fi elds. Nutrient Cycling in Agroecosystems 64, 59-69.

Cohen, J. E., Human population : The next half century, Science, 2003, 302, 1172-1175.

Y.Jagadeesh Babu, C. Li, S. Frolking, D.R.Nayak, A.Datta and T.K.Adhya, Current Science, Vol.,89. No. 11, 10 December 2005.

Li, C. et al., Reduced methane emissions from large-scale changes in water management in China’s rice paddies during 1980-2000, Geophys. Res. Lett., 2002,29.

Bouwman, A.F., Agronomic aspects of wetland rice cultivation & associated methane emission. Biogeochemistry, 1991, 15. 65-88.

N.N.Purkait, A.K. Saha & Sanghamitra De., Behavior of methane emission from a paddy field of high carbon content. Indian Journal of Radio & Space Physics,  Vol- 36, February 2007, pp- 52-58.

Parashar, D.C. et al., Methane budget from Indian paddy fields. In Methane and Nitrous oxide : Global Emission & Controls from Rice Fields and other Agricultural and Industrial Sources (eds Minami, K., Mosier, A. R. and Sass, R.) NIAES series 2, Tsukuba. Japan, 1994, pp- 27-39.

Mitra  A. P,  Gupta P K & Sharma C, Refinement in methodologies for methane budget estimation from rice paddies, Nut Cycl Agroeco (The Netherlands), 58 , 2002, 201.

Sass R. L., Fischer F.M, Harcombe P.A & Fund M.F., Methane emission from rice fields as influenced by solar radiation, temperature and straw, Global Biogeochem Cycles (Sweden). 5, 1991, 275.

Saha A.K., Rai J. Raman V, Sharma R.C, Parashar D.C, Sen S. P. & Sarkar B, Methane emission from inuandated fields in monsoon region . Indian J. Radio & Space Phys, 18,1989,215.

Matthews, R.B., Wassmann, R. & Arah,J., Using a crop /soil simulation model and GIS techniques to assess methane emissions from rice fields in Asia. I Model development, Nutr. Cycl. Agroecosyst., 2000, 58, 141- 159.

Cao, M., Dent, J.B. & Heal, W.O., Methane emission from China’s rice paddies. Agric. Ecosyst. Environ., 1995. 55, 129-137.

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Cole, C.V., Duxbury, J., Freney, J., Heinemeyer, O., Minami, K., Mosier, A., Paustian, K., Rosenberg, N., Sampson, N., Sauerbeck, D. and Zhao, Q., 1997. Global estimates of potential mitigation of greenhouse gas emissions by agriculture. Nutrient Cycling in Agroecosystems 49, 221–228.

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Sanjeet Kumar

Regional Institute of Education (NCERT)

Bhubaneswar.

A Preliminary study on phytochemical analysis of leaves of Bixa orellana (Kumkum)

This Article is published here.

Sanjeet kumar, M. Kabi and M. Kumari ,2010 “Study on phytochemical analysis from leaves of Bixa orellana (Kumkum)”, Emerging Science,Vol 2, No. 5 ,October 2010

Sanjeet Kumar

sanjeet.biotech@gmail.com

Abstract

In this study, the medicinal properties of Bixa orellana were evaluated by phytochemical screening of acetone & methanol extract .In acetone extract steroid, terpenoid & glycoside shown but in methanol extract tannin & flavonoid shown , these bioactive compounds indicated the medicinal value of  leaf of Bixa orellana.

Key words : Bixa orellana, Phytochemical screening, Medicinal value.

 Introduction



Fig : Plant of Bixa orellana



The state of Orissa possesses a rich bio-diversity of medicinal plants which are the richest and can provide diverse flora and natural vegetations, many of which are used in traditional medicine to cure various sickness and diseases. They not only serve as source of medicinal purpose, but also used for other purposes; which many due to their odoriferous nature and useful in flavoring or as food additives and preservatives.

                          The use of plants whether herbs, shrubs or trees, in parts or in whole, in the treatment and management of diseases and disorder date back to pre-historic days. Plant extracts or plant-derived compounds are likely to provide a valuable source of new medicinal compounds (Carvalho and Ferreira, 2001; Kayser and Kiderlen, 2001) and the urgent need for alternative treatment has led to screen natural products for potential therapeutic use in microbial and fungal infections. Plant parts have been used in folk medicine practices for the treatment of various ailments since antiquity. The medicinal properties of various plant materials and extracts have been recognized since the beginning of developing golden period of India. A rich store house of medicinal plants exist everywhere especially in Orissa which offers a vast reservoir of medicinal plants that have been categorized.

The current study is aimed to investigate the phytochemical properties of Bixa Orellana.

            Bixa orellana commonly called as Annato tree belongs to family Bixaceae and has been named as:-

·         Kumkum in Oriya

·         Sundri in Marathi

·         Latkan in Hindi & Bengoli.

·         Japhora in Tamil & Telgu.

·         Annato and Uruco in Brazil.

·         Achiott in Amezen India.

Botany:-

Shrub or small tree leaves ovate, base subcordate, apex acute to acuminate, Flowers, Brown, caduceus, sepals purplish red, broadly ovate to orbicular, petals purplish- pink to nearly white. Capsules ovoid, dark red, seed smooth.

Distributions:-

Cultivated and naturalized throughout the area and more in the central districts in Orissa. It is native of tropical America, now widely cultivated in tropical countries and frequently naturalized.

                    The outer coat of seed of Kumkum is used for colouring of fabrics in rural areas of Orissa; also seeds are very important for the isolation of active compounds which is Bixin, recognized as a safe colourent for different types of food like in butter, chocolate etc.

Traditional uses: -

Leaves are used naturally in Constipation, fevers, heartburn, asthma, gastrointestinal tonic (Lorenzi and Matos, 2002) Annatto extract is a natural food color, which is obtained from the outer coatings of the seeds of the Annatto tree (Bixa orellana L.) (Hagiwara et al., 2003). The use of annatto by the New World man dates back to ancient times. The indigenous Amazon people have used “urucum” for body. Painting for centuries. Seeds and leaves of the annatto tree were used by the Aztecs to prepare remedies for a variety of illnesses such as tonsillitis, asthma, pleurisy, rectal disorders, headache, jaundice, sunstroke, and burns (De Oliveira et al., 2003). Although the plant species originated in northern South America, it is now widely cultivated in tropical areas for commercial production (Hagiwara et al., 2003). Aqueous annatto extract had a hypocholesterolemic effect. (Heberth de Paula et al., 2009).

Chemical Constituents

Bixa orellana exhibited some level of antifungal activity when a group of Latin American plants were subjected to screening for antifungal activity (Freixma et al. 1998). In another experiment, the lipid fraction of B.orellana seeds was extracted using n-hexane and isolated by thin layer chromatography; it seems that Bixa seeds contain a higher concentration of delta-tocotrienol than any other vegetable species (Frega, Mozzon & Bocci 1998). Recently, three apocartenoids were isolated from annatto (B.orellana) and synthesized. They were: methyl (9Z)-8’-oxo-6, 8’diapocarten-6-oate (2), methyl Z)-10’-oxo-6, 10’diapocaroten-6-oate (4), and methyl (9Z)-14’-oxo-6,14’-diapocaroten-6-oate (5) (Haberli & Pfander 1999). In another experiment, three minor cartenoids were isolated from the seed coat of B.orellana fruits by chromatographic methods and, for the first time, geranylgeraniol has been found esterifies with a carotenoid carboxylic acid (Mercandante, steck & Pfander 1999).

Active compounds
Bixin and norbixin are the main pigments contributing to the color of Annatto extracts. Extracts are obtained from the outer layer of the seeds the principal pigment in annatto extract is cis-bixin, which is contained in the resinous coating of the seed itself. The seeds contain a higher concentration of delta-tocotrienol than any other vegetable species (Frega, Mozzon & Bocci 1998).

Materials and Methods:-

The leaves of Kumkum were collected from Ekamra kanan in Bhubaneswar, Orissa. The analysis for detection of phytochemicals was done at Biotechnotrics Pvt. Ltd. Bhubneshwar.

 Preparation of Plants Extract

The leaves of the plant were thoroughly washed with tap water. Each leaf was then dried with the help of tissue paper. The leaves were cut into small pieces and were washed with distilled water. The pieces of leaves were dried and their initial weight was taken. The leaves were then kept in a hot air oven at 60 degree Celsius for 12 hours. The pieces of leaves were then powdered with the help of mortar and pestle. The extract was prepared by using the solvents of methanol and acetone. The crude extracts were kept in sample bottles and was stored in refrigerator for further phytochemical analysis.

Phytochemical analysis

Phytochemical Screening was carried out following the methods provided by Sofowora, 1982 for qualitative analysis of methanol and acetone extracts of Bixa Orellana.( Kumkum)

1.    Test for Tannins :-

700 µl of leaf extracts was mixed with 50 ml of distilled water. 1% of ferric chloride was added to it as a drop. A dark green solution indicates the presence of tannins.

2.    Test for Flavonoids :-

Few drops of leaf extract were dissolved in 10% NaOH. Then concentrated HCl was added to it. A yellow solution that turns colourless indicates the presence of Flavonoids.

3.    Test for Terpenoids :-

1 ml of plant extract was taken and to it 400 µl of chloroform was mixed. Then few drops of concentrated Sulphuric acid was carefully added to form a layer. A reddish brown colouration of the interface was formed to indicate positive results for the presence of terpenoids.

4.    Test for Steroids :-

100 µl of plant extracts was taken and to it 400 µl of aceatic anhydride was added. To it few drops of concentrated sulphuric acid was added drops by drops.The formation of a brown ring indicates the presence of Steroids.

5.    Test of Saponins :-

About 1 ml of plant extracts was taken and to it 1% ferric chloride was added. Frothing or appearance of creamy mass of small bubbles shows the presence of saponins.

6.    Test for Glycosides :-

100 µl of plant extract was taken and to it 400 µl of acetic anhydride was added in a cool medium. Then few drops of concentrated sulphuric acid was added to it. The change of colour from violet to blue and then to green indicates the presence of Glycosides.

7.    Test for amino acids :-

2 ml of leaf extract which was dissolved in protein extracting buffer. To it 500 µl ninhydrin reagent solutions was added. The formation of purple colour indicates the presence of amino acids.

Results

Table no.1:-

Initial weight	Final weight
21.93 gm	7.75 gm

Table no. 2

The moisture % and the solid % of Bixa orellana leaves are:-

Moisture %	Solid %
64.66%	35.34%

Table no. 3:- Methanol Extract

Test	Results
Tannin	+ve
Flavonoid	+ve
Terpenoid	-ve
Saponin	-ve

Table no.4:- Acetone Extract

Test	Result
Tannin	-ve
Steroid	+ve
Terpenoid	+ve
Glycoside	+ve

Conclusion

The medicinal properties of the leaves of Bixa orellana could be attributed to the presence of one or more of the detected phytochemicals. The methanol extract of leaf contains flavonoids which has antioxidant properties. The acetone extract show positive for steroids which has indicative of stimulant properties.. The methanol extract also revealed the presence of terpenoids and it helps in the biosynthesis of lipids and increase cholesterol and decreases blood sugar.However, the pharmacological actions of the plant cannot be ascertained by only the qualitative result of the phytochemical screening. Further research can exhibit the detail pharmacological characteristics potent to its medicinal value.

References

·         Carvalho, P.B., Ferreira, E.I., 2001. Leishmaniasis phytotherapy. Nature’s leadership against an ancient disease-review. Fitoterapia 72, 599–618.

·         De Oliveira AC, Silva IB, Manhaes-Rocha DA,Paumgartten FJ (2003) Induction of liver monooxygenases by annatto and bixin in female rats. Braz J Med Biol Res 36:113-118.

·         (Frega, Mozzon & Bocci 1998. Frega, N., M.Mozzon,& F.Bocci.1998. Identification and estimation of tocotrienols in the annatto lipid fraction by gas chromatography mass spectrometry. Journal of the American Oil Chemists Society. 75 (12): 1723-1727.

·         Freixa, B., R. Vila, L. Vargas, N. Lozano, T. Adzet & S. Canigueral.1998.
Screening for antifungal activity in nineteen Latin American plants. Phytotherapy Research.12 (6): 427-430.

·         H.Sexena and M.Brahaman, The Flora of Orissa, Vol-1

·         Heberth de Paula Effect of an Aqueous Extract of Annatto (Bixa orellana) Seeds on Lipid Profile and Biochemical Markers of Renaland Hepatic Function in Hipercholesterolemic Rats, Braz. Arch. Biol. Technol. v.52 n. 6: pp. 1373-1378, Nov/Dec 2009.

·         Haberli, A.& H. Pfander. 1999. Synthesis of bixin and three minor carotenoids from annato (Bixa orellana).
Helvetica Chemica Acta.82 (5): 696-706.

·         Hagiwara A, Imai N, Ichihara T, Sano M, Tamano S,Aoki H, Yasuhara K, Koda T, Nakamura M, Shirai T(2003) A thirteen-week oral toxicity study of annatto extract (norbixin), a natural food color extracted from the seed coat of annatto (Bixa orellana L.), in Sprague-Dawley rats. Food Chem Toxicol 41:1157-1164.

·         (Kayser, O., Kiderlen, A.F., 2001. In vitro leishmanicidal activity of naturally occurring chalcones. Phytotherapy Research 15, 148–152.

·         Lorenzi, H., Matos, F.J.A., 2002. Plantas Medicinais do Brasil. Nova Odessa, Instituto Plantarum, S˜ao Paulo, p. 544.

·         Mercadante, A.Z., Steck, H. and Pfander, H. (1999). Three minor carotenoids from annatto (Bixa orellana).

Sanjeet Kumar, Regional Institute of Education (NCERT) Bhubaneswar.

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