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Rice straw is a low-density crop residue. It is produced in huge quantities every year across the country. Therefore, the management of rice residue has become a problem for farmers. Farmers have to vacant the field as early as possible for sowing of the next crop. Hence, they go for the burning of crop residue and now it has become the common practice but burning can result in up to 80% loss of tissue nitrogen by volatilization besides a significant source of air pollution. Therefore, proper management of rice straw has become a national issue. Scientists have developed some strategies for the ex-situ utilization of rice straw. For the production of mushrooms, compost, biochar, biogas, and bioethanol rice straw could be used efficiently. The problem of burning and air pollution could be solved easily by adopting these techniques without affecting the environment.
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Food and Scientific Reports
ISSN 2582-5437 foodandscientificreports.com
February, 2022Volume: 3, Issue: 02Page 42
Kavita Kumari1, Alka Rani2, Dinesh Jinger3, Anchal Dass4
1Scientist,ICAR-National Rice Research Institute, Cuttack, Odisha; 2Scientist,ICAR-Indian Institute of Soil Science, Bhopal, Madhya
Pradesh; 3Scientist, ICAR-Indian Institute of Soil and Water Conservation, Vasad, Anand, Gujarat; 4Principal Scientist, ICAR-Indian
Agricultural Research Institute, New Delhi
Article History
ABSTRACT
Received:
10th February 2022
Accepted:
24th February 2022
dineshjinger28@gmail.com
Rice straw is a low-density crop residue. It is produced in huge quantities every year across the
country. Therefore, the management of rice residue has become a problem for farmers. Farmers
have to vacant the field as early as possible for sowing of the next crop. Hence, they go for the
burning of crop residue and now it has become the common practice but burning can result in
up to 80% loss of tissue nitrogen by volatilization besides a significant source of air pollution.
Therefore, proper management of rice straw has become a national issue. Scientists have
developed some strategies for the ex-situ utilization of rice straw. For the production of
mushrooms, compost, biochar, biogas, and bioethanol rice straw could be used efficiently. The
problem of burning and air pollution could be solved easily by adopting these techniques
without affecting the environment.
Keywords: rice, straw, stubble burning
Rice is a major staple food crop of India which is
being cultivated in an approximate area of 44.4 million
hectares with a production of 115.6 million tonnes (mt).
As per the reports, every tonne of paddy produces 1.11.3
tonnes of straw and 0.230.25 tonnes of husk. So, roughly
130 mt of paddy straw is being produced in India every
year and a significant part of it is burnt in the field in
OctoberNovember in NorthWest India. As per
estimates, with each tonne of rice straw burnt, 5.5 kg
nitrogen, 2.3 kg phosphorus, 25 kg potassium, and 1.2 kg
of sulphur are potentially lost. The other harmful effects
involve loss of soil carbon and soil biodiversity, emission
of greenhouse gases causing global warming, and release
of soot particles causing health hazards to humans,
animals, and birds (Fig. 1). Therefore, it is the need of the
hour to stop this burning practice and to handle rice straw
sustainably by taking environmental protection and
economic viability into consideration.
Fig1. Consequences of rice residue burning
(source: Lohan et al., 2017)
Ex-situ utilization of rice straw
India produces a large amount of rice straw, and
a considerable amount of it is being used as cattle feed.
Apart from the cattle feed, it can also be economically
utilized for other purposes like mushroom production,
compost preparation, biochar, biogas, bio-ethanol
production, etc.
Mushroom production
Mushroom cultivation is a profitable agri-
business endeavor that may utilize rice straw in an
environmentally friendly manner. Rice straw can be used
as base a material that can provide 50100 kg of
mushrooms per 1 ton of dried straw. The paddy straw
mushroom (Volvariella volvacea) is one of the easiest
mushrooms to cultivate because of its short incubation
period of 14 days. The materials required for mushroom
production using paddy straw include paddy straw
(60/cage bundles), spawn bottle (2/cage), wooden cage 1
no. (1m x 50cm x 25cm), 1 drum (100-liter capacity),
polythene sheet (4 meters), binding thread (3 meters),
sprayer/rose can, Dithane Z-78/ Bavistin (200 gm),
Malathion (250 ml), Dettol/Formalin (1/2 liter), Dao
(hand chopper), and thermometer(Ahlawat and Tewari,
2007). The steps for the cage method of paddy straw
mushroom cultivation are depicted in figure 2 and 3.
Strategies for Ex-Situ Utilization of Rice Straw
Food and Scientific Reports
ISSN 2582-5437 foodandscientificreports.com
February, 2022Volume: 3, Issue: 02Page 43
Fig 2. Steps for Cage method of paddy straw mushroom
cultivation (Source: Ahlawat and Tewari, 2007)
Fig 3. Cage method of paddy mushroom cultivation
(Source: Ahlawat and Tewari, 2007)
Compost preparation
Compost is a good source of micronutrients, thus
maintaining soil health and saving external inorganic
fertilizers input. Rice straw can be used as principal
composting materials in a mixture with other legume
crops. For making good compost, adequate moisture, N
supply, and specific micro-organisms are needed.
1. Compost heap should be made on leveled, well-
drained, and shady place.
2. Heap should be in layers with chopped rice straw (3-5
cm) followed by layers of combined rice
straw:legume/manure in 2:1 ratio.
3. Cowdung slurry, a diluted solution of N fertilizer, and
micro-organism solution (e.g., Trichoderma
harzianum), can be added to compost to enhance the
composting rate. Maintaining optimum moisture will
further accelerate the process.
4. Mixing and turning up the heaps is required every two
weeks. Under proper moisture and temperature
condition, compost will be ready in 4-8 weeks (source:
IRRI).
Biochar production
Biochar is a carbon-rich soil amendment, which
improves soil productivity by increasing nutrient
availability, carbon sequestration, and water retention
(Lehmann and Joseph, 2009). There is a huge scope for
using rice straw to produce biochar. Biochar is produced
from paddy straw by the pyrolysis process i.e. thermal
decomposition of paddy straw under a limited supply of
oxygen and at temperatures ranging from 400 to 700°C
(Fig. 4).
Fig 4. Biochar produced from rice straw (Source: Chandra
and Bhattacharya, 2019)
Biogas production
Rice straw can be used to generate fuel, heat, or
electricity through thermal, chemical, or bioprocesses.
Approximately 300 m3 of biogas (consisting of 5560%
methane) can be generated from the anaerobic digestion
of one tonne of paddy straw. The spent slurry produced in
this process can be further used as manure in the crop
field. In this way, paddy straw can be used to generate
high-quality fuel gas in a non-destructive way along with
manure which can be recycled in the soil.
For generating gas from paddy straw, a small-
scale a batch-anaerobic digestion (AD) system has been
developed by Punjab Agricultural University (PAU),
Ludhiana. The main components of this system are batch-
digester and a gas holder or reservoir (Figure 5). Both of
these components are built with cement materials and the
cost of the whole system is INR 150,000.
Fig 5. Batch anaerobic digestion system using paddy
straw and cow dung (Source:IRRI Rice Knowledge Bank)
In batch anaerobic digester rice straw and cattle
dung are arranged layer by layer with the top layer as
cattle dung to cover up all substrates. Based on the
weight, the ratio of rice straw to cattle dung is kept as 4:1
(1.6 tons of chopped straw with 1518% MC and 0.4
tonnes of cow dung with 3040% MC) and fed into a
batch digester for 100120 days. Biogas is generated on
the 7th day of feeding, and gives an average yield of 45
m3/day in about 100 days.
Food and Scientific Reports
ISSN 2582-5437 foodandscientificreports.com
February, 2022Volume: 3, Issue: 02Page 44
Bioethanol production
Paddy straw has abundant lignocellulosic
biomass which can be used to produce bioethanol.
Bioethanol is produced by the conversion of paddy straw
biomass into fermentable sugars such as glucose and
xylose through enzymatic hydrolysis.
Fig 6. Ethanol production from rice straw (Source:
Khaleghian et al., 2015)
Rice straw is pre-treated with alkali solution and
enzymatic saccharification is carried out by the culture of
fungus and yeast added in it which ultimately produces
bioethanol (fig. 6). This bioethanol can be used as motor
fuel or as an additive in gasoline.
Conclusion
India produces a large amount of rice residue and
a sizeable amount is subjected to burning, which leads to
loss of nutrients, GHG emission, and affects population
health too. Keeping given these consequences, several
initiatives for its proper in-situ as well as ex-situ
management have to be taken up. It can be extensively
utilized for making compost, biochar, bioethanol,
mushroom production, and cattle bedding material.
Further paddy straw can be also used for industrial
purposes like the preparation of cardboards, papers,
packaging material, and power generation. So, the farmers
should leave the practice of paddy straw burning having
negative consequences and should adopt these practices
with associate stakeholders to get economic benefits from
the paddy straw in an economic and environment-friendly
manner.
References
Ahlawat, O.P., & Tewari, R.P. (2007). Cultivation
technology of paddy straw mushroom (Volvariella
volvacea). Technical Bulletin, National Research
Centre for Mushroom (ICAR), Chambaghat, Solan
(H.P.), p 36.
Chandra, S., & Bhattacharya, J. (2019). Influence of
temperature and duration of pyrolysis on the
property heterogeneity of rice straw biochar and
optimization of pyrolysis conditions for its
application in soils. Journal of Cleaner Production,
215,11231139.
Khaleghian, H., Karimi, K., & Behzad, T. (2015).
Ethanol production from rice straw by sodium
carbonate pretreatment and Mucor hiemalis
fermentation. Industrial Crops and Products,
76,10791085.
Lehmann, Johannes., & Joseph, S. (2009). Biochar for
environmental management: An introduction.
Biochar for environmental management. Science
and technology, Earth scan Publishers Ltd.
Lohan, S.K., Jat, H.S., Yadav, A.K., Sidhu, H.S., Jat, M.L
., Choudhary, M., & Sharma, P. C. (2017). Burning
issues of paddy residue management in north-west
states of India. Renewable and Sustainable Energy
Reviews, 81,693706.
http://www.knowledgebank.irri.org/training/fact-
sheets/nutrient-management/item/composting-rice-
residue-fact-sheet
ResearchGate has not been able to resolve any citations for this publication.
Article
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