This presentation is about composting of rice straw. Rice straw is an agrowaste and causes serious problems to environment. Its proper management is required. So composting is best option for proper management of rice straw.

1. BY
SOMYA SHUKLA
M.D. UNIVERSITY ROHTAK

2. CONTENTS
 Introduction
 Rice Straw and its Composition
 Management of rice straw
 Composting
 Types of composting
 Phases of composting
 Importance of C:N ratio
 Method
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3. INTRODUCTION
 Rice (Oryza sativa) is the most important staple food in the
world. It is the grain with the second-highest
worldwide production, after maize (corn).
 According to the Food and Agricultural Organization
(FAO) of the UN, 80% of the world rice production comes
from 7 countries which is China , India, Indonesia,
Bangladesh, Vietnam, Thailand , Myanmar, then other
countries Philippines, Brazil, Japan.
 Besides producing the grain, it also produces a large
amount of waste which is rice straw. Globally, roughly
800 to 1,000 million tons per year of rice straw is
produced, with about 600 to 800 million tons per year
produced in Asia. 3

4. It is one of the most abundant lignocellulosic crop
residues in the world and its improper management
causes serious problems in the environment. Rice straw,
as a lignocellulosic biomass, is comprised of three
components: lignin (10-20%), 43 % cellulose and 25 %
hemicellulose.
So proper management of rice straw is needed. The best
method of rice straw management is its composting.
Composting is an environment friendly treatment for
efficiently decreasing solid waste volume and recycling
organic nutrients.

5. RICE STRAW AND ITS COMPOSITION
 Rice straw is a major agricultural waste in rice producing countries. It is a
rice by-product produced when harvesting paddy. Each Kg of milled rice
produced results in roughly 0.7-1.4 Kg of rice straw depending on varieties,
cutting height of the stubbles, and moisture content during harvest.
 Rice straw is separated from the grains after the plants are threshed either
manually, using threshers or, more recently, by using combine harvesters.
 It is a major agriculture waste in rice producing countries. Rice straw, as a
lignocellulosic biomass, is comprised of three components: lignin ,cellulose
and hemicellulose. These could be fractioned through pretreatment.
 It contains silica, ash content, TDN (Total Digestable Nutrient), NPk,
Sodium, Calcium, Magnesium etc.
 Rice straw has a high C:N ratio of about 80:1 and is rich in silica and lignin
and polysaccharides which makes it difficult to be degrade.

6. MANAGEMENT OF RICE STRAW
 Rice is a agricultural waste and it is managed by
different ways. These are Burning of rice straw,
Mulching into field, Incorporation, but these
strategies causes serious environmental problems.
 The abundance of rice straw as an organic waste can
be converted to fertilizer throughout the process of
composting
 Composting is the best of man agent of rice straw.
According to many studies Composting of rice straw
arises as a safe alternative option which results in
reusability of nutrients contained in the residue.

7. COMPOSTING
 Composting was the first concept for using effective
microorganism (EM) in environment management. Crop
residues and animal wastes have been effectively
composted to produce biofertilizers.
 The high C:N ratio of rice straw (80:1) makes it less
desirable substrate for composting. Adding urea for
reducing the C: N ratio of crop waste has been practiced in
the past but the recent inclination towards organic farming
requires the use of nitrogen rich organic waste that can be
substituted this chemical source of nitrogen.
 Poultry manure is one such waste (C: N ratio 7:1) that may
fit in the category of organic nitrogen supplement.

8. TYPES OF COMPOSTING
AEROBIC COMPOSTING ANAEROBIC COMPOSTING
• Aerobic composting is the
process of degradation which
occur in the presence of
microorganism which require
oxygen.
• This process is fast.
• Resulting byproduct of this type
of composting is heat, CO2, and
water.
• It produces earthy smell.
• It require turning weakly.
• No pungent gas is produced.
• Anaerobic composting is the
process of degradation which
occur in the presence of
microorganism which do not
require oxygen.
• This process is slow.
• It releases methane.
• It produced a very strong odor.
• Doesn't require turning.
• Pungent gas is produced.

9. PHASES OF COMPOSTING
 In the process of composting microorganism breakdown
organic matter and produce carbon dioxide, water, heat,
and humus, the relatively stable organic end product.
 The composting process involve different phases, and
uses diverse micro flora such as bacteria, fungal and
Mesophilic and thermophilic Actinomycetes eventually
converting organic waste to humus.
 The four phases include: 1) the mesophilic phase; 2) the
thermophilic phase; 3) the cooling phase; and 4) the curing
phase also called (ageing or maturing phase)

10. IMPORTANCE OF C:N RATIO
 C:N ratio is one of the most important parameters
that determines the extent of composting and degree
of compost maturity. The ideal finished compost
should have a C: N ratio between 15:1 and 25:1
 The proportion of carbon and nitrogen (C: N) is a
major controlling factor in the composting processes.
The reduction in C: N ratio is regarded as a criteria
of maturity of compost. Hence, maintaining the
correct C: N ratio is important to obtain good quality
compost.

11. METHOD
 Rice straw is used as the main material for composting together
with poultry droppings and green leaves. Composting was carried
out in a shaded area.
 Chopped rice straw approx. 1inch in size. The chopped rice straw
was soaked in 0.1% urea solution for 3-4 minutes and then placed in
plastic bin.
 The composting bin were placed in a raised base to maintain the
leachate resulting from the composting process and covered from
plastic bags to prevent from the direct sunlight and rain. Aeration
was facilitated by bins design with holes around the bin.
 The moisture content was maintained at 50-60% by the addition of
water through the active composting process by frequent checking.

12.  The mixtures were turned at 7-day interval to maintain
porosity and were composted and maintained for 90
days. Turning (mixing) the matter also brings fresh,
oxygen rich air into the bins.
 Compost sample were taken from each treatment at 30,
60, and 90 days of the composting and were analyzed
for changes in physical and chemical properties
throughout the composting process.

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