Rice Organic Cultivation Guide By Natand

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Organic Farming in the
Tropics and Subtropics
Exemplary Description of 20 Crops
Rice
© Naturland e.V. – 1st edition 2002
These cultivation guidelines have been published by Naturland e.V. with the kind support of
the Deutsche Gesellschaft für Technische Zusammenarbeit mbH (GTZ, German Agency for
Technical Cooperation) financed by the Bundesministerium für Wirtschaftliche
Zusammenarbeit (BMZ, Federal Ministry for Development Cooperation). The cultivation
recommendations at hand for 20 crops of the tropics and subtropics being of significant
importance for the world economy were written by various authors.
Naturland would like mention the following authors and thank them for their contributions:
Franz Augstburger, Jörn Berger, Udo Censkowsky, Petra Heid,
Joachim Milz, Christine Streit, Vitoon Panyakul, Koen den Braber.
The cultivation guidelines are available in English, Spanish and German for the following
crops:
banana, brazil nut, cashew nut, cocoa, coconut, coffee,
cotton, hibiscus, macadamia, mango, papaya, peanut,
pepper, pineapple, sugar cane, sesame, tea, vanilla.
The cultivation guidelines for Bananas, Mangoes, Pineapples and Pepper were revised in
2001 for the United Nations Conference on Trade and Development (UNCTAD) by Udo
Censkowsky and Friederike Höngen.
In 2002 two more guidelines, for rice and date palms, were published in English.
All the authors emphasize, that the cultivation recommendations at hand can just provide
general information. They do not substitute technical assistance to the farmers with regard
to the location.
All indications, data and results of this cultivation guidelines have been compiled and
cross-checked most carefully by the authors. Yet mistakes with regard to the contents
cannot be precluded. The indicated legal regulations are based on the state of the year 1999
and are subject to alterations in future. Consequently all information has to be given in
exclusion of any obligation or guarantee by Naturland e.V. or the authors. Both Naturland
e.V. and authors therefore do not accept any responsibility or liability.
Furthermore the authors kindly call upon for critical remarks, additions and other important
information to be forwarded to the address below. The cultivation guidelines will be updated
regularly by Naturland e.V.
Naturland e.V.
Kleinhaderner Weg 1
82166 Gräfelfing
Germany
phone: +49 - (0)89 - 898082-0
fax: +49 - (0)89 - 898082-90
e-mail: naturland@naturland.de
website: www.naturland.de
We pass our gratitude to Peter Brul of Agro Eco for his helpful comments on the manuscript.
Our best thanks are also devoted to all supporters of this publication, in particular Mrs
Sybille Groschupf who cleaned up the text from errors in strenuous detail work and did the
attractive layout.
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Index
1.Introduction ............................................................................................................. 1
1.1. Botany................................................................................................................. 1
1.2. Varieties and countries of origin.......................................................................... 2
1.3. Uses and contents .............................................................................................. 2
2. Aspects of Plant Cultivation ................................................................................... 3
2.1. Site requirements................................................................................................ 3
2.2. Seeds.................................................................................................................. 4
2.3. Planting methods ................................................................................................ 5
2.4. Diversification strategies ..................................................................................... 5
2.5. Nutrients and organic fertilization management.................................................. 6
2.6. Biological methods of plant protection ................................................................ 6
2.6.1. Diseases .......................................................................................................... 7
2.6.2. Pests ................................................................................................................ 7
2.7. Crop monitoring and maintenance ...................................................................... 8
2.8. Harvesting and post harvest treatment ............................................................... 8
3. Product Specification and Quality Standards......................................................... 9
3.1. Wholegrain and white rice................................................................................... 9
3.2. Quality requirements......................................................................................... 10
3.3. Packaging and storage ..................................................................................... 11
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Organic Cultivation of Rice
1. Introduction
Rice is the main staple food crop in the world and the crop is closely associated with
the culture of billions of people around the world, particularly in Asia and Africa.
Archeological data show that rice was already grown 6,000 – 7,000 years ago in
countries such as China and Thailand. It is believed that the construction of irrigation
systems for rice cultivation formed one of the cornerstones for the development of
some of the major civilizations in South-East Asia, such as Angkor Wat.
Because the rice plant is highly adaptable to local environment and because human
has succeeded in modifying local agro-ecosystem, rice can now be grown in many
different locations and under a variety of climates. Rice farming can be found in all
continents of the world as far north as the Northeastern China at latitude 53°N down
south to many regions on the equator and down to New South Wales in Australia at
latitude 35°S. In most cultivation areas, rice is grown at or near sea level, but it can
also be found at high elevation such as those in Nepal where rice is cultivated at 2,000
meter above sea level. Rice is normally grown under moderately submerged
conditions but can be grown also under upland conditions or in 1 – 1.5 m deep water.
1.1. Botany
Rice is a typical representative of the family Gramineae (grasses) but it belongs to the
genus of Oryza. There are some 25 species of rice in the genus Oryza. The dominant
rice species is Oryza sativa, which is believed to have originated somewhere in
South-East Asia. Today, it is cultivated in Asia, Africa, Europe, Oceania and the
Americas. In Africa Oryza sativa has now almost fully replaced the local species O.
glaberrima, which was grown as a main staple crop in Western Africa before.
Other members of the Oryza genus are in general not cultivated but some indigenous
peoples collect them in times of food scarcity. The "red" or "black" rice also has some
popularity in the Western countries where they are sold as specialties. Some wild rice
is important weed in the cultivation of Oryza sativa and some of them are also used in
the breeding programs for O. sativa.
Within Oryza sativa, three sub-species are known: "japonica", "indica" and "javanica".
"Japonica" varieties have a short grain, are more or less glutinous and originate in
colder climates (Japan, Korea, North China). "Indica" varieties have a long grain, are
not glutinous and belong to the warm, tropical regions. "Javanica" varieties have a
medium long grain, are glutinous and are only grown in Indonesia.
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1.2. Varieties and countries of origin
There are many ways to distinguish rice varieties. The most common one is based on
the length. The main groups of varieties are thus long-grained and short-grained
varieties. The short-grained varieties are more adapted to colder climates and are
therefore commonly grown in Japan and Korea and in Europe. The long-grained
varieties are common to warmer climates. Some experts further classify varieties
based on the ratio between their length and their width. In this system the shortest rice
is almost round (the Spanish "bomba") and the longest one is the Basmati.
Because rice is such an ancient crop, farmers have over the centuries developed
many local varieties. "Modern" rice breeding started with the establishment of IRRI
(the International Rice Research Institute) in the early 1960s. Nowadays, most
national rice breeding programs, particularly in Asia, depend on IRRI for new
materials which are then crossed with local varieties in order to create varieties that
are well adapted to local agro-ecological conditions and consumption preferences.
1.3. Uses and contents
The rice grain is mostly consumed boiled (or fried) as main staple but it is also widely
used for snacks, appetizers, rice soups (congee) and desserts. Rice is also used as
flour, for making rice wine and as ingredient for beer and liquor. The rice bran is
sometimes processed and sold as food supplement. However, most of the bran and
other remains from the milling are used as animal feed. Rice straw, husks, bran, etc.
are also a valuable source to fertilize the rice field and for composting.
Rice is harvested from the field in form of grain, often referred to as "paddy". Each
grain consists of many layers. The outermost layer is called husk. Husk consists
mostly of silica and cellulose. The inner layers are called bran layers, the most
nutritious part of rice. Each layer consists of a very thin bran film. Bran is mainly fiber,
vitamin B, protein and fat. At the base of each grain is the embryo which will grow into
the new plant. The innermost part of the grain is the rice kernel, consisting mainly of
starch. Two main compositions of rice starch are amylose and amylopactin. The ratio
between these two determines the cooking texture of rice. Rice does not contain
gluten. Glutinous rice is therefore a very misleading term because the stickiness of
rice is not caused by gluten but by a high level of amylopactin.
During rice processing, i.e. milling and polishing, the husk, bran layers and embryo
are normally removed. The result is called white rice. For the socalled wholegrain rice,
the bran layers are still (partly) intact and this kind of rice therefore has a higher
nutritional value than the white rice. However, wholegrain rice cannot be stored as
long as white rice. In order to obtain a white rice but with a nutritional value more
similar to brown rice, the process of parboiling has been developed. Before polishing,
the rice is soaked, then steamed and finally dried. During this process some of the
nutrients from the bran is absorbed by the rice kernel so that they are maintained
during the following processing.
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Rice seed (paddy) contains 6.7-8.3% protein, 2.1-2.7% of crude fat, 8.4-12.1% crude
fiber, 62% starch and 19.1% dietary fiber.
2. Aspects of Plant Cultivation
Rice farming system has remains more or less unchanged since the immemorial time.
The major technological change occurred in early 1970s with the invent of “Green
Revolution” marked by the introduction of high yielding varieties (HYVs). Farmers
adopted green revolution package are encouraged to use HYV seeds, artificial
fertilizers and pesticides. With the use of artificial highly soluble fertilizer, the HYVs
are often vulnerable to pest and diseases. The application of pesticide upsets
agro-ecological system and destroys pest-natural enemy balance, causing further
pest infestation. As rice is largest cultivated crop in Asia, the total amount of
agrochemicals used in rice are also highest.
Beside substituting agrochemcials with natural organic fertilizers and mechanization
of land preparation and harvesting, the method of rice cultivation has more or less
remained unchanged from traditional rice farm thousand years ago.
2.1. Site requirements
From historical evidence dated around 2000 – 1500 B.C., rice was originally grown in
a broad belt of Asia, from central India in the far west to Southern China in the far east.
Later on rice cultivation was spread southward to Indonesia and the Philippines and to
the east of Korea and Japan. With colonial trade, rice was then introduced to North
and South America and Europe. This indicates that climatic condition for rice
cultivation is very diverse, ranging from tropical, sub-tropical or even temperate
zones.
Most people associate rice farming with flooded lowland plain areas. But in fact rice
can be grown in almost all different geographical conditions provided that appropriate
rice varieties is chosen and appropriate farming system is adopted. Upland farming is
the oldest method of rice cultivation and has undergone evolution to a system
presently known as shifting cultivation. Shifting cultivation is a very sustainable way of
farming provided that it is practiced with long fallow period. But shifting cultivation is
eroding fast due to government conservation policies prohibiting farming in forest
areas. Lowland farming is now the most popular way for rice cultivation. Table below
compares different rice farming system appropriate from particular geographical
conditions.
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Dry upland Shifting cultivation where rice field is
not leveled nor bunding. Rice seed is
broadcasted and rice plant relies on
rainfall only.
Traditional varieties with
medium tall (130-150 cm)
and yield around 1 tons/ha.
Rainfed
lowland
Field is leveled and bunded. Rice seed
can be broadcasted or transplanting of
seedling.
Traditional or improved
varieties with medium tall
(130-150 cm). Yield is around
2 tons/ha.
Irrigated
lowland
Similar to rainfed lowland but water
source comes from irrigation. Water is
sufficient and can be regulated,
allowing rice to be grown more than
one crop a year.
HYVs with semidwarf to
medium tall (100-130 cm).
Yield is around 3-3.5 tons/ha.
Floating
and
deepwater
Rice fields are flowed with water from a
depth of 30 cm and deeper (can be as
deep as 6 meter). Rice can be
broadcasted or transplanting.
Traditional variety with very
tall plant (above 150 cm) or
floating with water level. Yield
is around 1.5 tons/ha.
It should be noted that rice has a special characteristic that it can withstand
water-logging condition. Farmers utilize this special character by growing rice in
semi-aquatic conditions so that weeds can be more easily controlled. A new farming
method known as System of Rice Intensification (SRI) encouraging rice farming in
non water-logging conditions shows the possibility to increase rice yield by 2-3 times.
2.2. Seeds
Rice is an annual grass plant. Propagation can only done by seeding. Rice is
self-pollinated plant and therefore seed can be kept for following crop. But seed
selection is highly recommended because mixing of different varieties can reduce rice
quality when it is sold.
Seed preparation is normally done to encourage fast germination. But direct
broadcasting can be done without any preparation. Seed preparation starts with
washing and sorting dirt and immature grain. Then seed is soaked in water for 12
hours. After that soaked seed is packed into bag to incubate the seed, encouraging
seed germination. The incubation lasts for 1-2 days and the temperature should be
maintained at around 30 degree Celsius. During incubation, rice bag should be turn at
least once a day to allow air flow and prevent over heating.
For one hectare of rice transplanting, around 70-80 kg of rice seed is needed. For
direct broadcasting, around 90-100 kg of seed is needed.
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2.3. Planting methods
As there are diverse systems of rice farming, it is not possible to describe all systems
in satisfactory details. The following description limits only to lowland annual rice
cropping system. Lowland annual rice crop begins soon after the first rainfall. Rice
fields are ploughed to get rid of weed and left over rice stalks. Weed and stalk
residues are incorporated into the soil and the fields are left for the organic matters to
decompose. After the decomposition, the second plowing is done to loosen the topsoil
and to flatten the field in order to make it easier to regulate water level. Traditionally,
animal is used for all the land preparation. However, increasingly a small plowing
machine is used. Rice seedlings are prepared during the land preparation and
transplanted into the field 1-2 months after land preparation (seedling is around 30
days old).
Depending on variety, around 55-85 days after germination, rice will start to produce
tiller. During early tillering stage, rice plant needs high nitrogen fertilization in order to
encourage maximum tillers. Too much nitrogen fertilization, however, will lead to over
vegetative growth and cause the plant to collapse. After tillering, rice will start to
initiate panicle. Again, fertilization may be needed at this stage to encourage panicle
development. After this stage, there is little need for farm management for rice crop,
beside weeding and regulating water level in the field.
Rice plant takes around 90-150 days to mature and ready for harvesting. During
vegetative and flowering stages, rice fields must be kept moisture otherwise the rice
growth and yield can be severely affected.
2.4. Diversification strategies
It is rather difficult to do intercropping with rice if rice farming is done on semi-aquatic
condition. Upland rice farming can be intercropped with several annual field crops,
such as bean and vegetables. Crop rotation is also quite difficult unless water is
available during dry season. Perennial trees that can withdstand drought and
waterlogging can be grown in rice fields and around the bunds. Small shrub can also
be grown in field bunds. Tree planting is highly recommended as it helps to improve
farm bio-diversity.
If sufficient water is available during dry season, rotation with leguminous crops
should be encouraged. Legumes can serve as cover crop to protect soil surface, to
increase soil fertility through nitrogen fixation, and to produce organic matters. Also,
harvested bean can be sold to increase farm income. High nitrogen-demanding crop
(e.g. corn, leafy vegetable) should be avoided because soil fertility may be severely
depleted when such rotation is repeated continuously.
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2.5. Nutrients and organic fertilization management
Beside general organic soil management, (e.g. cover soil surface, incorporating
organic residue back to soil, improving soil structure with compost) organic rice
farming requires specific fertilization and nutrient management. As mention earlier,
there are at least two growth stages that require careful intervention, one during early
tillering and another during panicle initiation.
First let consider overall nutrient and fertilization strategy. With organic farming, it is
better to provide nutrient to soil and let soil feed the rice crop. Generally, green
manure is preferred to other organic fertilizer because green manure is easier to
handle and more effective in supplying nutrients. There are several varieties of
leguminous crops that can be used but each has its own special characters. Selection
of leguminous crop must take into account water, soil and labour conditions. The
following are suggested list of popular leguminous crop used in organic rice farming:
• green gram (Vigna radiata L.) broadcasting (at the same time as the rice)
• sesbania crop (Sesbania rostrata) sown early in the rainy season
• sword bean (Canavalia ensiformis) sown early in the rainy season or after
the rice harvest as rotation crop
• various bluegreen algae and azolla in flooded rice field
Compost of rice straw and animal manure should also be encouraged if straw is
removed from rice fields. Rice husk and bran should be added to the compost pile in
order to recycle nutrient back. Compost should be applied by spreading in the field
before first plowing so that it can be thoroughly incorporated into the soil.
For specific nutrient management of rice farming, animal manure is recommended.
Aged animal manure is used, e.g. non-battery chicken, pig or cow dung. Rice plant
should be monitored before applying animal manure because over fertilization may
cause pest infestation or excessive vegetative growth.
2.6. Biological methods of plant protection
Although one may think differently from the experience of the Green Revolution,
under normal conditions rice is a crop which rarely suffers from main yield losses
through pests and diseases. Main reasons for this are the crop's high capacity to
compensate for damage to leaves or tillers, the high level of naturally occurring
predators and parasites of most pests, and the fact that rice in many areas is
cultivated only once a year (with a long dry period in between crops).
To control pests, diseases and weeds, several biological methods are being used.
Cultivation methods for fertilization and water management are very important
because of their direct effect on crop health and because of their effect on the growing
conditions of the pest, disease or weed. Plant variety selection is also very important
and many local varieties have very good characteristics in terms of disease
resistance.
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And apart from these preventative measures, pests and diseases can also be directly
controlled by applying botanical pesticides or bacterial and virus preparations.
2.6.1. Diseases
The main diseases in rice are rice blast and sheath blight. However, a large number of
other diseases (fungi, bacteria, nematodes and virus) occur in the rice field which
could from time to time cause problems locally.
Disease management largely depends on variety selection and good management. A
good fertilizer management is important. For example, rice blast develops better
when nitrogen application is high. Plant spacing is also important to reduce the spread
of diseases. Some virus diseases such as tungro, can be transmitted by insects
(leafhoppers). For this disease vector management is therefore important, mainly by
stimulating the natural enemies of these insects or the application of botanical
pesticides.
An interesting method to prevent disease infestation is the simultaneously planting of
several rice varieties in one field.
2.6.2. Pests
Rice has a whole range of pests in all stages of its cultivation period. During the
seedling stage, rice gall midge and thrips are important, while in the tillering stage a
whole range of pests feed on the leafs and tillers. Important leaf feeding pests are
leaf-folders and case-worm, while stem-borers feed in the tillers. Sucking insects such
as leafhoppers, plant-hoppers and black bugs are also important during this stage.
During the ripening stage of the crop, rats and paddy bugs are the most important
pests. Birds can also cause problems in the ripening crop. Snails and crabs are
important in the younger stages of the rice crop.
Most rice pests have a large range of natural enemies and rarely cause significant
yield loss despite sometimes they may cause heavy damage to the plant. However,
as rice can recover itself very well and in spite of heavy damage on rice plant, the rice
plant can still deliver more or less the same yield as non-damaged crop. The
in rice there is no direct relation between damage and yield loss as trials with farmers
in many IPM (Integrated Pest Management) training programs have demonstrated.
These trials show that up to 30-40% of damage to leaves and 10-20% of damage to
tillers will not result in any yield loss because the rice plant is able to compensate for
lost leaves and tillers.
Insect pest management is rarely needed as explained above, but when farmers need
to intervene they can use botanical pesticides or bacterial and virus preparations.
They could also try to increase the number of natural enemies in their fields by
planting flowering plants on the bunds or leaves some straw in the field after
harvesting. Resistant varieties can also be useful in some cases.
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For the management of rats and snails many biological methods can be used, such as
trapping, hand picking, release of predators, etc. but there success is mostly
determined by the existence of good cooperation between farmers in a large area. For
these pests control measures should also be applied even when populations are low
and may not seem very important.
2.7. Crop monitoring and maintenance
Crop monitoring in rice should be based on observing crop health and the balance
between pests and natural enemies. Healthy plants will be better able to resist an
attack by an insect pest or an infestation by a disease. Most field observations by
farmers are directly related to this condition, for example when checking the water
level.
2.8. Harvesting and post harvest treatment
When rice grain in the field turns yellow, it is time for harvesting. If there is still water in
the field, it should be drained out and let the field dried for at 7 days. Rice grain is
harvested and left to dry in the field before threshing.
Traditionally, rice is harvested manually by hand using simple tools like sickle and
threshing is also performed manually. However, combine harvest machine or
threshing machine is replacing traditional method. In such cases, the risk of organic
grain mixing with conventional grain arises, so it is highly recommended that the
machine is properly cleaned before switching to handling organic crop.
If grain can not be dried in the field, other drying method is needed to bring moisture
content in the grain down. This can be done by spreading grain on the ground under
the sun or dried in silo with drying machine. Rice grain should have less than 15%
moisture before storage.
Dried grain then can be stored in jute or polyethylene bag.
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Wholegrain Rice
White Rice
Polishing
Bran Removal
De-husking
Harvested Paddy
3. Product Specification and Quality Standards
3.1. Wholegrain and white rice
Wholegrain rice is also known as husked rice, cargo rice or brown rice. It is the rice
grain that the husk has been removed. White rice is the rice grain that has its husk and
bran removed. Another method of processing paddy is parboiling where paddy is
pre-cooked before milling. Rice is normally sold either as wholegrain, white or
parboiled rice.
The following is a processing steps involved in different paddy processing.
Parboiled rice
De-husking
Drying
Heat Treatment
Soaking with water
Harvested Paddy
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3.2. Quality requirements
The following is the list of quality characteristics for wholegrain and white rice required
by importers. Different minimum and maximum values is subjected to negotiation
among importers and exporters but they must comply with national regulations
governing food and hygiene standards.
Quality characteristics Minimum or Maximum values
Physical Brown White
Foreign Bodies
- organic
- inorganic
1.5%
0.5%
0.5%
0.5%
Paddy 2.5% 0.3%
Damaged kernels 4.0% 3.0%
Immature kernels 12.0% 2.0%
Chalky kernels 11.0% 11.0%
Red kernels 12.0% 4.0%
Water content 15% max
Residues
Pesticides Not measurable
Mycotonins
Afaltoxin B1, B2, G1, G2 < 0.2 µg/kg
Salmonella Not measurable
Staphylococcus aureus < 100 CFU/g
Escherichia coli < 5 CFU/g
Clostridium prefringens < 10 CFU/g
Bacillus cereus < 10 CFU/g
Micro-organisms
Total Germ Count 100,000 CFU/g
Enterobactericeae < 100 CFU/g
Yeast < 100 CFU/g
Moulds < 100 CFU/g
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3.3. Packaging and storage
Packaging
Rice export-import normally requires fumigation treatment to control grain insects.
Conventional treatment either applies methyl bromide or aluminium phosphine. With
organic rice trade, two alternative treatments are currently available, vacuumed
treatment or carbon dioxide fumigation. The two methods then requires different
packaging materials as vacuumed treatment need non air-exchange bag while
fumigation need air-exchange bag.
Information printed on packaging during transport depends on whether the rice is
shipped in bulk on consumer package. Shipping in bulk, the rice package should
contain product name with specification that the rice is organic quality, name of
exporter or trader, country of origin, weight, and batch number. For consumer
package, the expiry date must be added.
Storage
Rice quality can be affected by temperature and air moisture. Different processed rice
(i.e. wholegrain, white or parboiled, required different storage conditions. Parboiled
rice should can be stored up to one year if keep at lower than 22 degree Celsius and
airtight storage. For wholegrain, the maximum storage is two years with airtight
storage and temperature is kept between 10-35 degree Celsius while white rice can
be stored up to three years.

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