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Innovative Production Technologies for Maximizing Rice Productivity and

Profit

Dr. R. Rajendran1 and Dr. M. Dhakshinamoorthy2

Food security to the people is the key issue pressing the scientists, bureaucrats

and politicians around the world. The demand for food grain is escalating day by

day due to ever growing population. Among the food grains, rice is one of the

important staple foods for world’s part of the population. Almost 90% of the

world’s rice is produced in Asia. China is the world’s leading producer, growing

nearly two-fifths of Asia’s total on 32 million ha. India possesses the largest rice

area (44 million ha) producing nearly a quarter of Asia. (Moya et al., 2004). About

60% of the rice area in Asia is irrigated which constitutes three-fourths of Asia’s

rice (Cassman and Pingali, 1995), Irrigated rice farming plays a vital role in

meeting the growing demand of rice eating population. But the rice production is

the challenging enterprise now because of stagnant/declining productivity,

increasing production cost and declining profits in the rice growing countries. The

growth rates of rice production declined from 3.25 (1967-84) to 1.5% (1984-96)

in Asia (Dawe and Dobermann, 1999). Recent estimates are that rice yields in

Asia must increase by about 14% from 2000 to 2010 and 25% from 2010 to 2020

(Dawe, 2001). Amidst the on-going efforts on genetic and grain quality

improvement, there is an urgent need to explore whether the present

management options meet the requirements of rice plant for achieving high

yields. The over all factor productivity is at decreasing trend which needs to be

considered more seriously to make rice farming profitable (Cassman and Pingali,

1995). Hence, the present management technologies must be fine tuned further

to reduce the cost of rice production and increase the profitability apart from

conserving scarce natural resources, maintaining soil fertility and protecting the

environment.

Rice is the staple food of Tamil Nadu, India, cultivated in an area of about

2.1 million ha producing 7.2 million tones. Rice is grown under three different

eco systems viz., irrigated, semi-irrigated and rainfed conditions. Irrigated rice

eco system is the predominant one which is being threatened by issues like

resource degradation, declining productivity, escalating input costs and

diminishing profitability (Moya et al., 2004). At this juncture, it is essential to

develop strategies for sustaining the productivity and profitability of irrigated

rice production in the country as whole. The productivity of semi-irrigated rice

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(dry sown in dry soil and flooded after 30-35 days) largely depends on the crop

establishment, water

***************************************************************************1.

Professor and Head, Krishi Vigyan Kendra, Sikkal, Nagapattinam District, Tamil Nadu 2. Professor of

Soil Science, TNAU, Coimbatore, Tamil Nadu

availability and weed management. Onset of monsoon rain, quantity and

distribution of rainfall decides the productivity of rainfed rice. In any case, the

yield gap between average farmers and potential farmers can be narrowed down

only by disseminating innovative production technologies through effective

transfer of technologies.

Irrigated eco system

Irrigated rice systems in Asia have become one of the most important food

production systems in the world. Nearly 75% of the rice area in Asia is irrigated

where rice is often grown in monoculture with two or even three crops a year

depending upon the water availability. In Tamil Nadu, India, irrigated rice is being

cultivated as transplanted or direct wet seeded crop. In both the systems, rice is

planted in the puddle soil by transplantation or direct seeding.

Transplanted Rice

Crop establishment

The rice nursery management technologies need to be reemphasized

among farmers in order to economically utilize the scarce farm inputs like water,

seed, labour and fertilizer. In the traditional wet nursery, farmers use excessive

seed and water, spend huge money on labor. In the conventional wet bed

nursery, seedlings do not attain the expected size even at 25-30 days after

seeding (DAS) because of invariably high seeding rate and poor nursery

management. The recently introduced Integrated Crop Management (ICM)

technology for rice has modified certain crop management practices of the

system of rice intensification (SRI) developed in Madagascar to enhance rice

productivity and profit to farmers. It involves the transplanting of young (15-d)

seedlings at wider spacing, mechanical weeding, intermittent irrigation etc.

Among the practices, using “young seedlings” is the single most important

practice contributing for high yields under the modified SRI system. Planting of

15-d old seedlings at one per hill produced higher rice yield than 21-d seedlings

in North Sumatra, Indonesia (Makarim et al., 2002). Production of robust, healthy

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seedling at 15 DAS becomes the pre requisite for the adoption of ICM (modified

SRI) method of rice cultivation. The management techniques for the modified

rice mat nursery were standardized at the Soil and Water Management Research

Institute Farm, Thanjavur, India (Rajendran et al., 2005).

Development of modified rice mat nursery

i) Selection of suitable medium – Among the organic materials tried, soil +

press mud (a by-product from sugarcane industry) mixture at 1:1 ratio

produced robust seedlings. About 1.8 t of press mud is required to raise 100

m2 mat nursery required for planting one hectare of main field.

ii) Thickness of mat nursery-The 4-cm thick medium was found to be adequate

to produce healthy, robust seedlings in 15 days.

iii)Lining for spreading the medium – Polyethylene lining was found to beideal

and economical at a cost of about Rs. 250 per 100 m2 of mat nursery.

Used polyethylene fertilizer gunnies can also be used for spreading over

the seed bed.

iv) Seed rate- seed rate of 5-7 kg per 100 m2 of mat nursery was sufficient to

transplant 1 ha with one seedling per hill.

v) Nutrition – Seed bed medium blended with well powdered with well

powdered Dap @ 0.5 g kg-1 of medium produced the healthy, robust and

tall seedlings. Drenching of seedlings with 0.5% urea solution at 9 DAS was

found to give better seedling growth. Urea drenching is only an optional

practice as it depends on the level of seedling growth and fertility status of

the seed bed medium use.

vi) Input use efficiency – Modified rice mat nursery reduces the land

requirement (88%), water use (55%), and saves cost on seed (85-90%),

fertilizer (90%) and labour (34%). It is therefore highly economical and

affordable to farmers.

vii) Savings – It was recorded that the nursery cost can be reduced by

Rs.1800/ha by adopting the modified rice mat nursery when comparing the

traditional wet nursery.

At present, crop establishment is highly critical and challenging because of

problems like water scarcity, escalated labor wages and high rental rates of

machineries. Farmers transplant aged seedlings with more number of seedlings

per hill at closer spacing in their traditional way. Proper land leveling plays a key

role on management practices like crop establishment, water-nutrient-weed

management. For example, in the Cauvery Delta Zone (CDZ), perfect land

leveling during the Thaladi rice favors better crop establishment and nutrient

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management in the succeeding rice fallow pulse crop as experienced by the

researchers and farmers.

Nutrient management

LCC guided N management

Integrated nutrient management options like various sources of organic

manure (Chen et al., 1990), green manure (Medhi and Deka, 1996), bio-fertilizer

application (Kannaiyan, 1995), splitting the N doses, use of slow release N

fertilizers (Mamaril and Villapando, 1984) and soil test based nutrient use

efficiency, but each method has its own merits and demerits. International Rice

Research Institute (IRRI), Philippines, developed an approach called, site-specific

nutrient management (SSNM) through a partnership of organizations across

major rice-growing countries in Asia, including the CDZ of Tamil Nadu. SSNM is a

plant-based approach for applying nutrients to lowland rice at optimal rates and

times to achieve high yield and increased profitability. It makes optimal use of

existing nutrients from soil, residues, and manures; applies N fertilizer at the

time and amount required by the rice crop and applies P and K fertilizer based on

crop need, as determined through the omission plot technique (Buresh et al.,

2005). SSNM provides guidelines to avoid excessive early use/basal application

of fertilizer N, and real time N management using the leaf color char (LCC). The

LCC is an easy to use and inexpensive tool to more efficiently manage N fertilizer

in rice (Balasubramanian et al., 1999). LCC readings are taken every 7 to 10 days

starting at 21 DAT and continue until booting (about 55 DAT in Kuruvai and 75

DAT in Thaladi). If the LCC reading is less than the critical value of 4 (or 3 for

transplanted White Ponni variety and direct seeded rice,) N is applied @ 35 kg N

per hectare in Kuruvai and 30 kg N per hectare in Thaladi season.

Site-specific P and K management

A nutrient omission plot technique is used to determine P and K

recommendations that enable use of sufficient fertilizer P and K to prevent

depletion of soil fertility arising from the removal with grain and straw. The use

of SSNM has consistently increased profit for rice farmers across Asia. The

benefits of SSNM are often associated with better matching of N applications

with the plant’s need for N and more balanced application of K. Use of the SSNM

approach as enabled the identifications of locations where rice yields and

profitability can be increased through improved management of fertilizer K. In

the Cauvery Delta of Tamil Nadu in southern India, for example, use of SSNM has

lead to a new K recommendation for increasing profit in the New Delta zone.

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A blanket dose of NPK (with regular application of Zn So4 in the Cauvery

Delta) has been recommended for irrigated rice through out the rice tracts in the

State irrespective of soil and climatic differences. SSNM approach resulted in

large scale increases in grain yield and profit in two distinctly different zones of

Cauvery Delta, typically in the order of 8-13% over the blanket fertilizer

application (Nagarajan et al., 2004). The on-farm evaluation trials conducted for

four seasons with refined N and K management practices during 2001-2003 and

demonstration trials during 2003-2004 confirmed the earlier findings. SSNM

consistently increased grain yield and profit across seasons at the two diverse

experimental sites of Cauvery Old and New Delta during 2001-2003

(Ramanathan et al., 2005).

Soil-water-weed management

The crop establishment techniques introduced through ICM method

included mechanical weeding and soil stirring by rotating conoweeder or rotary

weeder, and intermittent irrigation which had increased rice productivity in the in

Cauvery Delta Tamil Nadu. In the experiments conducted at Tamil Nadu

Agricultural University (TNAU) Farm, Coimbatore, modified SRI system showed a

savings in irrigation water of 56% to 50% for conventional and young seedlings

respectively, without a significant effect on grain yield but mechanical weeding

and soil stirring improved the soil aeration, enhanced nutrient availability to the

crop thereby increased the number of panicles per unit area, filled grains per

panicle and grain yield (Thiyagarajan et al., 2002). On-farm trials conducted

during the wet season 2002 in the CDZ had shown encouraging results about the

soil and crop management practices followed under ICM approach (Rajendran et

al., 2005). Farmers recorded higher number of panicles per square meter (322 to

645) and grain yield (5680 to 7650 kg per ha) in the ICM plots which represented

an increase of 32% to 50% over their conventional method. The average net

profit was Rs. 4800/ha for the conventional method and Rs.16800/ha for the ICM

method. Thus, farmers obtained and additional profit of Rs.12000/ha by adopting

ICM. Farmers could get this increased profit because of enhanced crop

productivity and reduced cost of production achieved through modified rice mat

nursery. The increased grain yield was due to the synergistic effect of better crop

establishment, innovative water, weed and nutrient management practices

followed under ICM approach (Thiyagarajan et al., 2002).

Water saving rice production

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Rice production in Asia needs to increase to feed an ever-growing

population. But the water crisis threatens the sustainability of the irrigated

system. Rice is sensitive to declining water availability as it requires more water

than any other food crop. At the farm level, the water productivity can be

increased by reducing the water loss through seepage, percolation and

evaporation. Water saving irrigation technologies is receiving renewed attention

(Bouman and Tuong, 2001). Since the mid 1980s, many studies have without a

significant reduction in rice yield (Wang, 1992). In the river basin areas/ deltaic

conditions, practicing alternate wetting and drying is the difficult task because of

the unique land topography and poor drainage facilities. A new concept of

growing rice using less water is aerobic rice: growing rice in non puddled aerobic

soil using supplementary irrigation just like upland crops.

Management oriented rice Productivity

The ICM of rice crop (square planting of 15 d old seedlings at 1 or 2

seedlings per hill with wider spacing at 22.5 x 22.5 cm, mechanical weeding and

soil stirring by rotating conoweeder, intermittent irrigation and addition of

organic manure with judicious use of inorganic fertilizers and leaf color chart

(LCC)-based N management) had shown positive signs for increasing the

productivity of existing varieties in te Cauvery Delta and Thamiraparani river

basin areas of Tamil Nadu. About 100 adaptive research trials (ART) each in the

Cauvery Delta and Thamiraparani river basin area of Tamil Nadu were conducted

during the wet season 2003-2004 under the State Government sponsored

promotion of modified SRI scheme for up scaling the technology. The results

obtained from both the river basin areas had shown enhanced rice productivity

by the adoption of ICM (modified SRI) technology. In the CDZ, out of 94 farmers,

17 farmers got less than 5 t/ha of grain yield with a mean of 585 kg/ha,

representing 10-53% more yield than their conventional cultivation; 29 farmers

received 5-6 t/ha with a mean of 5565 kg/ha and 6-43% more yield; 48 farmers

received> 6 t/ha with a mean of 6980 kg/ha and 7-65% additional yield. The

results clearly illustrated that the potential yield of the existing rice cultivars

could be substantially increased by such innovative soil and crop management

technologies. Similarly results were obtained in the Thamiraparani river basin

also. Farmers and farm labourers need to be trained on the production of robust

seedlings through modified rice mat nursery, square planting of seedlings,

integrated nutrient management including LCC based N application, mechanical

weeding and alternate wetting and drying methods.

Direct wet seeded rice

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Irrigated rice is established by transplantation or direct seeding. Direct

seeded rice is an ancient practice of rice cultivation in India. Out of 44 million ha

of rice area in India, 35% of area is under rainfed lowland ecosystem and 6.4%

under rainfed upland (Kannaiyan et al., 2000). Direct wet seeding has been

adopted as the most efficient rice planting method in Asian countries where

labor supply is limited and expensive. Approximately a quarter of rice area in

Asia is currently direct seeded (Pandey and Velasco, 2004). The traditional

transplanting has been steadily replaced by direct seeding as it eliminates labor

demands for rice nursery management, and also reduces water requirement to

some extent besides shortening the crop maturity period by about a week. The

major factors driving the direct seedling methods of weed control, increasing

water scarcity and raising cost of farm labour.

Crop establishment

Although direct wet seeding has many advantages, the direct seeding

technology didn’t spread fast in several rice growing tracts because of

constraints like poor crop establishment and difficult weed management. Crop

establishment is critical because of poor water management especially at the

time of early crop establishment. Following are some tips for successful crop

establishment in direct wet seeded rice.

Use good seed itself could enhance yield by 5-20%

Perfect land leveling

Good drainage all around the field

Uniform sowing with optimal seed rate

Initial weeding though mechanical weeders or pre-emergence

herbicides

Good water management

Integrated nutrient management

Improved agro-techniques for direct seeding and associated crop

management practices need to be developed. Broadcasting of pre-germinated

seeds in the puddle soil is the traditional method of crop establishment. In

broadcasting method, excess seed rate is used leading to competition between

rice plants resulting in poor crop yields. IRRI, Philippines has developed a drum

seeder for sowing seeds at the optimal rates and appropriate spacing. The

performance of the drum seeding technology was evaluated in many of the rice

growing countries in Asia including India under the Crop Resources Management

Network (CREMNET) programme. It is really a break through in direct wet

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seeding technology as it established a uniformly good crop stand with saving of

precious inputs like seed, water and labor. Drum seeded rice recorded higher net

returns than machine transplanted and broadcast seeded methods in Karnataka,

India (Manjappa et al., 2004).

Weed management

It is very difficult to produce economic yields without good crop

management including weed control in direct seeded rice even from varieties

with high yield potential. But weed problem is more serious, resulting in zero

yield under the dry seeded upland situation than under direct wet seeded or

transplanted rice. It is necessary to provide weed free environment during the

early period of crop growth for the direct sown rice. In direct seeded rice first 30-

35 days after seeding are considered to be the critical period of weed

competition. The pre-emergence herbicide pretilachlor plus safener @ 0.3 kg

ai/ha can be safely applied at 3-4 DAS to effectively control grasses and broad

leaved weeds without any phototoxic symptom on the growing rice crop

(Rajendran and Kempuchetty, 1999). Herbicides can be applied safe at the very

early crop growth (0-5 DAS) when mixed with safener chemicals in order to avoid

damage to the emerging rice seedlings. Although, chemical means of weed

control in direct wet seeded rice becomes inevitable and gives effective weed

control, none of the individual weed control can be achieved (Kandasamy et al.,

2000). The IWM practices include summer ploughing, use of weed seed free

seeds, perfect land leveling, good water management and efficient weed

management practices viz., adopting both chemical and mechanical methods of

weed control.

Water management

Water management during early crop establishment stage is critical for

ensuring optimal plant population. Water should be drained 18-20 hours after

seeding in the direct wet seeded rice. Ensuring optimism soil moisture up to 7

days of sowing is very important for uniform germination of seeds. Water level

can be maintained thereafter depending upon the growth of the rice seedlings.

Draining water during the early tillering stage around 30th day facilitates proper

soil aeration and better tiller production. Alternate wetting and drying is the

efficient method of water management up to flowering stage, provided if the

fields are supported with good drainage channel all around. Wetting and drying

paves way for high weed incidence. But application pre-emergence herbicide

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solves this problem to a certain extent. Water should be drained 10 days before

harvesting which in turn helps for faster grain maturity.

Economics

On-farm farmers’ participatory demonstration trials conducted in about 40

locations by the Tamil Nadu Rice Research Institute, Aduthurai revealed the

better performance of direct seeded rice under puddle condition using drum

seeder. Direct drum seeding produced 9-12% increased net income over the

traditional transplanted rice crop. The increased returns are due to reduced cost

of cultivation to the tune of 15-20% over the transplantation method (Kannaiyan

et al., 2000).

Semi-dry rice ecosystem

Rice is being grown under diversified situations. In Tamil Nadu, water

scarcity and non-availability of labor compel the farmers to go in for single crop

of rice sown in dry soil and subsequently brought under submerged condition on

receipt of rain or canal water. The CDZ, granary of Tamil Nadu State met with

severe water scarcity during 1986 during which time entire rice belt was covered

under semi-dry rice crop and reaped yield comparable with traditional

transplanted rice. In few dry districts like Ramanathapuram, Sivaganga and

Pudukkottai, rice is dry sown and later on irrigated through monsoon rain or

stored rain water in tanks/lakes. In the Nagapattinam district of CDZ, farmers

cultivate rice by dry seedling which is brought under submerged state either with

canal water or North East monsoon rains. Such type of semi-dry ecosystem is

sporadically increasing in the rice growing districts of Tamil Nadu and production

technologies need to be fine tuned to manage drought and weed problem. In

direct sown rice culture, weed problem is severe, reducing the rice yields up to

97% under uncontrolled situation (Saxena and Vaishya, 1993). Following are the

critical issues deciding the productivity semi-dry rice.

Good land preparation and land leveling

Pre-monsoon seeding at appropriate time

Early crop establishment with good weed management

Soil and crop management strategy to escape drought

Seeds are soaked in 1% KCl solution for 10 hrs and then shade dried until

the seeds attain the original moisture level. Such type of seed hardening enables

the sprouting young seedlings to withstand early drought because of the KC1

treatment. Osmopriming and hardening of seeds can be successfully integrated

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to enhance the vigor of coarse and fine rice and osmohardening seeds with CaCl2

revealed efficient seedling establishment (Basra et al., 2004). Field is ploughed

to a fine tilts and applied with P and K enriched FYM @ 750 kg/ha. The dry seeds

are sown by broadcast or seed drill at the appropriate week coinciding with onset

of monsoon rains in the few places of CDZ. Application of pre-emergence

herbicide pretilachlor plus followed by the hand weeding was very effective in

controlling the weeds with the maximum weed control efficiency of 855

(Rajendran and Kempuchetty, 1999). Rice crop is brought under submergence at

30-40 days with the help of rain water or canal water. After the submergence, N

and K fertilizers are top dressed as followed in the case of transplanted rice.

Rainfed rice

Rainfed upland constitutes about 19 million ha around the world under a

wide range of management practices varying form shifting cultivation to highly

mechanized systems. In Asia, upland rice constitutes a significant part of the rice

area in India, Bangladesh, Indonesia, the Philippines, Thailand, Lao PDR, Vietnam

and Myanmar. Yields of upland rice have remained low (< 1 t/ha), where as

lowland rice yields have improved substantially over the years (Galinato et al.,

1999). In Tamil Nadu, India the situation is entirely different where rainfed rice is

sown in dry soil and later flooded with the help of stored rain water available in

huge lakes/tanks or by the North East monsoon rain. Such type of rice cultivation

is being practiced in dry districts like Ramanathapuram, Virudunagar, Sivaganga

and Pudukkottai. Direct seeding could be an alternative to transplantation of

rice, but poor germination, uneven crop stand and high weed infestation are

among the min constraints to its adoption (Du and Tuong 2002).

The success of rainfed rice cultivation depends on the adoption of

following technologies,

Good land preparation prior to the onset of monsoon

Choice of drought tolerant variety

Seed treatment to withstand drought and pest and disease incidence

Appropriate time of sowing to harvest the monsoon rain

Early crop establishment and management

Nutrient management with effective water management

Water harvesting and moisture conservation to escape and resist

drought effect.

Aerobic rice

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In Asia, more than 50% of the water used for irrigation is used to irrigate

rice (Barker et al., 1999). Irrigated rice in Asia produces about 75% of the

worldwide rice production (IRRI 1997). However, this irrigated ecosystem is

increasingly threatened by water shortage. Therefore, there is urgent need to

decrease water use in rice production and increase its use efficiency.

The adoption of aerobic rice is facilitated by the availability of efficient

herbicides for managing weeds and seed treatment technologies. In China,

case studies showed yields to vary from 4.5 to 6.5 t/ha, which was about

double that of traditional upland rice varieties and bout 20-30% lower than

that of lowland varieties grown under flooded conditions with 60% reduced

water use (Wang, 2002). Castaneda et al., 2002 indicated the water use from

transplanting to harvest under aerobic rice as 650-830 mm and 1350 mm

under flooded conditions. Because water use decreased relatively more than

yield, water productivity under aerobic cultivation increased by 20-40% over

that flooded conditions.

The rice area in CDZ is in descending order due to poor rainfall and non

availability of Cauvery water. Among the three seasons, Kuruvai season is the

potential period for growing rice owing to the availability of very good

sunshine, less pest and disease incidence and better crop growth. The water

scarcity very much affected Kuruvai rice in the Delta. This makes an

imperative change of the existing cropping pattern during Kuruvai season and

farmers are advised to cultivate non-traditional crops in the Delta. In the New

Cauvery Delta, soil is sandy loam in nature which could be effectively utilized

for growing aerobic rice. Research on aerobic rice production should be

intensified for sustaining the rice production in the traditional rice growing

tracts.

Aerobic rice could be tried as suitable alternate strategic crop in the New

Cauvery Delta of Tamil Nadu by best utilizing the rainfall and or available

surface/ground water in order to stabilize rice production in the region.

A successful change from flooded to aerobic rice production requires the

breeding of special aerobic rice varieties and the development of appropriate

water and crop management practices.

Future of rice farmers and rice research

Rice farmers in developing countries are poor and caught in a cycle of

endless poverty. Farmers can benefit from technologies that boost production

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and/or increase their income and employment. Increases in rice production

and farmers’ income depend largely on enhanced productivity and efficiency

of the rice production system. Focus need to be given based on the farmers’

size of land holding and capabilities. For very poor farming households and

marginal farmers, the priority is not so much yield, but, rather, the lessening

of risk.

Evolving high yielding cultivars is the first priority irrespective of the rice

eco systems. However, the productivity of exiting varieties under the irrigated

rice ecosystem could be enhanced by fine tuning the crop management. The

success stories about the ICM or modified SRI revealed the potential prospects

for boosting irrigated rice productivity through innovative crop and soil

management approaches. Evolving high yielding cultivars/hybrids, fine tuning

of integrate crop management, integrated peat management, integrated peat

management, production of quality grains are some of the issues to be borne

in mind or making the irrigated rice farming more sustainable.

Following are some of the broader areas of rice research being intensively

taken up for increasing the livelihood of the rice growers and rice eating

population in general.

Applying agricultural biotechnology to produce salt and drought tolerant

rice cultivars

Evolving new plant types for maximizing rice productivity especially I

the irrigated rice eco system

Enhancing nutritional quality of rice grain through breeding and

biotechnologies approaches

Integrated rice crop management with fine tuning of production

technologies to reduce the cost of production and enhance productivity.

Assessing climate changes and its effect on rice production and

adaptive technologies

Mechanization of rice farming to sustain rice productivity of rice growers

and nutritional quality of consumers.

Intensification research on conserving natural resources like land, water

and labor.

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