Home > RICE-WHEAT CROPPING SYSTEMS IN THE INDO-GANGETIC PLAINS: ISSUES OF WATER PRODUCTIVITY IN RELATION TO NEW RESOURCE CONSERVING T
RICE-WHEAT
CROPPING SYSTEMS IN THE INDO-GANGETIC PLAINS: ISSUES OF WATER PRODUCTIVITY
IN RELATION TO NEW RESOURCE CONSERVING TECHNOLOGIES.1
Peter R. Hobbs and Raj K. Gupta2
The rice-wheat
cropping system is found on 13.5 million hectares in South Asia and
is one of the most important cropping patterns for food self security
in the region. This system is found in the fertile, hot
semiarid to hot sub-humid regions of the
Indus and Gangetic alluvial plains of Bangladesh, India, Nepal and Pakistan.
Irrigation is commonly used to stabilize the productivity of this system
using surface canal and sub-soil tubewell water. Area and yield growth
has been responsible for continued production growth for these cereals
over the past 30 years and has matched population growth and demand
for food. This growth over the past 30 years was based on key inputs
like variety, fertilizer and irrigation with most of the investment
from the public sector. Future growth required to meet population growth
will be close to 2.5% per year and must come from yield rather than
area growth since the latter will decline as urbanization and industries
spread to prime agricultural land. Competition for water will be a major
challenge for agriculture and it is imperative that this scarce resource
is used efficiently. This paper describes various resource conserving
technologies that are being promoted by the rice-wheat consortium (one
of 7 CGIAR eco-regional initiatives) to attain the goal of raising productivity
in the region and meeting food security needs while at the same time
efficiently using natural resources, including water, providing environmental
benefits and improving the rural livelihoods of farmers and helping
to alleviate poverty. This post green revolution technology will depend
on farmer adoption and investment. Increasing and improving stakeholder
participation in experimentation and fine-tuning of the technology will
be a key to success.
RICE-WHEAT CROPPING SYSTEMS IN THE INDO-GANGETIC PLAINS: ISSUES OF WATER PRODUCTIVITY IN RELATION TO NEW RESOURCE CONSERVING TECHNOLOGIES.
The rice-wheat
cropping system is found on 13.5 million hectares in South Asia and
is one of the most important cropping patterns for food self security
in the region. Another 10 million hectares are found in China, mostly
in the central areas of the
Yangtze River Valley. This system is found in the fertile, alluvial
Indo-Gangetic Plains (IGP) of Bangladesh, India, Nepal and Pakistan
of South Asia. In this system rice is grown in the warm, sub-humid
monsoon, summer months and wheat in the cooler, drier, winter season.
Both crops are grown in one calendar year. Other crops, particularly
in the winter, are also grown including pulses, oilseeds, potatoes,
vegetables, fodders and sugarcane. Irrigation is a common feature of
this system either from extensive surface canal systems or from
shallow wells groundwater and tubewells (shallow or
deep). Rainfed rice-wheat also exists, but the majority of farmers apply
at least one irrigation for wheat and many a full irrigation schedule.
The population
growth rate in the IGP is still about 2% per year and will take a few
decades to stabilize. It is estimated that about 2.5% growth in cereal
production will be required to meet food demands in the next decade
(Hobbs and Morris, 1996). During the past 30 years, agricultural production
has been able to keep pace with population demand for food. This came
about through significant area and yield growth. Area growth was a result
of new lands being farmed and through increases in cropping intensity,
from a single crop to double or even triple crops per calendar year.
Area growth will be less important in its contribution to production
growth in the future as more land is used for urban areas and industry.
Yield growth will have to be the mainstay for providing the means for
meeting future food demands unless food imports start to play a major
role in South Asia. Evidence from some long-term experiments, however,
show that problems of stagnating yields at levels far below the
potential productivity and even yield declines are occurring in
some areas in the rice-wheat systems of South Asia (Hobbs and
Morris, 1996; Regmi, 2001a and 2001b; Dawe, 2000 and Duxbury, 2000).
Total factor productivity is declining and farmers have to apply more
fertilizer to obtain the same yields. Soil organic matter is declining,
new weeds, pest and diseases are creating more problems, and paucity
of irrigation water in northwest
is resulting in excessive ground water
developmentpumping.
less available. Farmers are complaining about high input
costs and low prices for their produce. Marketing of excess production
is a burden for farmers and a problem to governments for storage. There
is therefore a huge challenge ahead in the region to sustainably meet
future food demands without damaging the natural resource base on which
agriculture depends, producing food at a cost that is affordable by
the poor, and with incentives to farmers that allow them to improve
their livelihoods and ultimately alleviate poverty.
Water, the
subject of this workshop, will become a major limiting factor for sustained
production in the next decade in the IGP. Rapidly growing urban areas
and industry will compete with agriculture for good quality water. There
are already reports of declining water tables in some areas (Harrington
1993) leading to more costly pumping of groundwater and increased costs
of production. In several other
canal command other areas of the IGP, water tables
are rising leading to secondary
soil salinization. and bringing salts from brackish groundwater
to the surface and degrading the soil. The inter-basin transfer
of irrigation water to meet evapo-transpiration demands of the RW system
is a key feature of intensively cultivated irrigated agriculture in
the IGP. The demands for water from the rice-wheat system exceed that
available from rain and canal supplies. Farmers often rely on
use surface and groundwateras well,, which
in places is low in quality either
due to excessive salt content or to
presence of residual alkalinity
is often saline or alkaline, with detrimental effects to
soil health. Long-term, regional hydrologic salt and water balances
as influenced by existing and alternate management practices and as
driven by policies (e.g., pricing, common property management) are crucial
information, if we are to achieve sustainable agriculture in the region.
Scientists are using crop growth simulation and risk analysis models
to evaluate risk-efficient water-use strategies at the district level.
Initial results suggest that improved water and energy pricing policies
could reduce water use by 25%.
This paper describes various resource conserving technologies that are being promoted by the rice-wheat consortium (one of 7 CGIAR eco-regional initiatives) to attain the goal of raising productivity in the region and meeting food security needs while at the same time efficiently using natural resources, including water, providing environmental benefits and improving the rural livelihoods of farmers.
The rice-wheat
consortium was established in 1994 as a CG eco-regional initiative.
A CGIAR eco-regional program is a combination of natural resource management
and production (extension) in a defined geographical area with site
specific socio-economic and policy environments (Figure 1). The rice-wheat
consortium (RWC) for the Indo-Gangetic Plains is a successful partnership
between national programs (Bangladesh, India, Nepal and Pakistan) in
South Asia; several International Centers of the CGIAR (CIMMYT, IRRI,
ICRISAT, CIP and IWMI) and various advanced international institutions
(Cornell University, IAC, Wageningen, IACR, Rothamsted, CABI (UK), and
Melbourne University). The RWC focuses on issues of raising the productivity
and sustainability of rice-wheat systems of South Asia in an efficient
way and by conserving natural resources leading to improved livelihoods
and reduction of poverty.
The major success
of the RWC in the last few years has been the development and deployment
of resource conserving technologies with farmers in the rice-wheat systems
of South Asia (Hobbs, 2001a and Hobbs, 2001b). One major hurdle was
the changing of the mindsets of all the partners concerned since the
old phrase ��the more you till the more the yield�� was stubbornly
adhered to and a lot of effort was required to overcome this bias. In
this paper, resource-conserving technologies (RCTs) are defined as any
practice that will result in improvement of the efficiency of natural
resources. Water is the major natural resource described in this paper.
Another term, used by FAO for RCTs is conservation agriculture. Globally,
these technologies are rapidly gaining popularity among farmers as they
result in higher production at less cost with significant benefits to
the environment and more efficient use of natural resources. This ultimately
results in higher profits, cheaper food, and improved farmer livelihoods.
Crop diversification is also easier as less land is needed to produce
staple cereals, freeing up land for other crops. Interestingly, farmers
are bearing the capital cost of this new technology as opposed to the
public sector.
Another major challenge in the region is how the knowledge intensive technologies are transferred to the farmers, especially with weak linkages of existing extension systems. This has been accomplished by the RWC through promotion of participatory approaches and expanded partnerships with stakeholders.
A basket of resource conserving technologies is being developed and made available to farmers for experimentation and adoption. Some are based on reduced tillage for wheat including zero-tillage. Bed planting systems are being promoted to increase water use efficiency and when combined with reduced tillage in a permanent bed system provide even more savings. Laser leveling combined with these tillage systems provides additional benefits. Many of the benefits of the tillage options for wheat are lost when rice soils are traditionally puddled (plowed while wet). System based technologies are now being promoted that do away with puddling so that total system productivity is raised. Use of groundwater to obtain early rice planting and efficient use of rainwater is another technology. The various technologies are described briefly below:
Surface seeding is the simplest zero-tillage system being promoted. In this tillage option wheat seed is placed onto a saturated soil surface without any land preparation. This is a traditional farmer practice for wheat, legume and other crop establishment in parts of Eastern India and Bangladesh. Wheat seed is either broadcast before the rice crop is harvested (relay planted) or after harvest.
Promotion of
surface seeding to plant wheat has been done for several years in areas
where the soils are fine textured, drain poorly, and where land preparation
is difficult and often results in a cloddy tilth. The key to success
with this system is having the correct soil moisture at seeding. Too
little moisture results in poor germination and too much moisture can
cause seed to rot. A saturated soil is best. The roots corkscrew
into germinate into the moist soil and follow the saturation
fringe as it drains down the soil profile. The high soil moisture reduces
soil strength and thus eliminates the need for tillage. Once the
root germinates and extends into the soil, the root can follow the saturation
fringe and still get sufficient oxygen for growth.
Additional irrigation may not be needed if the roots can penetrate
the surface layers., sSoils do not dry up
toor increase resistance for root
to penetrate and
so roots can follow the water table down the profile.
In China, where
surface seeding is also practiced, farmers apply cut straw to mulch
the soil, reduce evaporative losses of moisture and control weeds. The
standing stubble also protects the young seedlings from birds. However,
relay planting can be done only if the soil moisture is correct for
planting at this stage.
One of the major pluses of surface seeding is that no costly equipment is needed and any farmer can easily adopt this practice. Use of a drum or simple seeder for line sowing is found advantageous. This system is being monitored in farmer fields to determine if continuous surface seeding is possible or whether a rotation of tillage systems may be needed to control future weed problems.
This is another
RCT where the seed is placed into the soil by a seed drill without prior
land preparation. This technology, which has been tested in Pakistan
(Sheikh, 1993; Aslam, 1993), is presently being tested in other areas
of the Indo-Gangetic Flood Plains, including India and Nepal. This technology
is more relevant in the higher yielding, more mechanised areas of northwestern
India and Pakistan, where most land preparation is now done with four-wheel
tractors. However, in order to extend the technology in Eastern
parts areas of the IGP in Bangladesh, equipment
for 2-wheel hand tractors and bullocks is being modified .modified.
developed.
The basis for
this technology is the inverted-T openers (figure 2) that were developed
and imported from New Zealand. This coulter and seeding system places
the seed into a narrow slot made by the inverted-T as it is drawn through
the soil by the four-wheel tractor. The coulters can be rigid or spring-loaded
depending on the design and cost of the machine. This type of seed drill
works very well in situations where there is little surface
residue after rice harvest. This usually occurs after manual harvesting.
Not needed, can be deleted.
Where combine
harvesting is becoming popular, loose straw and residue creates a problem
for the inverted-T opener. Farmers presently burn residues to overcome
this problem of loose stubble whether they use 0-till or the traditional
system. Since the RWC want to discourage this practice, that has major
environmental and air pollution issues, future strategies will look
at alternative machinery and techniques to overcome this problem. Leaving
the straw as mulch on the soil surface has not been given much thought
in Asian agriculture. However, results from rainfed systems and some
preliminary results in Asia suggest that this may be very beneficial
to early establishment and vigour of crops planted this way
(Sayre, 2000) and for soil moisture conservation
, water infiltration and erosion. Studies are needed to explore
the regional scale benefits and longer term consequences
of this practice, already being
practicedadopted in some way in
the zero-till wheat system.idea
.
Interestingly,
significantly fewer weeds were found under zero-tillage compared to
conventional tillage (Verma and Srivastava 1994 and 1989; Singh, 1995)),
which is the opposite of the experience with zero-tillage systems in
developed countries (Kuipers 1991; Christian and Bacon 1990). This observation
has been confirmed in many other locations. Results from 336 on-farm
trials in Haryana are shown in Figure 3 where significantly lower weed
counts were found in fields with zero-tillage either before or after
herbicide applications. This difference can be explained by the nature
of the weeds found in the rice-wheat cropping system. Most of the weeds
affecting the wheat crop germinate during the croponly
in the wheat season, and since the soil is disturbed less under
zero-tillage, fewer weeds are exposed and fewer germinate. Also
before the weeds are able to grow and compete,
the main crop is able to cover up the surface and significantly
reduce weed biomass. Weed problems typically are more severe under
conventional tillage than under zero tillage, at least in the near term.
Longer-term research is needed to anticipate future consequences on
tillage changes on weed populations (for example, to quantify likely
shifts in weed species and the effects if those shifts on yield stability).
Earlier planting is the main reason for the additional yields obtained under zero-tillage (Table 1). Zero-tilled plots were planted as close as possible to 14- 20 November, the optimum date for planting wheat in India and Pakistan. The results of many trials suggest that the longer the farmer delays planting, the lower the yield. This finding has been confirmed in trials throughout the Indo-Gangetic plains in the past few years. In Haryana, surveys and crop cuts have shown that 0-till produces 4-500 kg/ha more grain than traditional systems. This is attributed to earlier, timely planting, less weeds, better plant stands and improved fertilizer efficiency because of placement with the seed drill. Some farmers are now in their 4th year of adoption of 0-till and find no deleterious effects that would make them revert back to the traditional system.
The Chinese
have developed a seeder for their 12 horsepower, two-wheel diesel tractor
that prepares the soil and plants the seed in one operation. This system
consists of a shallow rotovator followed by a six-row seeding system
and a roller for compaction of the soil. Several tractors and implements
were imported from Nanjing, China, into Nepal, Pakistan, and India,
where they have been tested over the past few years with positive results.
In Bangladesh, farmers are using more than 200,000 hand tractors from
China. Soil moisture was also
found to be critical in this reduced tillage system. The rotovator fluffs
up the soil, which then dries out faster than with normal land preparation.
The seeding coulter does not place the seed very deep, so soil moisture
must be high during seeding to ensure germination and root extension
before the soil dries appreciably. Modification of the seed coulter
to place the seed a little deeper would help correct this problem.
The main drawback of this technology is that the tractor and the various implements are not easily available and spare parts and maintenance is major issue. It would help if the private or public sector in South Asian countries could import this machinery or develop a local manufacturing capability. As it becomes more costly to keep and feed a pair of bullocks for a year, more farmers in the region are turning to significantly cheaper mechanized options of land preparation. One of the benefits of this tractor is that it comes with many options for other farm operations; it includes a reaper, rotary tiller, and a moldboard plough, and it can also drive a mechanical thresher, winnowing fan, or power source for pumping water. However, most farmers are attracted to the tractor because it can be hitched up to a trailer and used for transportation. For smaller-scale farmers who cannot afford their own tractors, custom hiring is a common alternative.
The Chinese tractor can also be used with a rotovator (Bangladesh) to quickly prepare the soil and incorporate the seed after a second pass. This speeds up the planting and results in better stands with less cost than traditional methods. However, the Chinese seeder attachment does a better job because the seed are placed at a uniform depth in the single pass. Engineers are experimenting with removing some of the blades that rototill the soil. In this way, a strip of soil is cultivated rather than the whole area. This reduces the power needs and costs and makes it easier for farmers to manage the tractor. In India, a four-wheel tractor version of this ��strip-tillage�� machinery is available.
In bed planting systems, wheat or other crops are planted on raised beds. This practice has increased dramatically in the last decade or so in the high yielding, irrigated wheat-growing area of northwestern Mexico (Meisner, 1992; K. Sayre, 1997). Bed planting in Mexico rose from 6% of farmers surveyed in 1981 to 75% in 1994, and farmers have given the following reasons for adopting the new system:
This system is now being assessed for suitability in the Asian Subcontinent. At Punjab Agricultural University, two bed widths and two or three rows of wheat planted per bed were compared with conventional flat bed planting. Two rows on 70cm beds were best. Two of the major constraints on higher yields in northwestern India and Pakistan are weeds and lodging. Both can be reduced in bed planting systems. The major weed species affecting wheat, Phalaris minor, is normally controlled using the herbicide Isoproturon, which is not always effective. Farmers do not always apply Isoproturon well or on time; in addition, recent reports have confirmed that P. minor has developed Isoproturon resistance (Malik and Singh 1995; Malik 1996; Malik, 1998). Alternative integrated weed strategies must be developed to overcome this problem. Preliminary observations indicate that P. minor is less prolific on dry tops of raised beds than on the wetter soil found in conventional flat bed planting. Cultivating between the beds can also reduce weeds. Thus bed planting provides farmers with additional options for controlling weeds.
Lodging is also less of a problem on raised beds. Additional light enters the canopy and strengthens the straw, and the soil around the base of the plant is drier. Reduced lodging can have a significant effect on yield, since many farmers in the Punjab do not irrigate after heading precisely because they want to avoid lodging. As a result, water can become limiting during grain filling, resulting in lower yields. On raised beds this irrigation need not be avoided for the reasons stated.
Results show that there are no significant difference between flat and bed planted systems, which means that yield was not sacrificed by moving to a bed system (table 2). In fact, with the proper variety (PBW 226), the yield from bed planting can surpass that of planting on the flat. Upright varieties such as HD 2329 perform poorly on beds and cannot compensate for the gap between the beds. Figure 4 shows some results from Haryana in 1998-99 and similar results are found since then. Wheat planted on beds is gaining popularity in Haryana and Punjab of India and in the Punjab of Pakistan. Farmers are particularly pleased with the water savings they obtain from bed systems.
An additional advantage of bed planting becomes apparent when beds are ��permanent�� – that is, when they are maintained over the medium term and not broken down and re-formed for every crop. In this system, wheat is harvested and straw is left or burnt. Passing a shovel down the furrows reshapes the beds. The next crop (soybean, maize, sunflower, cotton, etc.) can then be planted into the stubble in the same bed. Research in farmer fields has also shown that rice can be grown on beds making this system feasibility in the rice-wheat pattern. Rice can be grown on beds by either transplanting seedlings or direct seeded. At the moment, transplanting on beds is best since normal herbicides used for transplanted rice can be used to control weeds. As dry seeded herbicides become available and weeds can be managed, dry seeded rice on beds will become more attractive. One farmer in the Punjab obtained 9t/ha of rice transplanted on beds and saved more than 50% of the water he normally applies on flat, transplanted rice. This is being confirmed through monitoring water use in bed planted plots this year.
The use of beds also provides a way for improving fertilizer use efficiency. This is achieved by placing a band of fertilizer in the bed at planting or topdress. Using slow release formulations and experimenting with urea super granules can make further improvements. Both can be applied in the bed at the time of planting with the seed cum fertilizer drill.
Multi use of low quality water
Low quality
waters are often used in cyclic mode in the Indo-Gangetic plains. At
times they are blended with canal water in water
courses to improve the total water supply and also the flow rates.
Blending of low and good quality waters
have earlier been discouraged because of their adverse effect on crop
productivity. However, if the resultant electrical conductivity of the
blended water supplies is less than the threshold conductivity,
they can be used safely. In combination with new RCTs, blending of
water multi-quality water supplies in on-farm water storage
reservoirs not only improves the quality of
waters having residual sodium carbonates and
overcome problems associated with nightthis water, but
can also improve the use of rainwater
and water productivity and yields of
a bed planted wheat crop. Preliminary
results of a trial conducted in Pakistan have been very encouraging.
Bed planting system also offers scope for use of even
the saline waters. When saline waters are applied in raised
bed-furrow land configuration, it permits salt movement to the top of
the raised beds keeping the rootzone
relatively free of salts at the sill and
below the furrow. This improves the ability of the plants
to avoid early salt injury at seedling stage and subsequently improve
salt tolerance of the crop due to crop ontogeny.
Bed planting when combined with mulching or residue retention has the
potential to reduce evaporation losses from the soil surface, salinization
and further improve crop productivity
in saline environments.
Non-puddling for rice
The benefits of the new resource conserving tillage options listed above are lost when rice soils are puddle (ploughed when wet). The RWC is therefore encouraging research on-station and with farmers to find ways to eliminate this soil degrading process. Most rice farmers in South Asia traditionally puddle their soils to help pond water, reduce percolation losses and control weeds. Initial data indicates that rice fields do not need to be flooded after the first few weeks and that puddled soils have more cracking and need more water once the fields dry. Initial flooding though is important to promote tillering and to more effectively control weeds. Studies are also being initiated to determine the exact water balance for the puddled and non-puddled conditions at the field, water course and command level. This is being done for fields where bed planting is practiced and in fields with flat planting, with and without tillage. As mentioned above, farmers feel that bed planted rice saves water over the traditional system. Quantitative data will be available soon to confirm this.
Data presented in figure 5 shows that wheat yields are significantly better when wheat is planted with 0-till after non-puddled rice than after puddled rice. The data also shows that rice yields are similar between puddled and non-puddled situations if weeds can be controlled. This shows that RCTs need to be assessed on a systems basis and not on a single commodity.
Laser levelling
All the above technologies can benefit from levelled fields. This is being promoted in Pakistan as a means to improved water efficiency. However, when this is combined with 0-tillage, bed planting and non-puddled rice culture, plant stands are better, growth is more uniform and yields higher. Use of permanent bed systems and 0-tillage results in less soil disturbance and reduces the need for future levelling. India is also starting work on this and promoting levelling in farmer fields in Haryana and Western UP.
The winter
season following the long rainy season is short in Eastern India. Long-term
analysis of the rainfall data clearly indicates that there are three
distinct periods of moisture availability. The early moist period (evaporation
exceeds rainfall) extends over 12-18 days followed by 93-139 days of
humid moist period wherein precipitation exceeds potential evapo-transpiration.
This is followed by a moist period of 17-22 days where once again rainfall
is less than evapo-transpiration. If the rice seedlings and crop can
be established early in the first moist period, before the humid period,
the rice crop can benefit from the monsoon rain and grow without the
need for irrigation. Timely transplanting of rice also results in earlier
harvests and allows timely planting of the next wheat crop. The results
of farmer participatory field trials showed that the strategy of timely
transplanting of rice improves wheat yields. Rice wheat system productivity
was nearly 12-13 tons per ha when rice was transplanted before 28th
June. This was reduced by more than 40% when fields were planted after
15th August (to 6-7 tons/ha).
It was also reported that peripheral bunds 18-20 centimeter in height around fields could store nearly 90 percent of total rainwater in situ for improved growth and production of rice.
Farmers are
adopting the new RCT��s quickly. Figure 6 shows the rapid adoption
of 0-tillage in the region. More than 100,000 ha of wheat were grown
that way last year and this is expected to increase to a million in
the next few years. Farmer feedback on water savings with these new
technologies essentially says that they save water. For zero-tillage,
farmers report about 25-30% savings. This comes in several ways. First,
0-tillage is possible just after rice harvest and any residual moisture
is available for wheat germination. In many instances where wheat planting
is delayed after rice harvest farmers have to pre-irrigate their fields
before planting. 0-till saves this irrigation. Savings in water also
comes from the fact that an untilled soil has less infiltration than
a tilled soil and so water flows faster over the field. That means farmers
can apply irrigation much faster. Because 0-tillage takes immediate
advantage of residual moisture from the previous rice crop, as well
as cutting down on subsequent irrigation, water use is reduced by about
10 cm-hectares, or approximately 1 million liters per hectare. One additional
benefit is less waterlogging and yellowing of the wheat plants after
the first irrigation that is a common occurrence on normal ploughed
land. In 0-till, less water is applied in the first irrigation and this
yellowing is not seen.
Farmers also
report water savings in bed planting. Farmers commonly mention 30-50%
savings in this system. Farmers also indicate that it is easier to irrigate
with bed planting. Obviously, half the space is used for water and so
less water is used. The question is whether farmers need to apply more
number of irrigations with this system. This is being studied in a newly
started RWC ADB project in Pakistan and India. In the initial year of
planting rice on beds, farmers estimated they used 50-65% less water
than on the flat. They kept the beds flooded for the first week, but
were then able to cut down on irrigation frequency later. This also
needs to be confirmed with good quantitative data.
The On-Farm
water Management staff of Pakistan��s Punjab comparing RCT farms has
collected data on water use efficiency (Gill, 2000). This is presented
in table 3 for two locations. All the systems provided better water
use efficiency compared to traditional systems. Average water saved
with laser leveling, zero-tillage and bed planting over the traditional
was 715, 689, and 1329 m3/ha with a value of rupees 522,
503 and 970 per ha based on a water rate of Rs900/acre-foot for private
tubewells for the year 1999-2000.
We still need to collect the data for the water use under puddled and non-puddled rice cultivation. Definitely, water percolation will be higher in non-puddled situations, but the total water use may be less since no water is needed for seedling raising or puddling the main field. Also when puddled soils dry, and many farmers cannot keep their fields continuously flooded, soils crack and so the field needs more water to fill the profile when water is next added. Less cracking occurs in non-puddled soils. Data is also being accumulated that the rice crop does not need to be kept flooded the whole season. Standing water is needed early to help tillering and control weeds, but later this is not required.
Adoption of RCTs in South Asia has been rapid over the past few years, especially for 0-till with the inverted-T planter. Figure 6 show that more then 100,000 ha was grown last year. This success was possible because of the application of participatory approaches for accelerating adoption. The traditional extension system that was so effective in the early years of the GR was based on development of recommendations and packages and then having the extension service demonstrate the technology to farmers. Seed and fertilizer was easily packaged and it was possible to layout many trials at low cost. When this traditional extension system was used for extending RCTs, problems arose. The first problem was the availability of the machinery to conduct the demonstrations. However, the main constraint was convincing farmers, extension workers and at times scientists that this technology had any benefit. Success came once partners were allowed to work together and experiment with the technology. Local manufacturers had to be involved in the development and manufacture of the equipment. Machinery had to be of high quality, yet at a cost within the budgets of farmers. Farmers had to be shown how the drill worked and then allowed to experiment with the equipment, before he could be convinced to accept this radical technology. Stories abound of how the farmers who first tried the technology were ridiculed by his neighbors for trying something so alien. But once the seed germinated, farmers begged the innovator to help them sow their fields. It is now felt that 0-till wheat is an acceptable technology and will be part of the recommendations for planting wheat. Similarly, other RCTs like bed planting will become accepted practices, as machinery is made available and more farmers experiment with the system.
One question that is often asked is ��who can benefit from this technology? Is it just for the large, commercial farmer?�� The answer appears to indicate that this technology is scale neutral and that farmers from all social classes can benefit from the many advantages that this system brings to wheat cultivation. A survey conducted in Haryana in 2001 of 20 villages and 91 farmers showed that 24% of the 0-till adopters owned a tractor while the rest used service providers. The average farm size of adopters ranged from 0.8 to 20.2 hectares. Twenty two percent had less than 2 ha and 37% from 2-4 ha farms. All but one farmer agreed that 0-till was highly profitable and data shows that 0-till resulted in US$75/ha more than with conventional practices. Yields from 0-till were 5.4 versus 5.1 t/ha for conventional. Resource poor farmers and farmers without tractors are using contract services to plough their fields at the moment. It is becoming too expensive to keep a pair of bullocks just for land preparation and so using a service provider is more economic. When this is applied to 0-till or bed planting, the benefits are even more pronounced. In this case, the farmer has only to rent the service once and his fields are planted. This saves him money and time to do other activities. Data from socio-economic and impact assessment surveys in India and Pakistan show this to be true. The first innovators are larger, better endowed, tractor owners. Later less endowed farmers adopt the technology as they see the benefits and obtain the services for this technology.
Farmer responses and feed back to the RCT��s and especially 0-tillage provide valuable feedback to scientists in the RWC for improving the technology. At the same time, scientists have been monitoring the fields where these technologies are being adopted and collecting data on soil, biotic, and resource use.
The paper has described various resource conserving technologies available for testing in the RW systems of the Indo-Gangetic Plains. It describes the benefits to the region of farmers adopting various resource conserving technologies in terms of improved production at lower cost, improving the efficiency of natural resources, benefits to the environment, improved livelihoods of farmers and ultimately help in alleviating poverty. Water is particularly highlighted since farmers indicate that all the technologies result in water savings. There is a research need to more accurately measure these savings and a recent ADB project will do just that. It is also important to look at water balances at different scales to determine if water savings at the field level will also give savings at the watercourse, command and basin level.
The success
of this technology is dependent on rapid adoption by farmers. Accelerated
adoption was mainly the result of the change in paradigm for extending
the technology. Instead of the linear approach to extension commonly
found in the Green Revolution era, the importance of partnerships, expanded
stakeholders, and participatory approaches where farmers could experiment
and feedback information soon became apparent. Resource conserving technologies
are a key to ensuring sustainable food production in South Asia in the
next decade. Overcoming mindsets that hold traditional beliefs
about excessive tillage and providing the enabling factors that allow
exposure of the technology to all those involved in agriculture will
be key factors for future success. This technology revolution is seen
as one way to sustainably increase food production to meet future demands
while conserving natural resources, improving farmer livelihoods and
reducing the negative effects on the environment. Water is listed high
on the list of natural resources and its use and productivity can definitely
be improved with these new technologies. Of course, all of these benefits
will be of little use unless nations in South Asia control their population
growth.
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M., A. Majid, N.I. Hashmi, and P.R. Hobbs. 1993. Improving wheat yield
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Kurukshetra Districts, Haryana, India: Farmers' Practices, Problems
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Table
1. Comparison of zero-tillage and farmers�� practice for establishment
of wheat after rice in Punjab, Pakistan, at locations where planting
dates for the two methods differ.
Wheat yield (kg/ha)
________________________________________
Location Zero-tillage Farmers��
practice Days difference
Daska, site 2 3,143 3,209 10
Daska, site 1 3,842 2,735 13
Ahmed Nagar 4,308 3,526 20
Maujianwala 2,689 2,198 22
Mundir Sharif 4,245 2,660 33
Daska, site 3 3,838 3,420 44
________________________________________________________________________
Average 3,677a 2,598b 24
Source: Aslam et al. (1993).
Note: Means followed by the
same letter do not differ significantly at the 5% level using DMRT.
Table 2. Effects of bed size
configuration on wheat yield, Punjab Agricultural University, Ludhiana,
India, 1994-95
Sowing method
________________________________________________________________
On the flat 75 cm beds 90 cm beds
____________ _____________________ _______________________
Variety 25 cm row 2 rows/bed 2+1
rows 3 rows/bed 3+1 rows Mean
Wheat
yield (kg/ha)
PBW 226 5,740 6,170 6,390 6,160 6,320 6,160a
WH 542 6,290 5,830 6,360 6,000 6,040 6,110a
CPAN 3004 6,020 5,530 6,140 5,630 5,600 5,780b
PBW 154 5,460 5,110 6,000 5,930 5,880 5,680b
HD 2329 5,770 4,660 6,190 5,580 5,810 5,600b
PBW 34 5,650 5,610 5,800 5,580 5,630 5,650b
________________________________________________________________________
Mean 5,820 5,490 6,150 5,810 5,880
Source: Unpublished data from S.S. Dhillon, wheat agronomist, Punjab Agricultural University.
Note: Means followed by the
same letter do not differ significantly at the 5% level using DMRT.
Table 3. Effect of sowing on
water use efficiency in wheat production in Mona Project, Pakistan.
_______________________________________________________________________
Laser Zero Bed Normal
Leveling Tillage Planting Planting
_______________________________________________________________________
Water Applied (m3/ha)
2849 2933 2281 3610
Yield (t/ha) 4764
4188 4134 3968
WUE (kg/m3) 1.67 1.43 1.81 1.10
_______________________________________________________________________
Source: A report on the evaluation
of resource conserving technologies in rice-wheat systems. 2000. Gill
et al. OFWM, Lahore Pakistan.
Figure 2. A photograph of the
Inverted-T coulter used for 0-tillage in the IGP.
Sustainable
Natural
Resource
Management
Agricultural
Productivity
and Production
Figure 1. Conceptual diagram of a CGIAR Eco-regional project
Socio-economic
and Policy environment
Geographically defined area
Indo-Gangetic Plains
Improved Livelihoods
Leading to Poverty alleviation
1 Paper presented at a Water productivity workshop held at IWMI, Colombo, Sri Lanka from 15-16th November 2001.
2 Facilitators for the rice-wheat consortium and CIMMYT natural resource agronomists based in Kathmandu, Nepal and New Delhi, respectively
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