Fantastic Rice Yields Fact or Fallacy?

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> 2 Jul 2004 15:05:47 -0000

 

> Fantastic Rice Yields Fact or Fallacy?

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> ISIS Press Release 02/07/04

>

> Rice wars

> *********

>

> Rice, the stap

le food crop for more than half the

> world's

> population, among them the poorest, is the current

> target of

> genetic modification, an activity that has greatly

> intensified after the rice genome was announced two

> years

> ago (see " Rice is life " series, SiS 15, Summer 2002

> http://www.i-sis.org.uk/isisnews/sis15.php ). Since

> then,

> all major biotech giants are investing in rice

> research.

>

> At the same time, a low-input cultivation system

> that really

> benefits small farmers worldwide has been spreading,

> but is

> dismissed by the scientific establishment as

> " unscientific " .

> This is one among several recent innovations that

> increase

> yields and ward off disease without costly and

> harmful

> inputs, all enthusiastically and widely adopted by

> farmers.

>

> A war is building up between the corporate

> establishment and

> the peoples of the world for the possession of rice.

> The

> food security of billions is at stake, as is their

> right to

> grow the varieties of rice they have created and

> continue to

> create, and in the manner they choose.

>

> This extended series will not be appearing all at

> once, so

> look out for it.

>

> Fantastic Rice Yields Fact or Fallacy?

> ***************************************

>

> A low-input rice cultivation system invented in

> Madagascar

> and spreading all over the world is apparently

> exposed as

> without scientific basis. Dr. Mae-Wan Ho

> investigates

>

> Sources for this report are available in the ISIS

> members

> site http://www.i-sis.org.uk/full/RiceWarsFull.php.

> Full

> details here http://www.i-sis.org.uk/membership.php

>

> Rice feeds more than half the world's population,

> but yields

> of the crop have been levelling out, and 400 million

> are

> said to endure chronic hunger in rice-producing

> areas of

> Asia, Africa and South America. According to the

> United

> Nations, demand for rice is expected to rise by a

> further

> 38% within 30 years. To call attention to the

> problem, 2004

> has been declared the International Year of Rice.

> " Rice is

> on the front line in the fight against world hunger

> and

> poverty " , said Jacques Diouf, director-general of

> the UN

> Food and Agriculture Organisation.

>

> Many farmers all over Asia have already identified

> low-

> input, sustainable solutions to the problem (see

> other

> articles in this series).

>

> One simple method that boosts rice yields at much

> lower cost

> to farmers originated outside Asia. The System of

> Rice

> Intensification (SRI) developed in the late 1980s in

>

> Madagascar, has since been spreading to other parts

> in

> Africa and to Asia. In Madagascar itself, some 100

> 000

> farmers have converted to it. And more than 20 other

>

> countries, from Bangladesh to Thailand, have either

> adopted

> SRI, or field tested it, or expressed firm interest.

> In

> Cambodia, SRI was unheard of in 2000, but by 2003,

> nearly 10

> 000 farmers had converted to it, and that figure may

> reach

> 50 000 this year.

>

> Advocates of SRI routinely report yields up to twice

> or more

> those achieved by conventional agriculture.

>

> However, eminent agronomists are dismissing those

> claims as

> " poor record keeping and unscientific thinking " ; and

> results

> of new field trials, published in March 2004 in the

> journal

> Field Crop Research, appear to support this view.

>

> History of SRI

>

> SRI was developed nearly 20 years ago by Father

> Henri de

> Laulanié, a Jesuit priest who worked with farming

> communities in Madagascar from 1961 until his death

> in 1995.

> In conventional rice growing, the plants spend most

> of the

> season partially submerged in water. During a 1983

> drought,

> many farmers could not flood their paddy fields, and

> de

> Laulanié noticed that the rice plants, in

> particular, their

> roots, showed unusually vigorous growth.

>

> From this and other observations, de Laulanié

> developed the

> SRI practice: rice seedlings are transplanted

> quickly when

> young, spaced widely apart, and most importantly,

> the rice

> fields are kept moist but not flooded. In addition,

> he

> emphasized using organic compost over chemical

> fertilizers,

> so that poor and rich farmers alike could practise

> SRI.

>

> Norman Uphoff, a political scientist and director of

> the

> International Institute for Food, Agriculture and

> Development at Cornell University in Ithaca, New

> York,

> stepped into the picture in 1993. He was part of a

> team

> trying to find alternatives to the damaging types of

> slash

> and burn agriculture that was destroying

> Madagascar's

> rainforest. It was clear to Uphoff that if rice

> yields in

> the area could be increased from about 2 tonnes per

> hectare,

> as it was then, a lot of forest could be saved. He

> came

> across de Laulanié's not-for-profit organisation,

> 'Tefy

> Saina' meaning " to improve the mind " .

>

> Uphoff was looking for a yield of 4 tonnes per

> hectare, and

> when he heard them say they could get 5 or more, he

> did not

> believe them. But such doubts vanished once farmers

> in the

> rainforest regions started using SRI. The results

> were

> stunning. " By the end of the second growing season

> we were

> getting 8 tonnes per hectare " . In 1997, Uphoff began

>

> promoting SRI throughout Asia.

>

> Why SRI benefits farmers, consumers and the

> environment

>

> SRI's benefits lie in important differences from

> conventional rice growing practice, which,

> proponents

> believe, interact synergistically to give high

> yields.

>

> First, seedlings are transplanted at 8-12 days

> instead of 15

> to 30 days after germination, singly as opposed to

> 2-3

> seedlings, and spaced up to 6 times apart compared

> to

> traditional practice; for example, up to 50cm x 50cm

> instead

> of 20cm x 20cm. This represents a substantial saving

> on

> seeds, up to ten-fold or more in some cases. The

> increased

> spacing has the effect of encouraging tillers or

> side shoots

> to develop quickly, giving many more rice-forming

> panicles

> per plant.

>

> Second, the fields are kept moist during all or most

> of the

> growing season instead of being flooded

> continuously. This

> tremendous saving on water is particularly important

> in

> areas of water scarcity, and avoids the damages of

> salination that accompanies over-irrigation. It also

>

> encourages vigorous root development, which in turn

> gives

> more vigorous growth of the rice plants.

>

> Third, no herbicides are used. Weeding is done with

> or a

> simple rotary hoe, which returns the weeds to the

> soil as

> green manure. This financial saving is offset by

> increased

> labour, but labour shortage is seldom a problem for

> farmers

> in the Third World, and weeding becomes less arduous

> in

> successive years. Giving up herbicides is a health

> bonus for

> all concerned: the farm worker most of all, and the

> consumer; and there is no pollution of the

> environment and

> ground water.

>

> Fourth, no mineral fertilizers are used, only

> liberal

> application of organic compost. This financial

> saving is

> accompanied by an improvement to the quality and

> fertility

> of soil, reducing runoff, and improving its

> water-retaining

> properties.

>

> Despite its early start in Madagascar, SRI has only

> begun in

> other countries since 2000, and already, positive

> results

> are pouring in (see " Does SRI work? " this series).

>

> Critical scientists

>

> Major critics of SRI include John Sheehy, an

> agronomist at

> the International Rice Research Institute (IRRI) in

> Manila,

> the Philippines. He said most SRI field studies have

>

> appeared in conference proceedings and other

> publications

> not subject to peer review.

>

> That is hardly surprising given the lack of interest

> from

> mainstream scientists, and its relatively recent

> uptake in

> countries other than Madagascar.

>

> In March 2004, Sheehy, together with IRRI researcher

>

> Shaobing Peng, A. Dobermann of the University of

> Nebraska,

> Lincoln in the United States, and other researchers

> from

> Sheffield University in the UK; from Yangzhou

> University,

> Jiangsu, Hunan Agricultural University, Changsha,

> and

> Guangdong Academy of Agricultural Science,

> Guangdong, China,

> published their first trials of SRI under the

> telling title,

> " Fantastic yields in the system of rice

> intensification:

> fact or fallacy? "

>

> This report was written up as a news feature in the

> top

> journal Nature, under the yet more telling title,

> " Feast or

> famine? " asking whether SRI was a diversion from

> " more

> promising approaches " to increasing yield such as

> genetic

> engineering.

>

> Sheehy and coworkers planted a single rice cultivar,

> shanyou

> 63, at three experimental stations in Hunan,

> Guangdong and

> Jiangsu provinces of China, using SRI and

> conventional best

> practice in living-room-sized (8 x 5m) plots in the

> same

> fields. Weeds were suppressed with herbicides on the

>

> conventional plots but pulled by hand in the SRI

> plots. SRI

> plots received extra rapeseed cake fertilizer.

> Conventional

> plots were flooded as usual; SRI plots were kept

> saturated

> and only flooded 2 weeks before maturity.

>

> Overall, no significant differences were found

> between the

> two cropping systems. SRI yielded 8.5% higher in

> Jiangsu,

> but 8.8% worse in Hunan.

>

> Dobermann was reportedly " not surprised " , as he said

> every

> component of SRI had been studied before and found

> to have

> little effect. The results also fit Sheehy's

> theoretical

> calculation of how much rice a field can produce, an

> upper

> limit set by the amount of sunlight falling on it.

> Based on

> weather data for Madagascar, Sheehy calculated

> theoretical

> maximum outputs for areas that have reported the

> most

> impressive yields of 21 tonnes/ha under SRI. By his

> estimates, the yields are as much as 10 tonnes more

> than is

> possible. " You can't get out more than gets put in, "

> he

> reportedly said.

>

> They concluded that, " SRI has no major role in

> improving

> rice production generally " .

>

> That was a remarkable sweeping dismissal of the

> extensive

> research and trials done by both scientists and

> farmers on

> numerous rice varieties in 19 countries over two or

> more

> growing seasons. Especially so, when the conclusions

> are

> based on the results of limited trials of a single

> variety

> for only one growing season.

>

> Riposte

>

> Chinese scientists have experimented with SRI since

> 2000,

> and their experience had indicated that not all

> varieties

> responded to SRI, and that responses improve in

> successive

> seasons. Dobermann himself had referred to the

> possibility

> of confounding effects when SRI was compared to

> traditional

> systems that did not represent the current " best

> practice " .

> Of course, what is best practice for corporate

> agriculture

> is not necessarily best practice for the farmer.

>

> Thus, Sheehy and workers could have stressed the

> obvious

> benefits to small farmers, consumers and the

> environment,

> even from the results of their own trials. They have

>

> obtained the same yields with less than half the

> seeds in

> SRI, with no inputs of herbicides, and substantial

> saving on

> water.

>

> Norman Uphoff pointed out, in a detailed rebuttal to

> appear

> in Field Crop Research, that Sheehy and colleagues

> have

> simply not followed the SRI practice in their

> trials. It did

> not include the measures recommended for water

> management

> and weeding to ensure active soil aeration.

> Moreover, the

> high concentrations of chemical fertilizers used

> with the

> putative SRI plots (180-240 kg N/ha) would simply

> have

> inhibited the soil activity that enhances plant

> nutrition

> and growth.

>

> " The merits of SRI methods have been validated by

> scientists

> at leading institutions in China, India and

> Indonesia, the

> largest rice-producing countries in the world, " he

> remarked.

>

> Why are scientists in research stations failing to

> replicate

> the enormous yield gain with SRI methods obtained by

>

> farmers? For example, IRRI started trials with SRI

> at Los

> Baños in 2002, and obtained a yield of only

> 1.44t/ha; and

> the next season, it was still just 3t/ha. Yet,

> concurrent

> SRI trials in the government's Agricultural Training

> Centre

> in Mindanao, using three varieties (PSBRc18, 72H and

> 82)

> yielded an average of 12t/ha.

>

> When asked by IRRI staff why this discrepancy

> occurred,

> Uphoff suggested that IRRI's on-station soils, after

> decades

> of monocropping and application of fertilizers,

> insecticides, fungicides, herbicides etc., might be

> " almost

> dead " , and hence unable to respond to SRI practices,

> which

> depend on increasing the abundance and diversity of

> soil

> microorganisms to enhance plant growth and health.

>

> The basis for dismissing the high yields obtained in

> some

> parts of Madagascar as " fallacy " is highly

> questionable. It

> rests on a 'model' for predicting theoretical

> maximum yield

> using 'constants' derived solely from empirical

> observations

> on conventionally grown crops, which have no

> independent

> justification in terms of the plant's metabolism.

> For

> example, biomass accumulation depends on the balance

> between

> photosynthesis (which builds up biomass) and

> respiration

> (which decreases it), and that can change under

> different

> conditions. A healthy plant is also more efficient

> in using

> energy and accumulating biomass than an unhealthy

> one.

>

> An indication that yields more than 20 tonnes/ha may

> not be

> " impossible " is that such yields have been recorded

> for rice

> growing systems in China in historical times.

>

> Professor Yuan Longping, an expert in breeding

> high-yielding

> hybrid rice, who brought SRI to China, stated,

> " According to

> the estimates of most plant physiologists, rice can

> use

> about 5% of solar energy through photosynthesis.

> Even if

> this figure is discounted by 50%, the yield

> potential of

> rice would be as high as 22-23t/ha in temperate

> regions. "

>

> Uphoff maintained that the critics' assumptions are

> too

> firmly rooted in conventional practice. Models for

> estimating maximum yields will not necessarily

> translate to

> SRI. " The coefficients for the calculations are

> based on

> plants with stunted root systems. SRI plants have

> extensive

> root systems, " he said.

>

> Nor will single-season trials reveal the full

> potential of

> SRI, because over time, better oxygenation leads to

> the

> build-up of soil bacteria that interact with the

> roots and

> improve the condition of the soil. Even if SRI fails

> to

> increase yields when first introduced, as was the

> case in

> Thailand, for example, further seasons will see it

> come into

> its own.

>

> Proponents insist that SRI is popular because it

> really

> increases yields impressively. T.H. Thiyagarajan,

> dean of

> the Agricultural College and Research Institute in

> Killikulam, India, rejects criticisms of individual

> aspects

> of SRI. In combination, he says, the whole is

> greater than

> the sum of its parts. " The synergistic effect of all

> these

> components is the crucial thing. " He helped convince

> the

> Tamil Nadu state government to spend US$50 000 to

> promote

> SRI to local farmers.

>

> In fact, the individual components have been tested

> in

> Madagascar and other countries, and each component

> was found

> to increase yield. The one that appeared to give the

> most

> increase was transplanting younger seedlings. But

> this

> practice is more challenging for inexperienced

> farmers used

> to handling sturdier older seedlings.

>

> New evidence

>

> Norman Uphoff's weighty response drew attention to

> new

> evidence from scientists in China (see " Does SRI

> work? " this

> series), Indonesia and India. SRI evaluations were

> started

> in Tamil Nadu Agricultural University in India in

> 2001, and

> by 2003, it had demonstrated such improvements in

> yield and

> profitability that the state government provided $50

> 000 for

> spreading SRI practice. About half the rice crop in

> the

> Cauvery Delta, the main rice-producing area of Tamil

> Nadu,

> will be given over to SRI cultivation; the farmers

> are so

> impressed with the size of the harvest and cost

> savings,

> including water, over the past two years.

>

> While Sheehy and coworkers reported that SRI crops

> took 2

> weeks longer to mature, that was most likely due to

> the soil

> not being well drained and aerated. When properly

> managed,

> crops mature more quickly under SRI. In Andhra

> Pradesh SRI

> crops matured 10 days earlier, while in Cambodia,

> they

> ripened about one week before the conventional

> crops.

>

> The claim that SRI gave no advantage compared with

> " best

> practice " or officially recommended improved

> cultivation

> methods is also refuted. In Nepal, farmers compared

> SRI with

> their own usual practices and 'improved' practice.

> In 2002,

> the average SRI yield of 8.07t/ha was 37% higher

> than the

> average with improved practices, and 85% higher than

> the

> average with farmers' practices.

>

> A. Satyanarayana, rice geneticist responsible for

> introducing SRI in the Indian state of Andhra

> Pradesh since

> the summer season of 2003, responded to Nature's

> news

> feature by pointing out that, " The experiences of

> farmers

> are quite different from what is reported by

> sceptical

> scientists. "

>

> More importantly, the costs of SRI are low and its

> potential

> productivity very high, which is " more important

> than ever

> now that the Green Revolution technologies are

> showing signs

> of fatigue. "

>

> He gave further evidence that SRI definitely works

> for

> Andhra Pradesh farmers and called on scientists to

> collaborate constructively with farmers (see " Top

> Indian

> plant geneticist rebuts SRI critics " , this series).

>

>

>

>

========================================================

>

> This article can be found on the I-SIS website at

> http://www.i-sis.org.uk/RiceWars.php

>

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