Agronomic UFOs waste valuable scientific resources
By Thomas R. SINCLAIR
Cultivating paddy - The SRI way
Nation Building
Minister Salinda Dissanayake |
I read the Daily News, August 25, 2009 page 6 - article by Ishara
Mudugamuwa regarding Nation’ Building Minister Salinda Dissanayake’s
experience. Firstly, I like to congratulate Minister Dissanayake for
obtaining a record rice yield of 17 tonnes per hectare a miracle yield.
He has the answer to all our food and economic problems of Sri Lanka. He
should get the Government to stop the artificial fertilizer subsidy to
rice-farmers and get the SRI followed by all farmers. However, the
picture is different! SRI was promoted in Sri Lanka for the past ten
years but so far, reports show that the farmers are not adopting this
method.
Farmers are not fools - their judgments, are based on experience. The
high yields reported by SRI followers are highly questionable, heresay,
not scientific! While I was analyzing SRI, I was given an article
written by Dr. Thomas R. Sinclair of U.S.D.A. which analyses the SRI
very scientifically.
I hope readers and Minister Salinda Dissanayake read this carefully.
We Sri Lankans should not be taken on a Garden path to Heaven. Let us
consolidate on what we have achieved in our Rice cultivation where we
have achieved very much more than Madagascar.
It is well-known that International Non-Governmental Organizations
backed by Wheat Associations of U.S.A. funding programs to mitigate the
gains made by Asian Countries on rice productivity. The scientific
aspects of SRI is critically analyzed by Dr. Sinclair is given in
totality. Let the truth prevail!
Suranimala Wirasinghe Retired Director of Agricultural, Extension and
Training Department of Agriculture, Peradeniya
One lesson to be learned from the SRI experience of Unconfirmed Field
Observations (UFOs) is that there are no shortcuts to increasing crop
yields
Discussion of the System of Rice Intensification (SRI) is unfortunate
because it implies SRI merits serious consideration. SRI does not
deserve such attention. A multi-national team has shown from both
theoretical evaluation and a number of experimental tests that SRI
offers no yield advantage. Significantly, these results by Sheehy ettal
were published in Field Crops Research (2004), an international journal
that requires anonymous reviews.
Increasing harvest and reducing cultivation cost should be
the goal of research activities. Courtesy: Google |
Their research used the classical scientific approach of assessing a
concept’s consistency with existing facts and knowledge and conducting
critical experimental investigations with appropriate controls and
statistical tests.
Three components of the SRI strategy run directly counter
well-established principles for high crop growth. These principles were
developed over many years of careful testing and scrutiny by scientific
worldwide and they have stood the test of time.
First, SRI uses very low plant densities. Energy for crop growth
results from intercepted sunlight and amount of light intercepted
translates directly into plant growth. High plant density enhances light
interception, growth and yield. SRI suffers from poor light interception
because of low plant densities.
Second, SRI replaces paddy flooding by simply maintaining moist soil
conditions. The physiology and physics of plant water use have been
researched for more than 300 years and the relationship between growth
and plant water use is unambiguous? Ample water maximizes rice yields
and flooded paddy fields assure that not water limitations develop.
Third, SRI, emphasizes organic nutrient to the exclusion of mineral
fertilizer. SRI faces a serious challenge in obtaining sufficient
mineral nutrients from organic sources to achieve high yield.
Rice grains contain about 0.013 grams of nitrogen per gram of seed
(1.3 percent N). A claimed yields of 15t/ha requires nitrogen from over
50 t/ha of organic matter. Such a monumental demand for organic matter
creates huge challenges in sourcing, handling and managing these
materials.
Further, the basis for SRI is explained with misinterpreted or
fragmentary literature, which is used without a full understanding of
the overall processes regulating and influencing plant growth and yield.
Crop growth is fundamentally the accumulation of carbon and nitrogen and
their partitioning to growing seeds.
For example, one erroneous assumption is that shortening the
phyllochron (leaf emergence rate) in itself accelerates growth: no such
direct link to growth exists.
Another example of misunderstanding is the claim that not flooding
the soil overcomes the supposedly negative consequences of aerenchyma
(air channels) in rice roots. Aerenchyma are naturally present in rice
roots and form both when the roots are flooded and in SRI.
Further, aerenchyma form in the root cortex and neither infringe on
the vascular tissue nor negatively impact water or nutrient transport.
Regrettably, SRI appears to be only the latest in a family of
confirmed field observations (UFOs) that have several features in common
with their space UFO cousins.
While there is an abundance of sightings they are anecdotal and
reported by people who have minimum understanding of the basic
scientific principles being challenged by such reports. In many cases,
mysterious circumstances are invoked to explain the miraculous - for SRI
there are unexplained synergies and processes in the rhizosphere (the
zone in which plant roots interacts with soil microbial populations).
Egregiously, some people who have little or no research experience are
able to influence the agricultural research agenda and cause UFO reports
to be taken seriously.
Such decisions require widely publicized scientists to produce
documented responses, causing losses in time and resources that could
otherwise be committed to investigating well-founded hypotheses for true
understanding in maintaining and increasing crop productivity.
One lesson to be learned from the SRI experience is that there are no
shortcuts to increasing crop yields. The history of crop yield increase
tells of decades of hard-won scientific advances in understanding the
biology, biochemistry and physics of plant growth and yield. Research
requires intensive investigations by those trained to understand the
theoretical context of their research and to undertake the critical
experiments.
Most importantly, results are not accepted until the research is
described in an unbiased manner in a scientific journal that relies or
anonymous reviews.
It is hoped that the SRI experience will infuse those making founding
decisions for agricultural research with renewed skepticism and caution
upon the next sighting of an agronomic UFO.
The writer is a plant physiologist in the US Department of
Agriculture’s Agricultural Research Services |