Agriculture Reference
In-Depth Information
Input Strategies
A large international research program on site-specific nutrient management (SSNM),
which sought to optimize and balance chemical fertilizer inputs, has reported average
rice yield increases of 7 to 11 percent with its interventions, raising profitability, on aver-
age, by 12 percent (Dobermann et al. 2002). In 25 percent of the cases, however, farmers
experienced declines in net income with SSNM because of the cost involved in applica-
tion or a decline in yield. The program focused almost entirely on soil chemistry, with
little attention paid to the endogenous mobilization and cycling of nutrients within soil
systems by soil organisms. It thus regarded soils as more passive than active, with soil
chemistry emphasized over soil biology.
The percentage increases in rice yield achieved already with agroecological manage-
ment have been several times greater than those obtained recently by making genetic
improvements or by optimizing external inputs in soil-chemistry terms. Over the last
two decades there has been a slowing of the rates of yield increase with the gene-centered
approach, possibly indicating that the genocentric research paradigm, like so many phe-
nomena, may be encountering diminishing returns. World production of cereal grains
per capita peaked in 1984 (Dyson 1999), and the overall rates of yield growth have been
declining ever since. Total global grain production peaked in the mid-1990s.
The alternative approach, which emphasizes management, can benefit farmers by
generally reducing costs of production, while natural environments are better of with
reduced extractions of water from surface flows or groundwater reserves, and with less
application of agrochemicals that affect soil and hydrological ecosystems. The manage-
ment approach may also run into diminishing returns in the future; indeed, it would
be surprising if it were immune to this relationship, which is so ubiquitous. But for
the foreseeable future, agroecological management appears worth investigating, and
worth utilizing to the extent that its results warrant application. Openness to alternative
approaches has not been generally evident, however, as seen not only for SRI but also for
conservation agriculture, as noted below.
Resistance to Paradigm Change within the International
Scientific Community
What are referred to as “modern” agricultural technologies, and the knowledge base
and practices upon which they rest, have come to represent a dominant paradigm for
agricultural development. This paradigm is well entrenched in government, academic,
and private-sector institutions, as well as in policy circles. Some researchers who work
within that paradigm have found it difficult to accept the results of and explanations for
SRI's agroecological methods.
• Dobermann(2004),forexample,concluded,withverylimitedevidence,thatSRIisat
best “a niche innovation.” His argument relied mostly on a crop model with coefficients
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