*CA-CoP* *CONSERVATION AGRICULTURE COMMUNITY OF PRACTICE*
*for sustainable production intensification*
Dear Subscribers,
Every now and again, articles are published on CA based on desk analyses of
secondary information of mixed origin that generates mixed results and lead
to conclusions that can be misleading.
The article by Pittelkow et al. in Nature (on Productivity limits and
potentials of the principles of conservation agriculture) is one such
example (copy attached).
However, such articles do remind us that while we need to promote the
expansion of scientific research on CA, we also need to avoid or minimize
research that generates results of dubious quality.
In order to increase the generation of reliable scientific information on
CA, Derpsch et al. presented a paper at the 5th World Congress on
Conservation Agriculture in 2011 in Brisbane, Australia, suggesting that
some standardization would be helpful when conducting research on CA.
Subsequently, the article was published in a journal and a copy is attached.
Please see herebelow comments by Don Reicosky and Rolf Derpsch on the paper
by Pittlekow et al.
Don has mentioned elsewhere that there is clearly a need to develop a
glossary of terms for accurate representation of CA in our communication
and for comparison of research results.
*Amir Kassam*
*Moderator*
e-mail: [log in to unmask]
URL: www.fao.org/ag/ca
---------- Forwarded message ----------
From: Don Reicosky <[log in to unmask]>
Date: Sat, Nov 1, 2014 at 4:14 PM
Subject: No-Tillage paper
To: Don Reicosky <[log in to unmask]>
To all,
See the link below to a news release and the related attached article by
Pittelkow et al. on No-Till and conventional till yields.
http://www.news.ucdavis.edu/search/news_detail.lasso?id=11062
The recent paper on CA (primarily no-till ) showing lower yields with no
till than conventional till should serve as a “wake-up call” to the CA
community for improved definitions of methods used in CA research and
better communication of the environmental benefits to the broader
community. The paper also points to the need of more basic research to
understand the interactions in this complex system. A few additional points
and questions:
1. The paper did confirm and provided proof that no-till alone as CA
does not work. Much of the research reported in the article provided the
data, lessons and impetus to consider continuous crop residue cover and
diverse crop rotations and/or cover crop mixes to provide a proper carbon
balance in the CA system.
2. A primary concern is the definition of no-tillage in previous
research. The definition of no-tillage has been used very loosely and
inconsistently over the last 40 years. To some, no-till simply means no
plow. To others, the terms of minimum tillage, mulch tillage, reduced
tillage, strip tillage, rotational tillage, vertical tillage, conservation
tillage, etc., etc. can be lumped into the category of no-tillage; which do
not meet the criteria of “minimum soil disturbance” in CA. The definition
of conservation tillage with minimum of 30% residue cover is not adequate
for CA.
3. How do progressive farmers learn faster and get positive results
with their type of CA? The progressive CA farmers promote both the economic
and environmental benefits and will tell you that it is a truly sustainable
production system. The progressive farmers see and understand the soil and
environmental degradation associated with intensive tillage.
4. Why are the yields from large field, on-farm research studies as
good as or better than inversion tillage agriculture on large fields, but
not on small research plots?
5. What type and how much more detail do we in the scientific community
need to accurately characterize CA research methods and materials to enable
us to compare “apples to apples, not apples to oranges”?
6. What can we do to learn from and better understand the historical
results of the last 40-50 years of research to continue the development and
improvement of sustainable agriculture production systems?
Your candid thoughts with a science foundation on this subject would be
appreciated.
Don
Don Reicosky
Morris, MN USA 56267
e-mail: [log in to unmask]
Cell Phone 320-287-2314
---------- Forwarded message ----------
From: Rolf Derpsch <[log in to unmask]>
Date: Fri, Oct 24, 2014 at 3:35 PM
Subject: Re: Thank You and press release
To: Amir Kassam <[log in to unmask]>
Dear Amir, dear all,
When I read the arguments of this discussion it seems to me that to many
people have not yet read the attached article. Would you be so kind to
distribute it again in your CA-COP list with these following introductory
words? Thank you, Rolf
No-tillage is looked upon by many as a way to enable sustainable cropping
intensification to meet future agricultural demands. Although no-tillage
suggests merely the absence of tillage, in reality several components need
to be applied to a conservation agriculture system to guarantee equal or
higher yields and better environmental performance than with conventional
tillage systems.
We contend that broad understanding is lacking of what conservation
agriculture systems research means. This has led to a situation of
conflicting research results because different technologies, methodologies,
and definitions of conservation agriculture systems have been applied. The
term no-tillage has been used despite considerable soil movement in the
previous crop, to inject fertilizer or to establish the current crop.
Similarly, the term no-tillage has been used for systems with very little
or no crop mulch cover, extended fallow periods, alternating tillage and
no-tillage, or crops grown in monoculture. By not performing no-tillage
research in a systems approach, many problems can be encountered such as
reduced yields, high erosion, low infiltration, elevated fertilizer and
high pesticide use.
Rolf Derpsch
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