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.

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
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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