AGMODELS-L: 199612XX
is the compilation of discussion during Dec 96
via AB4EL Web Digests @ SunSITE
>From root@crcnis1.unl.edu Mon Dec 2 15:10 EST 1996
Date: Mon, 2 Dec 1996 13:56:34 -0600
Message-Id: <199612021956.AA19941@crcnis1.unl.edu>
Subject: AGMODELS-L digest 611
Contents:
Sugarcane models (Amare Retta <retta@weru.ksu.edu>)
Date: Mon, 2 Dec 1996 13:30:02 -0600 (CST)
From: Amare Retta <retta@weru.ksu.edu>
Subject: Sugarcane models
Need informations (manuals, papers, etc.) on APSIM, QCANE, or CANEGRO. Thank
you in advance for your time.
A. Retta
Wind erosion research unit
Kansas State University
Manhattan KS
End of Digest
>From root@crcnis1.unl.edu Tue Dec 3 16:04 EST 1996
Date: Tue, 3 Dec 1996 14:50:25 -0600
Message-Id: <199612032050.AA17625@crcnis1.unl.edu>
Subject: AGMODELS-L digest 612
Contents:
Announcement for DSSAT Workshop ("Paul W. Wilkens <pwilkens@ifdc.org>" <pwilkens@IFDC.org>)
Re: Sugarcane models ("Romeo R. Favreau" <rrfavreau@ucdavis.edu>)
Re: Announcement for DSSAT Workshop ("Romeo R. Favreau" <rrfavreau@ucdavis.edu>)
Date: Tue, 3 Dec 1996 10:59:58 -0600
From: "Paul W. Wilkens <pwilkens@ifdc.org>" <pwilkens@IFDC.org>
Subject: Announcement for DSSAT Workshop
>The International Fertilizer Development Center (IFDC), in
>collaboration with the University of Georgia, University of
>Florida, University of Hawaii, and International Consortium
>for Agricultural Systems Applications (ICASA), is organizing
>the International Training Program on Computer Simulation of
>Crop Growth and Management Responses at Muscle Shoals, Alabama,
>during May 12-23, 1997. The ASCII version of the program
>brochure is appended below.
>
>To apply, complete the enrollment form and mail, fax, or e-mail
>it to IFDC by May 1, 1997.
>
>For more information on the program, to register, or to request
>a written brochure, please respond to:
>
>Coordinator, Human Resource Development Unit
>International Fertilizer Development Center
>P.O. Box 2040
>Muscle Shoals, Alabama 35662
>U.S.A.
>
>Telefax : 205-381-7408
>Telephone: 205-381-6600
>E-Mail : hrdu@IFDC.org
>
>You may register via e-mail by replying to the email address
>above, NOT by responding to this listserver. If you have any
>questions regarding the content of the workshop, please
>address them to pwilkens@IFDC.org
>
>For more information about IFDC, its mission, and training
>programs, address your inquiries to:
>
>International Fertilizer Development Center
>P.O. Box 2040
>Muscle Shoals, Alabama 35662
>U.S.A.
>
>Telephone: 205-381-6600
>Telefax : 205-381-7408
>E-Mail : general@IFDC.org
>
>***************************************************************
>
>International Training Program on
>Computer Simulation of Crop Growth and Management Responses
>
>
>Rationale
>
>Today more than ever, increased food production depends on
>judicious use of resources. Many soil, climatic, plant, and
>management factors affect the way a crop will respond to
>irrigation, fertilizer, and other management practices.
>Determining appropriate crop management strategies under these
>uncertainties has major economic and environmental implications.
>Computer simulation models of the soil/crop/atmosphere system
>can make a valuable contribution to both furthering our
>understanding of the processes determining crop responses and
>predicting crop performance in different areas. With the
>increasing availability of personal computers, user-oriented
>simulation models will greatly facilitate the task of
>optimizing crop and nutrient management and deriving
>recommendations concerning crop management. They also can be
>used to investigate environmental and sustainability issues
>of agro-ecosystems. The International Fertilizer Development
>Center (IFDC), in collaboration with the University of Georgia,
>University of Florida, Michigan State University, University of
>Hawaii, and International Consortium for Agricultural Systems
>Applications (ICASA), has been at the forefront in developing
>crop models and decision support systems suitable for use and
>application in both developed- and developing-country
>agriculture. IFDC is organizing this International Training
>Program on Computer Simulation of Crop Growth and Management
>Responses at Muscle Shoals, Alabama, during May 12-23, 1997.
>
>Program Objectives
>
>In this training program, participants will learn how a
>comprehensive simulation model of crop growth and development
>and water and nutrient dynamics is constructed and how it can
>be applied to real world problems. Specifically, the program
>will focus on:
>
> Operation of the new DSSAT v3.1 software.
> Description of the CERES and CROPGRO computer simulation
> models.
> Data requirements and collection for systems simulation.
> Application of the simulation, models to cropping,
> environmental, and sustainability problems.
> Integration of the crop simulation models with data base
> management and geographic information systems.
>
>Program Content
>
>The program will describe the practical approaches to simulating
>the effects of soil, climatic, management, and pest factors and
>their interaction with the input needs of crops. The program
>will demonstrate how the processes of crop growth anddevelopment, water
>use, uptake of nutrients and response to
>irrigation, fertilizer, and other management decisions can be
>simulated. The program will make extensive use of "hands-on"
>practical sessions on personal computers that demonstrate the
>application of simulation models to cropping systems in various
>regions of the world. Together with these applications, the
>methods for assessing the economic risks and environmental
>impacts associated with agricultural production in real world
>problems will be discussed. Procedures for managing soil, crop,
>and weather data will be described.
>
>The program will make extensive use of the CERES (maize, wheat,
>rice, sorghum, barley, and millet), CROPGRO (peanut, soybean,
>dry bean, and tomato), SUBSTOR (potato), OILCROP (sunflower),
>and CROPSIM (cassava) models for crop growth, development, and
>response to water and nutrients. Techniques for simulation of
>synthetic weather sequences will be described. Programs to
>create, run, and analyze both single season simulations and
>crop rotation simulations will be explained. The crop
>simulation models, data preparation, and application programs
>have been integrated into the new Decision Support System for
>Agrotechnology Transfer (DSSAT) v3.1 software package.
>Participants will be provided with a complete copy of DSSAT
>v3.1.
>
>Faculty
>
>Experts from IFDC, Universities of Florida and Georgia, and
>international agricultural research centers will form the
>faculty.
>
>Qualifications for Application
>
>Participants should be university graduates currently engaged
>in crop production or agro-ecosystems related research,
>teaching, outreach, or planning. They should have some
>understanding of soil and crop science and be relatively
>familiar with the terminology used in these fields.
>An in-depth knowledge is, however, not a prerequisite.
>They should be familiar with DOS-based personal computers.
>They should be fluent in English.
>
>Registration Fee
>
>The fee for this training program is $1700 and is due with the
>application for enrollment. The fee can be paid by check/draft
>in favor of IFDC or by a major credit card-Visa, MasterCard,
>or American Express.
>
>The program fee covers the registration for the 2-week program,
>transportation for field trips, resource material including the
>DSSAT v3.1 software, and tea/coffee breaks. It does not cover
>food and lodging during the program nor air transportation and
>health insurance. Each participant is responsible for these
>costs. Food and hotel lodging will average about $75-$80/day.
>IFDC will make reservations for participants at a convenient,
>quality motel.
>
>About the Training Program
>
>The program will begin May 12 and end May 23, 1997. It will
>be held at IFDC Headquarters, Muscle Shoals, Alabama, U.S.A.
>Participants should plan to arrive 2 days before the program
>begins to adjust to time zone differences and recover from
>travel fatigue. Muscle Shoals airport is served by Northwest
>Airlink from Memphis, Tennessee. Muscle Shoals can
>also be reached from Huntsville, Alabama, airport, which is
>served by Delta, Northwest, USAir, and American airlines.
>Huntsville is 65 miles away from Muscle Shoals, and a taxi
>costs around $75 one way.
>
>How to Apply
>
>To apply, complete the enrollment form and mail, fax, or
>e-mail it to IFDC by May 1, 1997. Applications received
>thereafter will be accepted at IFDC's discretion. An
>organization wishing to enroll more than one participant must
>supply an enrollment form for each participant.
>Enrollment is limited to 30 participants.
>
>Visa Requirement
>
>A visa is required for entry into the United States. Each
>participant must obtain a visitor visa from the Embassy or
>Consulate of the United States in his or her country of
>residence and fulfill any required health formalities.
>
>
>Weather
>
>The weather in the Muscle Shoals area is warm in May. Daytime
>temperatures average 75-85 F (24-29 C), and nighttime
>temperatures average 55-60 F (12-15 C). Daytime relative
>humidity varies between 70% and 85%.
>
>What is IFDC?
>
>The International Fertilizer Development Center (IFDC) is an
>international nonprofit organization dedicated to increasing
>agricultural productivity and food production in the tropics
>and subtropics through the appropriate use of plant nutrients
>in sustainable crop production systems. Headquartered in
>Muscle Shoals, Alabama, U.S.A, IFDC conducts its research,
>training, and technical assistance programs in collaboration
>with private, national, and international organizations
>throughout the world.
>
>Cosponsors
>
>The University of Georgia
>University of Florida
>International Consortium for Agricultural Systems
>Applications (ICASA)
>
>International Fertilizer Development Center
>P.O. Box 2040
>Muscle Shoals, Alabama 35662
>U.S.A.
>
>Telephone: 205-381-6600
>Telefax : 205-381-7408
>E-Mail : general@IFDC.org
>
>IFDC reserves the right to modify or even to cancel any
>program as necessary.
>
>
>Please complete this enrollment form and return to IFDC
>before May 1, 1997.
>
>--------------------------------------------------------------
>
> Application for Enrollment
>
>
>Please Print or Type
>
>Name (Mr., Ms., Mrs., Miss, Dr.)______________________________
>Nationality ____________________ Birthdate _________________
> (Month)(Day)(Year)
>Name and Mailing Address of Employer
>______________________________________________________________
>______________________________________________________________
>______________________________________________________________
>
>Telephone _____________ E-Mail ____________ Telefax ________
>Present Position _____________________________________________
>Length of Experience in Agricultural Research or Extension ___
>Home Address and Telephone Number ____________________________
>______________________________________________________________
>______________________________________________________________
>
>Organization Funding Your Participation ______________________
>Education (Highest Degree Completed, Date, and Major Subject)
>______________________________________________________________
>Name and Address of Educational Institution __________________
>Objective for Enrolling in This Program ______________________
>______________________________________________________________
>Please e-mail or telefax name(s) of nominee(s) in advance.
>
> _________________________________
> Signature of Applicant
>
> _________________________________
> Signature of Nominating Authority
>
> _________________________________
> Date
>
>Mail form and fee to:
>
>Coordinator, Human Resource Development Unit
>International Fertilizer Development Center
>P.O. Box 2040
>Muscle Shoals, Alabama 35662
>U.S.A.
>
>Telefax : 205-381-7408
>Telephone: 205-381-6600
>E-Mail : general@IFDC.org
>
>Program fees are due before the commencement of the program
>and will be refunded in the event of nonattendance.
>
>
Date: Tue, 3 Dec 1996 10:56:26 -0800 (PST)
From: "Romeo R. Favreau" <rrfavreau@ucdavis.edu>
Subject: Re: Sugarcane models
Hi A. Retta
A description to CANEGRO (ver 3.1) can be found in Vol 4 of the DSSAT (ver
3.) manuals. The author is listed as Gregory A. Kiker & Geoff Inman-Bamber,
Dept. of Ag. Eng Scottsville South Africa.
Check out Gordon Y Tsuji at Univ of Hawaii for Dssat Manuals.
Good Luck
--------------------------------------------------------------------
Romeo R. Favreau
707 Oriole Ave.
Davis CA 95616
e-mail 76600.2252@compuserve.com or rrfavreau@ucdavis.edu
---------------------------------------------------------------------
At 01:44 PM 12/2/96 -0600, you wrote:
>Need informations (manuals, papers, etc.) on APSIM, QCANE, or CANEGRO. Thank
>you in advance for your time.
>
>A. Retta
>Wind erosion research unit
>Kansas State University
>Manhattan KS
>
>
---------------------------------------------------------------------
Romeo R. Favreau
707 Oriole Ave.
Davis CA 95616
e-mail 76600.2252@compuserve.com or rrfavreau@ucdavis.edu
---------------------------------------------------------------------
Date: Tue, 3 Dec 1996 11:04:32 -0800 (PST)
From: "Romeo R. Favreau" <rrfavreau@ucdavis.edu>
Subject: Re: Announcement for DSSAT Workshop
Hi Paul,
I'm wondering whether this course would be a repeat of of a lot of what we
obtained in last years DSSAT 3.1 course, or would it be a logical extention
to last years course??
I have been getting acquainted with ArcView and have been looking at the
data of a Site Specific Experiment going on here at UC Davis.
Regards
---------------------------------------------------------------------
Romeo R. Favreau
707 Oriole Ave.
Davis CA 95616
e-mail 76600.2252@compuserve.com or rrfavreau@ucdavis.edu
---------------------------------------------------------------------
At 11:10 AM 12/3/96 -0600, you wrote:
>
>>The International Fertilizer Development Center (IFDC), in
>>collaboration with the University of Georgia, University of
>>Florida, University of Hawaii, and International Consortium
>>for Agricultural Systems Applications (ICASA), is organizing
>>the International Training Program on Computer Simulation of
>>Crop Growth and Management Responses at Muscle Shoals, Alabama,
>>during May 12-23, 1997. The ASCII version of the program
>>brochure is appended below.
>>
>>To apply, complete the enrollment form and mail, fax, or e-mail
>>it to IFDC by May 1, 1997.
>>
>>For more information on the program, to register, or to request
>>a written brochure, please respond to:
>>
>>Coordinator, Human Resource Development Unit
>>International Fertilizer Development Center
>>P.O. Box 2040
>>Muscle Shoals, Alabama 35662
>>U.S.A.
>>
>>Telefax : 205-381-7408
>>Telephone: 205-381-6600
>>E-Mail : hrdu@IFDC.org
>>
---------------------------------------------------------------------
Romeo R. Favreau
707 Oriole Ave.
Davis CA 95616
e-mail 76600.2252@compuserve.com or rrfavreau@ucdavis.edu
---------------------------------------------------------------------
End of Digest
>From root@crcnis1.unl.edu Wed Dec 4 16:21 EST 1996
Date: Wed, 4 Dec 1996 15:06:34 -0600
Message-Id: <199612042106.AA18156@crcnis1.unl.edu>
Subject: AGMODELS-L digest 613
Contents:
Sustainable Ag. (MOHAMMAD BANNYAN AVVAL <sbxbam@sbn2.phes.nottingham.ac.uk>)
Date: Wed, 4 Dec 1996 09:44:09 GMT
From: MOHAMMAD BANNYAN AVVAL <sbxbam@sbn2.phes.nottingham.ac.uk>
Subject: Sustainable Ag.
I am looking for any published material on applying simulation
modelling in sustainable agriculture? Is there any review on it?
Does it mean that this application is special and different from
routine application of models or just is a kind of playing with
management factors level to find out how much the field, environment
..., will be polluted, affected, etc?
Thanks a lot for your time.
Regards
M.Bannayn
University of Nottingham, Faculty of Agriculture,
Department of Physiology and Environmental Sci.
Tel: (44)- 115 - 9516260 - x: 8776
Fax: (44)- 115 - 9516261
E-mail: sbxbam@sbn2.nott.ac.uk
Homepage:http://www.ccc.nottingham.ac.uk/~sbxbam/mbahome.htm
End of Digest
>From root@crcnis1.unl.edu Thu Dec 5 16:21 EST 1996
Date: Thu, 5 Dec 1996 15:07:17 -0600
Message-Id: <199612052107.AA25399@crcnis1.unl.edu>
Subject: AGMODELS-L digest 614
Contents:
Re: Sustainable Ag. ("E. John Sadler" <sadler@sunbrn.florence.ars.usda.gov>)
unsubscribe (Jeff Mack <jeff@dynet.com>)
Reply: Sustainable Ag. (griggs@brcsun0.tamu.edu (Ray H. Griggs))
Reply: Sustainable Ag., long term modeling (Tom Hodges <thodges@tricity.wsu.edu>)
Date: Thu, 5 Dec 1996 10:02:36 -0500
From: "E. John Sadler" <sadler@sunbrn.florence.ars.usda.gov>
Subject: Re: Sustainable Ag.
Mohammad,
Modeling with sustainability as a goal puts a strain on models that
they were not designed to handle, for the most part. When you operate
on a time frame that is longer than a year or so, the sensitivity of
the model becomes a major limiting factor. Many models do not have
structures built into them to predict subtle effects that become
important over multi-year time frames.
Remember that an appropriate model needs to be able to produce, for
each output variable, the mean value AND the derivative of that
value with respect to ALL IMPORTANT input variables. This is an
exacting condition for any model. If this condition is met, then the
model can be expected to produce realistic trends over long-term
runs. If not, errors accumulate and impeach the results. It is
difficult to make a sufficiently general model that is suitably
accurate for very many factors. And sustainability by definition
forces the integration into the model of many factors for which very
little empirical data are known, and even less is known about the
subtle effects they may have over decade or longer simulations.
This does not mean there is no value to modeling. Especially for
systems that are somewhat narrow in scope, models may be used
usefully in such an endeavor. They need to be used very carefully,
however.
I discussed this in a chapter on water use in sustainable
agriculture, and in another on modeling for precision agriculture.
Both discussions deal with accuracy of models, and the former deals
specifically with sustainable systems, in particular how systems
sustainable for centuries later failed because some other factor
became important.
Sadler, E.J., and N.C. Turner. 1994. Water relationships in a
sustainable agriculture system. Chptr 2 in J.L. Hatfield and D.L.
Karlen, eds. Lewis Publishers, Boca Raton, FL.
Sadler, E.J., and Graham Russell. 1997. Predicting crop yield
variability. In F. Pierce et al, eds. The State of Site-Specific
Management for Agriculture. ASA, Madison, WI. (Still only available
in preprint)
I would like to see a discussion on this topic here in the agmodels-l
list. I would particularly like to see methods modelers can use to
overcome these problems.
Hope this is useful for you,
John Sadler
==============================================================
E. John Sadler, Ph.D.
USDA-ARS sadler@florence.ars.usda.gov
Coastal Plains Soil, Water,
and Plant Research Center 803-669-5203x112 (voice)
2611 West Lucas St. 803-669-6970 (fax)
Florence, SC 29501-1241
U.S.A.
==============================================================
Date: Thu, 5 Dec 1996 09:17:38 -0600
From: Jeff Mack <jeff@dynet.com>
Subject: unsubscribe
unsubscribe
Date: Thu, 5 Dec 1996 09:42:59 -0500
From: griggs@brcsun0.tamu.edu (Ray H. Griggs)
Subject: Reply: Sustainable Ag.
Mohammad,
Several models do a relatively good job on a longterm basis (>30 years).
Of course, assumptions are generally made by the user as to what stays
constant (e.g. co2...). The models can handle changes but the data does
not always exist to support the necessary changes. If a model is really
correct in a one year simulation, it should be correct for a multiyear
simulation.
I strongly agree that no model handles all "subtle effects"; on the same
hand no scientist or even groups of scientists understand all of the
"subtle effects". Models are rarely better than the science used to
develop them. If a scientist has figured out and documented a new "subtle
difference", it can and should be incorporated into existing models.
I do agree with Dr. Sadler that a discussion of this topic would be of
great interest. I would suggest that we toss out some of the specific
"subtle differences" which are known and documented and not yet
incorporated in the existing models.
Ray
>Mohammad,
>
>Modeling with sustainability as a goal puts a strain on models that
>they were not designed to handle, for the most part. When you operate
>on a time frame that is longer than a year or so, the sensitivity of
>the model becomes a major limiting factor. Many models do not have
>structures built into them to predict subtle effects that become
>important over multi-year time frames.
>
>Remember that an appropriate model needs to be able to produce, for
>each output variable, the mean value AND the derivative of that
>value with respect to ALL IMPORTANT input variables. This is an
>exacting condition for any model. If this condition is met, then the
>model can be expected to produce realistic trends over long-term
>runs. If not, errors accumulate and impeach the results. It is
>difficult to make a sufficiently general model that is suitably
>accurate for very many factors. And sustainability by definition
>forces the integration into the model of many factors for which very
>little empirical data are known, and even less is known about the
>subtle effects they may have over decade or longer simulations.
>
>This does not mean there is no value to modeling. Especially for
>systems that are somewhat narrow in scope, models may be used
>usefully in such an endeavor. They need to be used very carefully,
>however.
>
>I discussed this in a chapter on water use in sustainable
>agriculture, and in another on modeling for precision agriculture.
>Both discussions deal with accuracy of models, and the former deals
>specifically with sustainable systems, in particular how systems
>sustainable for centuries later failed because some other factor
>became important.
>
>Sadler, E.J., and N.C. Turner. 1994. Water relationships in a
>sustainable agriculture system. Chptr 2 in J.L. Hatfield and D.L.
>Karlen, eds. Lewis Publishers, Boca Raton, FL.
>
>Sadler, E.J., and Graham Russell. 1997. Predicting crop yield
>variability. In F. Pierce et al, eds. The State of Site-Specific
>Management for Agriculture. ASA, Madison, WI. (Still only available
>in preprint)
>
>I would like to see a discussion on this topic here in the agmodels-l
>list. I would particularly like to see methods modelers can use to
>overcome these problems.
>
>Hope this is useful for you,
>John Sadler
>==============================================================
>E. John Sadler, Ph.D.
>USDA-ARS sadler@florence.ars.usda.gov
>Coastal Plains Soil, Water,
> and Plant Research Center 803-669-5203x112 (voice)
>2611 West Lucas St. 803-669-6970 (fax)
>Florence, SC 29501-1241
>U.S.A.
>==============================================================
Ray H. Griggs
Agricultural Engineer & Associate Research Scientist
Blackland Research Center
Texas Agricultural Experiment Station
808 East Blackland Road
Temple, TX 76502
(817) 770-6631
(817) 770-6561 FAX
griggs@brcsun0.tamu.edu
Date: Thu, 5 Dec 1996 08:34:39 -0800 (PST)
From: Tom Hodges <thodges@tricity.wsu.edu>
Subject: Reply: Sustainable Ag., long term modeling
One of the big problems here is simulating long term effects of cropping
systems on those soil qualities of most interest to sustainability.
E.g. condition of soil humus; buildup or depletion of nutrients in
available, somewhat available, and very insoluable forms; soil structure;
soil microbial activity and diversity; ion exchange capacity; ...
Small factors that are not detectable over one year can cause huge changes
over 30-100 years. We must be concerned with real factors that need to
be in long term models and with factors in models that are not reflected
in the real world.
Tom Hodges, thodges@tricity.wsu.edu
End of Digest
>From root@crcnis1.unl.edu Fri Dec 6 16:51 EST 1996
Date: Fri, 6 Dec 1996 15:38:43 -0600
Message-Id: <199612062138.AA25608@crcnis1.unl.edu>
Subject: AGMODELS-L digest 615
Contents:
Re: Sustainable Ag. (Rodney Beard <R.Beard@mailbox.uq.oz.au>)
Sustainable Ag. and Modelling (MOHAMMAD BANNYAN AVVAL <sbxbam@sbn2.phes.nottingham.ac.uk>)
Re: Sustainable Ag. and Modelling (Tom Hodges <thodges@tricity.wsu.edu>)
Re: Sustainable Ag. and Modelling ("E. John Sadler" <sadler@sunbrn.florence.ars.usda.gov>)
unsuscribe (HYEBALLS@aol.com)
Date: Fri, 6 Dec 1996 09:56:36 +1000 (GMT+1000)
From: Rodney Beard <R.Beard@mailbox.uq.oz.au>
Subject: Re: Sustainable Ag.
I think that before you discuss the issue of incorporating sustainability
in Ag models it's important to be clear what is meant by sustainability.
It is also important to realize that there is probably no consensus on
what is meant by sustainability. A soil scientist will have a different
view on sustainability to an agricultural economist for example. A pasture
specialist or range scientist may have a different view again. part of the
problem in defining sustainability and sustainable agriculture lies
perhaps in defining agriculture itself. Is grazing agriculture? the answer
is probably sometimes yes and sometimes no. Is forestry agriculture, again
sometimes yes and sometimes no.
A model designed to analyze the dynamics of grazing on extensive pastures
will have a different criteria of sustainability to a model that examines
improved intensively grazed pastures. and people are likely to disagree
about the degree to which each of these sytems are sustainable.
I work on bioeconomic models of pasture-herd dynamics, sustainability is
relatively easy to incoporate into these models, as for most population
dynamic models, as long as the models are deterministic. For stochastic
models, the situation is more tricky as steady-state analysis no longer
has the same meaning. In the stochastic setting existence of a
steady-state can no longer be equated with a sustainable state. In the
sense of an unchanging (positive) population state.
Crop and soil models in taking a systems (essentially
functional-systems ecological) approach have I think an even harder time
of incorporating any sort of sustainability criteria or constraint. This
compounded by the problem that sustainability of a cropping system cannot
be meant in the same way as an extensive pastoral system, a forest or a
fishery.
Issues of socially desirable depletion rates/and or sustainable paths of
the whole system (including other industries, I'm thinking of production
of chemical fertilizers here) come into sustainability of soils.
You really have to question the whole idea of sustainability for certain
types of agriculture and not just particular practices or technologies.
Anyway, that's my 2 cents worth.
But this is an issue that should be debated more, although I doubt
consensus is possible.
Regards,
Rodney Beard
------------------------------------------------
Department of Agriculture
Univerity of Queensland
St. Lucia 4072
Australia
Tel: +61 7 33652174
Webpage: http://www.uq.edu.au/agecon/rbeard.html
------------------------------------------------
Date: Fri, 6 Dec 1996 13:31:47 GMT
From: MOHAMMAD BANNYAN AVVAL <sbxbam@sbn2.phes.nottingham.ac.uk>
Subject: Sustainable Ag. and Modelling
So can we say that:
1- we cannot deal with sustainable Ag. with short term or rutine one
year modelling and it should be a kind of Seasonal Analysis ( Long
term ).
2- To make more simple and agronomic, can I say, for example, that
up to now there was no attempt on trying different management factors
levels through simulation models and find out their effect/s on
long term productivity of environment or destroying the
environment/field or...,.
3- Does it seem that the model/s which will deal with this issue
should be very complicated? or again like rutine use of models
according to the object of model ( the effect of special parameters on
special environment aspect ) it could be simple ?
Regards
M.Bannayan
University of Nottingham, Faculty of Agriculture,
Department of Physiology and Environmental Sci.
Tel: (44)- 115 - 9516260 - x: 8776
Fax: (44)- 115 - 9516261
E-mail: sbxbam@sbn2.nott.ac.uk
Homepage:http://www.ccc.nottingham.ac.uk/~sbxbam/mbahome.htm
Date: Fri, 6 Dec 1996 08:27:46 -0800 (PST)
From: Tom Hodges <thodges@tricity.wsu.edu>
Subject: Re: Sustainable Ag. and Modelling
Mohammad,
I have included part of Rodney Beard's post below also.
With regard to Rodney's comment (see part at end of this post), I think
we have a pretty good intuitive grasp of sustainability: systems that
can be used for many years (30-1000s) without accumulation of negative
effects on the environment and with fair results for producers and
consumers; the problem is in dealing with the details. If non-renewable
resources are used in a system there must be a plan/provision for
switching to other resources before they run out.
Tom Hodges
On Fri, 6 Dec 1996, MOHAMMAD BANNYAN AVVAL wrote:
> So can we say that:
> 1- we cannot deal with sustainable Ag. with short term or rutine one
> year modelling and it should be a kind of Seasonal Analysis ( Long
> term ).
I don't think so. Various sorts of models can be used to assess
sustainability but with awareness of their limitations in regard to
this purpose. For example, a model that appears to do an excellent job of
predicting downward water movement could be used to assess irrigation
schemes for sustainability.
> 2- To make more simple and agronomic, can I say, for example, that
> up to now there was no attempt on trying different management factors
> levels through simulation models and find out their effect/s on
> long term productivity of environment or destroying the
> environment/field or...,.
Single season models don't always give much attention to things happening
outside of the cropping season - nitrogen movement and transformation
when the crop is not in the field, effects of snow cover or freezing
soil, water movement, microbial activity, effects of fumigation, etc.
Also it is often not easy to "fix" a seasonal model to run continuously
across years. However some models were explicitly designed for long
term scenarios -- EPIC and Century for two.
> 3- Does it seem that the model/s which will deal with this issue
> should be very complicated? or again like rutine use of models
> according to the object of model ( the effect of special parameters on
> special environment aspect ) it could be simple ?
Yes? to both :-)
> Regards
> M.Bannayan
> University of Nottingham, Faculty of Agriculture,
> Department of Physiology and Environmental Sci.
> Tel: (44)- 115 - 9516260 - x: 8776
> Fax: (44)- 115 - 9516261
> E-mail: sbxbam@sbn2.nott.ac.uk
> Homepage:http://www.ccc.nottingham.ac.uk/~sbxbam/mbahome.htm
>
On Thu, 5 Dec 1996, Rodney Beard wrote:
>
> I think that before you discuss the issue of incorporating sustainability
> in Ag models it's important to be clear what is meant by sustainability.
> It is also important to realize that there is probably no consensus on
> what is meant by sustainability. A soil scientist will have a different
> view on sustainability to an agricultural economist for example. A pasture
> specialist or range scientist may have a different view again. part of the
> problem in defining sustainability and sustainable agriculture lies
> perhaps in defining agriculture itself. Is grazing agriculture? the answer
> is probably sometimes yes and sometimes no. Is forestry agriculture, again
> sometimes yes and sometimes no.
>
Sustainability of current cropping systems is probably pretty low for
economic as well as biological/chemical/physical reasons. Systems
that were run for 1000s of years (slash and burn) are failing due to
growing populations. Systems with low returns for producers are not
morally (economicly) sustainable if the farmers will be held in poverty
with poor health resources and unable to educate their children
regardless of the environmental effects.
Enough for now,
Tom thodges@tricity.wsu.edu
Date: Fri, 6 Dec 1996 14:18:34 -0500
From: "E. John Sadler" <sadler@sunbrn.florence.ars.usda.gov>
Subject: Re: Sustainable Ag. and Modelling
Greetings,
I think the only safe thing to conclude is that if one wants a model
to perform in a certain case, then the model must be built to
account for everything that will later prove to be important in that
case. Most models built for 1-year runs make some simplifying
assumptions about subtle effects that usually can't be measured in 1
year. As one respondent said yesterday, models can do about what the
current knowledge is. My point is that long-term simulations (and to
me, sustainable ag requires longer-term simulations) allow small
year-to-year effects to accumulate and eventually dominate an error.
And if the model does not incorporate such effects, the results
can't be very accurate, in the long term.
However, it cannot be said that nothing has yet been done, nor that
everything done so far is of little value. Those who have carefully
conducted simulation studies with models or data sets that account
for what will eventually matter can say that they have accomplished
such simulations. However, they must be doubly careful- in model
choice, data choice, and interpretation of outputs - because they are
simulating out to the future, clearly outside the range of
experiences that went into many models. Any conscientious modeler
would be so careful, and discussions with them about such simulations
bear this out. The primary difficulty is the first outside person
who uses the results; that person rarely is as aware of the model's
shortcomings. Consider the policy makers who use model results. Their
training and interests (and probably time to care) preclude them from
concentrating on the limitations of the results. It is up to the
modelers to qualify their work.
And, yes, the objective of the study (and the model) can be made as
specific as desired. If the question can be answered with a simple
model, so much the better. However, the simpler the model, the fewer
the causes and effects that can be studied. And the more likely it
will be that the model cannot account for some important factors.
It is good to discuss these things. Thank you for asking the
questions.
Sincerely,
John
==============================================================
E. John Sadler, Ph.D.
USDA-ARS sadler@florence.ars.usda.gov
Coastal Plains Soil, Water,
and Plant Research Center 803-669-5203x112 (voice)
2611 West Lucas St. 803-669-6970 (fax)
Florence, SC 29501-1241
U.S.A.
==============================================================
Date: Fri, 6 Dec 1996 16:18:32 -0500
From: HYEBALLS@aol.com
Subject: unsuscribe
Unsubscribe hyeball@aol.com from agmodels
End of Digest
>From root@crcnis1.unl.edu Sun Dec 8 19:45 EST 1996
Date: Sun, 8 Dec 1996 18:30:35 -0600
Message-Id: <199612090030.AA25225@crcnis1.unl.edu>
Subject: AGMODELS-L digest 616
Contents:
Re: unsuscribe (Stephen Ragan <ragan@minot.com>)
Date: Sun, 08 Dec 1996 18:14:47 -0800
From: Stephen Ragan <ragan@minot.com>
Subject: Re: unsuscribe
Unsubscribe ragan@minot.com from agmodels
End of Digest
>From root@crcnis1.unl.edu Mon Dec 9 19:44 EST 1996
Date: Mon, 9 Dec 1996 18:31:07 -0600
Message-Id: <199612100031.AA27853@crcnis1.unl.edu>
Subject: AGMODELS-L digest 617
Contents:
(dsalinas@sol.racsa.co.cr (Alberto Salinas))
(dsalinas@sol.racsa.co.cr (Alberto Salinas))
Re: unsuscribe (LEE CHING KEI <s958035@mailserv.cuhk.edu.hk>)
Re: Sustainable Ag. and Modelling ("Graham Russell" <GRUSSELL@srv0.bio.ed.ac.uk>)
unsuscribe (chi@crsa.bu.edu (Chi Ho Sham))
Date: Sun, 8 Dec 1996 21:14:17 -0600 (CST)
From: dsalinas@sol.racsa.co.cr (Alberto Salinas)
Subject:
Go and see this http address
http://www.alliedsystems.com/compounder/AS1250.html
Read it, follow up instructions (really suggestions), and give yourself the
opportunity of your life: test it if you come get richer.
Bye
Al
Date: Sun, 8 Dec 1996 21:26:43 -0600 (CST)
From: dsalinas@sol.racsa.co.cr (Alberto Salinas)
Subject:
Go and see this http address!!!
http://www.alliedsystems.com/compounder/AS1250.html
Read it, follow up instructions (really suggestions), and give yourself the
opportunity of your life; test it if you really want or long to get richer.
Bye
Al
Date: Mon, 9 Dec 1996 12:01:51 +0800 (HKT)
From: LEE CHING KEI <s958035@mailserv.cuhk.edu.hk>
Subject: Re: unsuscribe
Unsubscribe ragan@minot.com from agmodels
Date: Mon, 9 Dec 1996 09:42:02 +0000
From: "Graham Russell" <GRUSSELL@srv0.bio.ed.ac.uk>
Subject: Re: Sustainable Ag. and Modelling
Following on from John Sadler's comments, with which I
fully agree, one source of error in multi-year models is
that some system atributes move from being inputs to the
model to being normal state variables that are calculated.
These would include factors such as soil water content at
the start of the cycle, soil organic matter etc. Small
errors here will accumulate unless the long term effects
are included as part of the model rather than being
emergent properties of it. It would be nice for the trends
to appear from the model. However, our state of knowledge
requires us to adopt a cautious approach.
Best wishes,
Graham
Dr G. Russell
University of Edinburgh
Institute of Ecology & Resource Management (Agriculture Building)
West Mains Road
Edinburgh EH9 3JG
SCOTLAND
International phone +44 131 535 4063 Fax +44 131 667 2601
UK phone 0131 535 4063 Fax 0131 667 2601
Date: Mon, 9 Dec 1996 12:39:00 -0500 (EST)
From: chi@crsa.bu.edu (Chi Ho Sham)
Subject: unsuscribe
Unsubscribe chi@bu-geo.bu.edu
End of Digest
>From root@crcnis1.unl.edu Mon Dec 16 05:12 EST 1996
Date: Mon, 16 Dec 1996 03:58:54 -0600
Message-Id: <199612160958.AA10143@crcnis1.unl.edu>
Subject: AGMODELS-L digest 618
Contents:
Microbial biomass, respiration and qCO2 in soils with low clay (Torsten Muller <Torsten.Muller@agsci.kvl.dk>)
Date: Mon, 16 Dec 1996 09:10:01 +0100
From: Torsten Muller <Torsten.Muller@agsci.kvl.dk>
Subject: Microbial biomass, respiration and qCO2 in soils with low clay
In order to calibrate the microbial activity against the clay content in the
soil, I am looking for refenrences dealing with low clay contents (< 10
pct). At least the datasets should contain clay content, incubation
temperature, microbial biomass and soil respiration (or qCO2) measured
under steady state conditions with optimum water content. I know that
only a few works exist for those soils. Hence, references including only
one soil with low clay content or unpublished data would be interesting
too.
Dr. Torsten Mueller
The Royal Veterinary and Agricultural University
Dep. of Agricultural Sciences
Plant Nutrition and Soil Fertility Laboratory
Thorvaldsensvej 40
DK-1871 Frederiksberg C (Copenhagen), Denmark
phone: +45 35283499, fax: +45 35283460
e-mail: tm@kvl.dk, http://www.agsci.kvl.dk/~tomuj5
End of Digest
>From root@crcnis1.unl.edu Tue Dec 17 19:47 EST 1996
Date: Tue, 17 Dec 1996 18:34:20 -0600
Message-Id: <199612180034.AA02251@crcnis1.unl.edu>
Subject: AGMODELS-L digest 619
Contents:
Job Opening -- Calif. Pest Control Advisor ("Warren E. Clark" <ag-pr@agpr.com>)
Date: Tue, 17 Dec 1996 19:21:34 -0800
From: "Warren E. Clark" <ag-pr@agpr.com>
Subject: Job Opening -- Calif. Pest Control Advisor
PEST CONTROL ADVISOR-Growing crop protection services company located in
the Salinas Valley of California wants career oriented individual.
Primary responsibilities include monitoring client fields, providing
pest control recommendations and coordinating pesticide applications
with cultural opperations. Minimum requirements are the B.S. Degree in
agricultural or biological science and a California Pest Control
Advisors License or the ability to obtain. Salary commensurate with
experience.
Send resume to:
Tom Shannon
General Manager
Kleen Globe, Inc.
P.O. Box 1125
Castroville, CA 95012
Tel: (408)633-2043
Fax:(408)633-2185
E-mail: shannon@dedot.com
End of Digest
>From root@crcnis1.unl.edu Thu Dec 19 19:27 EST 1996
Date: Thu, 19 Dec 1996 18:14:46 -0600
Message-Id: <199612200014.AA08356@crcnis1.unl.edu>
Subject: AGMODELS-L digest 620
Contents:
Introduction (Said Amali <SaidAmali@kennedyjenks.com>)
Date: Thu, 19 Dec 1996 15:40:00 -0800
From: Said Amali <SaidAmali@kennedyjenks.com>
Subject: Introduction
Hello all
I am a new subscriber to the list and wanted to introduce myself.
I am a soil scientist working for Kennedy/Jenks Consultants in
Sacramento, California.
I do various environmental consulting work for a variety of clients.
These projects
require knowledge and information in various areas related to soils,
soil moisture
and groundwater. My major areas of experience include:
environmental investigations involving fate and mobility of organic and
inorganic pollutants;
environmental remediation in the vadose zone and the groundwater;
human health risk assessment;
modeling of environmental fate and transport processes of various
chemicals
in the vadose and saturated zones in vapor, solute and free-phase forms;
groundwater development;
groundwater quality investigations;
water resources planning; and
agricultural water conservation.
I am glad to be a mamber of this list and hope to contribute to its
discussions.
Said Amali, Ph.D.
Soil Physicist
saidamali@kennedyjenks.com
End of Digest
>From root@crcnis1.unl.edu Sat Dec 21 20:34 EST 1996
Date: Sat, 21 Dec 1996 19:21:17 -0600
Message-Id: <199612220121.AA25621@crcnis1.unl.edu>
Subject: AGMODELS-L digest 621
Contents:
Introducing myself ("Andreas J. Beblik" <A.Beblik@tu-bs.de>)
Date: Sun, 22 Dec 1996 01:54:57 +0100
From: "Andreas J. Beblik" <A.Beblik@tu-bs.de>
Subject: Introducing myself
Dear modellers,
as a novice to this forum, I would like to introduce myself for to invoke
further discussions.
>>name:
Andreas J. Beblik (AJB)
>>inst:
iBUG - Institut fuer Boden- und Gewaesserschutz
(Institute for Soil- and Waters protection)
P.O.Box 14 19
D-38004 Braunschweig (Germany)
phone/fax +49/0 531 37 74 89
e-mail A.Beblik @ tu-bs.de
also in close cooperation with Technical University of Braunschweig,
Dept. Geoecology and Geography (group of Prof.Dr. Joerg Richter)
>>areas of interest:
N dynamics and plant growth models, optimization of parameters, GIS-related
modelling, advisory, N fertilizer recommendations
... also: overland-flow, microscale runoff, remote sensing.
>>experiences:
(as an user) SHE, CREAMS, AGNPS, HERMES, LEACHN, Expert-N
(as developer) MINERVA, ABFLUSS
>>some facts about MINERVA:
mechanistic model, based on HERMES (Kersebaum & Richter); capacity model for
water-transport; convection-dispersion-equation for nitrate transport;
double exponential equation submodel for N mineralization; additional
submodels for denitrification, immobilisation and nitrification can be
switched on/off; crop growth based on SUCROS, parametrized for cereals
(winterwheat, rye, barley), maize, oilseed-rape; as well site specific as
linked with Geographical Information System (ArcInfo); so-called
'user-friendly' multiplatform C code; running under DOS, Windows 3.x and
Unix (SunOS, Linux); combined with plot management data base; validation:
more than 1000 sites in (northern) Germany, Russia, Italy, The Netherlands.
>>burning issues: 'optimizing parameter sets'
Besides the model I also developed an additional tool (NPAR), which is able
to optimize the parameter set (about 100 coefficients) for our plant growth
model. It does the fit simultaneously for different sites and years. So we
hope to get very reliable parameter sets, which should make safe local and
temporal transfer of the model.
>>Our assumptions are, that
... instead of some very coherent datasets (which make a lot of effort in
design and experimental work), more sparse but distributed measurements over
a range of climatic as well site specific conditions (soil, management) will
better reflect the situations during practical use after validation.
... on the other hand, we also need some detailed observations (for plant:
stage, dry matter of plant organs, N content; for soil: mineral N, moisture)
for fitting of internal distribution of assimilates.
??? How do you decide about setting of that parameters that cannot be
measured physically?
??? Do you re-calibrate your submodels again when you have collected more
observations from different growing conditions?
??? Would you agree that a good plant model should be able to describe the
full range from zero fertilizer input - maybe with additional water stress -
upto fully supplied and irrigated situations?
>>Our statement...
!!! For practical purposes we do need deterministic and flexible models!
Based on that skills it would be possible to diminish N fertilizer input (in
high production systems) or to improve yield (in low production systems) at
a reasonable high, but significatly lower contamination level!
Yours Andreas J. Beblik (iBUG-Braunschweig/Germany) e-mail: A.Beblik @ tu-bs.de
End of Digest
Prepared by Steve Modena, AB4EL
Suggestions and comments to: modena@SunSITE.unc.edu