Transcript Proračun trenda sadržaja organske materije tla primjenom

SOIL CONDITION INDEX – (SCI) AS AN INDICATOR
OF THE SOIL ORGANIC MATTER DYNAMICS AT
THE FARM BUTMIR NEAR SARAJEVO
Prof. Dr. Hamid Čustović
Tvica Mirza dipl. ing.
Why is good to know about trend in
SOM?
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Agricultural practices has the influence of on
ecological function of soil:
Production of biomass (Fertility of soil)
Soil as a recipient, filter and universal buffer
Role of soil in Climate change
The Global Carbon Cycle:
Soil organic carbon (1500 Gt C) constitutes more than twice as much stored
carbon as that of the earth’s vegetation (plants, trees, crops, and grasses 550 Gt C).
Man-made perturbations to the natural
cycling of carbon
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The use of fossil fuel, land clearing, and land
use change lie behind the increased
greenhouse effect
Significant topsoil losses due to erosion, and frequent
tillage operations have reduced carbon levels to less
than half of their native values.
Carbon Sequestration
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One way to help stabilize atmospheric CO2
would be to adopt practices worldwide that
increase soil carbon levels and reduce
emission CO2
What is SCI (Soil Condition Index)?
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Windows-Excel based Model developed by
NRSC (Natural Resource Conservation
Service) US Department of Agriculture
Can predict the consequences of cropping
systems and tillage practices on the status of
soil organic matter in a field.
The SCI combined with erosion prediction
technology can help assess these two basic
components of good soil management
Why SCI?
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The index is designed to help you plan and design
Conservation Crop Rotations and Residue Management
practices when low organic matter, poor soil tilt, surface
crusting, or erosion are identified as concerns.
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Soil organic matter is a primary indicator of soil quality and
carbon sequestration.
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You can run several “what if” scenarios, so farmers can see
for themselves which changes will have more or less effect on
improving the status of SOM.
The Aim os this presentation:
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Introduce the Model SCI on the example
Farm ”Butmir”
Compare amount of SOM before 25 years
and now
Compare trends of SOM by SCI Model and
by comparing amount of SOM before and
now
The Soil Conditioning Index has
three main components including:
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the amount of organic material returned to or
removed from the soil (OM),
the effects of tillage and field operations on
organic matter decomposition (FO), and
the effect of predicted soil erosion associated
with the management system (ER).
We need the following information
(inputs) about the field to be evaluated:
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! Soil texture
! Climate data
! All crops in the crop rotation
! Typical yield for each crop
! Additional applications of organic matter, such as
manure or compost, or removals of organic matter,
such as baling of straw.
! All field operations. This includes tillage, fertilizer
and manure application, and harvest.
! Rates of erosion
Input Data in the Model SCI - Method
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A
Choose a city with a climate most similar to the field being evaluated
(Albany, NY : Butmir)
Select a soil texture to represent the dominant soils on the field being
evaluated (Clay Loam).
The program will calculate a maintenance amount. The maintenance
amount refers to the amount of organic matter that must be added
annually to maintain soil organic matter levels. If your field operations
induce more or less decay than this standard, or if you have higher or
lower erosion rates, this will be accounted for in the Field Operations
and Erosion Subfactors.
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B
Enter the number of years in the crop rotation (7 years: 3 corn silage +
4 alfalfa)
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Input Data
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C
Column B: Use the drop-down lists on as many lines as
necessary to identify the crops grow. Be sure to account for all
crops grown in the rotation (3 years corn silage + 4 alfalfa)
Column C: For each crop enter the average yield for the site
being evaluated (corn silage t/ha; alfalfa t/ha dry mass)
Columns D through I: These values are filled in automatically.
Column J: Manure applications should be listed in as a positive
number ( kg/ha dry weight) and residue removal such as by
baling of straw should be listed as a negative number.
Input Data
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D
Enter all field operations. In Column E, enter the total number
of passes of that implement over the course of the rotation
(Conventional agricultural practises)
The operations table in Model includes soils disturbance
ratings (SDR) for almost 200 field operations. The data is used
to estimate the effect of field operations on reducing soil
organic matter levels.
E
Enter soil loss estimates in tons/acre using approved erosion
prediction technology (t/ha)
Part F
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After you have completed Parts A-E, the
overall Soil Conditioning Index value should
show in Part F.
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SCI = 0,4 OM + 0,4 FO + 0,2 ER
SCI = 0,91*0,4 + 0,33*0,4 + 0,50*02 = 0,60
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Part G
SCI = 0,91*0,4 + 0,33*0,4 + 0,50*02 = 0,60
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The recommendation statements that appear in Part G are
determined by whether the SCI value or the sub-factors are
positive or negative:
The organic mater (OM) subfactor is positive (0,91), biomass is
greater than maintenance amount for this location
Field operations (FO) factor is positive (0,33) - disturbance is
less than steady state conditions
The erosion rate (ER) is not excessive (0,50), however
additional erosion control may improve soil condition
The overall index (0,60) shows a steady or improving
condition.
Results and Comments
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Compared results of SOM analysis 1978
(3,28 % SOM) and 2004 (3,38 % SOM)) in
35 cm topsoil, indicate balanced (stabile)
amount of SOM
The overall index (0,60) shows a steady or
improving condition which indicate good
agricultural practises on The Farm Butmir
Conclusion
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The SCI is a quick way to characterize the organic matter
dynamics of a farming system
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If the SCI value is negative, note which sub-factor (s) are
influencing it the most. Modify the scenario by changing crops
or field operations to develop alternatives for consideration by
the producer.
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The results cannot be used to predict the amount of organic
matter or the rate of change.
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The SCI does not indicate a desirable or target level of soil
organic matter.
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If a farmer switches to a system that will improve soil organic
matter levels, it may take several years to measure an increase
in SOM, but soil aggregation, infiltration and the soil biological
community are likely to improve more quickly
THANK YOU!
Where to get the program
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The latest version of the Soil Conditioning Index is available at
the following ftp site:
ftp://ftp.nssc.nrcs.usda.gov/pub/agronomy/SCIfiles/latest_revisi
ons
Download the file named <sciver23.xls> or the latest version
with a higher number.
SCI is a Microsoft Excel file. You will need Excel 5.0 or a later
version to run it.
Eventually, the Soil Conditioning Index will be linked to
RUSLE2 and both models will run from the same input.