|
Deficiencies of S in crops are thought to be increasing due
to a combination of factors, including increased crop yields that result in
more S removal and decreased S deposition from the atmosphere. A database of
the S status of Ohio’s soils for crop growth was developed by combining inputs
from the atmosphere and organic matter with outputs to leaching and crop
removal. The database is organized by soil series within counties and includes
soils that were sampled but never given a series name. In addition to
predicting the S status of a particular soil for crop growth, the database
includes information on atmospheric S deposition, organic C, and texture that
influence a soil’s S status.
Instructions
|
The sulfur (or S) deficiency model was developed
for two rates of crop requirements. The low rate was for a crop requiring 15 kg
S/ha/year, such as corn, and the high rate was for a crop requiring 30 kg
S/ha/year, such as alfalfa. The model can be used to estimate the S status of
other crops that have S requirements similar to either corn or alfalfa.
You search the database by entering criteria in one or more data fields and then
clicking the "Submit" button. The data fields (County, Soil Series, S Status
(corn), etc.) have pop-up menus to choose from. When you do a search based on
one or more criteria, the program lists those soils that match the defined
criteria without regard for other characteristics that are not defined. For
example, if you select “moderately deficient” for S status (corn), the program
will list all soils that are estimated to be “moderately deficient” in S for
corn without regard for county, soil series, soil texture, SO4 deposition, soil
organic C, or the S status (alfalfa). If you want to find only those soils that
are “moderately deficient” in S for corn and have sandy loam texture, you must
select both “moderately deficient” under S status (corn) and sandy loam under
soil texture before submitting the request.
If doing a search based on SO4 deposition or soil organic C, the basic model has
pop-up menus from which you choose suggested minimum and maximum values. The
values in these pop-up menus are based on the ranges for SO4 deposition and soil
organic C in the database. Atmospheric SO4 deposition varied from 17.5 to 32.0
kg S/ha/yr. Soil organic C varied from 0.17% to 83.98%. If you click the
“Advanced” button, you can enter any values you choose for SO4 deposition or for
soil organic C.
As an example of a simple search that shows the results for all soils in Morrow
County in the database, select Morrow from the pop-up list under County. Then
click the '"Submit" button. The results will show the sulfur status for 7 soil
series in Morrow County.
There are five categories of S status that are based on the expected response of
a crop to supplemental S fertilization when grown on the particular soil series:
- Highly Sufficient - Response to S fertilization unlikely under any
circumstances.
- Adequate - Response to S fertilization unlikely but might occur under
certain conditions.
- Variably Deficient - Response to S fertilization will often occur
depending
on specific crop growth conditions (rainfall, etc.).
- Moderately Deficient - Response to S fertilization will usually occur.
- Highly Deficient - Response to S fertilization will always occur.
|
