Crop
Weather Outlook
2017 & Beyond
Blue Earth
16Dec 2015
• Before the Pyramids, people knew the
sun appeared in different places
according to season. The Moon too.
• But, for the Moon, it was 18.6 years after
the Moon came up furthest North until it
did it again.
Super Moon Flood Tide
•
Dr. Tiffany Troxler and correspondent David
Begnaud in a street suffering from a “king
tide” made worse by the supermoon.
CBS NEWS
Chinook
Wind Shift With Season
Wind Shift with time of Day
Wind Shift with time of Day
2016 10 days of low wind in June
http://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=173&network=SD_ASOS&
zstation=YKN&units=mph&_opt_p1=on&p1=0501-0510&_
Rain days per year have increased substantially
Ames, IA Precipitation by year 1893-2007
60
y = 0.0517x - 69.076
50
40
30
20
10
0
1880
1900
1920
1940
1960
1980
2000
2020
100+ yr Precipitation, 20%+ increase
1950-1993 Precipitation
Most of the United States experienced significant
precipitation increase. Diminished Tropical
Storms impacted Florida.
Heavy rain events are more common?
Increased River Flow (NE Iowa)
Turkey River at Garber, IA
3500
y = 6.932x - 12627
3000
2500
6-fold increase of Flood Prone Years
2000
1500
1000
500
0
1920
2-fold increase in annual river flow
1930
1940
1950
1960
1970
1980
1990
2000
2010
2020
Nishnabotna @Hamburg, IA
(SW Iowa)
Kishwaukee @ DeKalb
http://nwis.waterdata.usgs.gov/ia/nwis/annual
6000
6-fold increase of Flood Prone Years
5000
mean annual cfs
4000
3000
2000
1000
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
y = 18.825x - 35716
2-fold increase in annual river flow
Year
stable period 2
stable period 3
stable period 4
Beyond
137
Farmer Benner in
1885 noted dry/wet Dust Bowl
cycle.
History
19922004
Forecast
Periodic Impacts
Bu/a
1-in-3 chance of drought
vs
1-in-12 or 13
IA Corn
IA Corn
180
160
140
120
100
80
60
40
20
0
1900
1920
1940
1960
Year
1980
2000
Farmer Benner
On the average drought has a an 18.6 yr. period.
•
2012
Weather Volatility
Climate RISK in Agriculture is
likely to be greater during the
next 20 years
Management of RISK is of
increasing importance
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/season.JFM.nao.gif
Gleissberg
19 yr Dry/Wet
Tree rings indicate
climate cycles.
dry
wet
Heat & Water Stress
& 90
year
cycles
Tree Rings
Roanoke, NC cypress tree.
Dennis Blanton, Wm & Mary
College, David Stahle, Univ.
of Arkansas.
U.S. drought
starts here.
800 Year Rain (Virginia)
La Nina : Extremes
How to Evaluate the
Crop Year
Part 1: Knowing the Yield Trend
Annual precipitation 27.64 inch
http://yourweatherservice.com/
http://yourweatherservice.com/
•
NOTE
•
mygeohub.org/groups/u2u/acv
•
mygeohub.org/groups/u2u/acv
•
mygeohub.org/groups/u2u/acv
•
Webster County IA
•
•
What changed: 2011, 2012, 2013, 2014?
Were 1999 & 2000 identical?
•
•
• The USDA yield estimate is based on :
– Crop Development
– Crop Condition
– Some factors that influence yield do not
show up in the estimate considerations.
• Growing Degree Days, Heat Stress, Relative
Precipitation
mygeohub.org/groups/u2u/acv
M
flood
X
X
X
2009 High Yield SE SD
2011 Low Yield SE SD
http://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=32&network=SDCLIMATE
&station=SDC009&year=2011&var=low&dpi=100&_fmt=png
•
mesonet.agron.iastate.edu/plotting/auto/?q=32
•
mesonet.agron.iastate.edu/plotting/auto/?q=108
High
High
Low
Flood
Low
Low
Low
High
Big
•
Low
Flood
High
Low
Low
High
High
LowBig
Low
Flood
Low
Low
High
High
Big
High
Low
mesonet.agron.iastate.edu/plotting/auto/?q=108
END
Elwynn Taylor
Iowa State University
Climatologist
WWW.twitter.com/elwynntaylor
[email protected]
County Yield Trend and My Yield
Trend
• 30-year trend for Corn and Soy is publically available for the
Nation, state, and most Corn belt counties.
• Graphs, interactive graphs, and data sets are available at:
mygeohub.org/groups/u2u/acv
• Expand the map to find your county and click on any “red”
spot shown in the county (a few counties do not have yield
trend, so use one adjacent to the original choice).
• After locating the county of interest, click on any red spot
and then click “Select this station” then select “Yield Trend.”
• See the 30-year trend with yearly yields and options to see
the numerical values for yield and yield trend. (you will
later compute the % deviation from the trend for chosen
years.)
Know the yield record for your farm and for your county.
The bushel per acre yield is important, but the “Time Trend” is essential to the
evaluation of the crop success (or failure). Do not judge a crop by the Bushel yield as
compared to yields of a few years past. Yields over time are best evaluated by
comparative “percent of trend.”
First get your county yield history. The trend is ideally determined from a 30-year
record. County yield records (displayed as a graph or as a data sheet) are available
from “mygeohub…” a website produced by a consortium of extension across the
Midwest.
Second compile the history and trend of the fields or farms you operate. Do not
despair because you record is less than 30 years, use the records you have. Most
accomplish this using Microsoft Excel or the equivalent. Should you not have the
spreadsheet program or are less than comfortable operating it I suggest employing a
12-yr old in this project (if your local youth refuses, ask for a suggested computer geek
he/she knows). The Excel program will plot yields according to year and insert a trend
line, equation of the trend line, and compute what the trend yield is for each year. You
can have it display the yield as a percent of trend for any chosen year or years.
•
A yield that is 90% (or less) of the trend legally a drought.
It is useful to take note of yield as a percent of trend for the evaluation of “Good,