WEATHER-CROP YIELD CORRELATIONS AS APPLIED TO CROP YIELD ESTIMATES FOR THE EUROPEAN USSR

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP79-01093A000100150003-9
• Release Decision: RIFPUB
• Original Classification: S
• Document Page Count: 60
• Document Creation Date: November 9, 2016
• Document Release Date: October 19, 1998
• Sequence Number: 3
• Publication Date: May 26, 1952
• Content Type: IR

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SECURITY FORMATIONIbb
im
PROVISIONAL INTELLIGENCE REPORT
WEATHER-CROP YIELD CORRELATIONS
AS APPLIED TO CROP YIELD ESTIMATES
FOR THE EUROPEAN USSR
CIA/RR PR-15
26 May 1952
i.)f.:7(;UMENT
NO CI-IANGI'L IN u
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r....-HANaED TO:
FIEVIEW DATE:
L1J
CENTRAL INTELLIGENCE AGENCY
OFFICE OF RESEARCH AND REPORTS
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WARNING
This material contains information affecting
the national defense of the United States
within the meaning of the espionage laws,
Title 18, USC, Secs. 793 and 794, the trans-
mission or revelation of which in any manner
to an unauthorized person is prohibited bylaw.
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Approved For Release 1999/09/02: Cl
SE
SEC ? INFORMATION
9-01093A000100150003-9
CONFIDENTIAIL
PROVISIONAL INTELLIGENCE REPORT
WEATHER-CROP YIELD CORRELATIONS AS APPLIED TO am, YIELD ESTIMATES
FOR THE EUROPEAN USSR
CIA/RR FR-15
Note
The data and conclusions contained in this report
do not necessarily represent the final position of
ORB and should be regarded as provisional only and
subject to revision. Additional data or comments
which may be available to the user are solicited.
CENTRAL INTELLIGENCE AGENCY
Office of Research and Reports
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Summary
CONTENTS
I. Purpose and General Introduction
Page
1
3
II. Area Covered 5
III. Sources of Information and Its Tabulation . . ? ? 7
IV. Purpose and Method of Eliminating the Yield Trend 9
V. Methodology and Results 11
1. Weather Factors Used 11
2. Simple Correlations 13
3. Multiple Correlations 21
4. Multiple Regression Equations for Fore-
casting Yields 25
5. Assumptions 30
VI. Sources of Current Weather Data 33
VII. Additional Proposed Investigations 35
Appendix A. Tables
Appendix. B, Sources
Appendixes
Illustrations
39
63
Following Page
USSR: Weather-Crop Yield Study for European
USSR (Map) 6
Observed Yields and Yields Computed from Monthly
Weather Data for Selected Areas of the USSR
(Figures 1 to 7)
28
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CIA/RR PR-15 SECRET
(ORR Project 52-51) SECURITY INFORMATION
WEATHER-CROP YIELD CORRELATIONS AS APPLIED TO CROP YIELD ESTIMATES
FOR THE EUROPEAN USSR
Summary
In this report a study is made of the relationship between the
yields of three spring grains (wheat, barley, and oats) and selected
weather factors in the major grain-surplus-producing districts of the
European USSR. Total monthly precipitation and mean monthly maxi-
mum temperature values were selected as the weather factors to be
employed. Precipitation values were used both in the form of sepa-
rate monthly totals and in the form of combinations of monthly data.
Only individual mean monthly maximum values were used for temperature.
These weather data, as well as the grain yield information, cover
the period 1883-1915.
From an analysis involving these factors, multiple regression
equations have been developed in this study which, on the basis of
current weather information, will be employed for the first time by
ORB in estimating the yields of the 1952 grain crop in the USSR.
The weather components employed in the development of these predic-
tion equations were selected on the basis of comparative significance
as determined through the use of simple and multiple correlation
coefficients. The significance of certain of these correlation
coefficients formed the basis for hypothesizing certain months or
combinations of months as most "critical," with respect to precipi-
tation and maximum temperature, in determining the ultimate crop
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yield. The crop yield data were utilized in such a way that part
of them was employed in obtaining preliminary information and in
setting up the hypothesis as to "critical" months, and another part
was used to test the validity of this hypothesis. The correlation
coefficients computed in this study formed the basis for setting up
the multiple regression equations to be used in estimating future
grain yields in the USSR. However, since only a limited number of
weather factors can be included in a prediction equation, a result
obtained in any particular case may have to be readjusted in the
light of any significant meteorological or nonmeteorological factor
not considered in the equation.
On the basis of results obtained thus far, a continuation of
this weather-crop yield study is planned. In particular, the
relationship between crop yields and vapor pressure deficit values
will be investigated. Vapor pressure deficit, as a function of
both temperature and humidity, is a rough measure of the rate of
transpiration and evaporation from plants. Preliminary investiga-
tions indicate that significant results may be obtained, particularly
In regions of marginal precipitation.
In addition, studies on the major winter grains and other crops,
such as potatoes, sugar beets, and cotton, are planned.
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I. Purpose and General Introduction.
This report deals with a study of the problem of determining
past weather-crop yield correlations and ascertaining whether it is
practical to use these correlations in estimating future grain
yields in the European USSR. This study is a progress report, and
conclusions are based on analyses made up to the present time.
The importance of weather factors in relation to crop yields
has long been recognized, but it has been extremely difficult to
express these weather-crop yield relationships in mathematical terms
that could be applied to estimating grain yields. Many separate
weather factors affect the final crop yields, and the problem is
further complicated by the fact that there are numerous interactions
among the weather factors themselves. For example, in order to
determine the effect of precipitation on the yield of spring wheat
in any given area, not only the amount of precipitation but also
the period of its occurrence must first be considered. In addition
to precipitation, it is necessary to consider the effects of other
weather factors occurring during the same period. The effects of
these other factors are not independent of the precipitation or of
each other but are interrelated. Thus the problem is exceedingly
complex.
If practically unlimited time and data were available, it would
be ideally desirable to measure the relationships between weather
factors and crop yields by evaluating both the qualitative and the
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quantitative effects of every conceivable combination of weather
factors at regular intervals throughout the growing season. How-
ever, since both time and data are insufficient for such an ideal-
istic approach, the analysis of only a limited number of weather
factors is included in this study.
Since relatively comprehensive weather and crop yield informa-
tion in the European USSR is available only for the period 1883-1915,
dt was necessary to make use of this information even though it is
old. :For the purposes of a correlation study, however, such data
are entirely satisfactory, since the general pattern of the relation-
ships involved does not change.
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II. Area Covered.
The area selected for this study includes most of the grain-
surplus-producing districts of the European USSR.* With its apex
based in the Tsarist guberniya** of the Don the selected area
spreads away fanwise:
1. Northwestward, including the following guberniyas of
the Ukraine:
Yekaterinoslav, Poltava, Chernigov, and Kiev as
well as the southwest guberniya of Bessarabia;
2. Northward, including the following guberniyas of the
"Black Soil Belt": Voronezh, Kursk, Orel, Tambov, and Penza
as well as the semi-Black Soil guberniyas of Tula and Ryazan;
3. Northeastward, including the Volga River valley
guberniyas of Saratov, Samara, Simbirsk, and Kazan as well as
the Ural guberniya of Perm.
In terms of present-day (1952) boundaries, all or at least
portions of all of the following administrative divisions are
located in this area with its apex based in Rostov oblast of the
former Don guberniya (the northwestern part of Economic Region IV):
1. To the northwest in the Ukrainian group (Economic Re-
gion III) are located the following: Stalino, Voroshilovgrad,
* This area is outlined in the map following p. 6.
** Guberniyas, the larger administrative divisions in the early
1900's, correspond roughly to present-day oblasts, although in many
cases they were somewhat larger. The next smaller administrative
divisions in this period, the uyezds, though larger, are roughly
comparable to the present-day rayons.
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Zaporozh'ye, Dnepropetrovsk, Kirovograd, Poltava, Sumy, Chernigov,
Kiev, and Vinnitsa oblasts and the Moldavian SSR and Izmail
oblast;
2. To the north in the Black Soil and semi-Black Soil
Belts (the southern part of Economic Region VII) are located
4
the following: Kursk, Orel, Tula, Bryansk, Voronezh, Tambov,
Ryazan and Penza oblasts and Mordovskaya ASSR, Chuvashskaya
ASSR, and Mariyskaya ASSR;
3. To the northeast in the Volga group (Economic Region
VI) are located the following: Stalingrad, Saratov, Kuybyshev,
and Ul'yanovsk oblasts and Tatarskaya ASSR. In addition, two
Ural (Economic Region VIII) oblasts are included: Molotov west
of the Urals and Sverdlovsk east of the mountains.
6
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SECURITY INFORMATION
U.S.S.R.
WEATHER-CROP YIELD STUDY
FOR
EUROPEAN U.S.S.R.
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