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Value of Mean and Average Soil and Air Temperatures
Author(s) -
Smith Alfred
Publication year - 1940
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1940.036159950004000c0008x
Subject(s) - value (mathematics) , citation , library science , mathematics , computer science , statistics
ALFRED SMITH IN considering soil and biological processes it is difficult to evaluate the full importance of certain natural or superficial environmental conditions. The principles of rock weathering, soil aging, the interrelations of soils, plants and animals, as well as crop management methods, all take into account the various climatic elements. The amount and distribution of rainfall over a long period of years, as well as similar data in relation to irrigation waters, have been intensively studied by many investigators with the conclusion that there is a distinct correlation between the characteristics of the rainfall or irrigation practices and soil development and crop growth. With respect to the effects of varying temperatures upon soil and biological processes, greatest attention has been paid to atmospheric temperature and until recent years very little to soil temperature. All soil scientists have availed themselves of the contributions made by climatologists and we now find numerous references in soil literature, such as that certain soil conditions are formed under mesothertnal, microthermal, tundra, or other types of climate. The influence of temperature on certain soil characteristics or crop responses as the nitrate content of soil (2) reclamation of black alkali soil (10) chlorosis of gardenia (5) yields of specific crops as grain sorghum and potatoes (18), are a few illustrations of the widespread interest and importance of soil temperature investigations. Soil temperature is largely dependent upon the geographical location, conditions of the atmosphere, slope of the soil, and its drainage conditions. As an illustration of the great diversity of climatic conditions within the same geographical area we can use certain sections of California. Where soils are abundantly supplied with rainfall the temperature of the soil will be lower than in the drier areas. This of course is due to the high specific heat of water as compared to dry soil. The average annual rainfall for California is estimated as being about 23 inches, but a study of the rainfall map of California (Fig. i) will-show that approximately 17% of the state receives less than 5 inches rainfall annually and 18% over 40 inches. San Bernardino County in the southeastern part of FIG. I.—Rainfall map of California. Adapted from U. .S. D. A. Weather Bureau Monthly Climatological Data, California Section 36 (n) November, 1932.