Format:
7 Seiten, 96 Abbildungen.
Series Statement:
Miscellaneous publication / United States Department of Agriculture 421
Content:
Drought is a hazard from which few parts of the United States are entirely free. It is exceptional in the humid East, occurs moderately often in the subhumid Middle West, strikes with discouraging frequency in the semiarid Great Plains, and is chronic in the arid Southwest. Drought entails little or no agricultural risk in humid or arid climates. In the one, unfavorable years are too few to be taken into account, and in the other, favorable years are so unusual that agriculture is not attempted without irrigation. Drought takes its greatest toll in the transitional subhumid and semiarid regions. In the semiarid region the occasional favorable year encourages farming, but unfavorable years come so often that agriculture may be unprofitable or even impossible on a permanent basis. If coming droughts could be anticipated at planting time, much loss could be avoided. As yet, however, dependable seasonal forecasts cannot be made. Although drought years and flood years cannot be predicted, it is possible by using the many records of the United States Weather Bureau to determine the frequency with which droughts or other climatic events are likely to occur. Such information is of great aid in evaluating the agricultural potentialities of a region. It is essential to effective land use planning and to intelligent evaluation of erosion hazard. It can tell for a particular area whether, over a period of years, agricultural successes can be expected sufficiently often to make continued farming possible. Similar information can be obtained for the grazing regions.
Note:
Assistance in the preparation of the maps was furnished by the personnel of Work Projects Administration Official Project No. 65-2-42-282.
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CONTENTS: 1 The evolution of the climatic pattern 1 Vegetation as a climatic indicator 2 The determination of effective precipitation 2 The climates in the United States 2 Superhumid climate 2 Humid climate 3 Subhumid climates 3 Semiarid climate 4 Arid climate 4 Climatic variation 4 Literature cited 5 Selected list of references 5
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PLATES: Average annual precipitation over the earth 1 Climatic regions over the earth 2 Normal distribution of principal climates in the United States, annual 3 Normal distribution of principal climates in the United States, crop season 4 Climates of the United States for each year from 1900 to 1939 (annual climates, odd-numbered plates; crop-season climates, even-numbered plates) 5-84 Frequency of arid climate, annual 85 Frequency of arid climate, crop season 86 Frequency of semiarid and drier climates, annual 87 Frequency of semiarid and drier climates, crop season 88 Frequency of dry-subhumid and drier climates, annual 89 Frequency of dry-subhumid and drier climates, crop season 90 Frequency of moist-subhumid and drier climates, annual 91 Frequency of moist-subhumid and drier climates, crop season 92 Frequency of humid climate, annual 93 Frequency of humid climate, crop season 94 Frequency of superhumid climate, annual 95 Frequency of superhumid climate, crop season 96
Language:
English
Keywords:
Klimazone
;
Klimatyp
;
Regen
;
Atlas
DOI:
10.22004/ag.econ.338813
URL:
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