Agroclimatology

the division of climatology concerned with climate as a factor of agricultural production. Soil and its fertility, dry-land water resources, and vegetation are all determined to a significant degree by climate. Climatic conditions are taken into account in agricultural specialization. The history of agroclimatology is closely tied in with the practical needs of agriculture. The founder of our national agroclimatology was the Russian scientist A. I. Voieikov. Abroad, G. Azzi in Italy and B. Livingston in the United States were founders of the science. In the USSR, methods for agricultural evaluation of climate have appeared in the works of G. T. Selianinov, P. I. Koloskov, L. N. Babushkin, F. F. Davitaia, 1. A. Gol’tsberg, S. A. Sapozhnikova, D. I. Shashko, and others. Evaluation of agroclimatological resources of the USSR has been achieved; frosts, droughts, and sukhovei (very hot dry winds) have been thoroughly described. Individual agroclimatological manuals have been prepared on the basis of summarized observations and experimental studies made in all oblasts, krais, and republics.

Several tasks face agroclimatology: the agricultural evaluation of climate and agroclimatological zoning to promote the most expedient disposition of crops and crop varieties and also species and breeds of domestic animals; justification of particular procedures and of the complex of agricultural practices and their effectiveness under given climatic conditions; elaboration of means of control of adverse climatic and weather phenomena; and study of variation in the microclimate of agricultural lands. Of great practical significance is the research being done on the dependence on basic climatic factors of growth, development, and yield of crops. The numerical expressions of these relationships are called agroclimatological indices. Among such indices are the amount of temperature required by plants during the vegetation period and the amount of moisture necessary to realize a certain yield. Study of the distribution of agroclimatological indices by territory, with allowance for recurrence of such indices over a long period of years (60–80 years) in particular regions, makes possible the determination of the degree of correspondence between the requirements of agricultural crops and crop varieties on the one hand, and climatic conditions on the other. Methods for computing the climatic supply of heat, precipitation, reserves of soil moisture, duration of frost-free weather, and frequency of such factors as frost and sukhovei have been worked out in the USSR. Agroclimatology studies the climate of individual land areas and crop-rotation fields, with allowance for their relief, slope exposure, influence of vegetation, and agricultural and meliorative practices on the effect of meteorological elements during the sowing. The results from research in this area are used to refine and supplement the agricultural evaluation of climate and to supply material for justification of agricultural practices.

The basic lines of research in agroclimatology consist in further development of the theory of combined evaluation of the agroclimatological resources of a territory, in the development of combined yield indices for the leading crops, in the justification of meliorative practices for eliminating the consequences of unfavorable climatic phenomena (with allowance for the microclimatic features of crop-rotation lands), and in the devising of methods for the use of agro-climatological data in long-term agrometeorological forecasts of crop growth and development. Agroclimatological research in the USSR is conducted by the Main Administration of the Hydrometeorological Service, the All-Union Institute of Plant Growing, and a number of institutions of higher education.