Agronomic Physics

the science of physical methods in the study of the external conditions of plant life and of the physical processes in the activities of plants. Agronomic physics develops methods for control of physical conditions within the soil and in the near-ground atmospheric layer. It consists of several departments: soil physics (which includes the physics of the solid phase of the soil), soil hydrophysics, thermal soil science, and physics of the gaseous phase of the soil; physics of the near-ground layer of the atmosphere (the aerodynamic, radiational and other parameters); phytobiophysics (plant photophysiology, plant radiobiology); and methods and means of regulating environmental conditions of plant life in the interest of promoting productivity and early ripening.

Agronomic physics is a young science, dating only from the beginning of the 20th century. It is developing on the basis of the theoretical achievements of modern natural science, especially physics and biophysics, and also electronics and the physics of semiconductors, polymers, and plastics. Many scientists, both Soviet and foreign, have contributed substantially to agronomic physics, among whom may be mentioned D. N. Prianishnikov. A. G. Doiarenko, N. A. Kachinski, A. A. Rode, S. I. Dolgov, S. N. Ryzhov and B. V. Deriagin in the Soviet Union, E. Russell in England, and W. Shaw in the United States. In the USSR, A. F. Ioffe was the founder of the school of agrophysicists.

Agronomic physics employs both pot-culture and field methods of research, using precision instruments to assess conditions in the external medium and to study physiological processes within plants. In particular, physical processes involved in the interaction of plants with their environment (heat and water regimes, gas exchange, and so on) are studied using the modern experimental tools of physics such as semiconductors, electronic and ionic apparatus, and radioactive radiation. Many of the instruments are remote-controlled (the sensor is located at considerable distance from the observer). With the help of such instruments and special devices, it is possible to get information on the biological processes and also on the state of the surrounding medium of plants, to receive signals of the onset of unfavorable conditions (thus permitting frost forecasts); and so forth. At the same time, effective methods are being developed to influence both plants and their environment: electromagnetic, radioactive, ultrasonic and other types of plant irradiation, thermal and hydrological soil improvement measures, agricultural engineering techniques, and the like.

Research in agronomic physics is of great practical significance; its results are being used to develop new agricultural techniques and to perfect existing ones aimed at retention of soil moisture, improvement of soil heat regimes, discovery of better planting and faster tillage methods, and the like. Photoculture techniques for use in connection with sheltered ground, for example, shorten the vegetation period of vegetables and also increase yield. The use of polymer films in vegetable growing, the automatic regulation of vegetable growth in hothouses, and the automatic maintenance of optimal conditions in agricultural storage facilities, among other techniques, are all quite effective.

Scientific research in agronomic physics is being conducted by the V. V. Dokuchaev Soil Institute, the soil science departments of various universities and agricultural colleges, and, especially, the Agrophysical Scientific-Research Institute. The latter publishes Sbornik trudov po agronomicheskoi fizike (Collection of Works on Agronomic Physics). Problems of agronomic physics, especially soil physics, are discussed at congresses of the International Society of Soil Scientists.