Photoperiodism, a factor in determing the manurial efficiency and distribution of Crotalaria juncea

Singh, B.N.; Singh, S.N.; Srivastava, M.B.

Photoperiodism, a factor in determing the manurial efficiency and distribution of Crotalaria juncea

1937

Singh, B.N. | Singh, S.N. | Srivastava, M.B.

Investigations were conducted to study various plant responses in Crotalaria juncea to different exposures to light at different stages of development. The efficiency of the plant for green manuring was also determined on the basis of the fertilizing constituents that might be incorporated into the soil at different stages of growth. With an increase in the length of time of light exposure, an increase in the physical characters of the plant was observed, viz., height of the plant, number of leaves per plant, leaf area, root length, number and weight of root nodules, and length and yield of fiber. Some of these characters attained their maximum development under continued illumination, while others required only 20 hours' exposure, longer exposure resulting in solarization. The critical light period for Crotalaria apparently falls within the zone of a 16- to 20-hour day. Beyond this range flowering was completely suppressed and the plant remained purely vegetative. Manurial efficiency increased with an increase in the length of the photoperiod, attaining its highest value under 20 hours' exposure. During the early half of its life cycle, Crotalaria seems to require less light and plants growing under longer exposures are unable to economize the entire energy falling upon them. With further advance in age, however, the light requirements increase. Thus on the basis of these observations, it may be concluded that a photoperiod of 16 to 20 hours considerably increases the manurial efficiency of this crop. If other environmental factors do not interfere, it may be concluded that Crotalaria can be successfully introduced as a green manure crop into regions with long periods of daylight and that it may be grown to advantage in mixtures of early-maturing crops.

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