From PJTSAU Telangana Iam Msc Agronomy

2. Term paper on solar radiation and
physiology effects on plants
BASICS (MODERN) CONCEPTS OF CROP PODUCTION C.NO
AGRON501
3(3+0)
SUBMITTED TO :
Dr.srilatha madam &
Susheela madam
Department of agronomy
Maize & forage scientists
SUBMITTED BY :
k.Venkat kiran
reddy
ID NO; RAM/15 -03.

4. Solar radiation
 Solar radiation is radiant energy emitted by the
sun, particularly electromagnetic energy.
About half of the radiation is in the visible
shortwave part of the electromagnetic spectrum.
The other half is mostly in the near-infrared part,
with some in the ultraviolet part of the spectrum .

12.  Light is a climatic factor that is essential in the
production of chlorophyll and in photosynthesis, the
process by which plants manufacture food in the
form of sugar (carbohydrate).
 Other plant processes that are enhanced by this
climatic factor include: stomatal movement,
phototropism, photomorphogenesis, translocation,
mineral absorption, and abscission.

13.  Sorces of energy for all the physical process taking
place in the atmosphere like
Photosynthesis
Evaporation
Heating the soil & air.

14. TYPES OF SOLAR RADIATIONS
Direct
radiation
Global
radiation
Diffused
radiation

15. Forms of solar radiation
 DIRECT RADIATION : directly from sun
 DIFFUSED RADIATION :scattered by suspended
particles.
 GLOBAL RADATION : sum total of direct &
 Diffused radiation.

16. Solar radiation measure by
 PYRANOMETER

17. COMPONENTS
 QUALITY
 INTENSITY
 DURATION OF LIGHT are important.
1.Quality cant be controlled on a field scale –feasible on specialty
crops
2.Intensity of light (brightness) is an important factor.

18. Solar radiation for C4 and C3 species

19. Solar radiation
 Radiant energy is a significant factor in plant growth
and development.
 The quality , intensity, and duration of light are all
important.
 Clear – day radation is a useful indicator of the
amout of solar energy for physiological processes
within plants.
 Most of the plants are generally able top achieve
good growth at light intensities of less than full
daylight.

20. Contd……
 However, plants do differ in their response to light of
Varying intensity.
 Light intensity had marked effects on uptake of P
and K.
 It was observed that O2 uptake by the roots increased
with increasing light intensity.
 Changes in light intensity caused by shading exert
considerable influence on crop growth.

21.  With high plant populations, light penetration to
lower positions in the plant canopy may be
inadequate for bottom leaves to carry on
photosynthesis.
In wheat, the absorption of NH4
+ ,sulphate (so4
-2
),
and water was increased with increasing light
intensity but that absorption of Ca and Mg.

22. Losses of energy are: by
non-absorbed wavelengths: 60%.
Reflection and transmission:8%.
Heat dissipation: 8%
Metabolism: 19%

23. Light duration:
Photo - periodism : The behaviour of the plant in
relation to day length is termed photoperiodism.
Plants classified into :
Short day eg : maize , sorghum, and rice
Day neutral eg :cotton
Long day plants eg : wheat.
Most of tropical crops are short day plants.

24. Quality of light
 Quality of light
 White light contains different colours with varying
wave lengths .
 Wavelengths of different colours are –
 Voilet 400-450 nm
 Blue 435 – 490 nm
 Green 490 -574 nm
 Yellow 574 -595 nm
 Orange 595 –626 nm
 Red 626 -750 nm

25.  Green plants use a part of net solar radiation called
photosyntheticially Active Radiation .
 with wavelengths from 400 -700 nm for
photosynthesis.
 Plants mostly use wavelengths of violet and blue.
 Shorter rays viz., x- rays and gamma rays and longer
rays like infrared rays are detrimental for crop
growth.

26.  Plants intercept direct and diffuse sunlight .
 The upper leaves receive both types of radation,
 While lower leaves receive direct radiation.
 Diffused radiation more siginicant in lower leaves.

27.  The quantity of radiation intercepted by plant cover
is influnced by series of factors :-
 Leaf angle
 The properties of the leaf surface affecting light
refection, the thickness and chlorophyll conceration
 Horizontal leaves intercept more solar radiation than
vertical leaves.