Term paper on solar radiation and physiology effects on plants

BASICS (MODERN) CONCEPTS OF CROP PODUCTION C.NO AGRON5013(3+0)

SUBMITTED TO : Dr.srilatha madam &Susheela madamDepartment of agronomy Maize & forage scientists

SUBMITTED BY : k.Venkat kiranreddyID NO; RAM/15 -03.

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 .

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.

Sorces of energy for all the physical process taking place in the atmosphere like

Photosynthesis

Evaporation

Heating the soil & air.

TYPES OF SOLAR RADIATIONS

Direct radiation

Global radiation

Diffused radiation

Forms of solar radiation

DIRECT RADIATION : directly from sun

DIFFUSED RADIATION :scattered by suspended particles.

GLOBAL RADATION : sum total of direct &

Diffused radiation.

Solar radiation measure by

PYRANOMETER

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.

Solar radiation for C4 and C3 species

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.

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.

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.

Losses of energy are: by

non-absorbed wavelengths: 60%.

Reflection and transmission:8%.

Heat dissipation: 8%

Metabolism: 19%

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.

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

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.

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.

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.