What is Photosynthetic active Radiation and Crop Growth Rate. how Photosynthetic active Radiation effects the crop growth rate.how radiations increase and decrease the crop growth
3. PAR
Defination :
Photosnthetically Active Radiations ?
It is the amount of light available for photosynthesis which is light in
the 400 to 700 nanometer wavelenght range.
This range also known as visible light .
PAR can help determine the light levels in a greenhouse.
4.
5. PAR
Importance :
• It is needed for photosynthesis.
• It is essential for plant growth.
• It is an important parameter in measuring of biomass
production.
6. PAR
Fectors Affecting Of PAR :
• Fectors that reduce the amount of PAR available to plants include
anything that reduce sunlights such as …..
• Cloud covers.
• Shading by trees.
• Buildings
• Air pollution.
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9. PAR
How photosynthetically active radiation is measured ?
• Photosynthetically Active Radiation ( PAR ) is reported as millimoles
of light energy per square meter.
• Pericipitation and temprature are two of the major factor that
determine the proportion of PAR absorbed by plants.
10. PAR
Silicon photovoltaic detector :
• Photosynthetically Active Radiation (PAR) is measured by silicon
photovoltaic detector.
• This detector measures light in the 400 nanometer to 700 nanometer
range.
11. PAR
PAR value :
• PAR value range from 0 to 3000 millimoles per square meter.
• At night , PAR is zero.
• During mid day in the summer , PAR often reaches 2000 to
3000 millimoles per square meter.
12. PAR
LI-COR’s solution for measuring PAR :
• Light meter can be used to measure
Photosynthetically Active Radiation.
• The LI-191 line Quantum can be used to measure
average PAR over 1 meter lengths.
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14. CROP GROWTH RATE
Defination :
• The rate of dry matter production per unit area.
• Crop growth rate (CGR) show the growth of plant with passage of
time.
• Unit of crop growth rate is ( gm-2 das-1 )
15. CROP GROWTH RATE
Process :
• Randomly selected five plants from each sub plot at
regular interval for fifteen days.
• The sampling was started 45 days and continued up to
120 days.
16. CROP GROWTH RATE
• After harvest , samples were weighed to determine fresh weight.
• Plant sample thoroughly mixed and sun dried.
• Placed in an oven at 70℃.
• The dry weight per m-² was recorded.
17. CROP GRIWTH RATE
Formula :
• Crop growth rate was calculated by using the formula given by Hunt
(1978).
Crop growth rate (CGR)=W2–W1/ T2–T1
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19. CROP GROWTH RATE
• W2 = Dry weight per unit land area (g m-2) at secound harvest .
• W1 = Dry weight per unit land area (g m-2) at first harvest.
• T2 = Time corresponding to secound harvest.
• T1 = Time corresponding to first harvest.
20. How to increase crop growth rate ?
• Increase photosynthesis.
• Minimize respiration.
• Increase CO2.
• Minimize other constrains.
● Water stress
● Climatic hazard
● Mineral deficiency
● Pest and disease
