ENVIRONMENTAL FACTORS AFFECTING CROP PRODUCTION Flashcards
ABIOTIC FACTORS
1) climatic
2) edaphic
3) climatic stress
BIOTIC FACTORS
1) beneficial organisms
2) pests
3) allelopathy
WEATHER
1) set of all extant phenomena in a given atmosphere at a given time
2) over short periods
CLIMATE
average atmospheric conditions over longer periods of time
CLIMATIC FACTORS
1) solar radiation
2) temperature
3) wind movement
4) precipitation
5) relative humidity
6) mist and fog
SOLAR RADIATION
rate at which surfaces absorb radiation (watt/m2)
ASPECTS OF IRRADIANCE
1) intensity (lux/foot candles)
2) duration (hours/day)
3) wavelength (nanometer/color)
PHOTOENERGETIC EFFECT
direct effect of solar radiation on photosynthesis
PHYTOCYBERNETIC EFFECT
effect of solar radiation on development of plants
TOTAL DRY MATTER
influenced by intercepted radiation
RED AND BLUE WAVELENGTHS
photosynthesis
RED AND FAR RED WAVELENGTHS
photoperiodism
SOLAR CONSTANT
1) amount of solar radiation reaching outer limits of earth’s atmosphere
2) 2.0 cal/cm2/min (15% fluctuation within the year)
PAR
1) PHOTOSYNTHETICALLY ACTIVE RADIATION
2) used by plants for CO2 fixation in photosynthesis
SUN-LOVING PLANTS
heliophythes
SHADE-LOVING PLANTS
sciophythes
ALBEDO
1) reflected radiation
2) total incident light
=> 50-60% (polar regions)
=> 20-30% (tropical equatorial regions)
=> 80% (when reaches ground in absence of clouds)
INCREASES AS LATITUDE FROM EQUATOR INCREASES
daylength
FACTORS AFFECTED BY DAYLENGTH
1) flowering (photoperiodism)
2) germination (photoblastism)
FACTORS AFFECTING TEMPERATURE
1) solar radiation
2) surrounding land masses and bodies of water
3) altitude (0.6 decrease per 100 m rise in elevation)