Lecture 2 - The Tropics Tropical Farming Systems Flashcards
where are the topics located on the earths surface
between the Tropic of Cancer (23.5 N of the equator) and the Tropic of Capricorn (23.5 S of the equator)
what percentage of the earths and ocean surface does the tropics represent
36% of the earth’s surface
20% of the land surface
43% of ocean surface
why is ag productivity so low in the tropics
no winter so crops are grown all year with no breaks. This causes increase in pests and disease problems
at what degree is the earths axis rotated
66.5
parallelism of the axis
the angle of inclination of the earth’s axis is constant
the _______ relationship between the earth and sun is responsible for the earths climate
geometrical
revolution
is the movement of the earth in an elliptical orbit around the sun
average distance of the sun to the earth
93 million miles away
the time to travel 1 orbit around the sun
1 year
how many rotations of the earth are there in a year
365.25
climate determinants
solar radiation
surface receiving solar radiation
earth’s rotation
land/sea configuration and topography
factors determining the distribution of energy
- the intensity of solar radiation
- duration of solar energy
oblique rays deliver less energy because
- there energy is spread over a large surface
- they pass through a thick layer of absorbing atmosphere
is there higher or lower temperature variation the closer you get to the equator
lower
what are some main characteristics of the temperature in the tropics
little annual variation
daily range typically higher than monthly mean
cooler temp at higher altitudes
warmer temp in continental interiors
how are trade winds created
high solar input heats up the air, causing it to rise. that creates a low pressure area and causes air flow from the higher pressure zone at higher latitude
where is the ITC
slightly to the north of the equator and moves with the second path of the sum
What does the ITCZ stand for
intertropical convergence zone
location of hot dry deserts and semi deserts
sahara, large parts of egypt, libya, algeria, mauritania, central australian
soils of hot dry deserts and semi deserts
Aridisols soils
- may have problems with salt accumulation
- generally alkaline
- can be fertile if irrigated
how much rain does the hot dry desert and semi deserts
less than 250mm rain
location of semi-arid shrubland steppe
southern border of Sahara desert, west, southern mexico, australia
soils of the semi-arid shrubland steppe
aridisols soil
-may have a problem with salt accumulation
-generally alkaline
-can be fertile if irrigate
what ag practices are done on semi-arid shrubland steppe land, if any
some irrigated ag, ranching
what ag practices are done on hot dry deserts and semi deserts land, if any
little ag practiced
crops grown in the semi-arid shrubland steppe
sorghum, millet, cowpea, and pigeon pea
what are the most traded animals on the livestock market in the tropics
goats and camels
dry savanna wet seasons
2 wet seasons - short wet season and long wet season (monsoon
wet savanna wet seasons
2 wet seasons
what ag practices are done on dry savanna lands, if any
rainfed and irrigated ag, grazing, perennial crops with irrigation
what crops are grown in the dry savanna (annual and perennial)
annual - sorghum, sweet potatoes, common beans, and cowpea
perennial - sisal, cashew, tea, groundnuts, cotton, sorghum, millet, maize, rice
location of sub humid wet savanna
thialand, ghana, northern brazil
how many months of humidity and precipitation does the sub himid wet savanna get
7-9 humid months, 800-2000mm
what ag practices are done on sub humid wet savanna land, if any
major ag land
crops grown in the sub humid wet savanna
coffee, tea, bananas, sugarcane, cacao, pineapple, sweet potato, cassava, sorghum
location of the tropical forests
amazon basin, congo basin, SE asia, close to the equator
precipitation in the rain forest
2000-3000mm; continuously wet
precipitation in the seasonal forest (monsoon climate)
short dry season, 1000-2000 mm
what ag practices are done on lowland tropical forests, if any
very little, as the soil is poor and it is difficult to clear land
very intensive
agriculture potential of forests
moisture - good, well-distributed amount
soil - poor fertility, usually well drained
elevation - lower yields than lowland, cooler=slower growth
crops grown in tropical forests (perennials and annuals)
perennials - oil palm, cacao, coconut, banana, coffee
annuals - cassava, yams, sweet potatoes
location of swamp formations
Borneo, Sumatra, Malaysia, Guyana
soils of swamp formation
histosols soils
drained for use, may be too acid
crops grown in swamp formations (deep peat and moderate peat)
deep peat: pineapple
moderate peat: oil plam, coconut, coffee, cacao
crops grown in tropical highlands
subtropical to temperate crops like tea and coffee and potatoes
