Explain why slash-and-burn farming must constantly shift to new areas, when rainforests are normally thick with vegetation
Rainforest trees supply the tropical soils with most of the nutrients that the trees themselves need for growth. As leaves, flowers, and branches fall to the ground or roots die, numerous soil-dwelling animals and bacteria act on them, transforming forest litter into organic matter with vital nutrients. However, if the trees are removed, there is almost no replenishment of these nutrients and no natural barrier (forest litter and root systems) to prevent large amounts of rainwater from percolating through the soil. Percolating water dissolves and removes nutrients and minerals from the topsoil. The intense activities of microorganisms, worms, termites, ants, and other insects cause rapid deterioration of remaining organic debris, and soon all that remains is an infertile soil with a mixture of insoluble aluminum, iron, and manganese compounds.
You might also like to view...
In the anticyclone pictured here, the winds at area B are from the ________ bringing ________ temperatures.
A) north; warmer
B) south; warmer
C) north; cooler
D) south; cooler
You are a newly appointed advisor in a government project to help move a developing country forward economically. With limited financial resources and staffing, which of the following would be your highest priority?
A) Create new businesses by partnering with developed nations. B) Help the government promote family planning throughout the country. C) Shift the focus of agriculture to that which will produce the highest yields of nutritious foods. D) Build up the ports of the country to increase the ability to import and export products.
A ________ is an instrument that is used to record earthquake vibrations
A) seismograph B) seismogram C) triangulator D) compass
The diet of the Inuit and Aleuts consists of very little meat, and is based largely on foraging and subsistence agriculture
Indicate whether the statement is true or false