1. Soil erosion
Soil erosion is the washing or blowing away (by wind or water) of the top layer of soil (dirt).
This is a serious problem for people who want to grow crops. Crops are the foods that farmers
grow. If the soil has eroded, the crops will not grow very well.
Soil erosion was a big problem in the Midwestern United States in the 1930s dust bowl.
Erosion also leaves large holes in the earth, which can weaken buildings and even cause them to
collapse. Edited by:-Đéèpãķmeeņã Studied at rajasthan technical university kota (Raj.)
Soil erosion is one form of soil degradation along with soil compaction, low organic matter, loss
of soil structure, poor internal drainage, salinization, and soil acidity problems. These other
forms of soil degradation, serious in themselves, usually contribute to accelerated soil erosion.
Soil erosion is a naturally occurring process on all land. The agents of soil erosion are water and
wind, each contributing a significant amount of soil loss each year in Ontario. Soil erosion may
be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing
serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop
production potential, lower surface water quality and damaged drainage networks.
Atmospheric composition/ atmosphere
The atmosphere of Earth is mostly composed of nitrogen. It also contains oxygen used by
most organisms for respiration and carbon dioxide used
byplants, algae and cyanobacteria for photosynthesis. It protects living organisms from genetic
damage by solar ultraviolet radiation, solar wind andcosmic rays. Its current composition is the
product of billions of years of biochemical modification of the paleoatmosphere by living
organisms.
The term stellar atmosphere describes the outer region of a star, and typically includes the
portion starting from the opaque photosphere outwards. Stars with sufficiently low temperatures
may form compound molecules in their outer atmosphere.
In descending order of amount by volume (indicated by percentages), the atmosphere’s gases are
molecularnitrogen (N2, ~ 78%) and oxygen (O2, ~ 21%); argon (Ar, <1%); water vapor (H2O,
<1 % generally but highly variable); carbon dioxide (CO2, <400 ppm [parts per million]); and a
variety of ppm- (and lower) level trace gases such as helium, neon, krypton, molecular hydrogen,
methane, the chlorofluorocarbons,ozone, and various oxides of nitrogen. Of these, the space/time
distributions of water vapor and ozone (O3, <100 parts per billion generally but highly variable)
have important implications for both weather and climate.
Effect of large dam project

2. The environmental impacts associated with large scale dams often have significant negative
impacts on the environment. The Three Gorges Dam is no different. The creation of the dam
and associated reservoir has impacts both upstream from the dam and downstream. It
affects species in the area, some endangered, water quality, and may increase the
likelihood of earthquakes and mudslides in the area.
A number of species will be adversely affected by the construction of the dam. There are
300 species of fish in the Yangtze River. The dam will create a barrier in the river that these
species will not be able to cross. Fish will not be able to travel upstream to spawn, so the
populations of the species will decrease. Other affected species include the Chinese River
Dolphin, Chinese Sturgeon, Chinese Tiger, Chinese Alligator, Siberian Crane, and the Giant
Panda. There are a total of forty-seven rare or endangered species in the Three Gorges Dam
area that are protected by Chinese national law. The only natural habitat of the Chinese
River Dolphin is the Yangtze River, and there are less than one-hundred of these
endangered dolphins in the river. The reservoir created from the construction of the dam
covers a significant amount of the dolphins’ natural habitat. The government plans to
sustain the River Dolphin and other endangered species by creating natural reserves and
artificial spawning programs. It should be noted that past attempts to relocate the Yangtze
River Dolphin have failed.dolphins in the river. The reservoir created from the construction
of the dam covers a significant amount of the dolphins’ natural habitat. The government
plans to sustain the River Dolphin and other endangered species by creating natural
reserves and artificial spawning programs. It should be noted that past attempts to relocate
the Yangtze River Dolphin have failed.