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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Land | 1/9 | https://en.wikipedia.org/wiki/Land | reference | science, encyclopedia | 2026-05-05T07:20:45.096604+00:00 | kb-cron |
Land, also known as dry land, ground, or earth, is the solid terrestrial surface of Earth not submerged by the ocean or another body of water. It makes up 29.2% of Earth's surface and includes all continents and islands. Earth's land surface is almost entirely covered by regolith, a layer of rock, soil, and minerals that forms the outer part of the crust. Land plays an important role in Earth's climate system, being involved in the carbon cycle, nitrogen cycle, and water cycle. One-third of land is covered in trees, another third is used for agriculture, and one-tenth is covered in permanent snow and glaciers. The remainder consists of desert, savannah, and prairie. Land terrain varies greatly, consisting of mountains, deserts, plains, plateaus, glaciers, and other landforms. In physical geology, the land is divided into two major categories: Mountain ranges and relatively flat interiors called cratons. Both form over millions of years through plate tectonics. Streams – a major part of Earth's water cycle – shape the landscape, carve rocks, transport sediments, and replenish groundwater. At high elevations or latitudes, snow is compacted and recrystallized over hundreds or thousands of years to form glaciers, which can be so heavy that they warp the Earth's crust. About 30 percent of land has a dry climate, due to losing more water through evaporation than it gains from precipitation. Since warm air rises, this generates winds, though Earth's rotation and uneven sun distribution also play a part. Land is commonly defined as the solid, dry surface of Earth. It can also refer to the collective natural resources that the land holds, including rivers, lakes, and the biosphere. Human manipulation of the land, including agriculture and architecture, can also be considered part of land. Land is formed from the continental crust, the layer of rock on which soil, groundwater, and human and other animal activity sits. Though modern terrestrial plants and animals evolved from aquatic creatures, Earth's first cellular life likely originated on land. Survival on land relies on fresh water from rivers, streams, lakes, and glaciers, which constitute only three percent of the water on Earth. The vast majority of human activity throughout history has occurred in habitable land areas supporting agriculture and various natural resources. In recent decades, scientists and policymakers have emphasized the need to manage land and its biosphere more sustainably, through measures such as restoring degraded soil, preserving biodiversity, protecting endangered species, and addressing climate change.
== Definition == Land is often defined as the solid, dry surface of Earth. The word land may also collectively refer the collective natural resources of Earth, including its land cover, rivers, shallow lakes, its biosphere, the lowest layer of the atmosphere (troposphere), groundwater reserves, and the physical results of human activity on land, such as architecture and agriculture. The boundary between land and sea is called the shoreline.
== Etymology == The word land is derived from Old English, from the Proto-Germanic word *landą, "untilled land", and then the Proto-Indo-European *lendʰ-, especially in northern regions that were home to languages like Proto-Celtic and Proto-Slavic. Examples include Old Irish land, "land, plot, church building" and Old Irish ithlann, "threshing floor", and Old East Slavic ljadina "wasteland, weeds". A country or nation may be referred to as the motherland, fatherland, or homeland of its people. Many countries and other places have names incorporating the suffix -land (e.g. England, Greenland, and New Zealand). The equivalent suffix -stan from Indo-Iranian, ultimately derived from the Proto-Indo-Iranian *sthāna-, is also present in many country and location names, such as Pakistan, Afghanistan, and others throughout Central Asia. The suffix is also used more generally, as in Persian rigestân (ریگستان) "place of sand, desert", golestân (گلستان) "place of flowers, garden", gurestân (گورستان) "graveyard, cemetery", and Hindustân (هندوستان) "land of the Indo people".
== Physical science == The study of land and its history in general is called geography. Mineralogy is the study of minerals, and petrology is the study of rocks. Soil science is the study of soils, encompassing the sub-disciplines of pedology, which focuses on soil formation, and edaphology, which focuses on the relationship between soil and life.
=== Formation ===