Geography UNIT 3

• The primary sector's contribution to GDP has halved, to below 4% in 2020.
• Agriculture is the cultivation of land.
• Physical factors such as climate, relief and soil type can either help or make it more difficult to grow plants.
• Each plant needs specific temperatures, levels of sunlight and humidity to grow.
• In each climatic region, some crops grow better than others.
• Climate change is causing unusual weather patterns that restrict agricultural activity.
• Extreme cold slows down plant growth in areas with low spring frosts that ruin crops in full bloom or with ripened fruits.
• Plants cannot grow in areas where temperatures fall below zero.
• Most plants cannot grow below 10 0 C.
• Underwater farming is a method of growing crops in areas where soil is scarce.
• Heavy rainfall encourages weeds to grow and washes away the soil.
• Aridity restricts the development of agriculture as plants need a certain amount of water throughout their growth cycle.
• Low and irregular rainfall restricts the development of agriculture.
• Polar regions, deserts and rainforests are not suitable for agriculture due to their harsh climates.
• Greenhouses are enclosed areas made of a metal structure covered with plastic or glass to allow sunlight to enter.
• Inside greenhouses, optimum lighting, temperature and humidity conditions are artificially created so that plants will grow.
• Greenhouses make it possible to cultivate plants that would not usually grow in that location due to the climate.
• Greenhouses allow plants to ripen faster, resulting in earlier and more frequent harvests.
• Greenhouses protect plants from damage that can be caused by bad weather, such as sudden changes in temperature, torrential rain, strong winds, etc.
• Greenhouses make it easier to control pests and to use water and fertilisers efficiently, which reduces waste significantly.
• Altitude is a feature of relief that affects agricultural activity, as temperatures decrease at higher altitudes, preventing plants from growing above certain levels.
• Land at altitudes below 200 metres is usually the most suitable for agriculture.
• The incline of the terrain is another feature of relief that affects agricultural activity, as a greater incline of the terrain increases erosion and makes farming more difficult.
• An incline of 120 is usually considered the maximum on which to grow crops.
• Terraces, or steps, are constructed on slopes so they can be cultivated.
• Plants absorb the substances they need to grow from the soil, each type of plant needs soil with certain characteristics.
• The size and porosity of the grains of soil determine the amount of oxygen in the soil and the soil's capacity to retain water.
• The chemical and biological composition of the soil determines the acidity of the soil and how rich in nutrients and organic matter the soil is.
• The texture, fertility and acidity of soil can be improved through the use of fertilisers, manure and compost, artificial irrigation, etc.
• Normal sand retains very little of the nutrients that plants need, therefore, in sandy soil need to be watered frequently and given fertiliser.
• The Norwegian scientist Kristian Morten Olesen has developed technology that makes it possible to grow crops in deserts, which now cover almost 25 % of the Earth's surface.
• The technology consists of mixing water and clay nanoparticles, which have a high capacity to retain water, producing liquid clay, which makes the arid, sandy desert soil fertile.
• An agrarian holding is a group of areas of land or farms that are worked on by a person or company to produce agricultural, livestock or forestry products.
• Depending on their size, holdings can be large (large holdings), medium or small (small holdings).
• Depending on the main activity, they can be agricultural, livestock, forestry or mixed holdings.
• Agrarian holdings usually consist of one or various pieces of land called plots.
• In open-field landscapes, plots of land are not enclosed by fences, creating a rural habitat that is usually compact with human settlements, such as housing and other buildings, grouped together to form villages or hamlets.
• Cultivated land and pastures surround the settlements in open-field landscapes.
• The open-field landscape is the typical landscape of the great plains, like those in Central Europe and the inland areas of the continent of America, where cereal crops are usually grown.
• In closed-field landscapes, plots of land are enclosed by hedges, walls or wire fences, creating a mosaic of small, irregular, well-defined plots.