Overcrowding in Hong Kong

Hong Kong's population density is 5,860 persons per square kilometer. However, because of its uneven population distribution some areas, such as Mong Kok in Kowloon, have about 40,000 persons per square kilometer (about 100,000 per square mile).

Most of Hong Kong's slum areas have been replaced by public high-rise apartment blocks. Peaceful demonstrations have gained improved housing rights and improved buildings.

Hong Kong's government has reduced the demand for transport by building numerous planned communities near employment centers. Since many people in Hong Kong prefer living near their workplace, this approach has helped to accommodate Hong Kong's large population on its small area of land.

Wages are low in Hong Kong, but rents in public housing seldom rise above fifteen per cent of a family's income and most families pay well under ten per cent of their household income.

Some slum areas are still located in downtown Hong Kong and on steep hillsides. The people who live in these slums are often single men and women, many of them old, who never married. Many recent migrant families from China and Vietnam live in Hong Kong's harbor area.

Composition

Mineral particles make up the biggest ingredient of soil. Most minerals exist in the form of tiny particles. They are the remains of rock, which have been broken down over long periods by weathering and erosion. Some minerals are soluble. They may dissolve in water and so take on a liquid form.

Numerous creatures live in the soil. Some of these are visible to the naked eye - insects and earthworms, for example. But the vast majority of creatures are too small to be seen without the aid of a microscope. These are called microorganisms. Microorganisms help to break down plant litter to form humus. So they play a vital role in making the soil fertile.

When dead plants, leaves and other forms of plant litter enter the soil, they decay to form a dark-colored, jelly-like substance called humus. Humus nourishes plants. It also helps to hold soil particles together.

As rainwater moves through the soil it dissolves soluble minerals. It then distributes these minerals to plants that can them in liquid form through their roots. The dissolved minerals are called nutrients because they nourish the plants.

Air is found in many of the spaces between soil particles. The air supplies the oxygen and nitrogen that are vital to plant life and to the survival of microorganisms.

Soil conditions

Fertile soil produces rich vegetation by providing it with essential minerals

•These minerals include nitrogen for the production of leaves and potash to encourage plant roots. Once the area is sufficiently warm and there is no risk of frost, then the quality of the soil determines the various species.

•Some plants need many minerals for healthy growth. These include deciduous trees such as oak and ash. Other plants such as coniferous trees need few minerals and will grow on thin gravel or peat soils.

•Soils without lime are called acid soil. They support a limited variety of plants such as rhododendron, heather and coniferous trees. Soils with lime, however, support a much greater variety of plant life, such as most deciduous trees and rich grasses for dairying and beef rearing.

Deep soils are found in lowland plains and river valleys.

The depth of soil affects the type and height of plants

•Some plants need deep soils for support and the supply of essential minerals. Tall deciduous trees, such as oak and ash, have deep roots and a large network of other roots nearer the surface.

•Coniferous trees will naturally grow in upland areas where soils are thin. Their roots spread outwards just under the surface. Because of this they are easily uprooted during storms.

• Deep soils produce taller plants than shallow soils. This is especially noticeable when foundations of ancient houses, no longer visible on the surface, produce lighter and shorter plants than surrounding areas. These are called crop marks and are helpful to archaeologists in search of ancient buildings.

Date: 2015-12-18; view: 1071