Agroecology is the study of ecological processes that operate in agricultural production systems. The prefix agro- refers to agriculture. Bringing ecological principles to bear in agroecosystems can suggest novel management approaches that would not otherwise be considered. The term is often used imprecisely and may refer to "a science, a movement, or a practice."

• CLIMATE :

Climate is the long-term pattern of weather in a particular area. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate is different from weather, in that weather only describes the short-term conditions of these variables in a given region.

The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at 23°26′14.1″ (or 23.43725°) N and the Tropic of Capricorn in the southern hemisphere at 23°26′14.1″ (or 23.43725°) S; these latitudes correspond to the axial tilt of the Earth. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). The tropics include all the areas on the Earth where the Sun reaches a subsolar point, a point directly overhead at least once during the solar year.

Characteristics : High temperature, lot of rainfall, many agricultural activities and its crops (rubber, oil palm, cocoa, coconuts and sugarcane).

              2. TEMPERATE

The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arctic Circle (approximately 66.5° north latitude). The south temperate zone extends from the Tropic of Capricorn (approximately 23.5° south latitude) to the Antarctic Circle (at approximately 66.5° south latitude). The cooler parts of the temperate zone may be referred to as 'subtemperate'. Temperate climate also broadly includes subtropical climate variants: subtropical semidesert/desert, humid subtropical, oceanic subtropical and Mediterranean climate. However, typically temperate climate is one of the world's four climate zones (besides the polar, subtropical, and tropical zones).

Characteristics : Neither too warm nor too cold, too wet nor too dry, not extreme but changeable, has 4 seasons. Crops planted in spring, harvested in summer (eg. maize & wheat), vegetables continuously grown (winter in glass house). Livestock farming: most suitable. Large cattle reared for milk and beef performed best in the temperate region.

              3. TUNDRA

In physical geography, tundra is type of biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands", "treeless mountain tract". There are three types of tundra: arctic tundra, alpine tundra, and Antarctic tundra. In tundra, the vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline.

Characteristics : very low temperatures (below 0 celcius), long - cold dark winter (6-10 months), little water and sunshine, short growing season (6-10 weeks), dominant vegetation: grasses, mosses and lichens. Crops/livestock hardly grown/raised. Only in restricted enclosures adequate water supply. Three types of tundra; Arctic tundra, Antarctic tundra & Alpine tundra.

              4. DESERT

A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation. About one third of the land surface of the world is arid or semi-arid. This includes much of the polar regions where little precipitation occurs and which are sometimes called "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location.

Characteristics : very little precipitation, < than 250 mm annually, vegetation very sparse/rare, temperature very high in the day, very low at night, agriculture only possible with sufficient irrigation.

• WATER

Water (chemical formula: H2O) is a transparent fluid which forms the world's streams, lakes, oceans and rain, and is the major constituent of the fluids of organisms. As a chemical compound, a water molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds. Water is a liquid at standard ambient temperature and pressure, but it often co-exists on Earth with its solid state, ice; and gaseous state, steam (water vapor). It also exists as snow, fog, dew and cloud.

Water has shaped our civilizations since the beginning of humankind.  Our earliest ancestors used to be hunters and gatherers, wandering around to find food and water to sustain their needs.  Evolution led to early civilizations understanding agriculture which allowed them to stay in one place and create civilizations.  They would form small cities around water for agricultural reasons. The examples of civilization that existed and reach their "great age" because of the usage of water in agriculture : The Nile valley in Egypt & Tigris-Euphrates in Mesopotamia (Iraq)

• SOIL

Soil is the mixture of minerals, organic matter, gases, liquids, and the countless organisms that together support life on earth. Soil is a natural body known as the pedosphere and which performs four important functions: it is a medium for plant growth; it is a means of water storage, supply and purification; it is a modifier of the atmosphere of Earth; it is a habitat for organisms; all of which, in turn, modify the soil.

Soil is considered to be the "skin of the earth" and interfaces with its lithosphere, hydrosphere, atmosphere, and biosphere. Soil consists of a solid phase (minerals and organic matter) as well as a porous phase that holds gases and water.

Soil nitrogen cycle :

Soil Formation based on TOPOGRAPHY :

Location A = acid sulphate soil (along the coastline)

Location B = peat soil

Location C = coastal alluvium soil 

Location D = rapidly weathering soil (deep and red) 

Location E = easly eroded, shallow soil (esp. when lack of vegetation)

Location F = cool highland soils 

• HUMAN RESOURCE

Human resources is the set of individuals who make up the workforce of an organization, business sector, or economy. "Human capital" is sometimes used synonymously with human resources, although human capital typically refers to a more narrow view (i.e., the knowledge the individuals embody and economic growth). Likewise, other terms sometimes used include "manpower", "talent", "labour", or simply "people".

Human Resource in Agriculture :

Scientists - who conduct research from production level to processing and marketing. 

Teaching institutions of agriculture to produce graduates in numerous fields 

Supporting specialists such as extension specialist to pass the knowledge to the operators in the fields, marketing specialists and the economists. 

Human labour : land preparation, planting and harvesting

Can be replaced with machines (LIMITED)

Skilled operators needed

Foreign labour

3. IMPACT OF CLIMATIC CHANGE

Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors such as biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. Certain human activities have also been identified as significant causes of recent climate change, often referred to as "global warming".

The effects of climate change are :
GLOBAL WARMING

CAUSE : fossil fuels in industries and transportation releases greenhouse gas such as carbon dioxide, nitrous oxide and methane.
EFFECT : increased world temperature and caused climatic instability:
          i)  melting polar ice cap (inundation)
          ii) rise of sea level (flood) 

DESERTIFICATION

CAUSE : expansion of desert area due to climatic changes, agric. Mismanagement of agriculture activity. eg. overgrazing of dryland area in Chile

EFFECT : less arable land available for agriculture 

4. IMPACT OF POLLUTION

Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution.

The effects of pollution are :
ACID RAIN 
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Nitrogen oxides can also be produced naturally by lightning strikes and sulfur dioxide is produced by volcanic eruptions. The chemicals in acid rain can cause paint to peel, corrosion of steel structures such as bridges, and erosion of stone statues.

HEAVY METALS 
Toxic heavy metals are found naturally in the earth, and become concentrated as a result of human caused activities. They enter plant, animal and human tissues via inhalation, diet and manual handling, and can bind to, and interfere with the functioning of vital cellular components. The toxic effects of arsenic, mercury and lead were known to the ancients but methodical studies of the toxicity of some heavy metals appear to date from only 1868. In humans, heavy metal poisoning is generally treated by the administration of chelating agents. Some elements regarded as heavy metals are essential, in small quantities, for human health.

Agroecology is the study of ecological processes that operate in agricultural production systems. The prefix agro- refers to agriculture. Bringing ecological principles to bear in agroecosystems can suggest novel management approaches that would not otherwise be considered. The term is often used imprecisely and may refer to "a science, a movement, or a practice."

• CLIMATE :

Climate is the long-term pattern of weather in a particular area. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate is different from weather, in that weather only describes the short-term conditions of these variables in a given region.

The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at 23°26′14.1″ (or 23.43725°) N and the Tropic of Capricorn in the southern hemisphere at 23°26′14.1″ (or 23.43725°) S; these latitudes correspond to the axial tilt of the Earth. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). The tropics include all the areas on the Earth where the Sun reaches a subsolar point, a point directly overhead at least once during the solar year.

Characteristics : High temperature, lot of rainfall, many agricultural activities and its crops (rubber, oil palm, cocoa, coconuts and sugarcane).

              2. TEMPERATE

The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arctic Circle (approximately 66.5° north latitude). The south temperate zone extends from the Tropic of Capricorn (approximately 23.5° south latitude) to the Antarctic Circle (at approximately 66.5° south latitude). The cooler parts of the temperate zone may be referred to as 'subtemperate'. Temperate climate also broadly includes subtropical climate variants: subtropical semidesert/desert, humid subtropical, oceanic subtropical and Mediterranean climate. However, typically temperate climate is one of the world's four climate zones (besides the polar, subtropical, and tropical zones).

Characteristics : Neither too warm nor too cold, too wet nor too dry, not extreme but changeable, has 4 seasons. Crops planted in spring, harvested in summer (eg. maize & wheat), vegetables continuously grown (winter in glass house). Livestock farming: most suitable. Large cattle reared for milk and beef performed best in the temperate region.

              3. TUNDRA

In physical geography, tundra is type of biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands", "treeless mountain tract". There are three types of tundra: arctic tundra, alpine tundra, and Antarctic tundra. In tundra, the vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline.

Characteristics : very low temperatures (below 0 celcius), long - cold dark winter (6-10 months), little water and sunshine, short growing season (6-10 weeks), dominant vegetation: grasses, mosses and lichens. Crops/livestock hardly grown/raised. Only in restricted enclosures adequate water supply. Three types of tundra; Arctic tundra, Antarctic tundra & Alpine tundra.

              4. DESERT

A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation. About one third of the land surface of the world is arid or semi-arid. This includes much of the polar regions where little precipitation occurs and which are sometimes called "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location.

Characteristics : very little precipitation, < than 250 mm annually, vegetation very sparse/rare, temperature very high in the day, very low at night, agriculture only possible with sufficient irrigation.

• WATER

Water (chemical formula: H2O) is a transparent fluid which forms the world's streams, lakes, oceans and rain, and is the major constituent of the fluids of organisms. As a chemical compound, a water molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds. Water is a liquid at standard ambient temperature and pressure, but it often co-exists on Earth with its solid state, ice; and gaseous state, steam (water vapor). It also exists as snow, fog, dew and cloud.

Water has shaped our civilizations since the beginning of humankind.  Our earliest ancestors used to be hunters and gatherers, wandering around to find food and water to sustain their needs.  Evolution led to early civilizations understanding agriculture which allowed them to stay in one place and create civilizations.  They would form small cities around water for agricultural reasons. The examples of civilization that existed and reach their "great age" because of the usage of water in agriculture : The Nile valley in Egypt & Tigris-Euphrates in Mesopotamia (Iraq)

• SOIL

Soil is the mixture of minerals, organic matter, gases, liquids, and the countless organisms that together support life on earth. Soil is a natural body known as the pedosphere and which performs four important functions: it is a medium for plant growth; it is a means of water storage, supply and purification; it is a modifier of the atmosphere of Earth; it is a habitat for organisms; all of which, in turn, modify the soil.

Soil is considered to be the "skin of the earth" and interfaces with its lithosphere, hydrosphere, atmosphere, and biosphere. Soil consists of a solid phase (minerals and organic matter) as well as a porous phase that holds gases and water.

Soil nitrogen cycle :

Soil Formation based on TOPOGRAPHY :

Location A = acid sulphate soil (along the coastline)

Location B = peat soil

Location C = coastal alluvium soil 

Location D = rapidly weathering soil (deep and red) 

Location E = easly eroded, shallow soil (esp. when lack of vegetation)

Location F = cool highland soils 

• HUMAN RESOURCE

Human resources is the set of individuals who make up the workforce of an organization, business sector, or economy. "Human capital" is sometimes used synonymously with human resources, although human capital typically refers to a more narrow view (i.e., the knowledge the individuals embody and economic growth). Likewise, other terms sometimes used include "manpower", "talent", "labour", or simply "people".

Human Resource in Agriculture :

Scientists - who conduct research from production level to processing and marketing. 

Teaching institutions of agriculture to produce graduates in numerous fields 

Supporting specialists such as extension specialist to pass the knowledge to the operators in the fields, marketing specialists and the economists. 

Human labour : land preparation, planting and harvesting

Can be replaced with machines (LIMITED)

Skilled operators needed

Foreign labour

3. IMPACT OF CLIMATIC CHANGE

Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors such as biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. Certain human activities have also been identified as significant causes of recent climate change, often referred to as "global warming".

The effects of climate change are :
GLOBAL WARMING

CAUSE : fossil fuels in industries and transportation releases greenhouse gas such as carbon dioxide, nitrous oxide and methane.
EFFECT : increased world temperature and caused climatic instability:
          i)  melting polar ice cap (inundation)
          ii) rise of sea level (flood) 

DESERTIFICATION

CAUSE : expansion of desert area due to climatic changes, agric. Mismanagement of agriculture activity. eg. overgrazing of dryland area in Chile

EFFECT : less arable land available for agriculture 

4. IMPACT OF POLLUTION

Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution.

The effects of pollution are :
ACID RAIN 
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Nitrogen oxides can also be produced naturally by lightning strikes and sulfur dioxide is produced by volcanic eruptions. The chemicals in acid rain can cause paint to peel, corrosion of steel structures such as bridges, and erosion of stone statues.

HEAVY METALS 
Toxic heavy metals are found naturally in the earth, and become concentrated as a result of human caused activities. They enter plant, animal and human tissues via inhalation, diet and manual handling, and can bind to, and interfere with the functioning of vital cellular components. The toxic effects of arsenic, mercury and lead were known to the ancients but methodical studies of the toxicity of some heavy metals appear to date from only 1868. In humans, heavy metal poisoning is generally treated by the administration of chelating agents. Some elements regarded as heavy metals are essential, in small quantities, for human health.