Agrocenosis and agrosystems abstract on ecology. Presentation on the topic "agrocenoses and agroecosystems". Laboratory work "Composition and properties of the soil of agrocenosis"

Agrocenoses Biocenoses that occur on agricultural land are called agrocenoses. Gardens, parks, crops of agricultural plants are called agrocenoses. 1. Energy source? Not only sunlight, but the energy of applied organic fertilizers, energy labor activity man, the energy of the combustible fuel.

Agrocenoses 2. What is typical for producers? The biocenosis is characterized by a smaller variety of species; one crop of plants (monoculture) is often cultivated - wheat, rye, corn. 3. What is typical for consumers? Fewer species, but greater abundance. The rule of the German ecologist Thienemann is fulfilled: “The poorer the community, the higher the number of each individual species can be.”

Agrocenoses 6. Natural selection plays a leading role in natural biogeocenoses, but what about agrocenoses? The essential difference is that in agrocenoses the effect of natural selection is weakened, the guiding factor is artificial selection, selection in favor of the most productive plant varieties. 7. How does the productivity of agrocenosis differ from the productivity of natural ecosystems of the same zone? Usually somewhat lower. Fields are empty for part of the year, monoculture is not able to use all available resources.

Increasing the productivity of agrocenoses In 2000, 6 billion people lived on Earth. The annual net increase is 78 million people - almost as many people currently live in all of Germany. In a day, the number of earthlings increases by almost a quarter of a million people, in an hour - by 10 thousand. Many problems follow from this, one of which is an increase in the productivity of ecosystems. 1. Creation of highly productive plant varieties resistant to diseases and adapted to different climatic zones.

Increasing the productivity of agrocenoses It is more economically profitable to create drought-resistant plants than organize irrigation large areas. In addition, irrigation causes secondary soil salinization, so it is more expedient to pay attention to dry farming. Cultivated plants require a high culture of agriculture. Without human intervention, agrocenoses of grain and vegetable crops exist for no more than a year, fruit crops 2030 years.

Increasing the productivity of agrocenoses 2. The main resource of agrocenosis is soil. Proper and timely tillage is necessary, spring and autumn plowing, loosening, additional watering. To preserve humus (soil organic matter) in many places, moldboard plowing is replaced by moldboardless loosening of the soil; it is necessary to use organo-mineral fertilizers. The application of fertilizers should be fractional during different periods of the growing season, the plant requires various fertilizers, which must be applied in certain combinations strictly according to the norm.

Increasing the productivity of agrocenoses Examples: 1. Rabbits were dealt with by infecting them with a virus found in South American rabbits. 2. Prickly pear was dealt with with the help of a fire moth imported from Argentina. 3. In the last century, the Australian scale insect came from Australia to North America and then to Europe. It was possible to destroy only after the introduction of a natural enemy in Europe and America - a ladybug.

Increasing the productivity of agrocenoses To increase biodiversity - the basis of self-regulation of biogeocenoses - it is necessary to create agroecosystems - planned territories in which, in addition to agrocenoses, high biological diversity is maintained by alternating fields, meadows, forests, copses, forest belts, reservoirs.

Increasing the productivity of agrocenoses The most advanced direction of modern Agriculture is the transition from the principles of confrontation with nature to the principles of cooperation with it. This means maximum adherence to environmental laws in agricultural practice.

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If every person on a piece of his land would do everything he can, how beautiful our land would be. (A.P. Chekhov)

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Agrocenoses

Biocenoses that occur on agricultural land.

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Agrocenosis

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Agroecosystems

• Territories deliberately planned by man, in which the receipt of agricultural products and the return of its components to the fields are balanced.
• Properly planned agroecosystems, in addition to arable land, include pastures or meadows and livestock complexes

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Producers

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Consumers

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decomposers

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The role of man in the agroecosystem

A person is a consumer-phytophage (eats plants) and zoophage (eats meat and drinks milk). But the role of man is much greater, since, based on his interests, he forms the composition and structure of the agroecosystem and influences its trophic elements in order to obtain the greatest primary and secondary production.

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Comparison of agrobiogeocenosis and biogeocenosis

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Comparison of agrobiogeocenosis and biocenosis

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Laboratory work "Composition and properties of the soil of agrocenosis"

• Purpose: study of the composition and properties of the soil.
• Material and equipment: a monolith of a soil section, test tubes, chemical beakers, spirit lamps, tables with images of microorganisms and animals living in the soil

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Progress

Consider the monolith of the soil section, determine what layers it consists of, make a schematic drawing.

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Soil section monolith

• 1-loose, dark-colored arable layer
• 2-horizon, in which there is an increased leaching of soil mineral ions
• 3.4 - parent rock

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The presence of moisture in the soil

• A small sample of soil was placed in a dry test tube and heated on an alcohol lamp.
• Water droplets form on the walls of the test tube, therefore, the soil sample contains moisture.

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The presence of air in the soil

• A small sample of soil was dropped into a glass of water.
• The air bubbles were observed to rise to the surface of the water, hence the sample contains air.

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The presence of microorganisms in the soil

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soil organisms.

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conclusions

• Soil is the main resource of agrocenosis. Its fertility depends on the stock of organic matter - humus, nutrient content, structure.
• The structure of the soil is the shape and size of the lumps into which it breaks up. The best structure is finely lumpy.
• Soil fertility is affected by its moisture content. The yield is reduced with a lack of moisture.
• To preserve soil fertility, it is necessary to use it rationally.

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Agrocenosis (from Greek. agros -field) -

biocenosis that occurs on agricultural land.

Examples of agrocenoses are:

• Buckwheat field

• potato field

• cotton field

• Rice field

• Garden

The similarity of agrocenosis and biocenosis:

• Availability of producers
• Availability of consumers
• Presence of decomposers
• Plants are the beginning of the food chain
• Nutritional relationships between organisms
• Circulation of substances
• Daily and seasonal changes

Differences between agrocenosis and biocenosis:

• Reduced species diversity
• Short food chains
• The cycle of substances is incomplete ( primary production- harvest, taken by a person)
• Human cultivated species cannot compete with wild species without human support.
• Unstable system
• Significant use of additional energy (muscular strength of humans, animals; agricultural machinery) to maintain crop yields

Ideal agrocenosis

Consists of one single species

The ideal food chain of agrocenosis

• plant - man
• plant - animal

In agrocenoses, various communities are formed from species that can survive in conditions of constant anthropogenic impact

Food chains are formed from 3 - 4 links, competitive interactions and other types of relationships between species arise

Inhabitants of the potato field

wireworm

common potato aphid

Inhabitants of the potato field

golden potato nematode

Colorado beetle

Inhabitants of the wheat field

cornflower

Cockle

sow thistle

Wild oats

Inhabitants of the wheat field

field slug

grain moth

mouse vole

Gopher

Inhabitants of the wheat field

Viper

Lun

Viper

Quail

boomerang effect

In agriculture, a variety of chemical plant protection products are used in abundance - pesticides.

That. regulatory connections arising in agrocenoses are violated.

The remaining part of the pests gives a new, even higher outbreak of numbers.

Biological method of struggle

Biological method of struggle

Riders and egg-eaters are human helpers in the fight against agricultural pests: top left and bottom left – female egg-eaters on the eggs of the host insect; top right - rider on aphids; bottom right - dead aphids after the development of ichneumons in them

Food chain in agrocenosis

Bread mosquito

grain moth

Wheat

Lun

Meadow coinage

Agroecosystem -

a territory consciously planned by man, in which the receipt of agricultural products and the return of its components to the fields are balanced

Created by man to obtain a high yield - pure production of autotrophs (producers)

Well-planned agro-ecosystems include:

1) arable land

2) pastures (or meadows)

3) livestock complexes

Features of agroecosystems:

• Plant nutrients taken from the fields along with the harvest are returned to the biological cycle along with organic and mineral fertilizers.

• Biological diversity is maintained through special landscape planning: the alternation of fields, meadows, forests, copses, forest belts, reservoirs, etc.

• The variety of species in the fields is supported by the alternation of crops not only in time but also in space.

• A person controls the work of agroecosystems, introducing a significant amount of additional energy into them (tillage, irrigation, fertilizers, pesticides, etc.)

Describe the proverbs by relating them to the topic studied.

• What goes around comes around

• It still doesn’t matter that there is a quinoa in the rye, otherwise it’s a disaster, no matter how rye or quinoa

Make a food chain using the suggested organisms:

• wheat
• mouse vole
• quail
• kite
• polecat (ferret)

• grain moth
• meadow coinage
• viper
• Fox

Answer the questions:

• Explain why cultivated plants cannot compete with weeds.

• Describe the ways in which nutrients are returned to the soil.
• Why does the soil in agrocenoses quickly deplete?

Homework

• Lecture summary
• Answer the questions:

• Indicate the importance of agrocenoses for providing the population with food, for the development of the national economy.
• What are the ways to increase the productivity of agrocenoses?

Surface area and annual production of major ecosystems Ecosystem type Rainforest Temperate forest Tundra Cropland Area, % net production,%

folk wisdom Without a master, the land is an orphan. Return the debt to the earth - there will be a sense. Where there is water, there the garden will bloom. This is a good time - you will gather a mountain of bread. Lots of snow, lots of bread. The earth takes labor and gives back a pood. Do not spare labors, there will be more pounds. Live and learn.

The difference between agrocenoses and biogeocenoses In agrocenoses: - reduced species diversity; - human cultivated species cannot compete with wild species without human support; - significant use of additional energy (muscular strength of humans, animals, agricultural machinery) to maintain plant yields; - food chains are short (in the natural community - branched food chains); - the circulation of substances is incomplete; - agrocenosis is an unstable system, and natural biogeocenosis can exist for a long time.

Increasing the productivity of agrocenosis: - application of fertilizers, their scientifically substantiated use; - watering; - selection of crops; maintaining a competent crop rotation; - the use of high-yielding varieties, taking into account natural and climatic conditions; - protection of plants from diseases, pests and weeds