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If every person on a piece of his land did everything he could, how beautiful our land would be. (A.P. Chekhov)
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Agrocenoses
Biocenoses that arise on agricultural lands.
Slide 4
Agrocenosis
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Agroecosystems
- Territories consciously 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 lands, 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 humans in the agroecosystem
Man is a phytophagous consumer (eats plants) and a zoophage (eats meat and drinks milk). But the role of man is much greater, because based on his interests, he shapes 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 agrocenosis soil”
- Goal: study the composition and properties of soil.
- Materials and equipment: soil section monolith, test tubes, beakers, alcohol lamps, tables with images of microorganisms and animals living in the soil
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Progress
Examine the monolith of the soil section, determine what layers it consists of, and make a schematic drawing.
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Soil section monolith
- 1-loose, dark-colored topsoil
- 2-horizon, in which increased leaching of soil mineral ions occurs
- 3.4 – mother rock
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Presence of moisture in the soil
- A small soil sample 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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Presence of air in the soil
- A small soil sample was dipped into a glass of water.
- Air bubbles were observed to rise to the surface of the water, therefore the sample contained air.
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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 supply of organic matter - humus, the content of nutrients, and 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 supply. The yield decreases with a lack of moisture.
- To maintain soil fertility, it is necessary to use it rationally.
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Slide captions:
“Agrocenosis and agroecosystem” GBPOU RO “RKRIPT” Biology teacher Petrikina O.B.
Agrocenosis (from the Greek agros – field) is a biocenosis that occurs on agricultural lands. Examples of agrocenoses include:
Potato field Buckwheat field
Cotton field Rice field
Garden Garden
Similarities between agrocenosis and biocenosis: Presence of producers Presence of consumers Presence of decomposers Plants are the initial link in the food chain Food connections between organisms Cycle of substances Daily and seasonal changes
Differences between agrocenosis and biocenosis: Reduced species diversity Short food chains Incomplete cycle of substances (primary production - harvest, taken by humans) Species cultivated by humans cannot withstand competition with wild species without human support Unstable system Significant use of additional energy (muscular strength of humans, animals ; agricultural machinery) to maintain plant yields
Ideal agrocenosis plant - human plant - animal Ideal food chain of agrocenosis Consists of one single species
In agrocenoses, various communities of species are formed that can survive under constant anthropogenic influence. Food chains of 3–4 links are formed, 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 potato beetle
Inhabitants of the wheat field Cornflower Sow Ovsyug Kukol sowing
Inhabitants of a wheat field Mouse vole Gopher Field slug Grain moth
Viper Inhabitants of the wheat field Hedgehog Quail Viper Harrier
Biological method of control Ichondritus and egg eaters are human assistants in the fight against agricultural pests: at the top and bottom left - female egg eaters on the eggs of the host insect; top right – aphid rider; bottom right – dead aphids after the development of ichneumon parasites in them
Food chain in the agrocenosis Harrier Wheat Meadow mint Grain mosquito Grain moth
An agroecosystem is a territory deliberately planned by man, in which the production of agricultural products and the return of its components to the fields are balanced. Created by man to obtain a high yield - the pure product of autotrophs (producers)
Properly planned agroecosystems include: 1) arable land 3) livestock complexes 2) pastures (or meadows)
Features of agroecosystems: Plant nutrients removed from the fields along with the harvest are returned to the biological cycle system along with organic and mineral fertilizers. Biological diversity is maintained through special landscape planning: alternation of fields, meadows, forests, coppices, shelter belts, ponds, etc. The diversity of species in the fields is maintained by the rotation of crops not only in time, but also in space. Humans control the operation of agroecosystems, introducing a significant amount of additional energy into them (tillage, watering, fertilizers, pesticides, etc.)
Describe the proverbs by connecting them with the topic you have studied. What goes around comes around
Compose food chains using the proposed organisms: wheat mouse vole quail kite polecat (ferret) grain moth meadow moth viper fox hedgehog
Answer the questions: Explain why cultivated plants cannot compete with weeds. Indicate ways to return nutrients to the soil. Why is soil quickly depleted in agrocenoses?
Homework Lecture notes Answer the questions: Indicate the importance of agrocenoses for providing the population with food and developing the national economy. What are the ways to increase the productivity of agrocenoses?
Surface area and annual production of major ecosystems Ecosystem type Tropical forest Temperate forest Tundra Cropland Area,% Net production,%
Popular wisdom: Without an owner, the earth is an orphan. Return the debt to the earth - it will help. Where there is water, the garden will bloom. In good times, you will gather a mountain of bread. A lot of snow means a lot of bread. The earth takes labor and gives back pounds. Do not spare your efforts, there will be more pounds. Live and learn.
Difference between agrocenoses and biogeocenoses In agrocenoses: - reduced species diversity; - species cultivated by humans cannot withstand competition 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 based use; - watering; - selection of crops; maintaining proper crop rotation; - use of high-yielding varieties taking into account natural and climatic conditions; - protection of plants from diseases, pests and weeds
Agrocenoses Biocenoses that arise on agricultural lands are called agrocenoses. Gardens, parks, and crops are called agrocenoses. 1. Energy source? Not only sunlight, but the energy of applied organic fertilizers, the energy of human labor activity, the energy of burned fuel.
Agrocenoses 2. What is characteristic of producers? The biocenosis is characterized by less variety of species; often one crop of plants (monoculture) is cultivated: wheat, rye, corn. 3. What is characteristic of consumers? Fewer species, but larger numbers. The rule of the German ecologist Thienemann is fulfilled: “The poorer the community in species, the higher the number of each individual species can be.”
Agrocenoses 6. In natural biogeocenoses, natural selection plays a leading role, but in agrocenoses? A significant 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 an agrocenosis differ from the productivity of natural ecosystems in the same zone? Usually somewhat lower. The fields are empty for part of the year; the 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 the same number currently living in all of Germany. The number of earthlings increases by almost a quarter of a million people per day, and by 10 thousand per hour. This gives rise to many problems, one of which is increasing the productivity of ecosystems. 1. Creation of highly productive plant varieties that are 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 to organize irrigation of large areas. In addition, irrigation causes secondary soil salinization, so it is more advisable to pay attention to dry farming. Cultivated plants require high cultivation standards. Without human intervention, agrocenoses of grain and vegetable crops exist for no more than a year, fruit crops for 2030 years.
Increasing the productivity of agrocenoses 2. The main resource of the agrocenosis is soil. Proper and timely tillage of the soil is necessary: spring and autumn plowing, loosening, and additional watering. To preserve humus (soil organic matter), in many places moldboard plowing is being replaced by moldless soil loosening; the use of organomineral fertilizers is necessary. Fertilizer application should be fractional; at different periods of the growing season, the plant requires different fertilizers, which must be applied in certain combinations strictly according to the norm.
Increasing the productivity of agrocenoses Examples: 1. Rabbits were controlled by infecting them with a virus found in South American rabbits. 2. Prickly pear was controlled with the help of a fire butterfly 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 it only after the introduction of a natural enemy - the ladybug - into Europe and America.
Increasing the productivity of agrocenoses To increase biodiversity - the basis for 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, and 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 practices.
