Artificial communities agroecosystems presentation. Presentation on the topic "agrocenoses and agroecosystems". Common potato aphid

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"Agrocenosis and agroecosystem" GBPOU RO "RKRIPT" Biology teacher Petrikina OB

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

The similarity of agrocenosis and biocenosis: The presence of producers The presence of consumers The presence of decomposers Plants are the initial link in the food chain Food connections between organisms The cycle 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 is the harvest, taken by humans) Species cultivated by humans cannot compete with wild species without human support Unstable system Significant use of additional energy (muscle strength of humans, animals ; agricultural machinery) to maintain crop yields

Ideal agrocenosis plant - human plant - animal Ideal food chain of agrocenosis Consists of one single species

In agrocenoses, diverse communities of species are formed that can survive under conditions of constant anthropogenic impact Food chains of 3 - 4 links are formed, competitive interactions and other types of relationships arise between species

Inhabitants of the potato field Wireworm Potato aphid

Inhabitants of the potato field Golden potato nematode Colorado potato beetle

Inhabitants of the wheat field Cornflower Osot Ovsyug Kukol sowing

Inhabitants of a wheat field Mouse vole Ground squirrel Field slug Grain moth

Viper Wheat field inhabitants Hedgehog Quail Viper Harrier

Biological method of control Riders and egg-eaters are human helpers in the fight against agricultural pests: on the left above and below - female egg-eaters on the eggs of the host insect; top right - aphid rider; bottom right - dead aphids after the development of riders in them

Food chain in the agrocenosis Harrier Wheat Meadow mint Bread gnat Cereal moth

Agroecosystem is a territory deliberately planned by a person, where the receipt of agricultural products and the return of its components to the fields are balanced.Created by a person to obtain a high yield - pure products of autotrophs (producers)

Properly planned agroecosystems include: 1) arable land 3) livestock complexes 2) pastures (or meadows)

Peculiarities of agroecosystems: Plant nutrients taken from the fields along with the harvest are returned to the biological cycle together with organic and mineral fertilizers. Biodiversity is maintained through special landscape planning: alternation of fields, meadows, forests, copses, forest belts, water bodies, 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 linking them to the studied topic What you sow - so you reap It is not a problem that there is quinoa in the rye, otherwise it’s a trouble, no matter how rye or quinoa

Build food chains using the suggested organisms: wheat mouse vole quail kite ferret (ferret) already grain moth chisel meadow viper fox hedgehog

Answer the questions: Explain why crops cannot compete with weeds. Indicate the ways of returning nutrients to the soil. Why is the soil rapidly depleting in agrocenoses?

Homework Lecture notes Answer the questions: Indicate the importance of agrocenoses for providing the population with food, the development of the national economy. What are the ways to increase the productivity of agrocenoses?

Agrocenosis (from the Greek. agros –Field) -

biocenosis that occurs on agricultural land.

Examples of agrocenoses include:

• Buckwheat field

• Potato field

• Cotton field

• Rice field

• Garden

Similarities between agrocenosis and biocenosis:

• Availability of producers
• Availability of consumers
• The presence of reducers
• Plants are the first 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
• The cycle of substances is incomplete (primary production is the harvest, taken by man)
• 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

Ideal food chain of agrocenosis

• plant - human
• plant - animal

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

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 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

Harrier

Viper

Quail

Boomerang effect

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

So regulatory links arising in agrocenoses are disrupted.

The rest of the pests gives a new, even higher outbreak.

Biological control method

Biological control method

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

Food chain in agrocenosis

Bread gnat

Grain moth

Wheat

Harrier

Meadow mint

Agroecosystem -

a territory deliberately 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 products of autotrophs (producers)

Properly planned agroecosystems include:

1) arable land

2) pastures (or meadows)

3) livestock complexes

Features of agroecosystems:

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

• Biodiversity is maintained through special landscape planning: alternation of fields, meadows, forests, copses, forest belts, water bodies, 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 linking them to the topic studied

• What goes around comes around

• It’s not a problem that there is quinoa in the rye, but it’s a trouble, no matter how rye or quinoa

Build food chains using the suggested organisms:

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

• grain moth
• meadow mint
• viper
• fox

Answer the questions:

• Explain why crop plants cannot compete with weeds.

• Indicate the ways of returning nutrients to the soil.
• Why is the soil rapidly depleting in agrocenoses?

Homework

• Lecture notes
• Answer the questions:

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

Slide 2

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

Slide 3

Agrocenoses

Biocenoses that arise on agricultural land.

Slide 4

Agrocenosis

View all slides

Goal: to acquaint students with the system of organization of artificially created ecosystems - agrocenoses.

• formation of knowledge about the structure and functions of agrocenoses;
• develop the ability to work with additional literature;
• to educate a careful attitude to soils, as one of the most important components of agrocenoses.

Equipment: articles from periodicals, photographs or reproductions, illustrating agrocenoses and agroecosystems, tablets with inscriptions on the roles of conference participants; presentation.

During the classes

I. Organizational moment

On the screen (from the presentation): "If every person on a piece of his land would do everything he can, how beautiful our land would be." (A.P. Chekhov).

To hold a press conference, it is necessary to assign roles in advance, select the appropriate questions; the teacher offers a list of references.

II. Learning new material

The presenter of the press conference is the teacher. Introduction by the teacher:

The issues of rational nature management in agriculture are studied by agricultural ecology, or agroecology. A properly organized farm produces environmentally friendly products and does not pollute the atmosphere and water. At today's press conference, there are specialists who will help us understand issues related to agrocenoses.

What is an agrocenosis?

Chief agronomist of the state farm "Harvest without nitrates"

Agrocenosis is an anthropogenic biocenosis. Agroecosystems are agricultural land created and maintained by humans.

Man determines their structure and productivity: he plows part of the land, sows agricultural crops, creates hayfields and pastures in place of forests, and breeds farm animals. Agroecosystems are autotrophic: their main source is the sun. The additional energy they receive does not exceed 1% of solar energy.

Producers in the agroecosystem are cultivated plants, hayfields or pastures, and garden trees. At the same time, weeds, companions of cultivated plants, are also producers.

Reducers in the agroecosystem are mainly bacteria. They support soil fertility.

All components of the agroecosystem are closely related, but complete ecological balance does not arise in it. Man himself must maintain balance in the agroecosystem.

What role do microorganisms play in maintaining soil fertility?

Chief Researcher, Institute of Soil Science

Soil is the main resource of the agroecosystem. Soil fertility depends on the supply of organic matter - humus, the content of nutrients available to plants, structure, and moisture supply. Humus is formed by microorganisms - gummification from the remains of plants and animals. The stock of the humus layer depends on the thickness of the humus layer and on the percentage of humus in it. Other microorganisms release nutrients from the humus into the soil solution. Among them, there are macroelements (nitrogen, phosphorus, potassium), which are required by plants in greater quantities, and microelements (manganese, boron, copper), which plants require little.

Nitrogen can enter, and the soil as a result of the vital activity of microorganisms - symbiotrophs that freely live in the soil or in nodules on the roots of legumes. To increase biological nitrogen fixation, the area under crops of peas, soybeans, alfalfa, etc. is expanded.

The soil structure is the shape and size of the lumps into which it breaks down. The best structure is fine lumpy. Inside the lumps, conditions are created for the activity of microorganisms - gummifiers that form humus, and between the lumps - for microorganisms that decompose humus to mineral compounds available to plants.

Report on laboratory work "Composition and properties of soil" (presentation)

Are there environmental problems associated with agriculture?

Employee of the Institute "Expert - Ecology"

Agricultural development in Russia is 13%, 2/3 of this territory is arable land (131.7 million hectares), but this area is decreasing from year to year.

Every year from agricultural use, more than 1 million hectares are lost as a result of erosion and 100 thousand. hectares are "eaten" by ravines. Annually Russian soils lose more than 0.5 tons of humus per 1 ha. From 5, 9 mln. More than half of these soils are salinized on hectares of irrigated land and yield extremely low yields. Every fourth hectare of arable land has acidic soils due to acid rain and the use of fertilizers, which also reduces yields. The area of \u200b\u200barable land is shrinking as a result of the "sprawl" of cities, construction of roads and industrial facilities. During the years of reform, the situation in Russian agriculture has worsened. The application of organic fertilizers was reduced by 2 times, and of mineral fertilizers - by 3.5 times.

What is the impact of agricultural pollution on human health?

PhD in Medicine from the Institute of Nutrition

A very dangerous agricultural pollution is pollution with pesticides (substances that are used in agriculture to control weeds, pests). Pesticide residues can get into water (especially from irrigated agriculture and rice cultivation), into the atmosphere, and into food. Most pesticides and their incomplete degradation products are toxic and adversely affect human health.

Nitrates are dangerous food contaminants. Once in the human body with food, they disrupt the normal functioning of the circulatory system, which is especially dangerous for infants. Nitrates enter into complex complex compounds called nitrous. Nitrous compounds are carcinogenic, that is, they can cause the development of cancerous tumors.

To prevent nitrates from accumulating in vegetables, it is necessary to limit the use of mineral nitrogen fertilizers and use them simultaneously with organic fertilizers (manure). Plants accumulate nitrates when there is a lack of light.

It is useful to know how nitrates are distributed in vegetables. So, in beets, nitrates are concentrated in the upper part of the root crop. In carrots, there is more nitrate in the central yellow part than in the surrounding red part. The most dangerous part of cabbage is the stalk. When fermented, nitrates evaporate. Potatoes have more nitrates in small tubers than in large ones. They are also concentrated under the skin.

What is the role of crop rotations for increasing the productivity of agrocenoses?

Agronomist of the farm "Agricultural Resource"

Correctly organized crop rotations contribute to the restoration of soil composition. The features of crop rotations depend on climatic and soil conditions and on the economic problem: they can be grain, fodder, beet, potato. The crop that was grown in the field last year is called the predecessor. Peas, which enrich the soil with nitrogen, are an excellent precursor for cereals and row crops. Winter rye clears the fields from weeds due to the friendly development from spring and early harvesting, which allows early fall plowing and provokes the germination of weed seeds. After rye, an additional green manure can be sown, which is then plowed into the soil like a green fertilizer. Spring grains (wheat and barley) are good precursors for peas, sugar beets, sunflowers, and rapeseed.

Usually, fallow fields are included in the crop rotation, the soil of which, as it were, rests from intensive use. Couples can be clean and busy. Clean vapors are useful in that they store moisture, which is absorbed into the well-loosened soil. But it is economically unprofitable, since the person loses the area, deprived of the area from which to get the harvest. Vapors increase nitrogen deficiency. Busy fallows do not have these disadvantages when a soil-improving crop is grown on a fallow field. This crop produces a harvest. There is no erosion on occupied vapors, but moisture does not accumulate. If the following year is dry, the harvest will decline. Different pairs are used in different zones. In the steppes, it is more expedient to have clean vapors, since the main thing for the future harvest is the moisture supply. Busy couples are used in areas with high rainfall and forest soils that are poor in nutrients.

How is insect pests and diseases controlled in agrocenoses?

PhD in Biological Sciences

In natural ecosystems, there are no problems associated with pests, weeds, and diseases. In human-created agroecosystems, ecological balance does not form on its own. The weak competitive ability of cultivated plants contributes to the massive development of weeds. With the massive development of weeds, the yield decreases. A person is forced to apply special methods to control the density of weed populations in order to protect cultivated plants.

Weed plants are controlled by agrotechnical methods. At the same time, cultivation and autumn autumn tillage are carried out. Such treatment provokes the germination of weed seeds, and they die from frost. Biological methods of controlling weeds, pests and diseases also play an important role. Crop crops, such as perennial grasses, manage weeds on their own, and use mycoherbicides, the spores of fungi that attack certain types of weeds, to help weaker crops compete with weeds. Insects are very effective in the fight against weeds - pests that eat away their flower buds and flower ovaries.

In agroecosystems, agroecology strives to create an ecological balance, like natural ecosystems. The main thing in the formation of such a balance is the creation of a system of useful symbiotic bonds. The main links of such a system are birds of prey and insectivorous birds. For their reproduction in agroecosystems, shelters are created.

The teacher invites the students to solve the problem: in the spring, collective farmers are preparing potatoes for planting, and a pest, a nematode, has lurked on the field since last year. In their cocoons, they can wait for more than one year, but as soon as they smell the potato juice from the tubers damaged during planting, they will crawl out of the cocoons and get to the delicacy - potatoes. You can treat fields with chemicals, but pests adapt to them. It is also harmful to animals. How to be?

Answer: A few days before planting, the potatoes are watered. Mixed with rotten potato juice. This makes pests - nematodes get out of their cocoons, counting on the abundance of food.

III. Summing up the conference results

Students summarize the results of the conference and draw conclusions.

• Agrocenoses differ from natural biogeocenoses in that the species composition in them is much lower than in the natural community.
• Biogeocenoses use only solar energy, while in agrocenoses, additional energy inputs are used: the energy of technology, the associated energy of fertilizers, the cost of irrigation, etc.
• Agrocenosis is an unstable system, since the harvest is constantly being taken, and the cycle of substances is not fully supported.
• The degree of self-regulation of agrocenoses is much lower than that of biogeocenoses.
• Agrocenoses cannot exist independently. A person must control and change the influence of natural factors.
• Crop plants cannot resist weeds and pests due to the reduced species diversity in the system.

The teacher marks the most interesting questions, students' answers, puts marks.

IV. Homework

Paragraph 70; solve the problem: during sowing, birds bring a lot of troubles, which fly into the fields and peck a lot of seeds. In the old days, the Romans scared birds with stuffed animals. What to do now, because the fields have become huge?