"Protecting Soil" PPT courseware

"Protecting Soil" PPT courseware

Part One: Knowledge Review

1. There are three major categories of organisms in soil: ________, ________, and ________. Among them, _________ play an important role in maintaining water and soil and preventing soil erosion.

2. Soil is composed of ________, ________, ________ and ________. The main component of soil is ________. According to its different components, soil can be divided into ________ soil ________ soil _______ _Three major categories of soil. The ________ soil is the most suitable for plant growth.

Protect Soil PPT, Part 2: Soil is an important resource

Soil provides water and inorganic salts for plant growth

Soil provides food for soil organisms.

Humans cannot grow crops without soil.

The following are models of the world's land area and cultivated land area. What information can you obtain based on these two models?

Conclusion: In the world, land area accounts for ________ of the total area, but arable land only accounts for ________ of the land area, so soil resources are very scarce in the world.

Protect Soil PPT, Part 3: Soil Pollution and Protection

1. The biggest danger to soil resources comes from soil pollution and over-exploitation.

Soil pollution:

It refers to the phenomenon that when excessive amounts of toxic and harmful substances enter the soil and exceed the self-purification ability of the soil, the soil structure and soil ecosystem are damaged, thereby losing the original soil function.

What do you think are the contaminants of soil?

Indiscriminate discharge of wastewater and solid waste

Extensive use of pesticides and fertilizers

Certain germs, parasites and viruses

Industrial waste gas (SO2, SO3)

Arbitrary emissions of heavy metals

domestic waste

White pollution

Radioactive contamination caused by nuclear reactions

Pesticides will accumulate residues in the soil, and there are pesticide residues in the crops grown, which directly harms the health of humans and animals.

① Long-term application of nitrogen fertilizer will compact the soil and destroy the soil structure;

② Excessive application of phosphorus fertilizer will cause the soil to be deficient in zinc, iron and phosphorus and become insoluble and cannot be used.

③Leading to eutrophication pollution of water bodies.

Pollution type

(1) Chemical pollution: The arbitrary discharge of wastewater and solid waste, and the extensive use of pesticides and chemical fertilizers may cause chemical pollution of the soil, thereby destroying the structure and properties of the soil.

(2). Biological pollution: Certain bacteria, parasites and viruses contaminate the soil.

(3). Physical pollution: such as radioactive pollution caused by nuclear reactions

Protecting Soil PPT, Part 4: Practice

1. The land area on the earth’s surface is unsuitable for agricultural production in ________, ________, ________ and ________. The reason why there are few plants in the desert and agricultural production cannot be carried out is ________. The reason why Antarctica is basically not suitable for crop production is ________.

2. The widespread use of plastic-based agricultural soil films in our country will destroy ________.

3.The biggest threats to soil resources come from ________ and ________.

4. Which of the following will not cause soil pollution---- ( )

A. Do not pay attention to recycling plastic film after use

B. Extensive use of chemical fertilizers and pesticides in agricultural production

C. A large amount of industrial waste is discharged into the soil

D. A large number of dead plants and leaves rotted in the fields.

Keywords: Zhejiang Education Edition eighth grade science PPT courseware for the second volume free download, soil protection PPT download, .PPT format;

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"Protecting Soil" PPT:

"Protecting Soil" PPT Part One: Soil Resources 1. Soil is an important resource. The following are models of the world's land area and cultivated land area. What information can you get based on these two models? my country ranks fourth in the world in terms of arable land area, but per capita...