Unit B Lesson B11 Human Use of Soil
Completion requirements
Lesson B11: Human Use of Soil
Video Lesson
People affect the quality of soil by clearing land and farming. The videos you will view later show some positive and negative ways that humans affect soil.
Lesson B11: Human Use of Soil
Figure B.3.11.1 – Farms in dry desert areas require lots of water.
Figure B.3.11.2 – Irrigation canals carry water from rivers to farmland.
Farming in the Desert
Many dry desert areas occur around the world. Warm, dry places have temperatures ideal for growing crops. However, rain is seldom, which results in poor conditions for growing plants. The lack of water in dry areas is solved by digging irrigation canals or installing pipelines to carry water from rivers and lakes. Then, farmers can pump water into irrigation equipment to water their crops.
Southern Alberta has a dry climate. Several long irrigation canals are located in rural southern Alberta. The Okanagan Valley in British Columbia has an extremely dry climate, also. Much of the valley has been irrigated to allow fruit orchards and grape vineyards to flourish in the valley during the hot summers.
Many dry desert areas occur around the world. Warm, dry places have temperatures ideal for growing crops. However, rain is seldom, which results in poor conditions for growing plants. The lack of water in dry areas is solved by digging irrigation canals or installing pipelines to carry water from rivers and lakes. Then, farmers can pump water into irrigation equipment to water their crops.
Southern Alberta has a dry climate. Several long irrigation canals are located in rural southern Alberta. The Okanagan Valley in British Columbia has an extremely dry climate, also. Much of the valley has been irrigated to allow fruit orchards and grape vineyards to flourish in the valley during the hot summers.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 143–149
Materials:
empty 500 mL plastic pop bottle, water, balloon, rubber band, scissors, houseplant
Figure B.3.11.3 – Irrigation canals extend for long distances.
Figure B.3.11.4 – Farms in the Okanagan Valley of B.C. are irrigated.
Watch More
Videos on Irrigation
Afghanistan is one of the world’s poorest countries. Most of the country is desert. Irrigation canals help farming in the desert. Farming provides jobs and food, and hopefully, that will help bring peace to the country.
Afghanistan is one of the world’s poorest countries. Most of the country is desert. Irrigation canals help farming in the desert. Farming provides jobs and food, and hopefully, that will help bring peace to the country.
Deserts can bloom! … just add essential water!
California Drought
California’s Central Valley grows most of the fresh fruit and vegetables that Americans and Canadians eat. The Central Valley has a hot and dry climate with warm winters. This climate is excellent for growing a large variety of produce year-round. We eat food from California that we cannot grow in Canada, such as almond nuts and citrus fruit as well as vegetables during our winter.
California’s Central Valley grows most of the fresh fruit and vegetables that Americans and Canadians eat. The Central Valley has a hot and dry climate with warm winters. This climate is excellent for growing a large variety of produce year-round. We eat food from California that we cannot grow in Canada, such as almond nuts and citrus fruit as well as vegetables during our winter.
Because little rain falls in California in summer, most of the water in California begins as snow in its mountains. Aqueducts (big water pipes) and irrigation canals carry water to farms.
Since 2011, California has been in a drought, which is a long period without much rain. California has received less rain than it usually does during winter. Also, winter snow is less in the California mountains. Lakes, irrigation canals, and aqueducts are empty or very low. Farmers are pumping water from wells. However, the underground water is being depleted, too. This may lead to huge reductions in the amount of fresh fruit and vegetables grown in California. Canadians might have to obtain more vegetables and fruit from other sources, such as Chile or Argentina, for example. The cost of transportation is much higher.
Figure B.3.11.5 – Lakes have dried up in California.
Figure B.3.11.6 – Low water in California lakes and rivers means that no water can flow into irrigation canals.
Figure B.3.11.7 – Farmers in California are pumping water from the ground to keep their plants growing.
Watch More
California Drought
This video explains more about the drought in California. (This video is from 2014, but 2015 was also a drought.)
This video explains more about the drought in California. (This video is from 2014, but 2015 was also a drought.)
The drought in California is a concern for Canadians. Watch this video to learn why.
Try It!
Houseplant Drip Irrigation
Drip irrigation is a way to water plants slowly. Only a little water at a time trickles to the plant roots. Drip irrigation prevents water from evaporating from the soil surface. Try this simple experiment to make a drip irrigator for a houseplant.
Materials:
Drip irrigation is a way to water plants slowly. Only a little water at a time trickles to the plant roots. Drip irrigation prevents water from evaporating from the soil surface. Try this simple experiment to make a drip irrigator for a houseplant.
Materials:
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1 empty 500 mL plastic pop bottle
- water
- balloon
- rubber band
- scissors
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1 houseplant (not a cactus)
Safety Warning
Take care with scissors; don't cut yourself or anyone else!
Instructions:
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Fill the pop bottle with water.
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Cut the balloon in half lengthwise.
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Stretch half the balloon tightly over the pop bottle opening. Wrap an elastic band tightly around the balloon and the neck of the pop bottle to make a tight seal.
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With the point of the scissors, poke 3 small holes in the balloon rubber. Turn the bottle upside down over a sink to be sure that water can drip (or run) out slowly.
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Use your finger to make a hole in the soil beside the houseplant in the pot. Be careful not to damage the plant! Turn the pop bottle upside down and press the pop bottle, balloon-end down, into the soil . The bottle should be pushed deeply enough so that
it stands on its own.
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Observe the bottle every day for a week. What happens to the water level in the pop bottle? Dig your finger into the soil. What do you notice about the soil?
Here is a similar procedure. You can poke holes in the pop bottle cap if you do not have a balloon.
Questions:
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
The water level in the bottle lowered slowly during the week. The water trickled slowly from the bottle into the soil and to the roots of the plant.
The soil may be dry on the surface. When you poked your finger into the soil, the soil probably felt damp every day. This is because water was trickling constantly from the bottle into the soil.
Making Fertilizer
One of the most important inventions in the early 1900s was the Haber-Bosch process, named after its German inventors. This process takes nitrogen from the air and makes it into a chemical called ammonia. Plants require nitrogen to grow quickly, but they cannot absorb nitrogen directly from the air. When nitrogen is in the form of ammonia, plants are able to absorb it. Today, the methane of natural gas is the primary source of nitrogen for fertilizer.
The ability to make fertilizer from nitrogen has helped farmers to grow crops that are more productive. This helps feed the large population on Earth. Without human-made chemical fertilizers, we would struggle to grow enough food to feed everyone on the planet.
One of the most important inventions in the early 1900s was the Haber-Bosch process, named after its German inventors. This process takes nitrogen from the air and makes it into a chemical called ammonia. Plants require nitrogen to grow quickly, but they cannot absorb nitrogen directly from the air. When nitrogen is in the form of ammonia, plants are able to absorb it. Today, the methane of natural gas is the primary source of nitrogen for fertilizer.
The ability to make fertilizer from nitrogen has helped farmers to grow crops that are more productive. This helps feed the large population on Earth. Without human-made chemical fertilizers, we would struggle to grow enough food to feed everyone on the planet.
Figure B.3.11.8 – People add fertilizer to their lawns in the spring to make them grow thicker and greener.
Figure B.3.11.9 – Farmers spread large amounts of fertilizer on fields.
Figure B.3.11.10 – Ammonia is an important chemical used in fertilizers applied before seeding.
Watch More
Haber-Bosch Process
This video explains more about the Haber-Bosch process of turning nitrogen into ammonia.
This video explains more about the Haber-Bosch process of turning nitrogen into ammonia.
Potash for Fertilizer
Potash is a mineral that contains potassium, which is important for plant growth and disease resistance. One way of making potash is suggested in its name. People used to make their own potash fertilizer by burning wood into white ashes. Then, they collected the ashes and ran hot water over them, extracting a substance called lye. The lye was boiled to a solid residue in the pot -- hence, potash.
Large deposits of potash are found deep underground. Potash is mined and added to fertilizers. One of the world’s largest underground deposits of potash is located in southern Saskatchewan.
Potash is a mineral that contains potassium, which is important for plant growth and disease resistance. One way of making potash is suggested in its name. People used to make their own potash fertilizer by burning wood into white ashes. Then, they collected the ashes and ran hot water over them, extracting a substance called lye. The lye was boiled to a solid residue in the pot -- hence, potash.
Large deposits of potash are found deep underground. Potash is mined and added to fertilizers. One of the world’s largest underground deposits of potash is located in southern Saskatchewan.
Figure B.3.11.11 – Some potash minerals are pink.
Figure B.3.11.12 – Saskatchewan has some large potash mines.
Watch More
Potash Mining
Watch this video to learn more about why potash is found underground and how miners get it from the ground.
Watch this video to learn more about why potash is found underground and how miners get it from the ground.
Connections
Connections: Environment
>> Fertilizers and Algae Growth
Fertilizer spread on fields is not always absorbed by plants immediately. In heavy rains, fertilizers can wash from the surface of the soil into waterways such as rivers and lakes.
If too much fertilizer gets into rivers and lakes, algae in the water reproduce quickly. Algae are not plants, but they are small organisms that make their own food by photosynthesis. The nitrogen and phosphorus nutrients in fertilizer help algae to reproduce.
Extra algae can take over a waterway. This is called an algae bloom. The algae bloom uses the oxygen in the water, which leaves very little oxygen for other organisms such as fish. Eventually, the healthy water ecosystem is destroyed.
>> Fertilizers and Algae Growth
Fertilizer spread on fields is not always absorbed by plants immediately. In heavy rains, fertilizers can wash from the surface of the soil into waterways such as rivers and lakes.
If too much fertilizer gets into rivers and lakes, algae in the water reproduce quickly. Algae are not plants, but they are small organisms that make their own food by photosynthesis. The nitrogen and phosphorus nutrients in fertilizer help algae to reproduce.
Extra algae can take over a waterway. This is called an algae bloom. The algae bloom uses the oxygen in the water, which leaves very little oxygen for other organisms such as fish. Eventually, the healthy water ecosystem is destroyed.
Figure B.3.11.13 – Excess algae in ponds or lakes covers the water with green scum.
Figure B.3.11.14 – Algae blooms affect the habitat of other species in the environment.
Watch More
Lake Erie Algae Bloom
Currently, algae blooms are a problem in the Great Lakes, especially in Lake Erie. Watch this video to learn more about algae blooms in Lake Erie.
Currently, algae blooms are a problem in the Great Lakes, especially in Lake Erie. Watch this video to learn more about algae blooms in Lake Erie.
Composting
For many years, people have made fertilizer by composting dead plant materials and animal wastes. Plant and animal wastes should not be applied directly to gardens. They need to decompose first to be a safe and effective fertilizer. Bacteria help decompose organic wastes to produce fertilizer with lots of nutrients for new plants.
To learn more about composting, click here to Explore with Elsie.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to
guide your learning.
Unit B Lesson 11 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
- DOWNLOAD the self-check quiz by clicking here.
- ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
- COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
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REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
- SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
- CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Self-Check Time!
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Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
An advantage of using chemical fertilizers made from ammonia and potash is that they let humans grow lots of plants for food quickly. The nitrogen and potassium nutrients in the fertilizers are very useful for plant growth. Without chemical
fertilizers, feeding the 7 billion people on Earth would be more difficult.
A disadvantage of using chemical fertilizers made from ammonia and potash is that they can run from farm fields into waterways, causing algae to reproduce. Nitrogen and potassium nutrients in chemical fertilizers are used by algae. Too much
algae in waterways can kill other species in the water.
The man is using crop rotation in his garden. He is changing the location of plants in the garden so that soil nutrients are not used up completely in one area by one type of plant.
Compost should have a mix of greens (such as vegetable scraps) and browns (such as dried leaves or shredded newspaper) so that the mixture decomposes without smelling. Also, you should never put meat, bones, or dairy products into an outdoor
compost bin.
Irrigation canal systems have been built across much of southern Alberta to bring water to dry farm fields during the summer so that crops can grow well.