Lesson 6: Nourishing the Plant in the 21st Century

Evaluate

• Appreciate how soil properties contribute to plant health

• Recognize that nutrient deficiencies limit crop productivity

• Understand the role of fertilizer in growing crop plants and in restoring nutrient balance to agricultural soils

• Relate crop productivity to the need for more farmland

• Describe challenges associated with feeding the world’s growing population

What we’re learning!

By the end of this lesson, you’ll be able to:

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Warm-up: Mission

Your role:

Agricultural Expert

Your mission:

Make farming recommendations to increase the world’s food supply

Warm-up: The problem

The problem: Feeding the world’s increasing population

Today, the world population is about 7 billion. By 2050, it will increase by 2-3 billion people.

How old will you be in 2050?

Warm-up: What about you?

Let’s calculate it!

Video: Food and Human History

Mission: Memo from the Secretary General

Earth Food BankMemo

To: Chairperson of the Earth Food Bank Executive Committee on Increasing Our World’s Food Supply

From: Secretary General of Earth Food BankAbout: Recommendations about Farming

Regarding our initiative Nourishing the Planet in the 21st Century, I have received the preliminary report from the Committee on Increasing Crop Yields. I am preparing an executive summary that will be released worldwide to the press. This press release needs to include the recommendations that the committee feels are most important to help farmers feed our growing population. Although the final committee report will discuss these recommendations in detail, the press release needs to be short and to the point.

I have included with this memo a list of 10 recommendations from the preliminary report. I would like the executive committee to review these recommendations and select what it considers to be the top five most-important recommendations about farming. I will include these recommendations in my executive summary.

Thank you for your hard work and dedication to this important project.

1. Essential elements

2. Properties of soils

3. Moving nutrients through plants

4. Nutrient deficiencies

5. Land use

Mission prep: What do you know?

What do you know?

• Plants and humans require similar sets of essential nutrients.

• Plants obtain their essential nutrients from air, water, and soil.

• Plants require 17 essential nutrients to complete their life cycle.

Lesson 1 Review: Essential elements

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What do you know?

• Soils vary in their compositions.

• Soils are a “bank” of nutrients.

• Soils contain both organic and inorganic material.

• Soils contain differing amounts of air space.

• Soils differ in their abilities to hold and transmit water.

Lesson 2 Review: Properties of soil

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What do you know?

• Plants remove water and nutrients from the soil through the plant’s root system.

• Some nutrients move into root cells from the soil by diffusion and others by an energy-requiring process (active transport).

• The plant vascular system has similarities to the human circulatory system.

• Plants transport water from the roots to the rest of the plant using the xylem.

• Plants transport food from the leaves to the rest of the plant using the phloem.

Lesson 3 Review: Moving nutrients through plants

Copyright © 2013 Discovery Education. All rights reserved. Discovery Education Inc. is a subsidiary of Discovery Communications, LLC.

• Plants, like most people, require essential elements to be present in certain quantities in order to be healthy.

• Plants extract nutrients from the soil; people remove nutrients as crops.

• Plants with nutrient deficiencies show specific symptoms.

• Fertilizer is food for plants.

• The soil is a “nutrient bank” that can hold a limited amount of nutrients. Fertilizers put more “money” in the bank by restoring nutrient balance to agricultural soils.

What do you know?

Lesson 4 Review: Nutrient deficiencies

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What do you know?

• Only a portion of Earth’s surface is used to grow food.

• The world’s population is growing at a steady rate.

• Unless food productivity increases, more land will have to be farmed.

• Fertilizers can be commercial or organic.

• Excessive amounts of nutrients can pollute water, soil, and air.

Lesson 5 Review: Land use

World Population Growth

(9.6)

(7.19)2013

(3.0)

(1.5)(1.0)

Year

Po

pu

latio

n in b

illio

ns

Copyright © 2013 Discovery Education. All rights reserved. Discovery Education Inc. is a subsidiary of Discovery Communications, LLC.

Earth Food Bank Memo

1. Farmers should use soils that allow plants to develop a healthy root system.

2. Whenever possible, farmers should use organic fertilizers.

3. Farmers should only grow crops in soils that have enough air space to allow water and

oxygen gas to seep in and support plant growth.

4. Farmers should use commercial fertilizers to obtain the greatest crop yields.

5. Farmers should use methods that minimize nutrient losses to air and water.

6. Farmers should learn to diagnose plant nutrient deficiencies and use fertilizers to treat them.

7. Farmers should use methods that maintain the long-term fertility of the soil.

8. Land without fertile soil should not be used for farming.

9. Farmers should use proper amounts of fertilizers that supply essential nutrients that are

missing from their soil.

10. Farmers should use the least amount of land necessary to feed the world’s population.

Mission: Recommendations for Nourishing the Plant