Author: Theresa Schallhorn

HYDROPONICS

plant growth without soil
BOTANY CLASS—SPRING 2013

Small scale to large scale

making the transition from plant nutrition to hydroponics

We have been talking about plant nutrition and health lately on a small scale—the effects of nutrient levels in soil, environmental requirements such as sunlight, water and space—and we even learned about basic care for houseplants. Now let’s take a look at how these things come into play on a much larger scale.

Describe or draw a picture of what you think about when you see/hear the word ‘agriculture’. How would you define agriculture?

Taking care of houseplants and small garden have been made fairly easily when it comes to ensuring they have enough nutrients, sunlight, space and water because of fertilizers, repotting and transplanting techniques and constant access to water.
How do farmers take care of these same growth requirements on a much larger scale, though?

The average backyard garden is about 100-1000 ft2. The average commercial farm is 500 acres or 21,780,000 ft2!

Past, present and future

the history of agriculture

THINK: small and large scale, urban and rural, tools and methods, etc.

Many of the agriculture and farming techniques we see today, such as ranches, rotating crops, and organic farms, have been in development for nearly 10,000 years. Alternative methods are currently being developed that might revolutionize the field (no pun intended).
What are some old AND new methods of agriculture you have seen/heard/read about?

The development of irrigation and fertilizing techniques are just two of the many inventions that greatly advanced agricultural methods. With them, farmers were better able to provide for a growing population.
This past summer has been recorded as one of the hottest summers in the history of the United States. Because of such high temperatures and ensued drought, many farmers crops died before harvesting thus increasing the prices of crops in grocery stores nationwide.
What other inventions or situations have occurred or may occur that might affect crop production for better? For worse?

THINK: tools and techniques used both past and present, environmental relationships, costs, etc.

Timline of events

the history of agriculture

What was it??	Who/Where / invented it??	When??	Why??
Domestication of wheat	Fertile Crescent of the Middle East	BC9500	Aided in the transition from hunter-gatherers to farmers.
Farming / Communities	Central Europe	BC4500—4900	Aided in the spread of intensive farming techniques and domesticated animals and plants from Asia to Europe.
Medieval Green Revolution	Asia-Pacific, / Middle East, North Africa	700	Crops went global—trades of sorghum, citrus fruits, rice, cotton and sugar cane resulted in changes in economy, agriculture, population ,diet and clothing.

Timline of events (CONTINUED)

the history of agriculture

What was it??	Who/Where / invented it??	When??	Why??
British / Agricultural / Revolution	Britain	1700	Major increase in agricultural productivity that supported the growing population and aided in the development of the industrial revolution there.
Industrial / Agriculture	Worldwide	1920	Increased knowledge of plant and animal nutrition, expansion of shipping networks, improved agricultural technology.
Organic / movement	Worldwide	1970	Increased awareness of the effects of the use of fertilizers and pesticides on the environment.
Genetically / modified plants	Worldwide	1990	Increased plants resistance to pests, herbicides and harsh environmental conditions. Improved crop shelf life and nutritional value.

Agriculture: what’s coming next?

IDENTIFY the mechanisms for each of the following alternative agricultural methods and
EXPLAIN how it has improved on soil-based, commercial agricultural methods.

Biodynamic / Agriculture
Biointensive / Agriculture
Permaculture
Aquaponics

Hydroponics

What is it? How does it work?

Based on the history that we learned about yesterday, the agriculture realm seems to have hit a plateau with inventions. But what you might not have realized is that researchers have begun to develop alternative methods sort of behind the scenes.
One such development is called hydroponics; plant growth without soil. Knowing only this key difference:
PREDICT what the main components of a hydroponics system are and ...
EXPLAIN how the plant growth requirements would be met compared to the tradition soil-based methods.

Hydroponics Notes page

an overview

What is hydroponics?

What are the main components of a hydroponics system?
Why are they needed?

Hydroponics

a calendar of events

For lettuce grown via hydroponics:
Day 1: Germination of seeds in hydroponic media with frequent watering.
Day 4: Sprouting of seeds with frequent watering and fertilizing.
Day 4-13: Transplant #1 to unit that contains less plants per area.
Day 13: Transplant #2: to unit that contains even less plants per area —more light and space.
Day 26: Transplant #3 to unit that contains even less plants per area
Day 26—45: Transition to the production zone .
Day 45: Harvesting

For blueberries grown in Michigan:
Month 1: Dormancy
Month 2: Sprouting of seeds.
Month 3: Beginning of fruit production
Month 4: Late fruit production and coloring.
Month 5: Harvest

Hydroponics

Identifying mechanisms of a variety of hydroponic systems

TYPE OF HYDROPONIC SYSTEM	MECHANISM

HYDROPONICS

DEBRIEFING: what are the components of hydroponic systems

Yesterday, we learned that there are specific features that are found in every hydroponics system. We remember these by using the acronym “L.A.W.N.S.”. What does each letter in “LAWNS” represent again?

Look at the sheet that you filled in yesterday that describes the mechanisms of each type of hydroponics system. Are the LAWNS requirements met in each one? Do you think one system might be more effective than another? Why or why not?

Typically, hydroponic systems are used for growing vegetables such as tomatoes or lettuce (from the YouTube video!). Why do you think vegetables are the most common plant grown this way? Do you think that other plants would survive just as well? Are there plants you can think of that would not/could not survive if grown via hydroponics?

HYDROPONICS

constructing a hydroponics system

Using only common household materials, can you design and construct a functional hydroponics system??
On this paper, draw and label every part of your system. Also,
answer the following questions.

We talked about how plants will need ‘support’ to keep them from being completely submerged in the soil. What ‘support’ will you provide your plants?
We talked about how plants need ‘water’ that contains ‘nutrients’ to constantly be in contact with the roots. How will your system do this?

John Foley’s TED talk calls agriculture “the other inconvenient truth”

By: Cameron Scherer

The following article summarizes the video that we watched at the end of class on Thursday. For homework, read this article and answer the questions at the end on a separate piece of paper to be turned in on Friday, March 1.

When asked to identify the greatest threats to our 21st century lifestyle, most of us would likely choose war or economic crisis over farming. But according to Jonathan Foley, Director of the Institute on the Environment at the University of Minnesota, agriculture is in fact the “single most powerful force unleashed on this planet since the end of the Ice Age.”
The Aral Sea used to be a source of irrigation and fish. Today, as a result of intensive agriculture, only a fraction of its original volume remains. (Photo credit: http://www.mirutadelaseda.com/)
In an online video of his recent TED Talk “The Other Inconvenient Truth,” Foley speaks in depth about the havoc modern agriculture is wreaking on our global environment. He says the Earth is running out of available land for farming. Today, we devote 16 million square kilometers – an area the size of South America – to croplands, and 30 million square kilometers – an area the size of Africa – to pasture for livestock. Together, this acreage comprises 40 percent of Earth’s land surface, an area 60 times greater than urban and suburban land combined.
As agriculture expands into deserts and other arid climates, our global demand for crops is putting a huge strain on our fresh-water resources as well. Seventy percent of the water we consume goes towards agriculture. Looking at it a different way, we use enough water to fill 7,305 Empire State Buildings every day.
Foley points to the example of the Aral Sea drying up as a result of increased farming in Eastern Europe. As a result of such large-scale evaporation, several fish species have died out and toxic waste that had accumulated at the bottom of the sea has become airborne, posing a serious threat to public health.

Agriculture is also responsible for 30 percent of greenhouses gases, making it the single largest contributor to climate change – more than transportation or industry manufacturing.
Unfortunately, the environmental implications of modern agriculture are not going away any time soon. Between a global population growing by 75 million people per year, changing diets, and an oil crisis driving the market for biofuels, the demand for agricultural output is only increasing. It is increasing so fast that, Foley predicts, we will need to double global agricultural production in our lifetime.
Instead of finding new arable land to cultivate, he says, we need to farm the land that we have more sustainably. “There are opportunities to make this work,” he says. “But we have to do it in a way that is sensitive to meeting the food security needs of the future and the environmental security needs of the future.”
According to Foley, we need to develop a new kind of agriculture that blends Green Revolution technologies, organic farming methods, and environmental conservation. He labels this type of agriculture “terraculture,” or “farming for the whole planet.” Solutions he proposes include, but are by no means limited to: new crop varieties, drip irrigation, greywater recycling, and smarter diets.
We have no other option, he says, but to rethink agriculture to feed the world “sustainably, equitably, and justly.”
Here is the link to video in case you are interested in watching the entire thing:
http://video.ted.com/talk/podcast/2010X/None/JonathanFoley_2010X-480p.mp4
What were your initial thoughts upon reading the facts presented in this article? Were there any that stood out to you? Why?
Much research has gone into calculating ones’ “ecological footprint”. This term refers to the ‘pressures’ that humans put on the environment. What might these pressures be?
Jonathan Foley uses the term “sustainable” quite often in that agricultural methods we use now must become “sustainable” in order to support our lifestyles. What does this term mean? In what ways can agriculture become sustainable?
Based on what we have learned thus far in the class and from what you’ve read, what do you think might be a solution (there can be more than one, too!) that will meet both food and environmental needs?

AGRICULTURE’S FOOTPRINT

comparing and contrasting traditional and alternative agricultural methods

DRIVING QUESTION:	SOIL BASED:	AQUAPONICS:
HOW MUCH SPACE DO WE NEED?
HOW MUCH DOES IT COST?
WATER:
ENERGY:
FERTILIZERS AND / PESTICIDES:
GREENHOUSE GAS EMISSIONS:
CROP PRODUCTION:

NAME:__________________________ HOUR:___________ DATE:_______________________