Recently my friend, Farmer John, called me. We were talking about his farm and he explained to me that his irrigation system for his farm was recently shutdown due to a problem with the freshwater source. Farmer John explained that he would not be able to use the stream water he had been relying on due to low water volumes from the dry summer. He said he could only take some water from the stream as other wildlife like salmon depended on it to swim to their spawning grounds. Farmer John said the state is only allowing him to capture a small amount of water. He’s worried about the crops he’s planted. However, I told him why not use some of the saltwater from the ocean nearby. I said, “You could mix it with the freshwater you’re allowed to harvest and conserve your freshwater and grow your crops!” I told him we’ve been experimenting with different levels of salinity. We could study the problem and share our findings. I said, “We’ll find the range of tolerance for the crops.” He said, “That would be great!”

Well, you guys have heard the story. Now, we need to think about the experimental design. What do you think we can set-up to help Farmer John determine how salinity could affect his crops?

What we decided for our experimental design:

•  Create 4 different saltwater solutions. Label one with 0, another 1, … 2, and 4.
•  Set-up a tray of crops with 4 different cups. Label one with 0 another 1, … 2, and 4.
•  In each cup place 4 corn  seeds, 4 pea seeds, 3 barley seeds and 3 radish seeds.
•  Plant all seeds in the cups with about a cup of soil.
• Water each cup with 50 ml from the saltwater solution that’s the same as the cup label.
• Observe what happens.