Resource Material

Plant Growth and Root Development

Caliche

Caliche is a shallow layer of soil or sediment in which the particles have been cemented together by mineral matter. Also known as calcrete, hardpan, and duricrust, this layer is a common feature in arid or semiarid areas throughout the world. In the United States, caliche is a familiar deposit in many parts of the Southwest, especially Arizona, California, Nevada, New Mexico, and Texas. Caliche results from minerals precipitated in soils where evaporation exceeds precipitation, as found in arid regions. The cement is usually calcium carbonate; however, cements of magnesium carbonate, gypsum, silica, iron oxide, and a combination of these materials are known. In some locations there are multiple ancient caliche layers.

Caliche is often a challenge to agriculture. It interferes with proper soil drainage, the formation of plant roots, and it also can contain soluble minerals that are not beneficial to plants. The impermeable caliche prevents plant roots from penetrating to deeper soil layers, which limits the supply of nutrients, water, and space, making it difficult for the plants to develop normally.

The Plant Growth and Root Development project was brought to you by the Great Basin Rangelands Research Unit in Reno, NV. 

Plant Growth and Root Development

Water is a critical element for plant growth, but certain soils or sediments can actually block water from getting to the deeper soil layers. For example, caliche is a hard, shallow layer of soil often found in the southwest and other arid and semiarid parts of the world. Caliche inhibits water from reaching the deeper soils, making it harder for plants to grow. It also prevents roots from reaching the deeper soils, depriving the plant of nutrients. Consequently, this “barrier” could stunt a plant’s growth, or cause the plant to wilt and die. (See Appendix A for more information)

About the Experiment

For this experiment, we’re going to test the effect a hard soil layer has on plant growth and root development.

	Details Ages - 10+
	Time - 1 hour set up - a few minutes a day for 3+ weeks
	Difficulty - Easy/moderate

 What You'll Need

• 3 clear plastic cups (e.g. Solo cups)
• 3 non-clear plastic cups
• Potting soil (Small bag, 6-8 qt.)
• Wheatgrass or cat grass seed (100 seeds, available online or at local pet store)
• Piece of cardboard
• Baking soda
• Duct tape
• Measuring cups
• Drill & small bit

Let's Do This!

Step 1. Drill 3 small holes in the bottom of 3 clear plastic cups. (Have an adult help with this step for safety).

Step 2. Cut 2 pieces of cardboard so it fits tightly about 1.5” from the top of one clear cup (cup with holes). Trace the opening of the cup and cut 1/4” inside the line.

Make sure the cardboard fits tightly. Mark where the cardboard is on the cup, remove cardboard and fill up to the line with soil. Place cardboard on top of the soil.

Step 3. Using duct tape, tear skinny strips and place around the edge of the cardboard to seal to the cup. Make sure to only cover edges of the cardboard with tape.

Step 4. Fill the cup with soil ½” from the top (label this “Cup 1”). Repeat the process, but place cardboard about 3” (halfway) from the top of the second cup.

For a tight fit, trace the top of the cup and cut cardboard 1/2” inside line. (label this “Cup 2”).

Fill 3rd clear cup ½” from the top with soil (No cardboard) (Label this “Cup 3”).

Place the cups inside 3 non-clear cups.

Step 5. Pour ½ cup water in each cup. Wait 1 minute and pour another ½ cup of water in each cup. OBSERVE: Which cup has standing water after a minute? Record answer on data sheet.

Step 6. Place 30 grass seeds in each cup and cover with 1/8” soil. Gently add a little more water to wet topsoil. 

Let seeds germinate and grow for 1 week.

Let’s Look At The Results!

After 1 week count the number of plants in each cup and measure the tallest blades of grass in each cup.

Remove clear cups from non-clear cups and observe the amount of water in the non-clear cup. Which cup has the most?

Observe the amount of roots in the clear cups. Are the roots below the “caliche” layer? Which cup has the most roots? Record your answers and observations on the data sheet.

After 1 week, add ¼ cup water to each cup. Do Not add any more water.

Observe how many days till plants in each cup wilt (may take a week or more) and record answers on data sheet.

Record any other observations you have during the experiment on the data sheet.

Finally, summarize what you think occurred in your experiment and why based on the observations you made and the data you collected.

Mind Your Meatballs

Meatball lovers, take note! ARS food safety researchers studied ways to cook meatballs so that any bacteria in the meat is sure to be killed. They came up with times and temperatures that chefs and home cooks can use to safely cook beef or veal meatballs. Learn more at "Study Shows Safest Ways To Cook Meatballs."

ARS Helps Farmers and Ranchers Prospect for Non-Fossil Oil and Gas

Agricultural producers may soon hit a trifecta – the ability to clean up the environment, reduce dependence on fossil fuel, and create a new source of income.

ARS scientists at the Eastern Regional Research Center are testing a thermo-catalytic system to help farmers and ranchers convert farm and ranch leftovers and waste to sources of bioenergy (oil and gas), and high-value by-products. The system uses heat in a no-oxygen environment, called pyrolysis, to create crude bio-oil and bio-char.

The Combustion Reduction Integrated Pyrolysis System (CRIPS) travels to farms and can run “off-the-grid” to process low-value crop leftovers like grasses grown on marginal-quality lands, forest residues, and animal manure. CRIPS can produce about 40 gallons of gasoline-quality fuel per 1,000 pounds of dry farm waste

Read the blog to learn more.

Imperfect Fruits and Veggies Get a Second Chance

Fruits and veggies that are too small, blemished, or oddly shaped probably won’t make it to your grocery store’s produce section, but thanks to ARS, they might end up in the healthy-snack aisle instead. To help reduce food waste, ARS food technologists created tasty new products, like fruit bars, wraps, and snacks, made from fruits and vegetables that might not be perfect, but are still nutritious.

Read Turning Food Waste into Healthful Delights to learn more.

Science and Serendipity Defeat Invasion of the Air Potato

The plot could have come from Hollywood — an insidious alien invader threatens to overrun the land, but intrepid scientists discover a secret weapon in the far-off, exotic land of Nepal and bring the pestilence to heel. But this is not fiction; it’s true.

The air potato plant (Dioscorea bulbifera) is an exotic vine from Asia that was introduced to Florida about 115 years ago to make medicine. After escaping from the lab, it multiplied and smothered native plant communities in all of Florida’s 67 counties in vines that grew 6 inches per day.

All attempts to manage the air potato were unsuccessful, until scientists from the ARS Invasive Plant Research Laboratory in Fort Lauderdale, FL, made their historic trip to Nepal.

To learn more read this article.

How Can an App Beef Up Cattle Production?

Everyone would like to see a few extra dollars in their wallets, right? Ranchers are no exception, and researchers at ARS’ Meat Animal Research Center in Clay Center, NE, are developing a web-based tool that will help cattle producers do just that. Called iGENDEC, for internet genetic decisions, the internet app will give beef cattle producers a way to select the best bull for their herds. Early testing has shown promising results.

Read Want To Beef Up Cattle Production? There Will Soon Be an App for That to learn more.

Grape Expectations

When was the last time you had to pick seeds out of your teeth when you ate a grape? Most likely, never! That's because ARS has bred "seedless" grape varieties with seeds so tiny that you can't even detect them.

Popular varieties include Flame Seedless, Crimson Seedless, Thomcord, and Autumn King, to name just a few. Sunpreme is a variety perfect for drying raisins on the vine. ARS pioneered a technique called "embryo rescue" to create new seedless varieties from existing ones.

Watch this video New Sunpreme Grape Variety from USDA-ARS

Really-Good-For-You Health Bars

Micronutrients are vitamins and minerals we need in small amounts for best health. ARS researchers helped formulate a tasty fruit-based bar with specific micronutrients and other health-promoting ingredients. Study participants who ate two bars a day for 8 weeks had improvements in several health indicators without making any other dietary changes.

To learn more read "Micronutrient-Packed Bar Improving Metabolic Health Goes Commercial."