School. Today s Children Tomorrow s Leaders

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1 in AG theclassroom W A S H I N G T O N School Volume 10, Issue /2011 Published by Washington Agriculture in the Classroom Give A Cheer For SOIL! The entire earth every ecosystem, every living plant and animal depends upon soil. It is a complex mixture of minerals, air, water, and organic matter (living organisms and decaying remains of once-living plants and animals). Farmers know that on average it takes 500 years to create an inch of topsoil, so they understand the importance of taking good care of the soil. After all, every day is Earth Day for agriculture! Today s Children Tomorrow s Leaders soil, n. the top layer of earth suitable for growing plants

2 Let s Use the Scientific Method The scientific method is a way to ask and answer scientific questions by making observations and doing experiments. These are the steps: Ask Question The World Depends on Soil The importance of soil is often ignored. There is a saying, as common as dirt, which means something of little or no value. Soil is not dirt, and good soil is extremely valuable. Dirt is what you track across your mom s clean floor or what you find under your bed. Soil however, makes our lives possible. All living things depend on the soil for life. We eat food grown in soil. The soil cleans and stores the water we drink, and gives us a place to build our houses, roads, schools, and cities. We breathe air made by trees and plants growing in soil. We get medicines from soils and wear clothes made from plants and animals that need soil. The entire earth every ecosystem, every living organism relies on soil. Without soil, the earth s surface would be barren rock and sand and could not support life. Soil is a complex layer teeming with life, where the atmosphere, water, sunlight, and the earth s crust mix and interact. Almost all of the biological activity in the soil takes place in the top one or two inches, an area usually referred to as topsoil. Farmers today use many methods to conserve soil, from advances in machinery, to increased knowledge of the chemical and physical properties of soil. Many Washington farms have major challenges to soil conservation because of precipitation (too much, too little, too fast) as well as the topography of the land (physical features like hills and valleys). A Rainbow of Soil Words F.D. Hole 1985 A rainbow of soil is under our feet; red as a barn and black as a peat. It s yellow as lemon and white as the snow; bluish gray. So many colors below. Hidden in darkness as thick as the night; The only rainbow that can form without light. Dig you a pit, or bore you a hole, you ll find enough colors to well rest your soil. Hypothesis is True Do Background Research Construct Hypothesis Test with an Experiment Analyze Results Draw Conclusion Report Results It is important for your experiment to be a fair test. A fair test occurs when you change only one factor (variable) and keep all other conditions the same. Let s do an experiment! 1. The question is, Does grass help prevent erosion and also filter water? 2. Background research shows that roots and other organic matter will hold soil. 3. Our hypothesis (what we will assume is true) is that grass sod will have cleaner water run-off than bare soil (less soil will erode). 4. We test the hypothesis with an experiment. Use two large foil baking pans (approx. 12 X 15 ). Cut a V-notch in one end to allow for drainage. Fill one with soil only and the second one with a piece of grass sod cut to fit the pan Raise one end of the pans to allow water to drain and arrange a shallow container to catch drainage. Carefully saturate both pans ( just enough water until excess starts to drain away). Slowly add measured amounts of additional water across the highest surface of the pans and collect the drained water. Measure the amount of drainage from each pan and note the color of the water. Take the drained water from the bare soil pan and add it back to the sod. What happens to the dirty water? 5. We conclude that grass roots not only keep soil from eroding, they can also filter sediment from dirty water. 6. So our hypothesis was true. Grass sod has a cleaner run-off than bare soil. How Is Soil Made? The world has thousands of different soils (70,000 just in the US). Parent rock (like lava, limestone, granite) is broken apart into finer particles by a process called weathering. Temperature and water are critical in this process. Water dissolves minerals and is important in chemical reactions and in supporting living organisms. Freezing and thawing and heating and cooling also break down rocks. Plant roots can enter cracks in the rocks and break them apart. Roots can also form acids that help break down particles. When plants and animals die, they add organic matter to the weathered parent material. Bacteria, fungi, and worms enrich the soil by breaking down organic matter to form topsoil. Soil formation is very slow, taking thousands or even millions of years. Hypothesis is False or Partially True frost Think! Try Again Weathering wind rain hail ice parent material heat cold mechanical weathering fine parent material 2

3 CAN YOU DIG IT? Soils are made of three basic particle sizes called sand, silt, and clay. The difference in size between the three would be like comparing a basketball (sand), a golf ball (silt), and the tip of a ballpoint pen (clay). Soils from different locations vary in their amounts of each of the three particles. The amount of each type of particle is important because that determines the capacity of the soil to hold water and air. In the Columbia Basin soil can be very sandy whereas near Mica, WA the soil is nearly all clay, in fact there is a business there that uses the soil to make bricks. Ideally soil is: 45% particles (sand, silt, and clay) 5% organic matter (dead plants and animals) 50% empty space (pores) with half filled with air, and half filled with water Without decayed organic matter (humus), the soil loses its capacity to retain the water and air that soil organisms need. The Amazing Palouse Hills Extending south from Spokane WA for approximately 175 miles to Grangeville, ID, this area of the two states is called the Palouse Hills. These steep, rolling hills are actually huge windblown silt dunes, with tremendously deep, rich topsoil. Scientists are unsure of both the age and origin of the Palouse Hills. They were formed sometime in the last three million years and could have blown in from the glaciated regions of NE Washington or from the desert areas of south central Washington and Oregon. The name Palouse (pah-loose) is derived from the name of the Native American tribe living in the region. 3

4 Sustainable Agriculture Requires soil conservation Sustainable agriculture meets the needs of today but does not use up resources for the future. It must be: Environmentally friendly; taking care of the soil so it will remain productive now and in the future Profitable enough to keep farmers in business bottoms were originally cultivated. In the 1870s and 1880s immigrants from Eastern Europe began cultivating the Palouse hills and growing winter wheat. It was not an easy task and took large teams of horses and mules to pull the farm equipment around the hills, but the crop yields were significant. Able to improve the quality of life for farmers and all of society Conservation is the controlled use and planned protection of a natural resource, like soil. Unfortunately, some of the same physical forces that create soil also cause erosion (picking up soil and carrying it away). Every raindrop splash can move soil particles. USDA-NRCS photo Whitman County in the heart of the Palouse region has great examples of both soil erosion and soil conservation efforts. When settlers first arrived in the area the tall bunch grass was used for grazing land. Only the river 4 Whitman County consistently leads the state (and often the nation) as the county with the highest production of wheat, barley, peas, and lentils. Those giant dunes of soil are extremely productive, even without irrigation and only about 17 inches of rainfall. Unfortunately, when it rains too much at one time or when the snow cover melts too quickly, water carries soil particles down those hills (remember the experiment you did on page 2).

5 American agriculture is the most earth-friendly in the world. Our farmers know they need to be friends of the land, soil and water. Why? If they treat the earth well, it will be able to keep giving back and not just for us today, but for future generations too. Farmers found that they could stop some of the erosion if they could slow the water down. They could cultivate their fields going around the hills rather than up and down (contour farming). They could make flatter areas (terraces) around the hills that Using no-till practices in the large field agriculture of Whitman County can have many benefits. Wind and water erosion are greatly reduced. More water filters into the soil and that soil moisture is not lost through evaporation since the soil is not turned over with tillage. Soil quality is improved by keeping or increasing the amount of organic matter. The amount of fertilizer necessary to produce a crop is reduced because nutrients left in the crop residue are would slow the water down. They could plant strips of grass or other crops that would catch water and sediment (strip cropping and grass waterways). Leaving crop residue (stems, straw, and roots) from the previous year s crop also holds water (and soil) in place. Changes in equipment have allowed farmers to reduce the amount of tillage saving soil, moisture, time, and fuel. Many farmers are adopting no-till practices where the seed and fertilizer are placed directly into the soil beneath the old crop residue and no other soil preparation is used. available for recycling. With more organic matter, the number of living organisms in the soil also increases. 5 No-tilling the steep slopes of the Palouse Region. Photo courtesy of John Aeschliman

6 In a process called photosynthesis, plants use energy from the sun to change carbon dioxide (CO 2 - carbon and oxygen) and water (H 2 O- hydrogen and oxygen) into starches and sugars. These starches and sugars are the plant s food. In addition to the non-mineral nutrients of hydrogen, oxygen, and carbon, plants need 13 mineral nutrients. These nutrients come from the soil, are dissolved in water and absorbed through a plant s roots. The primary nutrients are nitrogen (N), phosphorus (P), and potassium (K). Nitrogen is a part of chlorophyll, the green pigment of the plant that is responsible for photosynthesis. Without nitrogen, plants are weak and look yellow. Phosphorus helps with plant maturation and withstanding stress. It encourages blooming and root growth. Potassium protects plants against diseases, helps in photosynthesis, and maintains fruit quality. A soil probe takes samples for nutrient analysis Crops can use up nutrients in the soil, so farmers and gardeners use fertilizers to add back the nutrients necessary to produce healthy plants and maximize yields. We can test the soil to determine how much of each nutrient to apply. Available nitrogen (N) Available potash (K 2 O) Available phosphate (P 2 O 5 ) All fertilizer labels have three bold numbers. The first number is the amount of nitrogen (N), the second number is the amount of phosphate (P 2 O 5 ) and the third number is the amount of potash (K 2 O). These three numbers represent the primary nutrients (nitrogen(n) - phosphorus(p) - potassium(k)). A bag of fertilizer contains 10 percent nitrogen, 10 percent phosphate and 10 percent potash. (70% filler) 6

7 Water The Most Common Material on Earth Condensation Precipitation Surface Runoff Percolation Lake Stream Flow Groundwater Flow THE WATER CYCLE Transpiration Evaporation Ocean Water, water everywhere and just a drop to drink Remember that about 70% of the earth is covered by oceans. Let s pretend that a gallon of water represents all the water on earth. Transfer the following to a small glass: 5 1/2 Tablespoons to show the amount of water held in icecaps and glaciers 1 1/2 Tablespoons to represent the water held as groundwater About 1/10 Tablespoon (maybe 8 drops) to represent all the rest of the freshwater held as surface water in lakes, streams, and rivers, as well as in the atmosphere The amount of water in the glass represents the total amount of freshwater in the world (and 3/4 of that is frozen in glaciers and icecaps). The amount left in the gallon jar is ocean (salt) water. Fortunately only pure water evaporates from the ocean to fall back to land as freshwater. The water cycle is the circulation of the earth s water in a neverending process. The heat from the sun causes (1) water from the ocean, streams, lakes, and even plants to evaporate. As the water vapor rises, it is cooled by the upper air. Cold air cannot hold as much water vapor as warm air so (2) water vapor condenses into water droplets and creates clouds. The wind carries clouds over the land and (3) water falls back to earth as precipitation. Water is Life! All living things (plants, animals, humans) must have water to survive. The amount of water on earth stays the same. It is never used up, but continues to move through the water cycle. However, the water in a specific location can change in amount or form, sometimes we have a drought and sometimes we have extra snow or rain. A growing human population puts pressure on available water. Condensation: The process of water vapor in the air turning into liquid. As water vapor rises it cools and becomes liquid again. These droplets form around dust particles in the air and become clouds. Evaporation: Changing from a liquid or solid state to a vapor or gas. Only pure water evaporates. Substances like salt and minerals are left behind when water evaporates. Groundwater: Water which has seeped below the earth s surface and is held there in the underlying sand and gravel. Water bearing layers are called aquifers. In Washington, 2/3 of the people get their drinking water from aquifers. Percolation: The movement of water into soil through pores, holes and cracks. Precipitation: Rain, snow, hail, sleet, dew, and frost. Transpiration: Water that is absorbed by plants, usually through the roots, is evaporated into the atmosphere from the plant surface through leaf pores.

8 Washington Agriculture Ta s t y Le g u m e s Dry peas, lentils, and garbanzo beans (chick peas) are legume crops grown in Eastern Washington that are tasty additions to our diets; rich in protein, fiber, vitamins and minerals. Legumes are fascinating plants that have the ability to take nitrogen from the air and convert it into ammonia, a nitrogen compound that plants can use as fertilizer. Actually it is not the plant that performs this amazing trick, but special soil bacteria that invade the tiny root hairs of legumes. The roots form swellings called nodules where the bacteria colonies thirve. This partnership between the legume plant and the bacteria is helpful to both (symbiotic). The plant furnishes the energy (plant sugars) to the bacteria to live, and the bacteria furnish ammonia for the plant to use as food. Nodules of bacteria on legume roots Because of this symbiotic relationship, legumes do not need the amounts of nitrogen fertilizer that grain crops do. Also, there is nitrogen remaining in the soil after legumes are harvested, so that nitrogen requirements for the next non-legume crop are not as large. Sometimes legumes are raised as green manure meaning that the whole crop is tilled into the soil to enrich the soil with nutrients and organic matter. 9 Across Ecosystems Depend on Soil Product to replace plant nutrients 3. Rotting organic matter 5. Rocks are broken to particles 9. Wiggly soil dwellers 10. It s not dirt Down 1. Fertile WA-ID region 4. The largest soil particle 6. Process that picks up and moves soil 7. Most productive earth layer 8. The smallest soil particle 10 8 Lentils ready for harvest Na t i o n a l Ar b o r Da y Ap r i l 29, 2011 The best time to plant a tree was 20 years ago. The next best time is now. ~Chinese Proverb Ca r e e r Hi g h l i g h t Name: Cal Barta Career: Crop Production Specialist Education: BS in Agronomy* Job description: Advise farmers on seed and application of fertilizers and pesticides, based on soil samples and appraisal of weed and insect populations. Skills: Knowledge of soils, crops, weeds, insects, cropping systems, fertilizer and chemical products. Ability to work with people as an advisor. Enjoy working outdoors with farmers, watching crops grow and develop. *Agronomy is the application of soil and plant sciences to soil management and crop production Sk a g i t Valley Tu l i p Fe s t i v a l April 1 - April 30 is the 28th annual Skagit Valley Tulip Festival. Washington is known for beautiful fields of tulips and daffodils. The bulbs are harvested for sale after blooming.