A Step by Step Guide

Transcription

1 Soil Characterization Protocols Table of Contents Soil Characterization Protocols: Field Analysis A Step by Step Guide Introduction We Study Soil Because It's A... Soil Forming Factors Soil Characterization Characterization and Sampling Options Instruments for Field Analysis Instruments for digging the pit or hole and conducting initial horizon identification Instruments for conducting Bulk Density and field protocols Instruments for recording data about soil profile Preparing for the field Finding and Describing Horizons Soil Pit Technique Exposed Profile (Road Cut) Technique Auger Technique Surface Sample Technique (1 of 5) [17/10/ :41:27 a.m.]

2 Soil Characterization Protocols Table of Contents Horizon Properties Soil Structure Soil Color Munsell Notation Hue Value Chroma Soil Consistence Soil Texture part 1 Soil Texture part 2 Soil Texture part 3 Soil Texture part 4 Presence of Roots and Rocks Test for Free Carbonates Soil Sampling Taking Bulk Density Samples Using the Soil Pit or Other Exposed Soil Profile Taking Bulk Density Samples Using the Soil Pit or Other Exposed Soil Profile, part 2 Taking Bulk Density Samples Using the Auger Method Taking Bulk Density Samples Using the Auger Method, part 2 (2 of 5) [17/10/ :41:27 a.m.]

3 Soil Characterization Protocols Table of Contents Taking Bulk Density Samples Using the Surface Sample Method If You Are Not Taking Bulk Density Samples and Using the Soil Pit or Other Exposed Road Cut Profile If You Are Not Taking Bulk Density Samples and Using the Auger Method If You Are Not Taking Bulk Density Samples and Using the Surface Sample Method Final Analysis Conclusion When You Are Finished Sampling Laboratory Analysis Characterization Laboratory Analysis Introduction Instruments for Laboratory Analysis Drying and Sieving Testing for Bulk Density Testing for Particle-Size Distribution Testing for ph Testing for Soil Fertility Laboratory Analysis Measuring Bulk Density and Preparing Samples for Other Lab Analyses Determining the Volume of Any Rocks That Are in a Sample (3 of 5) [17/10/ :41:27 a.m.]

4 Soil Characterization Protocols Table of Contents Preparing Samples for Other Lab Analyses (If You Are Not Measuring Bulk Density) Particle-Size Distribution, part 1 Particle-Size Distribution, part 2 Particle-Size Distribution, part 3 Particle-Size Distribution, part 4 Particle-Size Distribution, part 5 Particle-Size Distribution, part 6 Particle-Size Distribution, part 7 Making Sense of the Particle-Size Distribution Measurements, part 1 Making Sense of the Particle-Size Distribution Measurements, part 2 ph Measurements Soil Fertility: Preparation and Extraction Soil Fertility: Nitrate Nitrogen (N) Soil Fertility: Phosphorus (P) Soil Fertility: Potassium (K) Soil Particle Density: Introduction Soil Particle Density: Introduction part 2 Soil Particle Density: Introduction and comparision between bulk density and particle density Soil Particle Density, part 1 (4 of 5) [17/10/ :41:27 a.m.]

5 Soil Characterization Protocols Table of Contents Soil Particle Density, part 2 Soil Particle Density, part 3 If you wish to download PowerPoint presentations of this guide, please go to the GLOBE Soil Characterization Protocols Step by Step Guide PowerPoint Presentations. Back to Soil Science Education Home Page Webmaster: Izolda Trakhtenberg, izolda@ltpmail.gsfc.nasa.gov Information Contact: Izolda Trakhtenberg, izolda@ltpmail.gsfc.nasa.gov Responsible Civil Servant: Dr. Elissa Levine, globe@ltpmail.gsfc.nasa.gov Last Updated: April 2, (5 of 5) [17/10/ :41:27 a.m.]

6 Why We Study Soil... We Study Soil Because It's A(n) Medium of crop production Great integrator Filter of water and wastes Producer and absorber of gases Home to organisms (plants, animals and others) Medium for plant growth Source material for construction, medicine, art, etc. Snapshot of geologic, climatic, biological, and human history Essential natural resource Waste decomposer [17/10/ :41:37 a.m.]

7 Soil Forming Factors Soil Forming Factors Biota Climate Parent Material Topography (The first four factors over) Time These five factors work together to create a unique soil profile made of layers called horizons. For GLOBE Soil Characterization, we will describe, sample and analyze the soils from horizons of different soil profiles. [17/10/ :41:53 a.m.]

8 Soil Characterization Soil Characterization Following this protocol, you and your students will: expose the top 1 meter of soil describe the exposed soil profile take samples of each soil horizon prepare soil samples for lab analyses analyze the soil samples in the lab review the data to understand your soil better submit the data to GLOBE Sample at least two sites 1. near the Soil Moisture study site 2. within the Biology study site Field measurements are done once at each site Three replicate samples from each horizon are taken and reported one time for each site. (1 of 2) [17/10/ :42:10 a.m.]

9 Soil Characterization (2 of 2) [17/10/ :42:10 a.m.]

10 Characterization and Sampling Options Characterization and Sampling Options Soil Pit Dig a soil pit at least 1 meter deep and as big around as is necessary to easily observe all of the soil horizons from the bottom to the top of the pit. Exposed Profile (road cut) Use a road cut, excavation site, or other location where the top 1 meter of soil has been exposed. Auger Use an auger to remove soil samples to a depth of 1 meter. Surface Sample Use a garden trowel or shovel to sample only the top 10 cm of soil, if digging to a depth of 1 meter is not possible. (1 of 2) [17/10/ :42:25 a.m.]

11 Characterization and Sampling Options (2 of 2) [17/10/ :42:25 a.m.]

12 Instruments for Field Analysis Instruments for Field Analysis: Digging pit or hole Shovel or Auger Trowels Laying out profile Plastic Tarp or Trash Bag Marking horizons Nails, Golf Tees, or other tool for marking horizon boundary marker Measuring depth of profile Meter Stick Moistening profile face Squirt bottles General use (1 of 2) [17/10/ :42:36 a.m.]

13 Instruments for Field Analysis Paper Towels (2 of 2) [17/10/ :42:36 a.m.]

14 Instruments for Field Analysis Instruments for Field Analysis: Instruments for conducting Bulk Density and field protocols Soil sampling for lab protocols 4 Liter (1 Gallon) size Ziplock Bags or Containers Bulk Density Sampling Cans Wood Block and Hammer Soil color Soil Color Book Free Carbonate test Vinegar in acid bottle Study site slope (1 of 2) [17/10/ :42:54 a.m.]

15 Instruments for Field Analysis Clinometer (You may use the clinometer that you made for the Land cover/biology protocol.) (2 of 2) [17/10/ :42:54 a.m.]

16 Instruments for Field Analysis Instruments for Field Analysis: Instruments for recording data about soil profile Field protocol information Soil Characterization Information Sheet Data recording Soil Characterization and Bulk Density Data Entry Sheets Water Proof Marker and Pencils Soil Profile photograph Camera [17/10/ :43:31 a.m.]

17 Preparing for the Field Preparing for the Field 1. Fill acid bottle with vinegar 2. Fill squirt bottles with water 3. Make a clinometer (see Land Cover/Biology Protocol) 4. Collect bulk density containers For Pit, Exposed Profile, and Surface Sample Method a. find can weight b. find can volume by filling the can with water, pouring the water into a graduated cylinder, and reading the amount in ml. c. label cans d. hammer hole in bottom For Auger Method a. label the containers (1 of 2) [17/10/ :43:44 a.m.]

18 Preparing for the Field (2 of 2) [17/10/ :43:44 a.m.]

19 Soil Pit Technique Finding and Describing Horizons Soil Pit Technique First, obtain permission to dig a pit. Obey any and all safety precautions requested, and ask about power and water lines Starting from top, observe profile to determine properties and differences between horizons. Place golf tee or marker at the top and bottom of each horizon to clearly identify it. Look for: different colors, shapes, roots, the size and amount of stones, small dark nodules (called concretions), worms, or other small animals and insects, worm channels, and anything else that is noticeable. (1 of 3) [17/10/ :44:14 a.m.]

20 Soil Pit Technique Arid climate soil in New Mexico, USA (2 of 3) [17/10/ :44:14 a.m.]

21 Soil Pit Technique Forest soil in Florida, USA (3 of 3) [17/10/ :44:14 a.m.]

22 Exposed Profile (Road Cut) Technique Finding and Describing Horizons Exposed Profile (Road Cut) Technique First, obtain permission to take samples from the road cut, excavation, or other soil profile exposed by others. Obey any and all safety precautions requested. Ask about power and water lines. Expose a fresh soil face. Follow Soil Pit Technique directions. [17/10/ :44:31 a.m.]

23 Auger Technique Finding and Describing Horizons Auger Technique 1. Identify an area where you can dig four holes where the soil profiles should be similar. 2. Spread a plastic bag, tarp, board, or other surface on the ground next to where you will dig your first hole. 3. Assemble a profile of the top 1 meter of the soil by removing successive samples with the auger and laying them end-to-end as follows: (1 of 2) [17/10/ :44:39 a.m.]

24 Auger Technique 4. Identify each horizon and measure its thickness using the depth of the auger hole. (2 of 2) [17/10/ :44:39 a.m.]

25 Surface Sample Technique Finding and Describing Horizons Surface Sample Technique In situations where it is not possible to expose the top meter of soil, another option is to use the top 10 cm of soil as a horizon sample for soil characterization. 1. Use a garden trowel or shovel to carefully remove the top 10 cm of soil from a small area and set it on the ground. 2. Treat this sample as a horizon and proceed to characterize its properties. (1 of 2) [17/10/ :44:54 a.m.]

26 Surface Sample Technique (2 of 2) [17/10/ :44:54 a.m.]

27 Soil Structure Horizon Properties Soil Structure Soil structure is the shape that the soil takes based on its physical and chemical properties. Each individual unit of soil structure is called a ped. Take a sample of undisturbed soil in your hand (either from the pit or from the shovel or auger). Look closely at the soil in your hand and examine its structure. Possible choices of soil structure are: Granular: Resembles cookie crumbs and is usually less than 0.5 cm in diameter. Commonly found in surface horizons where roots have been growing. Blocky: Irregular blocks that are usually cm in diameter. Prismatic: Vertical columns of soil that might be a number of cm long. Usually found in lower horizons. Columnar: Vertical columns of soil that have a salt "cap" at the top. Found in soils of arid climates Platy: Thin, flat plates of soil that lie horizontally. Usually found in compacted soil. Single Grained: Soil is broken into individual particles that do not stick together. Always accompanies a loose consistence. Commonly found in sandy soils. (1 of 3) [17/10/ :45:47 a.m.]

28 Soil Structure Massive: Soil has no visible structure, is hard to break apart and appears in very large clods. If you wish download the protocol above so that you can use it in the field, here are pict files soil texture page 2. Below are some images of the different soil structures. With Structure: Granular Blocky Prismatic Columnar Platy Structureless: (2 of 3) [17/10/ :45:47 a.m.]

29 Soil Structure Single grained Massive (3 of 3) [17/10/ :45:47 a.m.]

30 Soil Color Horizon Properties Soil Color 1. Take a ped of soil from each horizon and note on the data sheet whether it is moist, dry or wet. If it is dry, moisten it slightly with water from your water bottle. 2. Break the ped 3. Stand with the sun over your shoulder so that sunlight shines on the color chart and the soil sample you are examining. Note: Sometimes, a soil sample may have more than one color. Record a maximum of two colors if necessary, and indicate (1) the Main (dominant color) and (2) the Other (1 of 2) [17/10/ :46:05 a.m.]

31 Soil Color (sub-dominant color). If you wish download the protocol above so that you can use it in the field, here are pict files soil texture page 2. (2 of 2) [17/10/ :46:05 a.m.]

32 Munsell Notation Horizon Properties Soil Color (continued) Munsell Notation The Munsell code below each color in the GLOBE color chart is a universal notation that describes the soils' color. [17/10/ :46:17 a.m.]

33 Munsell Notation: Hue Horizon Properties Soil Color (continued) Munsell Notation The Munsell code below each color in the GLOBE color chart is a universal notation that describes the soils' color. Hue The first set of number and letter symbols represents the hue. Hue represents the position of the color on the color wheel (Y=Yellow, R=Red, G=Green, B=Blue, YR=Yellow Red, RY=Red Yellow). Back to Munsell Notation [17/10/ :46:30 a.m.]

34 Munsell Notation: Value Horizon Properties Soil Color (continued) Munsell Notation The Munsell code below each color in the GLOBE color chart is a universal notation that describes the soils' color. Value The number before the slash is the Value. Value indicates the lightness of a color. The scale of value ranges from 0 for pure black to 10 for pure white. Back to Munsell Notation [17/10/ :46:33 a.m.]

35 Munsell Notation: Chroma Horizon Properties Soil Color (continued) Munsell Notation The Munsell code below each color in the GLOBE color chart is a universal notation that describes the soils' color. Chroma The number after the slash is the Chroma. Chroma describes how the ÒintensityÓ of a color. Colors of low chroma values are sometimes called weak, while those of high chroma are said to be highly saturated, strong, or vivid. the scale starts at zero, for neutral colors, but there is no arbitrary end to the scale. Back to Munsell Notation [17/10/ :46:37 a.m.]

36 Soil Consistence Horizon Properties Soil Consistence Take a ped from the top soil horizon. If the soil is very dry, moisten the face of the profile using a water bottle with a squirt top and then remove a ped to determine consistence. (Repeat this procedure for each horizon in your profile.) Holding it between your thumb and forefinger, gently squeeze the ped until it pops or falls apart. Record one of the following categories of soil consistence on the data sheet. Loose You have trouble picking out a single ped and the structure falls apart before you handle it.* * Soils with "single grained" structure always have loose consistence. Friable The ped breaks with a small amount of pressure. (1 of 2) [17/10/ :46:53 a.m.]

37 Soil Consistence Firm The ped breaks when you apply a good amount of pressure and dents your fingers before it breaks. Extremely Firm The ped can't be crushed with your fingers (you need a hammer!). If you wish download the protocol above so that you can use it in the field, here are pict files soil texture page 2. (2 of 2) [17/10/ :46:53 a.m.]

38 Soil Texture Horizon Properties Soil Texture The way a soil "feels" is called the soil texture. Soil texture depends on the amount of each size of particle in the soil. Sand, silt, and clay are names that describe the size of individual particles in the soil. Sand are the largest particles and they feel "gritty." Silt are medium sized, and they feel soft, silky or "floury." Clay are the smallest sized particles, and they feel "sticky" and they are hard to squeeze. Relative Size Comparison of Soil Particles Barrel Coin Sand Plate Silt (feels floury) ( mm, USDA) ( mm, ISSS) Clay (feels sticky) (< mm, USDA) (< mm, ISSS) (1 of 2) [17/10/ :47:26 a.m.]

39 Soil Texture (feels gritty) ( mm, USDA) ( mm, ISSS) (2 of 2) [17/10/ :47:26 a.m.]

40 Soil Texture (continued) Horizon Properties Soil Texture (continued) Step 1 (Get and moisten sample) Use the triangle to determine the soil texture of your horizon. To Determine Soil Texture Place some soil from a horizon (about the size of a small egg) in your hand, and, using the spray mist bottle, moisten the soil. Let the water soak in and then work the soil between your fingers until it is the same moisture throughout. Once the soil is moist, try to form a ball. If the soil forms a ball, go on to Step 2. If the soil does not form a ball, go to Step 5. Step 2 (Test for Clay) A. If the soil: Is really sticky Hard to squeeze Stains your hands Has a shine when rubbed Forms a long ribbon (5+ cm) without breaking, Call it a clay and go to Step 3. Otherwise, go to B. B. If the soil: Is somewhat sticky Is somewhat hard to squeeze Forms a medium ribbon (between 2-5 cm) Call it a clay loam and go to Step 3. Otherwise, go to C. C. If the soil is: Soft Smooth Easy to squeeze, At most slightly sticky, Forms a short ribbon (less than 2 cm) Call it a loam and go to Step 3. Otherwise, go to D. D. If the soil forms a ball but no ribbon, go to Step 4. If you wish download the protocol above so that you can use it in the field, here are pict files soil texture page 2. (1 of 2) [17/10/ :47:38 a.m.]

41 Soil Texture (continued) (2 of 2) [17/10/ :47:38 a.m.]

42 Soil Texture (continued) Horizon Properties Soil Texture (continued) To Determine Soil Texture Step 3 (Refine initial soil texture classification from Step 2 for relative amounts of sand and silt) Wet a small pinch of the soil in your palm and rub it with a forefinger. If the soil: Feels very gritty, go to E Feels very smooth, with no grittyfeeling, go to F Feels only a little gritty, go to G E. Add the word sandy to the initial classification. Soil texture is (check one): sandy clay, sandy clay loam, sandy loam F. Add the word silt or silty to the initial classification. Soil texture is (check one): silty clay, silty clay loam, silt loam Soil Texture is complete. Soil Texture is complete. G. Leave the original classification of (check one): clay, clay loam, loam (1 of 2) [17/10/ :47:47 a.m.]

43 Soil Texture (continued) Soil Texture is complete. Soil Texture is complete. If you wish download the protocol above so that you can use it in the field, here are pict files soil texture page 2. (2 of 2) [17/10/ :47:47 a.m.]

44 Soil Texture (continued) Horizon Properties Soil Texture (continued) To Determine Soil Texture Step 4 (Test for loamy sand or silt) If the soil: Forms a ball Forms no ribbon And is H. Very gritty Soil texture is: loamy sand Step 5 (Test for sand) If the soil: Forms no ball and falls apart in your hand, Soil texture is: sand Soil Texture is complete. Or I. Very soft and smooth with no gritty feeling, Soil texture is: silt Soil Texture is complete. Soil Texture is complete. If you wish download the protocol above so that you can use it in the field, here are pict files soil texture page 2. [17/10/ :48:18 a.m.]

45 Presence of Roots and Rocks Horizon Properties Presence of Roots and Rocks Presence of Roots Observe and record if there are none, few, or many roots in the horizon. Presence of Rocks Observe and record if there are none, few, or many rocks* in the horizon. * A rock is defined as being larger than 2 mm in size. [17/10/ :48:46 a.m.]

46 Test For Free Carbonates Horizon Properties Test For Free Carbonates Free carbonates are compounds that coat soil particles. They form under certain conditions such as in dry climates where the ph is above 7. They are also found in some soil profiles that have parent materials made of carbonates (such as limestone). This test is performed by squirting vinegar on the soil. If free carbonates are present, they will "effervesce" or bubble when the vinegar reacts with them. Record one of the following based on your observation: (1 of 2) [17/10/ :48:55 a.m.]

47 Test For Free Carbonates None: you observe no reaction (the soil has no free carbonates). Slight: you observe a slight amount of bubbling (the soil is coated with some carbonates). Strong: you observe a strong reaction (many bubbles) (the soil has many carbonate coatings present). (2 of 2) [17/10/ :48:55 a.m.]

48 Soil Sampling Taking Bulk Density Samples If you are using a Soil Pit or other Exposed Soil Profile (road cut) 1. For each horizon in your soil profile, push a can with a known volume into the side of the horizon. If necessary, wet the soil first so that the can will go in easily. Stop when you can see some of the soil poking through the small hole in the bottom of the can. (Remember, you will collect three samples from each horizon in your profile.) 2. If it is still difficult to push the can into the soil, you may need to place a piece of wood over the can and hit the wood with the hammer to spread the force of the hammer blow to all edges of the can at once and to minimize denting the can. Note: Some denting is allowed in the procedure, but if the can dents too badly, consider taking a bulk density sample using the auger method for dense, hard, or rocky horizons. (1 of 2) [17/10/ :49:07 a.m.]

49 (2 of 2) [17/10/ :49:07 a.m.]

50 Soil Sampling Taking Bulk Density Samples If you are using a Soil Pit or other Exposed Soil Profile (road cut) 3. Using a trowel or shovel, remove the can and the soil surrounding it. Trim the soil from around the can until it is flat against the edges of the can so that the volume of the soil is the same as the volume of the can. 4. Cover the labeled can with the lid or other cover and return it to the classroom. 5. Repeat this procedure so that you have three bulk density samples for each horizon. (1 of 2) [17/10/ :49:26 a.m.]

51 6. Weigh each sample in its can and record this moist weight on the Bulk Density Data Work Sheet. 7. Remove the covers. Place the samples in the soil drying oven until the soils are dry. (2 of 2) [17/10/ :49:26 a.m.]

52 Soil Sampling Taking Bulk Density Samples If you are using the Auger Method 1. Auger to a depth of 1 or 2 cm past the top of the horizon to be sampled.* * Use the depths from the first soil profile you withdrew with the auger as a guide. 2. Use the auger to remove a sample of the horizon. If the horizon is thinner than the length of the auger head, partially turn the auger so that the whole sample will be from one horizon. Do not turn the auger more than one complete circle (360 ) so that the soil does not become compacted. (1 of 2) [17/10/ :49:58 a.m.]

53 3. Measure the diameter of the hole the auger made. 4. Measure the depth of the hole the auger made. (2 of 2) [17/10/ :49:58 a.m.]

54 Soil Sampling Taking Bulk Density Samples If you are using the Auger Method 5. Once the sample is removed, transfer all the soil from the auger head into a sample container without losing any on the ground. 6. Repeat steps 1-5 for each horizon in the soil profile, for a total of three profiles. 7. Cover or seal the samples in labeled containers and transport them to the classroom. (1 of 2) [17/10/ :50:01 a.m.]

55 8. Weigh each sample in its can and record this moist weight on the Bulk Density Data Work Sheet. 9. Place the samples in the soil drying oven (be sure the covers are removed) until the samples are dry. (2 of 2) [17/10/ :50:01 a.m.]

56 Soil Sampling Taking Bulk Density Samples If you are using the Surface Sample 1. Choose three locations close to where you performed your soil characterization protocol and remove vegetation and other material from the soil surface. 2. At each location, push a can with a known volume into the surface of the soil. If necessary, wet the soil so that the can will go in easily. Stop when you can see some soil poking through the small hole in the bottom of the can. 3. If it is difficult to push the can into the soil, place a piece of wood over the can and hit the wood with the hammer to spread the force of the hammer blow to all edges of the can at once. (1 of 2) [17/10/ :50:22 a.m.]

57 (2 of 2) [17/10/ :50:22 a.m.]

58 Soil Sampling If You Are Not Taking Bulk Density Samples If you are using a Soil Pit or other Exposed Soil Profile (road cut) 1. Dig a large sample from each soil horizon. Avoid the area of the soil face that was tested for carbonates and avoid touching the soil samples so that you ph measurements will not be contaminated. 2. Place each sample in a bag or other soil container. 3. Label each bag with the site name, horizon name, and top and bottom depths. (1 of 2) [17/10/ :51:47 a.m.]

59 4. Bring these samples in from the field. 5. Spread the samples on separate plastic plates or sheets of newspaper to dry in the air. (2 of 2) [17/10/ :51:47 a.m.]

60 Soil Sampling If You Are Not Taking Bulk Density Samples If you are using the Auger Technique 1. Auger to a depth of 1 or 2 cm past the top of the horizon to be sampled. If the horizon is thinner than the length of the auger head, partially turn the auger so that the whole sample will be from one horizon. 2. Place the sample in a labeled bag or other soil conainer. Avoid touching the sample and contaminating it. (1 of 2) [17/10/ :51:50 a.m.]

61 4. Bring these samples in from the field, and spread them on separate plastic plates or sheets of newspaper to dry in the air. (2 of 2) [17/10/ :51:50 a.m.]

62 Soil Sampling If You Are Not Taking Bulk Density Samples If you are using the Surface Sample Method 1. Dig three large samples from the soil surface. Avoid the area of the soil face that was tested for carbonates and avoid touching the soil samples so that you ph measurements will not be contaminated. 2. Place each sample in a bag or other soil container. (1 of 2) [17/10/ :52:06 a.m.]

63 3. Label each bag with the site name and top and bottom depths. 4. Bring these samples in from the field, and spread them on separate plastic plates or sheets of newspaper to dry in the air. (2 of 2) [17/10/ :52:06 a.m.]

64 Field Analysis Conclusion When You Are Finished Sampling 1. Photograph the face of the pit, or the soil profile you have removed and placed on the ground with the auger. Place a tape measure along the profile (in the pit or next to the auger sample profile you created) so that 0 cm is at the top of the profile to record horizon depths for the picture. Take another photograph of the landscape outside the pit or around the auger hole. Send these photographs to: the GLOBE Student Data Archive at the address given in the TeacherÕs Guide, or if they were taken with a digital camera, submit them to the GLOBE Student Data Archive electronically. [17/10/ :52:48 a.m.]

65 Characterization Laboratory Analysis Characterization Laboratory Analysis You will perform four sets of measurements in the laboratory on the samples you collected in the field: Bulk Density Particle Size Distribution ph Soil Fertility (1 of 2) [17/10/ :53:16 a.m.]

66 Characterization Laboratory Analysis These observations will help the GLOBE Scientists understand more about the properties of soil. (2 of 2) [17/10/ :53:16 a.m.]

67 Instruments for Laboratory Analysis: Drying and Sieving Instruments for Laboratory Analysis: Drying and Sieving Newspapers or plastic plates #10 Sieve (2 mm mesh openings) Liter-sized bags, jars, or containers for storing soil samples and extra soil Rubber gloves Drying oven or microwave (not shown) Rolling pin, hammer, or other utensil for crushing peds and separating particles [17/10/ :53:22 a.m.]

68 Instruments for Laboratory Analysis: Bulk Density Instruments for Laboratory Analysis: Testing for Bulk Density Oven-dry soil in a sampling can for which the mass and volume are known Balance 100 ml graduated cylinder and water (not distilled) to determine the volume of rocks Soil Bulk Density Data Work Sheet [17/10/ :53:30 a.m.]

69 Instruments for Laboratory Analysis: Particle Size Distribution Instruments for Laboratory Analysis: Testing for Particle Size Distribution Dry, sieved soil One 500 ml Graduated Cylinder (clear plastic) 250 ml or larger, beaker Squirt bottle for washing soil out of beaker Hydrometer Thermometer Plastic Wrap (or other cover for cylinder) Particle-Size Distribution Data Work Sheet [17/10/ :53:39 a.m.]

70 Instruments for Lab Analysis: ph Instruments for Laboratory Analysis: Testing for ph Dry, sieved soil Three 100 ml Beakers Balance ph paper, pen or Meter Glass stirrers or spoon Distilled Water 100 ml Graduated Cylinder Soil ph Data Work Sheet [17/10/ :53:46 a.m.]

71 Instruments for Laboratory Analysis: Testing for Soil Fertility Instruments for Laboratory Analysis: Testing for Soil Fertility Dry, sieved soil Distilled water Teaspoon Cup or test tube rack to hold tubes Soil Fertility Data Work Sheet Soil Fertility Kit with reagents to measure N, P, and K [17/10/ :53:59 a.m.]

72 Measuring Bulk Density Laboratory Analysis Measuring Bulk Density and Preparing Samples for Other Lab Analyses (Skip this part if you are not measuring bulk density.) 1. Weigh each dry bulk density sample in its container and record this dry weight on the Bulk Density Data Work Sheet. 2. Place a sieve (#10, 2 mm mesh) on a large piece of paper (such as newspaper) and pour one sample into the sieve. Put on rubber gloves to avoid contaminating your sample with acids from your skin. (1 of 2) [17/10/ :54:11 a.m.]

73 Measuring Bulk Density 3. Carefully push the dried soil material through the mesh onto the paper. Be careful not to bend the wire mesh by forcing the soil through. Rocks will stay on top of the sieve. (If no sieve is available, carefully remove the rocks by hand.) Save the sieved soil from each sample for the other lab analyses. If rocks are present, use the following procedure to determine the volume of the rocks. (2 of 2) [17/10/ :54:11 a.m.]

74 Measuring Bulk Density Laboratory Analysis Measuring Bulk Density and Preparing Samples for Other Lab Analyses (Skip this part if you are not measuring bulk density.) 1. Weigh the rocks that are left on top of the sieve and record this weight on the Bulk Density Data Work Sheet. 2. Place 30 ml of water in a 100 ml graduated cylinder, and without spilling, add the rocks to the water. Read the level of the water after all the rocks have been added and record this value and the original volume of water on the Bulk Density Data Work Sheet. (1 of 2) [17/10/ :54:19 a.m.]

75 Measuring Bulk Density Without Rocks With Rocks Note: As you add the rocks, if the volume of the water comes close to 100 ml, record the increase in volume, empty the cylinder and repeat the procedure for the remaining rocks. In this case, you must record the sum of the water volumes with the rocks and the sum of the water volumes without the rocks. (2 of 2) [17/10/ :54:19 a.m.]

76 Preparing Samples for Lab Analysis Laboratory Analysis Preparing Samples for Other Lab Analyses (If you are not measuring bulk density.) 1. Put the #10 sieve (2 mm openings) on a large piece of paper and pour one sample into the sieve. Put on rubber gloves so the acids in your skin don't contaminate the soil ph measurement. 2. Carefully push the dried soil material through the mesh onto the paper. Be careful not to bend the wire mesh by forcing the soil through. Remove the rocks (and other pieces of debris) that stay on top of the sieve and discard. Save the sieved soil from each sample for the other lab analyses. (1 of 3) [17/10/ :54:27 a.m.]

77 Preparing Samples for Lab Analysis Note: If no sieve is available, carefully remove the rocks by hand. 3. Transfer the rock-free, dry soil from the paper under the sieve into new, clean, dry plastic bags or containers. Seal the containers, and label them the same way that they were labeled in the field (horizon number, top and bottom depth, date, site name, site location, etc.). This is the soil that will be used for the other lab analyses. On the label, include: Site name, Sample number, Horizon number, Top depth, Bottom depth, Date (2 of 3) [17/10/ :54:27 a.m.]

78 Preparing Samples for Lab Analysis 4. Store these samples in a safe, dry place until they are used. (3 of 3) [17/10/ :54:27 a.m.]

79 Soil Particle Size Distribution Laboratory Analysis Particle-Size Distribution 1. Prepare the dispersing solution by mixing 50 g of Sodium Hexametaphosphate (or other soil dispersing agent) in 1 L of distilled water. Stir or shake until the dispersing agent has all dissolved. 2. Weigh 25 g of dried, sieved soil and pour it into a 250 ml or larger beaker. Add 100 ml of the dispersing solution and about 50 ml of distilled water to the beaker. Stir vigorously with a spoon or sitrring rod for at least one minute. Be sure the soil is thoroughly mixed and does not stick to the bottom of the beaker. Do not let any of the soil suspension spill out the top. (1 of 3) [17/10/ :54:44 a.m.]

80 Soil Particle Size Distribution (2 of 3) [17/10/ :54:44 a.m.]

81 Soil Particle Size Distribution (3 of 3) [17/10/ :54:44 a.m.]

82 Soil Particle Size Distribution Laboratory Analysis Particle-Size Distribution 3. When the soil and dispersing solution are thoroughly mixed, set the beaker aside in a safe place and allow it to sit for roughly 24 hours (for this step, the soil/dispersing solution mixture can sit over the weekend until the next class). 4. Measure the distance between the 500 ml mark and the base of the cylinder. (You can place the measuring stick inside the cylinder to get this measurement.). (1 of 2) [17/10/ :54:57 a.m.]

83 Soil Particle Size Distribution 5. Read the temperature at which your hydrometer has been calibrated (such as 15.6 C [60 F] or 20 C) which is found on the body of the hydrometer. Record both the distance and the temperature on the Particle-Size Distribution Data Work Sheet. (2 of 2) [17/10/ :54:57 a.m.]

84 Soil Particle Size Distribution Laboratory Analysis Particle-Size Distribution (continued) 6. At the next class, stir the suspension in the beaker again, and pour it into a 500 ml graduated cylinder. Use a squirt bottle to rinse out the beaker and add this to the soil mixture in the cylinder. (1 of 3) [17/10/ :55:12 a.m.]

85 Soil Particle Size Distribution 7. Add enough water to fill the cylinder to the 500 ml mark. 8. Securely cover the top of the cylinder using plastic wrap or other secure cover. 9. Mix vigorously by rotating the covered cylinder hand-over-hand at least 10 times. Be sure the soil is thoroughly mixed in the solution and does not stick to the bottom of the cylinder. Try not to let any of the suspension leak out the top. (2 of 3) [17/10/ :55:12 a.m.]

86 Soil Particle Size Distribution (3 of 3) [17/10/ :55:12 a.m.]

87 Soil Particle Size Distribution Laboratory Analysis Particle-Size Distribution (continued) 10. Gently set the cylinder down in a safe place, and immediately begin timing with a stop watch or clock with a second hand. 11. After 1 minute, carefully lower the hydrometer into the cylinder so it floats in the suspension. Steady the hydrometer to keep it from bobbing up and down. (Sample starting time) (1 of 2) [17/10/ :55:29 a.m.]

88 Soil Particle Size Distribution 12. At exactly 2 minutes after the cylinder was set down, read the line on the hydrometer that is closest to the surface of the soil suspension and record your result on the Particle-Size Distribution Data Work Sheet. 13. Remove the hydrometer, rinse it, dry it, and gently put it down in a safe place. (2 of 2) [17/10/ :55:29 a.m.]

89 Soil Particle Size Distribution Laboratory Analysis Particle-Size Distribution (continued) [17/10/ :55:38 a.m.]

90 Soil Particle Size Distribution Laboratory Analysis Particle-Size Distribution (continued) 14. Place the thermometer into the soil suspension for about 1 minute. At the end of 1 minute, remove the thermometer from the suspension, read the temperature, and record the result on the Particle-Size Distribution Data Work Sheet. 15. Take another hydrometer reading in the undisturbed cylinder at 12 minutes. Place the hydrometer carefully in the suspension about 30 seconds before making the reading to allow it to settle. (1 of 2) [17/10/ :55:45 a.m.]

91 Soil Particle Size Distribution 16. Take and record another temperature reading for the suspension. 17. Rinse the hydrometer and thermometer off when they have been removed from the suspension and dry them. 18. Record these results on the Particle-Size Distribution Data Work Sheet. (2 of 2) [17/10/ :55:45 a.m.]

92 Soil Particle Size Distribution Laboratory Analysis Particle-Size Distribution (continued) 19. Leave the cylinder undisturbed for 24 hours (or until the beginning of the same class period the next day). 20. Take another hydrometer and temperature reading at 24 hours. (Note: this time period is critical and should not be longer than 24 hours). Record the results on the Particle-Size Distribution Data Work Sheet. (1 of 2) [17/10/ :55:50 a.m.]

93 Soil Particle Size Distribution 21. Discard the soil suspension by pouring it into a special pail and spill the contents outside in a place for discarding soil materials. Do not pour the suspension down the sink! 22. Carefully rinse and dry the hydrometer, thermometer, beakers, and cylinders, and repeat the above steps two more times for the same horizon so that you have a total of three sets of results for each sample. 23. Repeat this procedure for each soil sample from every horizon. (2 of 2) [17/10/ :55:50 a.m.]

94 Making Sense of Soil Particle Size Laboratory Analysis Making Sense of Particle-Size Distribution (Note: Refer to the Learning Activity in the 1997 Supplement to the GLOBE Teacher's Guide) The amount of each size particle (sand, silt, or clay) in the soil is called the particle-size distribution. Knowing the particle-size distribution of a soil sample helps to understand many soil properties such as how much water, heat, and nutrients the soil will hold, how fast water and heat will move through the soil, and what kind of structure, bulk density and consistence the soil will have. Sand, silt, and clay are the three particle sizes of mineral material found in soils. The amount of each of these is called the "particle-size distribution" and the way it feels is called the "soil texture." Sand is the largest sized particle, Silt is medium sized, and Clay is the smallest. Relative Size Comparison of Soil Particles Beachball Frisbee Dime Silt Clay Sand (1 of 2) [17/10/ :55:58 a.m.]

95 Making Sense of Soil Particle Size There is disagreement in the scientific community about the exact size ranges of sand and silt. For GLOBE, we will measure sand and silt based on two different size definitions. 1. US Department of Agriculture (USDA) which defines the size of: sand = 2.0 mm mm silt = mm 2. The International Soil Science Society (ISSS) which defines the size of: sand = 2.0 mm mm silt = mm Clays are the smallest particles and are defined (by both organizations) as being smaller than mm. Particles greater than 2.0 mm (sand size) are called stones or gravels and are not considered to be soil material. (2 of 2) [17/10/ :55:58 a.m.]

96 Making Sense of Soil Particle Size Laboratory Analysis Making Sense of Particle-Size Distribution (continued) Heavy, large particles settle first, so when a soil sample is stirred or shaken in a 500 ml cylinder, sand particles (according to the USDA definition) settle to the bottom of the cylinder after 2 minutes, while the clay and silt size particles stay in suspension. Sample Starting Time After 12 minutes, the sand, according to the ISSS definition, has settled, leaving the clay and silt size particles in suspension. After 24 hours, the silt size particles have settled, and only the clay stays in suspension to be recorded by the hydrometer. (1 of 2) [17/10/ :56:01 a.m.]

97 Making Sense of Soil Particle Size The Next Day Soil Particles Dispersed in Beaker Here are the calculation worksheet and the specific gravity conversion table to help figure out the exact percentages of sand, silt, and clay. And here is a draft of the new calculation worksheet. (2 of 2) [17/10/ :56:01 a.m.]

98 ph Measurements Laboratory Analysis ph Measurements 1. In a cup or beaker, measure the ph of the distilled water you will be using. Dip the ph paper or calibrated pen or meter, into the water and obtain a reading. 2. In another cup or beaker, mix 40 g of dried and sieved soil with 40 ml of distilled water (or other amount in a 1:1 soil to water ratio) using a spoon or other utensil to transfer the soil. Stir with a spoon or other stirrer until the soil and water are thoroughly mixed. (1 of 3) [17/10/ :56:13 a.m.]

99 ph Measurements 3. Stir the soil-water mixture for 30 seconds every 3 minutes for a total of five stirring/waiting cycles. Then, allow the mixture to settle until a supernatant (clearer liquid above the settled soil) forms (about 5 minutes). 4. Measure the ph of the supernatant using the ph paper, pen, or meter. Place the bottom of the ph pen in the Supernatant (clearer liquid above the settled soil). The ph of this soil is (2 of 3) [17/10/ :56:13 a.m.]

100 ph Measurements 5. Repeat steps 1-4 for each sample from each soil horizon, and record your results on the Soil ph Data Worksheet. Back Next Top (3 of 3) [17/10/ :56:13 a.m.]

101 Soil Fertility Laboratory Analysis Soil Fertility Preparation and Extraction 1. Fill the extraction tube from your Soil Test Kit to the 30 ml line with distilled water. 2. Add 2 Floc-Ex tablets. Cap the tube and mix well until both tablets have disintegrated. (1 of 3) [17/10/ :56:25 a.m.]

102 Soil Fertility 3. Remove the cap and add one heaping spoonful of dry, sieved soil. 4. Cap the tube and shake for one minute. 5. Let the tube stand until the soil settles out (usually about 5 minutes). The clear solution above the soil will be used for the nitrate (N), phosphorus (P), and potassium (K) tests. Note: For some soils, especially those with a high clay content, there may not be enough clear solution extracted. If more clear solution is needed, repeat steps (2 of 3) [17/10/ :56:25 a.m.]

103 Soil Fertility (3 of 3) [17/10/ :56:25 a.m.]

104 Soil Fertility: Nitrogen (N) Laboratory Analysis Soil Fertility (continued) Part 2: Nitrate Nitrogen (N) 1. Use the pipette to transfer the clear solution above the soil to one of the test tubes in the Soil Test Kit until the tube is filled to the shoulder. (If more solution is needed, repeat Part 1). 2. Add one Nitrate WR CTA Tablet. Be sure that all the pieces of the tablet are added to the test tube and try not to touch the tablet as you place it into the tube. Cap and mix until the tablet disintegrates. 3. Rest the test tube in a cup or beaker. Wait 5 minutes for color to develop. (Do not wait longer than 10 minutes). 4. Compare the pink color of the solution to the Nitrogen Color Chart in the Soil Test Kit. Record your results (High, Medium, Low, or None) on the Soil Fertility Data Work Sheet. (1 of 2) [17/10/ :56:31 a.m.]

105 Soil Fertility: Nitrogen (N) 5. Discard the solution and wash the tube and the pipette with distilled water. 6. Repeat this procedure with the liquid from each of the soil samples. Be sure to rinse the pipette and tube with distilled water after they are used. (2 of 2) [17/10/ :56:31 a.m.]

106 Soil Fertility: Phosphorus (P) Laboratory Analysis Soil Fertility (continued) Part 3: Phosphorus (P) 1. Use the clean pipette to transfer 25 drops of the clear solution above the soil to a clean test tube. (If more solution is needed, repeat Part 1). 2. Fill the tube to the shoulder with distilled water. 3. Add one Phosphorus Tablet to the tube and cap it. Be sure that all the pieces of the tablet are added to the test tube. Mix until the tablet disintegrates. (1 of 2) [17/10/ :56:39 a.m.]

107 Soil Fertility: Phosphorus (P) 4. Rest the test tube in a cup or beaker. Wait 5 minutes (but no more than 10 minutes) for color to develop. 5. Compare the blue color of the solution to Phosphorus on the color chart in the Soil Test Kit. Record your results (High, Medium, Low, or None) on the Soil Fertility Data Worksheet. 6. Discard the solution and wash the tube and the pipette with distilled water. 7. Repeat this procedure with the liquid from each of the soil samples. Be sure to rinse the pipette and tube with distilled water after they are used. (2 of 2) [17/10/ :56:39 a.m.]

108 Soil Fertility: Potassium (K) Laboratory Analysis Soil Fertility (continued) Part 4: Potassium (K) 1. Use the clean pipette to transfer the clear solution above the soil to a clean test tube until it is filled to the shoulder. (If more solution is needed, repeat Part 1). 2. Add one Potassium Soil Tablet to the tube. Be sure that all the pieces of the tablet are added to the test tube. Cap and mix until the tablet disintegrates. 3. Hold the tube over the black boxes in the left column of the K portion of the color chart. Look through the "cloudiness" of the solution in the test tube and compare it to the shaded boxes in the right column. Record your results (High, Medium, Low, or None) on the Soil Fertility Data Work Sheet. (1 of 2) [17/10/ :56:47 a.m.]

109 Soil Fertility: Potassium (K) 4. Discard the solution and wash the tube and the pipette with distilled water. 5. Repeat this procedure with the liquid from each of the soil samples. Be sure to rinse the pipette and tube with distilled water after they are used. (2 of 2) [17/10/ :56:47 a.m.]

110 Soil Particle Density Laboratory Analysis Particle Density 1. A good soil for growing plants should generally contain about 50% pore space and 50% solids. The pore space should consist of half air and half water, and the solids should be made up mostly of minerals (sand, silt, and clay particles) mixed with some organic matter. 2. In the soil, air and water are found within the pore spaces between the particles. If this ideal soil were dried out, and all the pore space were compressed so that there was no more air and no more space, all that would remain would be the solid portion of the soil. Back Next Top [17/10/ :56:57 a.m.]

111 Soil Particle Density Laboratory Analysis Particle Density (continued) 3. To calculate bulk density, we would measure the mass of the total volume of a soil sample. 4. To calculate particle density, we would measure the mass of the volume of only the solids in the soil sample. Back Next Top [17/10/ :57:03 a.m.]

112 Soil Particle Density Laboratory Analysis Particle Density (continued) Back Next Top [17/10/ :57:11 a.m.]

113 Soil Particle Density Laboratory Analysis Particle Density (continued) 5. Weigh out 25g soil and pour Distilled water in squirt bottle. 6. Weigh empty flask without the cap. 7. Place 25g of soil into flask (wipe outside of flask clean) and get their mass without the cap. (1 of 2) [17/10/ :57:19 a.m.]

114 Soil Particle Density 8. Using squirt bottle, add approximately 50mL Distilled water into the flask. (Wash any soil on the neck back into the bottom of the flask.) Back Next Top (2 of 2) [17/10/ :57:19 a.m.]

115 Soil Particle Density Laboratory Analysis Particle Density (continued) 9. Bring soil and water mixture to a gentle boil for 10 minutes. 10. During this time, agitate the flask for 10 seconds every minute. (1 of 3) [17/10/ :57:24 a.m.]

116 Soil Particle Density 11. Remove flask from heat and allow it to cool. Cap flask and let sit for 24 hours. Cap flask and let sit for 24 hours. (2 of 3) [17/10/ :57:24 a.m.]

117 Soil Particle Density Back Next Top (3 of 3) [17/10/ :57:24 a.m.]

118 Soil Particle Density Laboratory Analysis Particle Density (continued) 12. At 24 hours, remove cap and add enough Distilled H2O to bring volume to 100mL (the bottom of the meniscus should be at 100mL). 13. Weigh the soil and water mixture without the cap. 14. Take temperature reading by placing thermometer into the water in the flask for one minute. (Take out, clean and dry thermometer.) (1 of 2) [17/10/ :57:30 a.m.]

119 Soil Particle Density 15. Calculate the soil particle density using the Soil Particle Density Data Sheet. Back End Top (2 of 2) [17/10/ :57:30 a.m.]

120 step by step powerpoint presentations GLOBE Soil Characterization Protocols Step by Step Guide PowerPoint Presentations Below are Powerpoint presentations of the step by step soil characterization field and lab protocol guide. Feel free to download these and use them for training and teaching purposes. If you have any questions, please contact: Izolda Trakhtenberg. Field Viewgraphs field1.ppt field2.ppt field3.ppt field4.ppt Ý Lab Viewgraphs lab1.ppt lab2.ppt lab3.ppt lab4.ppt Ý Ý Ý Back to the Step By Step Guide online Back to Soil Science Education Home Page Webmaster: Izolda Trakhtenberg, Information Contact: Izolda Trakhtenberg, Responsible Civil Servant: Dr. Elissa Levine, Last Updated: October 19, 1999 Ý [17/10/ :57:31 a.m.]

121 Soil Science Education Page Welcome to the Soil Science Education Home Page. This page contains a lot of new, exciting, fun and informative material on the soil. There is a Soil Gallery, where you can see what soil looks like and read some soil stories in Once Upon a Sandy Loam. You can even sing some soil songs in Rock 'N Soil. You can also find out about some Secrets Hidden in the Soil. Do you know how much soil there is on the earth? Does it have different shapes? Do you know what the soil does? Do you need ideas for science fair projects? All these questions are answered down below. If you have other questions about the soil, let us know. Send us an at globe@ltpmail.gsfc.nasa.gov. July, 2001 July 9, 2001, Evidence of D.C. Toxins Unheeded, Steve Vogel, The Washington Post. July 15, 2001, Contamination in Spring Valley, Editorial, The Washington Post. Go to the Soil in the News Archive. July 15, 2001, Pisa Puts New Slant On Leaning Tower, Associated Press. July 15, 2001, Repaying A Debt To Nature: New Wetlands Offset Filled Ones, Chris L. Jenkins, The Washington Post. New on the page: Download a field guide for Soil Science protocols. Updated graphics in the Soil Protocols Step-By-Step Guide. See new carbonate reaction graphics, new structure images, and a much easier way of doing the soil texture by feel protocol (including soil triangles). (1 of 3) [17/10/ :57:48 a.m.]