Grow Your Own, Nevada! Spring 2013: Gardening in Nevada's Soils- A Hero's Journey


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  • Soils Melody Hefner 05/06/13
  • Slide of 67 Good soil structure is very important to the functioning of your small-acreage property. Many on-farm activities can destroy soil structure over time, including tilling and plowing or driving on wet soils. A good quality soil has the characteristics listed on this slide. Most of these characteristics are also associated with good soil structure. 05/06/13 Melody Hefner Soils
  • Five major influences on soil formation include the nature of the original parent material, weathering time, climate, land surface features or topography, and the actions of plants and animals. These factors determine the physical and chemical properties of various kinds of soil. Compare a soil that formed on steep slopes over 10,000 years in a rainy climate, where trees dominate and the parent material is granite, with one that formed in the last 2,000 years in a valley near a river in a cold climate, where grasses dominate and the parent material is limestone. 05/06/13 Melody Hefner Soils
  • 05/06/13 Melody Hefner Soils
  • Soils Melody Hefner 05/06/13
  • Slide of 67 The differences in soil layers affect such things as drainage, water holding capacity, root penetration, and tilth. The soil on the left has very distinctive color changes from horizon to horizon. Over time, iron leached from the horizons above to the horizons below, changing the appearance. The slide on the right shows changes in the size of particles with depth. Notice the increase in numbers of cobbles (small rocks) in the deeper horizons. The cobbles probably increase the drainage capacity of the soil while lowering its water holding capacity. 05/06/13 Melody Hefner Soils
  • Soils are composed of mineral material and organic matter, and contain pore spaces filled with water or air and soluble nutrients. Organic matter serves as a binder for mineral particles, contributing to good soil structure and tilth, which refers to the behavior of soil under cultivation. Minerals comprise the largest part of the soil, and organic matter is usually the smallest portion of the soil. Most people don’t think about the presence of air in the soil, and yet it is essential for plant growth and soil biology. 05/06/13 Melody Hefner Soils
  • Slide of 65 Atypical “loam” soil is composed of about 45 to 50 percent pore space. This pore space volume can be as little as 30 percent in a sandy soil and as much as 50 percent in clay soils. Pore space determines the amount of water potentially available to plants. Instructor: Ask the students, “Which weighs more, a bucket of dry sand, or a bucket of dry clay?” The answer is sand, due to its increased density (mass per unit volume). However, students will usually guess clay, opening the door for fruitful discussion. 05/06/13 Melody Hefner Soils
  • The mineral fraction of the soil refers to the primary minerals that make up the sand, silts and clays. Sand, silt and clay particles give the soil its particular texture. Sand particles can be seen with the naked eye, while silt and clay particles are microscopic. Because of its platy structure, clay has enormous surface area. This surface area provides habitat for microorganisms and is the location of many chemical reactions in soils. One gram of fine colloidal clay can have between 10 square meters and 1000 square meters of surface area. 05/06/13 Melody Hefner Soils
  • You can make a rough determination of soil texture based on the way it feels in your hand. Texture refers to the relative proportions of sand, silt and clay in the soil. The textural triangle is used to organize soils based on their textural class according to the varying percentages of sand, silt and clay. Sandy soils feel gritty to the touch. Silt soils will feel very slippery or viscous when very wet, like baby powder. Clay soil is sticky when moist, and can form a long ribbon when molded in the hand. The ideal soil for agriculture, as can be seen in this chart at the center of the triangle, is a loam soil. These soils have high water holding capacity as well as good “workability” and drainage properties. The blue area in the circle marked “loam” represents the most desirable soil texture type. The outer green circle represents those soil texture types that are acceptable or amendable. The remainder of the triangle, colored brown, represents those soil textures that are least desirable. 05/06/13 Melody Hefner Soils
  • Notice that loam soils have moderate amounts of all three textural classes. 05/06/13 Melody Hefner Soils
  • The next three slides demonstrate an indoor soil texture exercise. In this exercise, we will determine texture by feel. We will go through an example first and then working individually, you can determine the texture of several samples found at the back of the room. Instructor: The next three slides demonstrate an indoor texturing exercise you can use with your students. Materials needed: Three or more different soils from the local area in buckets Several squirt bottles filled with water Newspapers or drop cloths to prevent messes Paper towels Handout of the flow chart Have students determine the texture of at least two different types of soil. 05/06/13 Melody Hefner Soils
  • Slide of 67 05/06/13 Melody Hefner Soils
  • Slide of 67 05/06/13 Melody Hefner Soils
  • You may be wondering why we’re talking about soil texture. While this is a property of the soil that you cannot change, by knowing your soil texture you can make predictions about how it will behave. For example, a coarse sandy soil is easy to till, has plenty of aeration for good root growth, and is easily wetted, but it also dries out rapidly and loses plant nutrients as water drains away. High clay content soils (more than 27 percent clay) have very small particles that fit tightly together, leaving little open pore space. This means that there is little room for water to flow into the soil, making clayey soils difficult to wet, difficult to drain, and difficult to till. Anyone who has tried to hack through a hardpan area is all too familiar with this! 05/06/13 Melody Hefner Soils
  • Slide of 65 Water infiltrates differently in soils with different textures. Water spreads more widely in a clay soil because of higher water tension compared to sandy soils. You’ll also note that the depth to which the soil has wetted is greater in the sandy soil due to lower water-holding capacity. In soil with 50 percent available water content, if you apply an inch of water, in a sandy soil the water will move downward 40 inches; in a fine sandy loam, 24 inches; and in a loam soil, only 12 inches. This slide also provides a good demonstration of what can occur when a drip system is used. The placement of the drip line relative to the plant is an important consideration, especially in sandy soils. 05/06/13 Melody Hefner Soils
  • Instructor: This is a great demonstration you can use in the classroom. In lieu of a wooden stand, use clear one-liter soda bottles. Cut the bottles in half, and turn the spout end upside down. Place soil in the bottom half of the spout section. Use some old nylon netting to cover the spout so the soil doesn’t fall through. Try to use very different soil textures. Use equal amounts of soil (measure with a plastic cup). Add equal amounts of water and see how quickly they drain, and how much water drains through. If you begin this demonstration early in the class, you can revisit it at the break. 05/06/13 Melody Hefner Soils
  • Slide of 67 Sandy soils drain rapidly and don’t hold water well. 05/06/13 Melody Hefner Soils
  • Slide of 67 Clay soils drain slowly and have a high water-holding capacity. Note that the water is clearer with less suspended material. 05/06/13 Melody Hefner Soils
  • Slide of 67 Loam soils have good drainage but also have good water holding capacity - something to strive for in your soil. The organic matter from the loam soil leached through as the water slowly passed from top to bottom, providing a brownish color. Instructor: Be aware that this type of leaching demonstration can contradict theory of drainage because the soil structure was disrupted when creating the tubes. Therefore, you could end up with a silty clay loam that drains better than a sandy loam. Try the experiment before you use it with your students. 05/06/13 Melody Hefner Soils
  • Different soil types transmit water differently. Sandy soils allow water to infiltrate rapidly, but water also drains easily from the large pores. Infiltration rates for clay soils can be quite slow, and the runoff potential is high. But, the water holding-capacity is large due to the finer pore space. 05/06/13 Melody Hefner Soils
  • Slide of 65 When considering which plants to grow, remember that most moisture is extracted by the plant roots present in the upper half of the rooting zone. In this idealized graphic, 40 percent of extraction occurs in the top one-quarter of the root zone, 30 percent in the next quarter, and only 30 percent in the lower half of the rooting zone. The upper rooting zone is the area where the soil will tend to dry out fastest, and where most nutrients are extracted. It’s important to manage irrigation water to keep it within the effective rooting zone. Water that moves below this root zone becomes unavailable to the crop, is effectively “wasted,” and can leach nutrients into groundwater. Every plant is different in its rooting habits, of course, and restrictive soil layers may affect rooting depths. Photo source: Adapted by A. Miller, Black Dog Graphics, from Soil Water Monitoring and Measurement. PNW 475. A Pacific Northwest Publication. Washington, Oregon and Idaho. Thomas Ley et al. 05/06/13 Melody Hefner Soils
  • Slide of 67 Soil organic matter has several parts: The living microbes in the soil such as bacteria and fungi, which break down very rapidly when they die. Partially decayed plant material and microbes, such as plant material or manure (either deliberately mixed in or naturally occurring). The stable material formed from decomposed plants and microbes. This material is called humus, and is broken down very slowly. Organic matter affects both chemical and physical properties of the soil. 05/06/13 Melody Hefner Soils
  • Slide of 67 The benefits of a soil rich in organic matter and humus are many, and include: Chemical effects: Organic matter releases many plant nutrients as it is broken down in the soil, including nitrogen (N), phosphorus (P) and sulfur (S). It is also one of two sources of cation exchange capacity (CEC) in the soil. (Clay is the other major source.) CEC represents the sites in the soil that can hold positively charged nutrients like calcium (Ca++), magnesium (Mg+) and potassium (K+). If CEC is increased, the soil can hold more nutrients and release them for plant growth. To increase CEC, you have to increase organic matter. Physical effects: Organic matter loosens the soil, which increases the amount of pore space. This has several important effects. The soil becomes less dense (less compacted) and the soil structure improves. This means that the sand, silt and clay particles in the soil stick together, forming aggregates or crumbs. Because there is more pore space, the soil is able to hold more water and more air. Plants grown in healthy soils won’t be as stressed by drought or excess water. Water also flows into the soil from the surface more quickly. With less compaction, it is also easier for plant roots to grow through the soil. 05/06/13 Melody Hefner Soils
  • CEC is the capacity of the soil to attract and bond with positively charged nutrients. Clay and humus are the only particles in the soil that can attract and bond with the nutrients. That is because they are negatively charged. If the CEC in soil is low then these nutrients will go into solution and be washed away with water or irrigation. 05/06/13 Melody Hefner Soils
  • Slide of 67 Soil particles and organic matter are often found together in natural soil structures called soil peds, or aggregates. Cycles of wetting and drying and freezing and thawing promote ped formation. For this reason farmers often leave their fields exposed in winter to mellow the soil, but this practice can lead to compaction and erosion if no residue is left on the field. A well-developed soil structure enhances water and air movement and root growth. Soil structure is classified by the shape and size of soil peds. Granular structure is common under sod and refers to small balls of soil that easily separate. Soils with granular structure have larger pore spaces. Blocky structure is common in older clay soils in humid regions. Well-developed prisms and columns can be found in some clayey subsoils. Mud pie example: What happens to soil structure when you make a mud pie? Does that mud pie have the same physical characteristics as that of the original soil it was taken from? If you let the mud pie dry out, will it absorb water poured on it rapidly or slowly? Instructor: The specific categories of soil structure, referred to by soil scientists, are not mentioned here except to describe the photos in the slide. 05/06/13 Melody Hefner Soils
  • Slide of 67 In a compacted soil, the air space may be reduced to as little as 5 percent, reducing the ability of the soil to support plant growth. 05/06/13 Melody Hefner Soils
  • Slide of 67 Compaction reduces pore space and destroys soil structure. This site will not be good for growing anything unless it is treated with deep tillage and organic matter. Similarly, rototilling or plowing wet soil can lead to long term compaction problems. 05/06/13 Melody Hefner Soils
  • Slide of 67 The organic soil component includes all of the living creatures in the soil, as well as dead ones in various stages of decomposition. One cubic yard of live soil can contain as many as a billion colonies of bacteria, one hundred million fungi, one hundred thousand algae, billions of protozoa, thousands of mites, nematodes, collembola and earthworms. Without this fraction, the soil loses its ability to support plants and recycle nutrients. 05/06/13 Melody Hefner Soils
  • Soil organisms are the key to the soil food web and maintaining the soil ecosystem. Worms play a major role in recycling soil nutrients by burrowing tunnels and processing soils through their digestive tracts. They leave behind nutrient-rich worm castings. They not only release nutrients to the soil, but also aerate the soil with their burrows. Microorganisms such as bacteria, fungi and actinomycetes decompose organic matter and cycle nutrients in the soil to make them available to plants. Overuse of fertilizers and excessive disturbance or tilling of the soil reduces the number of organisms living in the soil. 05/06/13 Melody Hefner Soils
  • Slide of 67 Scientific studies and observation have shown that by preserving soil organic matter, soils function better. Soil organic matter is a small proportion of the total composition of the soil, yet its role in improving soil health and soil quality is enormous. Adding organic matter to parcels around freshly built homes is gaining in popularity because of water quality concerns. Organic matter will increase water infiltration in this soil. Without the addition of organic matter, this soil will shed water much as the road does. 05/06/13 Melody Hefner Soils
  • Slide of 67 05/06/13 Melody Hefner Soils
  • If you don’t have a source of manure to compost, don’t despair! Ask a neighbor for some (most likely, they’ll be thrilled!) or compost grass clippings, household vegetable debris, leaves, and other plant materials. 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • 05/06/13 Master Gardener Training 2013 Understanding Nevada’s Soils
  • The pH scale ranges from 0 to 14. It measures the acidity or alkalinity of a solution. A pH of 7 means it is a neutral solution. Pure water has a pH of 7. A pH of less than 7 means the solution is acidic. A pH of more than 7 means the solution is basic, also called alkaline. The lower the pH, the more acidic the solution is. The higher the pH, the more basic the solution is. Each change of number in either direction represents a tenfold change in acidity or alkalinity. Most soils lie in the range of pH 5.5 to 8.5. Item pH Most acid soils 4.0 - 6.0 Lemon juice 2.2 - 2.4 Orange juice 3.4 - 4.0 Vinegar 4.0 - 4.5 Acid rain 3.0 - 5.0 Clean rain water 5.5 - 5.7 Fresh milk 6.3 - 6.6 Blood plasma 7.2 - 7.4 Mild soap solution 8.5 - 10.0 Instructor: Use indicator paper to measure the pH of some common substances, such as tap water, lemon juice, soda, etc. 05/06/13 Melody Hefner Soils
  • Soil pH affects the availability of plant nutrients as well as the biological activity of soils. Most essential plant nutrients are available at or around a neutral pH of about 7. As soils become more acidic (< pH 7) or alkaline (> pH 7), nutrients become less available. Also, bacteria tend not to do well in more acidic environments. Phosphorus is never readily soluble in the soil but is most available in soil with a pH range centered around 6.5. Extremely acidic soils (pH 4.0 - 5.0) can have high concentrations of soluble aluminum, iron and manganese that may be toxic to the growth of some plants. A pH range of approximately 6 to 7 promotes the best nutrient availability. 05/06/13 Melody Hefner Soils
  • Soil testing laboratories will report the salinity (conductivity) of soil in millimhos/cm (mmhos) or millisiemens/cm (mS). These two terms (mmhos and mS) are identical. The salinity of irrigation water is typically reported in micromhos (umhos) or microsiemens (uS). Conductivity is defined as the ability of a solution to conduct an electrical current, or the reciprocal of the solution's ability to resist the current. This current is conducted by electrically charged particles called ions, which are present in almost all solutions. Different solutions have different kinds and amounts of ions: distilled water has very few ions, and therefore a low conductivity, while sea water has a large number of ions, and a high conductivity. The greater the conductivity of the solution, the higher the reading. Salt affected soils are commonly classified for management purposes into three groups: saline, sodic, and saline-sodic. Two criteria are used for this classification, the electrical conductivity of the soil saturation extract (EC) and the exchangeable sodium percentage (ESP). Electrical conductivity is directly related to soluble salt concentration in soils. The exchangeable sodium percentage is a measure of the amount of sodium on soil exchange sites. 05/06/13 Melody Hefner Soils
  • Slide of 67 Managing these soils for growing crops can be difficult. In some cases, leaching with excess irrigation water to get rid of excess salts may be needed. If irrigation water is of low quality, the quantity of water applied should continually exceed the plant’s needs by 15 to 20 percent to provide enough water to maintain the root zone at safe salt levels. Make frequent, low volume irrigations to avoid plant stress. 05/06/13 Melody Hefner Soils
  • Sulfur Essential plant food for production of protein. Promotes activity and development of enzymes and vitamins. Helps in chlorophyll formation. Improves root growth and seed production. Helps with vigorous plant growth and resistance to cold. Sulfur may be supplied to the soil from rainwater. It is also added in some fertilizers as an impurity, especially the lower grade fertilizers. The use of gypsum also increases soil sulfur levels.  Excess Calcuim Symptoms. As mentioned, a proper balance between the concentrations of potassium, calcium and magnesium ions is important. Too much calcium can result in either magnesium or potassium deficiency.
  • All plants, including crops, require many nutrients for proper growth and development. Macronutrients are nutrients needed in large quantities. Micronutrients are those needed in small quantities. Crops get carbon, hydrogen, and oxygen from air and water. The other nutrients come from the soil. To get economic crop yields, farmers must often add extra nitrogen, phosphorus, and potassium (beyond what exists naturally in the soil) in the form of commercial fertilizers and manure. The portion of these chemicals that is not used by crops may leach through the soil profile and into groundwater supplies used for drinking water. Phosphorus and potassium are not toxic, but nitrate levels in groundwater can reach toxic levels when certain soil types, weather conditions, and agricultural practices prevail. For this reason, it is important to use the results of your soil test to determine the nutrient needs of your soil and plants. 05/06/13 Melody Hefner Soils
  • The nine main nutrients are called macronutrients. These substances (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, carbon, hydrogen, and oxygen) are required in relatively large amounts. Nitrogen (N) is the plant nutrient most universally deficient for high crop yields. Nitrogen is the key ingredient for grass leaf growth. Be cautious in using nitrogen fertilizers. Nitrates are completely soluble in water and are easily washed away or leached below the plant’s root zone by over-irrigation, especially in sandy soils. This pollutes groundwater supplies and can result in unacceptable drinking water quality. Phosphorus is important for developing strong root systems, and for flowering and fruiting. In general, phosphorus does not leach through soils because it is tightly bound to soil particles and chemically reacts with other elements to form insoluble soil compounds. It can be lost via soil erosion. Potassium is necessary for durability and disease resistance. It seldom causes water quality problems because it is not hazardous in drinking water and is not a limiting nutrient for growth of aquatic plants. It is usually very abundant in the soil in western states. Like phosphorus, it is tightly held by soil particles, and can be lost by erosion. Previously, we mentioned that carbon, hydrogen, and oxygen were absorbed by plants from the air and water. The remaining three macronutrients are calcium, magnesium, and sulfur. Calcium is an essential part in all cell walls and membranes, and must be present for the formation of new cells. Young tissue is affected first in calcium-deficient soils. In alkaline soils where calcium availability can be quite low, supplemental calcium may be needed to adequately supply the plants. Sulfur is a constituent of three amino acids and is essential for protein synthesis and nodule formation on legume roots. The characteristic odors of plants such as garlic and onion can be traced to sulfur present in oil compounds. Sulfur deficiencies occur in a wide range of soil and climate conditions, and may result in retarded growth rates and delayed maturity. Magnesium is essential for photosynthesis and serves as an activator for many plant enzymes required in growth processes. While it is generally prevalent in western soils, it is more often deficient than calcium, especially in sandy soils. Yellowing of older leaves is a common sign of magnesium deficiency. 05/06/13 Melody Hefner Soils
  • The nine micronutrients (iron, manganese, zinc, boron, molybdenum, nickel, copper, cobalt, and chlorine) are required in tiny amounts. Except for chlorine, the primary role of the micronutrients is as activators in numerous enzyme systems. You will need to specially request micronutrient analysis, and it will increase the cost of the soil test. An adjustment in soil pH usually corrects deficiencies of the micronutrients. Each of these elements has a specific role in plant growth. A deficiency or an excess of any one will impair plant growth until the problem is corrected. Watching plant growth, testing the soil, and analyzing the plant tissue are ways to assess nutrient needs. Iron and manganese are the micronutrients most often deficient in landscape plants. Iron is most likely to be deficient in wet, clayey, or over limed soils. Manganese is more likely to be deficient in sands, calcareous soils, or organic soils. An adjustment in soil pH usually corrects deficiencies of the micronutrients. 05/06/13 Melody Hefner Soils
  • Slide of 67 Organic fertilizers are made from materials derived from living things. Animal manures, compost, bone meal and blood meal are organic fertilizers. Chemical fertilizers are manufactured from non-living materials. Rock phosphate, for example, is a common source of phosphorus in chemical fertilizers. Mineral fertilizers are made from naturally occurring raw materials containing nutrients which normally have been transformed into a more plant-available form by industrial processing. Although the number of chemical processes used is relatively small, there is a wide variety of finished products. Organic fertilizers are not immediately available to plants. Before the plants can use them, they must be broken down by soil microorganisms into simpler, inorganic molecules and ions. In contrast, the nutrients in chemical fertilizers are already in inorganic form and can be immediately used by the plants. It is important to understand that there is no fundamental difference in nutritional quality between organic and inorganic fertilizers. It makes no difference to the beet root if the atoms of potassium it absorbs are from an organic fertilizer such as wood ash or an inorganic one such as muriate of potash. Although they are immediately available to plants, inorganic fertilizers have three main disadvantages. They are subject to leaching, which occurs when the fertilizers are washed by rain or irrigation water down below the level of the plant roots. Nitrogen is particularly susceptible to leaching. Heavy applications of chemical fertilizers can "burn" seedlings and young plants. This is actually a process of drying out, or desiccation, due to the presence of chemical salts within the commercial fertilizers. A third problem associated with the use of commercial fertilizers is that overly heavy applications can build up toxic concentrations of salts in the soil and create chemical imbalances. A listing of organic fertilizers nutrient content, release times and pros and cons of different organic fertilizers can be found on the Organic Fertilizers Information Sheet. 05/06/13 Melody Hefner Soils
  • A variety of fertilizers are available commercially. Some provide only a single nutrient, such as ammonium nitrate, or triple superphosphate. Others contain three macro-nutrients: nitrogen, phosphorus, and potassium (potash). Nitrogen is expressed on the elemental basis (N) and phosphate and potash are expressed as the oxides (P 2 O 5 and K 2 O) rather than elemental phosphorus (P) and potassium (K). A fertilizer grade of 28-14-5 means that a 100-pound bag of fertilizer contains 28 percent or 28 pounds of nitrogen, 14 percent or 14 pounds of phosphorus ( P 2 O 5 ) , and 5 percent or 5 pounds of potassium (K 2 O) . The remaining 53 percent consists of other ingredients that help in packaging and spreading. Some fertilizers contain only one major nutrient. An example is 33-0-0 (33 percent nitrogen, no phosphorus or potassium). If there is a fourth number, it represents the percentage of sulfur (S). Nitrogen fertilizers can be divided into two categories: those that are quickly available to plants, called soluble or quick release, and those that are slowly available to plants, called slow release. The quick release fertilizers are salts that are very soluble in water, including ammonium sulfate, ammonium nitrate, ammonium phosphate, and potassium nitrate. Quick release nitrogen is easily misused, resulting in waste, plant burn and water pollution. To avoid these problems, split the fertilization into two separate applications three to five weeks apart. Irrigate carefully to avoid deep leaching into water supplies and surface runoff to irrigation ditches, streams, rivers, and other water bodies. Slow release N sources include materials that dissolve very slowly in water, materials that have been coated to delay release (sulfur-coated urea), and the natural organic types mentioned above. Natural organic N sources such as manure must be broken down by microorganisms in the soil. The rate of release of N will depend on soil moisture and temperature. Slow release forms of N provide lower concentrations of nutrients over a longer period of time. This decreases the likelihood of plant burn and increases the probability that nutrients will be used by the intended plants rather than pollute streams and lakes. Instructor: Make sure participants understand the forms in which P and K are generally provided, and how to calculate actual amounts of P and K. 05/06/13 Melody Hefner Soils
  • 05/06/13 Melody Hefner Soils
  • Slide of 67 Be sure the test that you request will provide you with the information you need. Nutrients are not the only factor in good crop production. Before sending samples, contact the laboratory first. They may have special requirements for packing etc. Contact your local extension office for a list of analytical laboratories that serve your area. The results of a soil test can be used to make a fertilizer recommendation for certain crops and pastures. Soil testing laboratories use different test methods that may influence results and sufficiency ranges. Because labs may use different methods of analyses, and different analyses are appropriate for different soil types, it is advisable to send a soil sample to a lab in the same region where the soil sample is taken. A lab in your region may be more likely to use procedures suited for your soil type, and they may have data correlating the results to plant responses on similar soils. 05/06/13 Melody Hefner Soils
  • Slide of 67 When taking a soil sample, choose areas of the field that have conditions in common, as shown in this slide. Avoid areas where you know fertilizer has been placed recently. Sample unusual areas, such as low spots, separately. If areas are very different, you will need to collect separate samples. Be sure to use clean equipment to avoid contamination. Call the lab you have selected to test your samples prior to actual sampling for their specific recommendations on sample handling. 05/06/13 Melody Hefner Soils
  • Slide of 67 The accuracy of the soil test is a reflection of the sample taken, so make sure you have a good sample! Start by selecting about 15 locations randomly. Avoid sampling near gravel, manure or compost, septic leach fields, brush piles, or under eaves. 05/06/13 Melody Hefner Soils
  • Slide of 67 Dig a hole 6 to12 inches deep. Slide your shovel or trowel down the side of the hole from top to bottom, removing a “slice” of soil. Place all of the subsamples together in a clean pail and mix them thoroughly. Remove pebbles and debris. Let the sample dry. When dry, place about 1 to 2 cups of soil in a zip top bag, label and date the bag, and send the sample to the lab. Keep the sample cool and out of the sun. The lab may have other shipping requirements, so check with them first. 05/06/13 Melody Hefner Soils
  • Slide of 67 05/06/13 Melody Hefner Soils
  • Grow Your Own, Nevada! Spring 2013: Gardening in Nevada's Soils- A Hero's Journey

    1. 1. Gardening in Nevada’s SoilsGardening in Nevada’s Soils
    2. 2. Gardening in Nevada’s SoilsGardening in Nevada’s SoilsWhat is healthy soil?How does soil form?Soil has many components:– Textural or structural– Biological– ChemicalHow can you improve your soil?
    3. 3. OSU Extension ServiceHealthy soil has:Healthy soil has:Good porosityGood drainageGood water-holding capacityGood tilth, meaning they’reeasy to workLots of organic matterLots of organismsA pH of about 7Low salinity and sodium levels
    4. 4. How are soils formed?How are soils formed?A. Miller
    5. 5. Nevada SoilsNevada SoilsMany challenges– Climate– Organisms– Parent material– Time– Topography
    6. 6.
    7. 7. Young streamYoung stream
    8. 8. Middle-aged streamMiddle-aged stream
    9. 9. Mature streamMature stream
    10. 10. Very mature streamVery mature stream
    11. 11.
    12. 12.
    13. 13. It’s not your fault!It’s not your fault!You didn’t do anything wrong!We have very young soils geologicallyTheir youth makes them:– Highly variable both vertically andhorizontally– Low in organic matter– Still a work in progress
    14. 14. Compare horizonsCompare horizonsOSU Extension Service
    15. 15. What are soils made of?What are soils made of?MineralsAirWaterOrganic matter(humus)www.statlab.iastate.eduUSDA NRCS
    16. 16. Water = 20 to 30%Air = 20 to 30%MineralFraction(sand, silt,clay) = 45 to 50%Organic Matter = 0 to 5%““Ideal” composition of a soilIdeal” composition of a soil
    17. 17. SoilSoilmineralsmineralstexturaltexturalclassesclassesA. Miller
    18. 18. TheThedreadeddreadedsoilsoiltexturaltexturaltriangle!triangle!A. Miller
    19. 19. NRCS, Bozeman Mont.TexturalTexturaltriangletrianglefor thefor thegraphicallygraphicallychallengedchallenged
    20. 20. Texture by feel: SandTexture by feel: SandAdapted from NRCS, Bozeman Mont. by A. Miller
    21. 21. Texture by feel: Loamy sandTexture by feel: Loamy sandAdapted from NRCS, Bozeman Mont. by A. Miller
    22. 22. Texture by feel: Loams and claysTexture by feel: Loams and claysAdapted from NRCS, Bozeman Mont. by A. Miller
    23. 23. Why determine soil texture?Why determine soil texture?Soil texture influences:Ease of tillageAmount of pore space or porosityWater infiltration ratesWater-holding capacitySoil fertility or nutrient-holding capacity
    24. 24. WaterWaterspreadsspreadsdifferentlydifferentlyinindifferentdifferentsoilsoiltexturestexturesDeepestpenetrationModeratespread andinfiltrationWide, but moreshallow, infiltration  CLAYSILTSAND
    25. 25. In thisexperiment,an equalamount ofwater wasapplied tothree soiltypes.NRCS, Bozeman, Mont.Soil texture affects infiltrationSoil texture affects infiltration
    26. 26. Note the amount ofwater that drainedfrom the sandy loamsoil.NRCS, Bozeman, Mont.Soil texture affects infiltrationSoil texture affects infiltration
    27. 27. Less water hasdrained from the siltyclay loam soil.Soil texture affects infiltrationSoil texture affects infiltrationNRCS, Bozeman, Mont.
    28. 28. The loam soildrained almost asmuch as the sandyloam.Soil texture affects infiltrationSoil texture affects infiltrationNRCS, Bozeman, Mont.
    29. 29. Soil texture and infiltrationSoil texture and infiltrationSoil textureInfiltration rate,inches per hourSand 2 - 4Sandy loam 1 - 3Silt loam, loams 0.25 – 1.5Silty clay loams, clay 0.1 – 0.3A. Miller
    30. 30. Sand versus ClaySand versus ClayClay - “Heavy” soil- High water-holding capacity- Slow infiltration- High nutrient-holding capacitySand - “Light” soil- Low water-holding capacity- Fast infiltration- Low nutrient-holding capacity
    31. 31. Water InfiltrationWater Infiltration
    32. 32. Where do plants get their waterWhere do plants get their waterfrom in the root zone?from in the root zone?Adapted from PNW 475 by A. Miller
    33. 33. Soil textureSoil textureSandy soil watering tipsSandy soil watering tips Emitters close to theplant Higher volume perhour emitters Low duration Increased frequencyClay soil watering tipsClay soil watering tips Emitters further fromthe plant Lower volume perhour emitters Higher duration Lower frequency
    34. 34. Can you change soil texture?Can you change soil texture?No, not really!Add sand to clay – mess!Add clay to sand – mess!Texture may limit yourplant choicesHow can you improveyour soil texture? – addorganic matter!
    35. 35. Soil organic matter consists of:Soil organic matter consists of:LivingorganismsDead organismsPlant matterOtherdecomposingorganicmaterialsUNCE, Reno, Nev.
    36. 36. Benefits of soil organic matterBenefits of soil organic matterImproved water infiltrationIncreased water- and nutrient-holding capacityFormation of soil into stableaggregatesReduced soil compaction
    37. 37. Nutrient-holding capacityNutrient-holding capacity
    38. 38. Water moleculeWater molecule
    39. 39. NutrientsNutrientsheld in theheld in thesoil aresoil areavailableavailablefor plantfor
    40. 40. Soil StructureSoil Structure
    41. 41. structure:Soil structure:How particles are grouped together intostable collections by organic matter “glue,”also called “peds” or soil aggregates
    42. 42. Composition of a compacted soilComposition of a compacted soilNote the reduced air space in acompacted soil.Before After70%50%
    43. 43. Soil CompactionSoil Compaction
    44. 44. Soil compactionSoil compaction
    45. 45. Avoid walking or driving on wet soilAvoid working wet soilOSU Extension Service
    46. 46. extension.umn.eduThe wetterThe wetterthe soil, thethe soil, theworse theworse thecompactioncompactioneffect byeffect bymechanizedmechanizedequipmentequipment
    47. 47. Adding organic matter:Adding organic matter:Improves water infiltrationIncreases water- and nutrient-holdingcapacityForms soil into stable aggregatesReduces soil compaction Also – feeds soil biota!
    48. 48. USDA NRCSThe living soilThe living soil
    49. 49. wormwormUSDA NRCS
    50. 50. Add organic matter to your soilAdd organic matter to your soilOSU Extension ServiceWhat kind of organic matter?Composted or well-aged OM
    51. 51. What about manure?OSU Extension ServiceUncomposted manure can be high in salts(burns plants and seeds) and can contain weedseeds, diseases, and insect eggs and larva.
    52. 52. Household vegetable debris andgrass clippings can also be usedto make compostUNCE Reno, Nev.
    53. 53. Types of compostingTypes of compostingSlow composting– Less labor intensive– Slower product production– Good for folks that produce low volumesFast composting– More labor intensive– Quicker production– Good for folks that produce higher volumes
    54. 54. Types of compostersTypes of compostersCompost piles– Can be messy– Easy access for animals– Harder to turn?
    55. 55. Types of compostersTypes of compostersCompost tumblersBin composters– Neater, cleaner
    56. 56. Steps to creating a compost pileSteps to creating a compost pilePick a site– Level, well-drained– Build on bare soil forbacteria– Shade– Near water and sourceof raw materials– Esthetically pleasing?
    57. 57. Steps to creating a compost pileSteps to creating a compost pilePile size– Cool or slow composting– Hot or active composting• At least a cubic yard (3’ x 3’ x 3’)• Not more than 5’ cube
    58. 58. Steps to creating a compost pileSteps to creating a compost pileIngredients– Ratio of 1:2 (1:1) green to brown material– Finer the size, quicker to compost– Too fine and it will compact 1-1.5” is best– Sprinkle some soil or finished compostevery 8 to 12 inches as you build the pile
    59. 59. What to CompostWhat to CompostGreen Materials– Grass clippings– Animal manure (from herbivores only)– Non-animal-based kitchen wastes– Garden trimmingsDry or Woody (“Brown”) Materials– Fall leaves, dry cornstalks– Wood chips or sawdust (caution)– Hay or straw (soiled or clean)
    60. 60. WhatWhat notnot to compostto compost Yard trimmings or grass clippings treated withpesticides. They may kill the beneficial organisms in thecompost pile or later in your garden. Weeds, if the pile will not be hot enough to kill theseeds. Diseased or insect-infested plant parts. The diseases orinsects may be transferred to the soil with the compost. Parts of any plant known to contain poisons or toxins,such as black walnut. Fats, grease, lard or oils. These do not break downquickly and may attract pests, vermin, dogs or largecarnivores. Meat or fish bones or scraps. Dairy products.
    61. 61. Oh dear!Oh dear!
    62. 62. WhatWhat notnot to compostto compost Too much of any plant that contains tannins or resinsthat inhibit decomposition, such as junipers, pine,spruce, arborvitae, oak or cottonwood. Charcoal ash, as this may contain substances harmfulto plants. Fireplace ashes, since they have a very high pH, as doour native soils. High pH levels can result in nutrientdeficiencies and other plant problems. Pet wastes, such as dog or cat feces or soiled cat litter.They may contain parasites, bacteria or viruses harmfulto humans. Swine or other omnivore wastes. They also may containparasites, bacteria or viruses harmful to humans.
    63. 63. Steps to creating a compost pileSteps to creating a compost pileAddWater
    64. 64. Steps to creating a compost pileSteps to creating a compost pileMix the pile– Weekly for hot or active composting– Whatever for slow or cool composting– Should reach 120 to 160 degrees– After 6-8 weeks of cooking, pile needs tocure for another 4-8 weeks– Turn pile while it is curing also
    65. 65. Preventing problemsPreventing problemsNuisance insects andanimalsFood wastes can attractthemMay need to vermicultureor worm compost orcompost tumble highvolumes of food wastes
    66. 66. Compost troubleshootingCompost troubleshooting
    67. 67. Composting Pros and ConsComposting Pros and ConsPROS Recycle nutrients backinto your soil Reduces waste to yourgarbage can and landfill It is a cost-effectivemethod of improvingyour soil Get good at producingit, you will have manyfriends wanting someCONS Can be messy and/orsmelly Can be labor intensive Can attract vermin,predators, stray dogs, etc. Can be weather dependent Do you have space? Do you have time tomanage?
    68. 68. What if I don’t want toWhat if I don’t want tocompost?compost?How about buying organic matter to addto my soil?– Steer manure– Compost– Worm castings– “Triple mix”– Neighbor’s horse manure– “fill dirt”
    69. 69. Use caution adding soilUse caution adding soilamendments!amendments!
    70. 70. Amendment Pros and ConsAmendment Pros and ConsPROS Good quality organicmatter amendments willimprove your soil No down time Less labor involvedCONS Good quality organicmatter amendmentscost $ May be introducing anew problem– Weed seeds– Insect eggs or larva– Diseases
    71. 71. Add “pantryAdd “pantryshelves” -shelves” -nutrientsnutrientsare held inare held inthe soil onthe soil
    72. 72. Chemical Properties of SoilChemical Properties of SoilpH – potential of HydrogenEC – Electrical ConductivityNutrient content (plant nutrients)
    73. 73. pHpHIndicates relative acidity or alkalinitypH 7 = neutral; less than pH 7 = acid;more than pH 7 = alkaline or basicAdapted from by A. Miller
    74. 74. pH – Potential of HydrogenpH – Potential of HydrogenMeasure of the amount of hydrogenNegative logarithm of hydrogen ionactivity - 1 pH point is a ten-fold changepH of 7 = 1.0 x 10-7hydrogen ions equalH+and OH-ionspH of 3 = 1.0 x 10-3Hydrogen ionsmore H+ than OH- acidicpH of 10 = 1.0 x 10-10Hydrogen ions moreOH-than H+alkaline or basic
    75. 75. Soil pHSoil pHandandnutrientsnutrientsAdapted from by A. MillerWidest part of the bar indicates maximum availability
    76. 76. Can I change my soil pH?Can I change my soil pH?Not really – our soils are alkalineLimestone (calcium carbonate) buffersour soilsCaCO3 + 2HCl = 2Cl-+ Ca+2+ H2O + CO2 (gas)Can add sulfur, but takes time to lowerpH and change is not always notpermanent
    77. 77. EC or Electrical ConductivityEC or Electrical ConductivityMeasures how well soil conducts anelectric currentSalts that dissolve in water conductelectricityPlants need some “salts” – these arenutrientsVery high EC = high salt contentIf salt contents are high, it can interferewith plant growth
    78. 78. Classifying salt-affected soilsClassifying salt-affected soilsElectrical conductivity measurements (EC)Exchangeable sodium percentage (ESP)Salt-affected soils are commonly classifiedfor management purposes into threegroups: saline, sodic, and saline-sodicbased on EC and ESP
    79. 79. What to do aboutWhat to do aboutsalt-affected soil?salt-affected soil?If you have tested and find you have salt-affected soil:– Flush the soil with water to wash the saltdown below the growing zoneProblem:– High water tables, poorly drained soil andhigh salt content irrigation water are oftenthe cause of or contribute to high salinity
    80. 80. Managing salt-affected soilsManaging salt-affected soilsSelect plants that can tolerate salinityAvoid excess or salty forms offertilizersIncorporate organic matterIf appropriate, add sulfur to lower thepHIf a serious problem, go to raised bedswith good drainage
    81. 81. A word about gypsumA word about gypsumGypsum is CaSO4.H2OGood source of Calcium and SulfurGood for Sodium-Affected SoilsNOT a panacea for clay soils!Too much Ca can interfere withchemical balance in soil and cancontribute to a magnesium deficiencyand interfere with other micronutrientavailability
    82. 82. Sulfur:Sulfur:• Essential plant food for production ofprotein• Promotes activity and development ofenzymes and vitamins• Helps in chlorophyll formation• Improves root growth and seed production• Helps with vigorous plant growth andresistance to cold
    83. 83. Plant nutrientsPlant nutrientsSubstances necessary for plant growthPlants make their own food – these arethe vitamins and minerals plants need tomake their food and to growExcess or improper use of fertilizersmay result in plant damage and waterpollutionSplit into two groups, based on theamount of the nutrients the plants needto survive and thrive
    84. 84. MacronutrientsMacronutrientsN = nitrogenP = phosphorusK = potassiumH = hydrogenO = oxygenC = carbonCa = calciumMg = magnesiumS = sulfur
    85. 85. MicronutrientsMicronutrientsFe = ironMn = manganeseZn = zincB = boronMo = molybdenumNi = nickelCu = copperCo = cobaltCl = chlorine
    86. 86. How do we add nutrients?How do we add nutrients?Minor amounts in compostMinor amounts in soil “amendments”Generally added as fertilizer
    87. 87. Types of fertilizersTypes of fertilizersChemical fertilizersOrganic fertilizers or amendments(bone meal, compost, manure, etc.)
    88. 88. Complete vs incomplete fertilizerComplete vs incomplete fertilizer“Complete” fertilizers contains the top 3nutrients, like 16-16-16 general fertilizer:– Nitrogen (N)– Phosphorus (P)– Potassium (K)– 4thnumber, if present, is Sulfur (S)“Incomplete” fertilizers do not contain thetop 3 nutrients, like Ammonium Sulfate21-0-0
    89. 89. What’s inWhat’s inthe bag?the bag?WAY TO GROWFERTILIZER28 – 14 - 5GUARANTEED ANALYSISTotal nitrogen 28%6% Ammonium nitrogen14% Urea nitrogenAvailable phosphoric acid 14%Soluble potash 5%Derived from sulfur-coated urea,etc.Product nameNPK formulaNitrogen contentPhosphorus contentPotassium contentSpecific sources
    90. 90. How doHow doI knowI knowwhat towhat toadd toadd tomymysoil???soil???A. MillerTestTestyouryoursoil!soil!
    91. 91. What should I test for?What should I test for?Soil textural analysispH and saltsSoil nutrient contentFertilizer recommendationsCall your local extension office fora list of soil testing labsWhat information does a normalWhat information does a normalsoil test provide?soil test provide?
    92. 92. Call the Lab FIRST!Call the Lab FIRST!Find out what they test forFind out if they have package dealsFind out how much sample they wantyou to takeFind out how they want the sampledelivered to themCall UNCE 784-4848 for list of labs
    93. 93. How to take a sampleHow to take a sampleFirst, select thesite. Your soilsample shouldrepresent onlyone soil type orsoil condition.OSU Extension Service
    94. 94. Each sampleshould consist ofsub-samples takenfrom about 5-15locations withinthe same soil typeor sampling area.OSU Extension ServiceHow to take a sampleHow to take a sample
    95. 95. Use the “slice”method for arepresentativesample.UNCE, Reno, Nev.How to take a sampleHow to take a sample
    96. 96. Erosion ControlErosion ControlAnother method to manage soilSoil takes time to form – you don’twant to lose it!Keep a cover on the soil – plants,mulch, etc.Provide for drainage paths and armorthem to reduce the potential forerosion
    97. 97. Protect slopesProtect slopes
    98. 98. Redirect the rainRedirect the rain
    99. 99. Check irrigation oftenCheck irrigation often
    100. 100. How can I manage my soils toHow can I manage my soils toimprove them?improve them?Increase the organic matter content• Increases water- and nutrient-holding capacityAvoid compaction by:• Reducing tillage of wet soils• Reducing traffic on wet soils• Establish pathsMaintain cover with vegetation or mulchto reduce potential for erosionFertilize when needed