Slide 1 Master Gardener Soils and Fertility Training Or... It s not dirt, it s soil! Soils and Fertility. Dirt is not soil. Soil is not dirt. Dirt is soil out of place. Dirt is what you have under your fingernails after you re through gardening. Dirt is what you have on your knees. Dirt is what your kids track into the freshly washed kitchen floor. Soil, on the other hand, is the living matrix of material between the rock crust of the Earth and the green growing plants. It is the material that will support plant life, and therefore, life on Earth. Please read chapters 2 (Indiana Soils) and 6 (Fertilizers).
Slide 2 What is Soil? Soil is a mixture of materials that supports plant growth. Soil Components: Inorganic- weathered particles of rock, air, water Organic- living and dead animals and plants 2 What is soil? Mixture of materials that support plant growth (inorganic, organic).
Slide 3 Soil is a Natural Resource Soil is an important natural resource providing us with plants for food, clothing, shelter, and natural beauty. Soils differ widely across the landscape Soil properties need to be considered for construction of roads, buildings, sewage disposal systems, lakes, etc. 3 Besides gardening and farming, soils are used in a variety of ways that shape our daily lives. Properly categorizing their features allow a variety of professionals to make informed decisions on planning developments, roads, homes, septic systems and other infrastructure items essential in our everyday life.
Slide 4 What Soil is Water 25% Minerals 45% Air 25% OM 5% 4 Pie chart of soil components. Soil is 45% mineral matter (sand, silt and clay), and 5% organic matter (OM) (basically, decomposed plant material, humus, etc.). This makes up the visible part of soil, but it s only half of the soil. The other half of the soil is made up of pore spaces which hold both air and water. Without the ability to hold air and water, you don t have soil you actually do have dirt! Roots must have access to both water AND air in order to survive.
Slide 5 Soil composition 5 Soil particles (mineral and organic materials) do not fill perfectly together. There are spaces (pores) between particles. This is where air and water component is found. Roots also grow around (not through) these soil particles.
Slide 6 How soil is formed 6 This is one of the possible mechanisms for soil formation. Exposed rock cracks and disintegrates over thousands of years of freezing and thawing. Over time, simple plants (moss, algae) gain a foothold in cracks and dust. As they live and die, they begin to add organic matter to the soil. Broken rock continues to disintegrate into simpler particles. As broken rock continues to break down, and as organic matter continues to increase, more complex plants get started. Their roots help break down the parent material further, and they add even more organic matter as they die. In a fully mature soil, distinct layers form. Roots can grow down deeply enough to support a wide range of plants.
Slide 7 A horizon Surface layer, topsoil Shallow, usually darker B horizon Subsoil Usually different color Higher clay content C horizon Parent material Soil Horizons 7 The A horizon, also called the surface layer (and sometimes the topsoil). Because it is an area of organic matter (O.M.) accumulation and is associated with the rooting zone, is generally shallow when compared to the other horizons. In most parts of the Indiana, it is not more than 8-10 inches in depth and in many cases may be shallower. The uppermost layer of the surface layer is the topsoil; it is very high in organic matter. This layer tends to be very well drained, with lots of soil pores and oxygen; high amounts of fungi, bacteria, mycorrhizae, earthworms, and other micro- and macro-organisms. The B horizon (subsoil) is a layer of accumulation of clay and minerals moved by water over time in a process called illuviation. The B horizon will grow over time as the weathering process moves minerals from the A layer and develops the uppermost of the C layer into the B layer as well. Very little pore space and oxygen, because weight of soil above it crushes it. Normally, little or no rooting occurs here; little in the way of microbes or earthworms (no oxygen). C horizon (parent material) is weathered, disintegrating bedrock. Most important thing to know: in a developed area (subdivision, strip mall, etc.), you won t see this. The first thing developers do is bulldoze off all of the A horizon, because the subsoil provides a firmer support for buildings. (I m a big fan of buildings not falling over.) When the developers are through building, they throw grass seed over the compacted subsoil and call the job finished. This leaves the new owner with a yard that won t grow grass, trees, or garden plants without major work. Topsoil sold by most excavators and landscapers is not technically topsoil. In Evansville, it might be river-bottom silt. In other areas, it could just be fill dirt. There is no legal definition for topsoil in the US.
Slide 8 Soil compaction 8 Soil compaction is caused by heavy traffic over the soil. This includes vehicles, building supplies, bulldozers, and even foot traffic. Compacted soil has very little in the way of pore spaces, so there is little air available to the roots. This leads to poor root growth, which leads to poor plant growth. Over watering in compacted soil causes root death from oxygen deprivation.
Slide 9 Soil texture refers to the size of soil particles (sand, silt, and clay) and the relative percentages of each in the soil. Soil Texture influences: water holding capacity, infiltration, ease of tillage, seedbed preparation, and nutrient holding capacity Soil Texture 9 Soil texture is determined by the inorganic mixture of sand, silt and clay in the soil. In the lab, the amount of each can be determined exactly. In the field, this is determined by touch, sight and experience. The soil texture greatly effects a soil s capacity to grow plants and serve as a building medium.
Slide 10 Pictorial Size Comparison 10 Picture of soil particles, for comparison. Sand: 2.0 to.05 mm (visible to the naked eye). Think of sand particles as the size of a basketball. Soils with a lot of sand feel gritty. Silt :.05 to.002 mm (can only be seen with a microscope). In comparison, they are the size of a garden pea. Soils with a lot of silt feel soft, silky; like bread flour. Clay: less than.002 mm (can only be seen with an electron microscope). In comparison, they are smaller than the period at the end of this sentence. Soils with a lot of clay are stiff and sticky. In combination, these 3 minerals can affect a soil s potential for erosion and compaction; its ability to hold air, water, and minerals.
Slide 11 Sand 11 Sand particles magnified. Very large, irregularly shaped particles; do not stack on top of each other neatly. Visible to the naked eye.
Slide 12 Silt 12 Silt (dust storm). Silt is very light, and does not stick together. Silt gives the soil a smooth, floury feel. Magnified through a normal microscope, silt looks a lot like sand: miniature rocks. The dust storms of the 1930s were caused by silt blowing off the farm fields.
Slide 13 Clay 13 Clay particles magnified. Clay particles are the smallest particles, about the size of bacteria and viruses. They can only be seen through an electron microscope. Clay particles are very flat, pancake-shaped objects, and are very sticky. They stack on top of each other like plates (or pancakes). Air and water have to move between these particles, which is why these soils are considered poorly drained.
Slide 14 Soil triangle 14 Most soils are a mixture of sand, silt and clay particles. Different ratios of each of 3 minerals gives us different soil types, and different characteristics. Illustrated on page 73. Don t panic! Let s break this down!
Slide 15 Soil Texture By Feel Loam up to 1 ribbon Sand no ribbon 15 Ribbon Method (Feel Method) for determining soil texture. See page 75 and 76. To determine a soil s texture, take a handful of soil and add enough water to make it damp and pliable (not soupy). Squeeze it into a ball if it doesn t stay in a ball (form a cast), it is considered a sand. Roll the ball between your fingers to make a ribbon or snake. The length of the ribbon created will give a very good indication of what soil class it should be in. As shown above, a loam soil will make an approximately 1 inch ribbon, while sand will not form a ribbon at all. Loam soils are very soft and easy to manipulate.
Slide 16 Soil Texture By Feel Clay Loam ribbon is 1-2 Clay ribbon is more than 2 16 Soil texture by feel: Clay loams will feel stiff and moderately sticky. It will make a ribbon 1 to 2 inches long. Clay soils are very stiff, and very sticky (think pottery clay). You can make very long ribbons with it.
Slide 17 Step 1: make a ribbon Clay Clay Loam Loam 17 Now using the exercise from previous 2 slides, let s build our own soil triangle. Squeeze soil try to make a ribbon. Soft, easy to squeeze, makes ribbon < 1 inch long = Loam Stiff, sticky, like modeling clay, makes a ribbon 1-2 inches long = Clay Loam Extremely stiff, very sticky, makes a ribbon > 2 inches long = Clay
Slide 18 Step 2: gritty or smooth? Clay Sandy Clay Silty Clay Sandy Clay Loam Clay Loam Silty Clay Loam Sandy Loam Loam Silt Loam 18 Now need to give the soil an adjective, to describe what type of loam or clay loam we have. Feel samples for grittiness. Smooth and floury = Silty Extremely gritty = Sandy Slightly gritty, slightly smooth = no adjective
Slide 19 Scientific way to determine soil type 19 Soil labs will take a measured amount of soil, and use water to break up the 3 minerals, then compare the relative amounts to calculate actual percentages. This is explained on page 74. Add sample, water, 1 drop dish detergent. Shake for 3 minutes. Let settle. After 1 minute: make a marker on the jar where the top of the settled material is. This will be the sand, which is heaviest and settles out first. After 1 hour, make another mark at the top of the settled material. This will be the silt layer, which is the next smallest particle. After 24 hours, make the final mark. This indicates the clay level, because clay particles are tiniest and take the longest to settle. Use a ruler, and measure the 3 layers in millimeters. Calculate percentages for each layer: if total soil is 100 mm high, and the sand layer is 30 mm high, then the sand layer is 30%. Do this for all particles, and then go to the next slide.
Slide 20 20 Put it together to make soil triangle. Percent sand is measured on bottom line, from 0% sand on the right to 100% sand on the left. The amount of sand is measured upwards and to the left. Percent silt is measured along the upper right line, from 0% silt at the top to 100% silt at the lower right. Silt percentages are measured downwards and to the left. Clay is measured along the upper left line, from 0% clay at the bottom to 100% clay at the top. Clay percentages are measured horizontally to the right. What type of soil has 40% sand, 40% silt, and 20% clay? You should end up with loam. See page 73 for more information.
Slide 21 Soil Texture Soil Texture Groups: Coarse: sandy, loamy sand, sandy loam Medium: loam and silt loam Fine: clay loam, silty clay loam, silty clay, clay 21 Different soil textures are grouped by similar characteristics: coarse, medium, and fine.
Slide 22 Soil Type What does this mean? Aeration & Water Infiltration Nutrient & Water Capacity Ability to Work Soil Coarse Excellent Poor Excellent Medium Average Average Average Fine Poor Excellent Poor 22 Soil texture groups and drainage. A repeat/review from slide 16: Sandy soils have lots of sand in them (duh!): large particles, with large pore spaces between them. Water moves through this soil very quickly too quickly, in fact: sandy soils have poor water retention. Because of the size of the particles, sandy soils don t compact easily. Also, because of the large particle size and chemical makeup of the sand particles, sandy soils do not hold onto nutrients (fertilizer) very well. Clay soils have lots of clay particles. Clay particles are very tiny, and therefore the pore spaces around them are very tiny. Water moves though clay soils slowly. We say clay soils have poor drainage, but excellent water retention. Because of the tiny particle size and the chemical structure of the clay particles, clay soils hold a large amount of nutrients. Loam soils have a balance of clay, sand and silt. They have optimum levels of drainage and water retention. Because of the particle size and chemical structure of the silt particle, they do not hold onto nutrients very well slightly better than sand, but nowhere near as well as clay.
Slide 23 Soil Type What does this mean? Aeration & Water Infiltration Nutrient & Water Capacity Ability to Work Soil Coarse Excellent Poor Excellent Medium Average Average Average Fine Poor Excellent Poor 23 Soil texture groups and drainage. Coarse textured soils have lots of sand in them: large particles, with large pore spaces between them. Water moves through this soil very quickly too quickly, in fact: sandy soils have poor water retention. Because of the size of the particles, sandy soils don t compact easily. Also, because of the large particle size and chemical makeup of the sand particles, sandy soils do not hold onto nutrients (fertilizer) very well. Fine textured soils have lots of clay particles. Clay particles are very tiny, and therefore the pore spaces around them are very tiny. Water moves though clay soils slowly. We say clay soils have poor drainage, but excellent water retention. Because of the tiny particle size and the chemical structure of the clay particles, clay soils hold a large amount of nutrients. Medium textured soils have a balance of clay, sand and silt. They have optimum levels of drainage and water retention. Because of the particle size and chemical structure of the silt particle, they do not hold onto nutrients very well slightly better than sand, but nowhere near as well as clay.
Slide 24 Holding Other Nutrients Nutrients are held because: Soil particles are electrically charged (generally negative - - -) Nutrient particles (ions) are electrically charged (generally positive + + +) This characteristic of soil is called: 24 Nutrients are held because soil particles are negatively charged, and nutrient particles are positively charged. Opposites attract. Positively charged particles are called cations. The measurement of how many positively charged cations can be held by a negatively charged soil is known as the Cation Exchange Capacity, or CEC. This is not calculable by gardeners, and for the most part, you don t need to know it; it s important for the soil scientists in the lab as they write up your recommendations.
Slide 25 Nutrients, soils and roots 25 Positively charged mineral nutrients (cations) are held by soil particles and organic matter. They are exchanged for hydrogen ions on the surface of the root hairs. The root hairs can then absorb the mineral ion, and carry it up to the rest of the plant in the xylem. Negatively charged ions (anions) are not held, and wash out of the soil.
Slide 26 Moisture holding ability 26 Let s return to this picture, and go into more detail on a soil s ability to hold water. Note that water moves between soil particles, not through them. Water is held by soil particles by a series of physical forces.
Slide 27 Water holding 27 Notice the water droplet on this twig. Water should drop to ground by gravity, but it is held by the twig. A row of water molecules adheres to the twig, are hard to dislodge. More water molecules cohere to this first row of water molecules; they are bound indirectly to the twig, but are easier to remove.
Slide 28 Soil Water Wilting point Field capacity Unavailable water Available Water Saturation 28 Unavailable Water: water is so tightly bound to soil particles (adhesion) that plant roots can not pull water molecules off the soil. This water is not available to plants. Available Water: water molecules cling to (cohesion) the adhered water molecules. They are held by the soil, but plant roots can pull them off. Saturation: So much water in the soil that that the water molecules can t hold onto each other any more, and the excess water leaches downward by gravity. Wilting point: soil dries out to point where all the water is unavailable. Field Capacity: water is added to soil to the point where soil particles cannot hold (cohere) any more water molecules, so gravity can pull this excess water downwards deeper into soil profile.
Slide 29 Soil Water vs. Texture 29 How well a soil can hold water varies because of its texture. Sand has the lowest ability to hold water while clay has the highest ability. Therefore, clay soils have a much higher field capacity for water than sandy soils do. However, clay holds water so well that the plants cannot have access to most of it. A clay soil has a large amount of water tied up by the soil particles, and unavailable. In fact, a clay soil can hold more moisture than a sandy soil, but be drier (as far as the plant is concerned), because of all of the unavailable water. So, the soil that can both hold a lot of water and make most of it available for plant use are in the Medium textures of Loam and Silt Loam. The graph illustrates this phenomenon.
Slide 30 How can we improve poor soil structure? Coarse Medium Fine 30 How can we improve poor soil structure? How can we optimize water drainage and retention, while also increasing the soil s ability to hold nutrients? By adding organic matter! Organic matter is material that has come from a once-living organism; usually decayed.
Slide 31 Much misinformation on soil amendments. Some from ignorance of soil science, others trying to sell you stuff. Get your info from CES!
Slide 32 Organic Matter Improves Soil Structure O. M. and organic acids it produces glue the mineral soil particles together Water Holding Capacity Increases the size of spaces between particles Nutrient Source Soil Organisms 32 This is the single most important practice we can implement. Whether it be store-bought or homemade, adding organic matter via compost, mulch or peat moss will help aid a soils ability to hold water, allow root penetration and improve a soil s structure. It will help the good bugs and organisms by both feeding them and making the soil looser for them to penetrate. In addition, O.M. will also act as holding site for which fertilizers to hold onto until plants need them. Chemically this is called the soil s Cation Exchange Capacity.
Slide 33 Organics Feed Micro- and Marco-Organisms OM feeds micro-organisms, which help roots absorb water and nutrients. OM feeds macro-organisms (earthworms), which open channels in soil and promote drainage and deeper root growth.
Slide 34 34 Finely textured mineral soil (clay) without Organic Matter: small spaces between soil particles. This allows for slow movement of water (poor drainage).
Slide 35 35 Organic matter acts as glue, binds small clay particles together, creates larger clumps. Water can move between larger clumps better than between individual clay particles.
Slide 36 Sources of Organic Matter Peat Leaves Compost Manure Cover Crops 36 Sources of organic matter: basically, anything that was a plant! Cover crops are also known as green manure. Plants are grown, then mowed down and plowed into soil.
Slide 37 Why NOT Add Sand? Can t add enough to make a difference Need as much as 12 inches of sand mixed into top 12 inches of soil Sand grains must touch one another so there are pore spaces between particles that can hold air and/or water. Otherwise, clay particles fill spaces between sand, and you get concrete. 37 Why not add sand to improve drainage, etc?
Slide 38 Why NOT Add Sand? Can t mix well enough Hundreds of years of soil moving through earthworms. Use Cuisinart to mix Every Cubic Inch! 38 Why not add sand? Can t mix well enough. Get clods covered with sand. A true soil, with structure and texture, doesn t allow you to see individual sand, silt and clay particles. They ve been mixed too well by earthworms, etc.
Slide 39 Other amendments that don t work... Gypsum: calcium sulfate. Only works on high-sodium soils Out West Oil rig spills Neutral doesn t change ph Lime: Only raises ph of soil Sulfur: Lowers ph of soil, necessary nutrient 39 Other amendments that won t work... Gypsum: calcium sulfate. Soils with lots of sodium collapse on themselves, and prevent water from draining. Calcium knocks the sodium off of high-sodic soils. Sodium washes out of soil. These soils don t exist in Indiana!
Slide 40 Soil Soil Microorganisms Microbes Amount of organisms in top foot of soil Organism Number/gram soil Typical Pounds/acre-foot soil Bacteria 1 Billion 750 Actinomycetes 15 Million 1,100 Fungi 1 Million 1,700 Protozoa 1 Million 300 Algae 100,000 250 Yeasts 1,000 --- Worms and Insects --- 900 T.M. McCalla, Neb. Ag. Exp. Sta. Research Bulletin, 1959 40 Microbes: Big market push for these very little research backs up their use. Why? Organic product marketers make it sound like your bad management (ie use of man-made fertilizers) has killed off all native microbes. Unless you are gardening at Chernobyl, this is a LIE! Huge numbers of microbes already in your soil you can t add enough to make a difference! (Note, most magic microbe packages contain less than a pound of microbes see slide above to see how many hundreds of pounds exist per acre!
If not native...probably won t survive your soil s environment.
Slide 41 Topsoil over compacted layer 41 Adding topsoil over compacted layer can cause water movement problems. Water moves through the topsoil layer quickly, but then hits the interface between the new topsoil and the native clay soil. Water will not cross this interface until so much water collects above it that gravity can pull it across. This leads to actually more root drowning problems than not having added anything at all! By the way: what you get when you buy a load of topsoil is not really topsoil, as we defined it in slide 8. In the Evansville area, topsoil is really river bottom silt that is dredged up from a field next to the Ohio River. No organic matter in it; it can actually compact and form bricks.
Slide 42 Adding topsoil to compacted soil 42 How to add topsoil over native compacted soil. Basically: rototill the native soil as deeply as possible. Add 2 or 3 inches of topsoil. Rototill again. Add another 2 or 3 inches of topsoil. Rototill again. Repeat until you ve raised the grade to where you want it. Lots of work! But the benefit is that we do not create an interface between topsoil and native soil. The soil structure changes gradually from near 100% topsoil at the top to 100% native soil at the bottom. Water can move through the gradually changing soil types very easily.
Slide 43 Irrigation 1 inch of water per week ~ ½ gallon water per square foot 43 Irrigation, 1 inch per week. This equals slightly over ½ gallon of water per square foot. Over watering is actually more common than underwatering.
Slide 44 Irrigation 44 Deep watering promotes deep root systems. 1 inch water goes down 8-12 inches, and the roots follow this moisture downward. Light, frequent waterings do nothing more than wet the dust; it promotes shallow roots, thatch. Apply all water at one time.
Slide 45 Irrigating beds 45 When irrigating plants in beds or planters, apply slightly more than 1/2 gallon per square foot/ week. This is the equivalent of 1 inch of water.
Slide 46 Irrigation 46 Make sure you irrigate entire root system, not just under branches.
Slide 47 Plant Nutrition Plant Nutrition
Slide 48 The Periodical Table 118 known elements. Over 60 elements found in plant. But only 16 are essential for plant growth.
Slide 49 Plant essential elements: An element is essential if the plant cannot complete its life cycle (produce seed) without the element, or if the element is a part of a plant component such as Mg in chlorophyll. Essential elements Plant essential elements, definition.
Slide 50 Essential Nutrients (16) Carbon Hydrogen Oxygen Nitrogen Phosphorus Potassium Sulfur Magnesium Calcium Iron Boron Manganese Copper Zinc Molybdenum Chlorine 16 Essential elements
Slide 51 Macronutrients (tons/acre) From Air and Water C H O Carbon, Hydrogen, Oxygen Carbon, hydrogen and oxygen are the macro nutrients needed by plants for growth. They are used on the scale of tons per acre by plants. Fortunately, water and air supply these needs for plant growth. Otherwise, we would be in big trouble. Imagine going to the garden supply store to buy carbon for your plants!
Slide 52 Macronutrients (pounds/acre) Primary Nitrogen - N Phosphorus - P Potassium - K Secondary Sulfur - S Calcium - Ca Magnesium - Mg Macronutrients are needed in large amounts by the plant, measured in pounds per acre. Primary macronutrients are the ones that are used in the highest quantities, and frequently need to be replaced through fertilization. The secondary nutrients are needed in large amounts, too, but these are usually in such sufficient quantities in most soils that they are not regularly added in fertilizers.
Slide 53 Micronutrients (ounces/acre) Iron - Fe Boron - B Manganese - Mn Copper - Cu Zinc - Zn Molybdenum - Mo Chlorine - Cl Micronutrients (sometimes called trace elements ) are needed by plants in very tiny amounts - on an ounces per acre basis. Plant needs vary greatly on micronutrients. For instance, red maples and pin oaks both need iron, however oaks need even more. Consequently, both trees can be in a yard with the oak suffering an iron deficiency while the maple does fine.
Slide 54 Some important nutrients and deficiency symptoms We will now examine a few of the more important nutrients for plants, and discover what they do for the plant. We will also look at what happens to the plant when it doesn t get enough of a certain nutrient in other words, we want to look at the symptoms of a nutrient deficiency. An important thing to know is that where the deficiency symptoms first appear. That will help us diagnose what might be missing. And where the deficiency symptoms first appear on a plant is based on that nutrient s mobility within the plant.
Slide 55 Nutrients that are Mobile within the plant The biggest sink for nutrients (the part of the plant that needs the nutrients the most) are the growing points: meristems, buds, etc. Everything is being pulled to this growing point. In other words: nutrients are required most by NEW growth. If a plant is deficient in a nutrient, sometimes it can pull that nutrient from the OLD growth. If a nutrient can be pulled from the old growth and sent to the new growth, we say that this nutrient is mobile within the plant. An example would be nitrogen. Because the nutrients are being pulled from the old growth first, the symptoms of that deficiency will show up in the old growth first.
Slide 56 Nutrients that are Immobile within the plant The biggest sink for nutrients (the part of the plant that needs the nutrients the most) are the growing points: meristems, buds, etc. Everything is being pulled to this growing point. In other words: nutrients are required most by NEW growth. If a plant is deficient in a nutrient, sometimes it can t pull that nutrient from the OLD growth. That nutrient would be said to be immobile (or non-mobile) within the plant. In this situation, the symptoms of deficiency will be in the NEW growth first. Symptoms can be yellowing of the leaves, stunting of growth, and even death of growing points. An example of an immobile element would be calcium, which can cause buds to die. It s also responsible for blossom end rot in tomatoes.
Slide 57 Nitrogen N 78% of the air contains N 2 gas Atmospheric N supplies soil with N through fixation by bacteria. Some forms of N can be mobile in soils Absorbed in Nitrate, Ammonia and Urea forms through roots Legumes absorb N directly from rhizobium bacteria that live in the roots Promotes leaf and shoot growth N deficiency symptoms: yellowing, stunting, browning along leaf margins, symptoms show up first on older leaves If its growing, it needs nitrogen. Nitrogen is a building block nutrient needed for DNA and RNA. So, every time a cell splits or reproduction occurs, nitrogen is needed. N is adsorbed by plant roots in the form of nitrates, ammonium, and urea. Another form of nitrogen, nitrite, is poisonous to plants and detrimental to plant growth. Ironically, roots and plants are swimming in nitrogen they cannot use. Nitrogen, in gaseous N2 form, is useless until it is fixed into a usable form. In the case of legumes, these roots are infected with bacteria that fix the atmospheric nitrogen and feed the plant. To return the favor, the plants feed and protect the bacteria. A win-win solution for the plant and the bacteria. The single most important thing to remember about nitrogen is that it promotes leaf and shoot growth. If there is not enough nitrogen, the plant is deficient, and will not grow properly. The symptoms of nitrogen deficiency include yellowing of the older leaves, stunting of new growth. Nitrogen is MOBILE within the plant, because the first symptoms appear on the old growth.
Slide 58 Excess Nitrogen... Excess nitrogen can cause too much leaf growth. Over-fertilizing lawns can cause rampant growth, necessitating frequent mowing. Another example would be a 10 foot tall tomato plant with no fruit the plant is being forced to devote all its food resources to leaf and stem growth, at the expense of flowers and fruit.
Slide 59 Phosphorus - P Promotes early growth, rooting, maturity, seed set Promotes flowers, fruit, and roots P deficiency symptoms: slow growth, purplish color, poor fruiting. P is mobile so symptoms will show up first in older leaves Phosphorus: The element s symbol is P. It is usually absorbed by the plant in the form of phosphate ions (P2O4). Phosphorus promotes early growth and rooting, so it is often used as a starter fertilizer when transplanting. The big thing to remember is that phosphorus promotes the growth of flowers, fruits, and roots. Deficiency symptoms are very noticeable. Phosphorus is MOBILE within the plant, because the symptoms appear on the older leaves first.
Slide 60 Potassium - K Promotes translocation of sugars, rooting, stem strength, and disease resistance K deficiency symptoms: tip and margin burn, weak stalks, stunted fruit, slow growth Shows up first in older leaves first Potassium (K) promotes rooting, stem strength, and disease resistance. It is rare to have Potassium deficiencies in southern Indiana. Potassium is absorbed and measured as potash (K2O).
Slide 61 Iron - Fe Chlorophyll constituent involved with N fixation and respiration Fe deficiency symptoms: interveinal chlorosis, twig dieback, Symptoms appear first on younger leaves Common on pin oaks, azaleas Iron (Fe) has several biochemical uses in plants, mostly involved with chlorophyll production. Since chlorophyll is the pigment that makes plants green, a deficiency in iron should cause some sort of yellowing. And it does. Iron deficiency symptoms show up as interveinal chlorosis, which means that the veins stay green, and all the tissue between the veins turns yellow. The symptoms appear on the NEW growth first, because iron is IMMOBILE within the plant. In southern Indiana, iron deficiency is very common on pin oaks, azaleas, blueberries, and other acid-loving plants.
Slide 62 Iron Deficiency Know of a puny pin oak in your area? It is most, likely suffering from iron deficiency. Notice the interveinal chlorosis, and the dieback from the tips of the branches. The textbook answer is that this tree should not be planted here. This doesn't work well when grandpa planted the tree and the family thinks of Grandpa each year when the have a picnic underneath. Slowly lowering the ph of the soil through the use of sulfur and the use of chelated iron sprayed and watered into the ground may help the tree come back to better health.
Slide 63 Soil ph ph is a measure of the soil s acidity or alkalinity Scale of 1=extremely acid, 7=neutral, 14=extremely alkaline ph scale is logarithmic rather than linear Soil ph is a measurement of the acidity or the alkalinity of the soil. ph stands for powers of hydrogen. So what is neutral? Pure water has neither acids or bases in it. It is neutral with a ph of 7. On the other hand, a pure acid has a ph of 0 and a pure base has a ph of 14. Either one will eat the chrome off your bumper!
Slide 64 Soil ph Soil ph affects the availability of plant nutrients. Soil ph affects nutrient availability. Bigger (wider) the bar, the more is available at that ph. Notice the bar for iron at the bottom. The bar is very wide at ph of 4 (highly acidic). As the ph rises (becomes less acidic), the amount of iron available to the plant decreases. The iron doesn t disappear it just gets tied up into forms (chemicals) that the plant cannot absorb. At highly alkaline ph, the amount of iron available to the plant is extremely low. This is why some gardeners locally cannot grow blueberries or pin oaks their soil ph is too high (too alkaline). Now look at calcium and magnesium (3 rd bar down). There is lots of magnesium available to the plant under alkaline conditions. However, as the soil becomes more acidic, the magnesium gets tied up into unavailable forms. Under highly acidic conditions, the plant will be highly deficient in magnesium, even though there is plenty in the soil. Why is this important? Because many of the micronutrients are present in adequate amounts in most Indiana soils. However, because of the ph, they may not be available. Instead of adding iron to help a blueberry plant, we might want to do something to change the soil ph, and free up the iron. Why is this important, part 2: The symptoms of iron deficiency are very similar to magnesium deficiency. If you look at a leaf s symptoms and just guess what it needs, you may 1) not only NOT solve the problem, but 2) you could very well make the problem worse! Most plants prefer a ph of 6.0 and 7.0 because that is where the highest level of the most nutrients can be found.
Slide 65 How do I change the ph? The ph is raised (made more alkaline) by adding lime. The ph is lowered by adding sulfur, aluminum sulfate or other compounds that turn to acid and acidify the soil. Remember: neither should be applied without the recommendation of a properly sampled soil test. Changing ph
Slide 66 Fertilizer Terms Analysis: Percentage by weight of water soluble content of nitrogen (N), phosphorus (P, expressed as P 2 O 5 ) and potassium (K, expressed as K 2 O) in the fertilizer. Ratio: The analysis broken down into the least common denominator (yikes!) Brand- Trademark of the company which produced the fertilizer. Complete Fertilizer: Fertilizer which supplies all three primary nutrients, (N,P,K) Fertilizer terms: analysis, ratio, brand, complete fertilizer. Analysis: Percent by weight of N, P2O5 and K2O in the package of fertilizer. Ratio: Analysis broken down into the least common denominators. For example: a fertilizer with the analysis of 5-10-5 has a ratio of 1-2-1 (the analysis divided by 5). Brand: Trademark. I applied Scotts Fertilizer. Doesn t really tell me much. Even telling me it s Scott s Season Long Lawn Food doesn t tell me much, unless I Google the name. If someone wants to know about whether their fertilizer product is the right stuff to use, I need to know the analysis. Complete Fertilizer: This is a marketing term. Simply means that the fertilizer contains all 3 primary macronutrients (NPK). They make it sound like you re a bad gardener if you don t give a complete fertilizer to your garden.but think! Why apply nutrients that your garden/lawn doesn t need?
Slide 67 Fertilizer terms Quick release/fast release Nutrients are readily available to the plant, all at once Can cause chemical burn to roots, water contamination Can be depleted quickly; multiple applications needed over course of garden season Slow release Nutrients released over time, not all at once Chemical burn less likely; less water contamination, usually One application can last several months May not help plant fast enough if serious deficiency exists See page 143 for comparison of these products! See page 142 for definition of quick and slow release products. See page 143 for comparison of processed, quick release, slow release, and organic fertilizer products.
Slide 68 Fertilizers Added to keep the soil s nutrient pool in good supply. Fertilizer analysis: 16-4-8 (relative percentages) 16% total Nitrogen 4% P 2O 5 (phosphoric acid, or phosphate) 8% K 20 (soluble potash) and remainder is inert filler Fertilizer is added to replace the nutrients that your plants have removed from the soil. By definition, fertilizer is a natural, manufactured, or processed material or mixture of materials that contains one or more of the essential nutrients. Inert material is filler. It may be water, ground corncobs, clay, lime, or any other product to make the fertilizer spread easily. There is no fertilizer in this line. You can use the information on this bag to know EXACTLY how much of each nutrient is in this bag, and how many bags you ll need to fertilize an area. For example This bag weighs 50 pounds (50#). We know that 16% of this bag, by weight, is Nitrogen (N). How much nitrogen is actually in this bag? 16% of 50 pounds = 0.16 X 50 = 8. Therefore, there are exactly 8 pounds of N in this bag of fertilizer. Now let s say that the Purdue recommendation for fertilizing a lawn is to apply 1 pound of Nitrogen per 1000 square feet (1# N/1000 sf). You have a large lawn area that measures 50 feet wide by 200 feet deep (50 X 200 ). How much total fertilizer (tot. fert.) do you need? 50 X 200 = 10,000 square feet. 1# N/1000 sf X 10,000 sf = 10 # N needed for the whole job. 16% of tot. fert. = 10 pounds? Do a little basic algebra Tot. fert. = 10 # / 0.16 = 62.5 #. Therefore, you would need a total of 62.5 pounds of total fertilizer to apply the correct rate of this fertilizer product to your entire lawn. You will need to buy 2 bags of this product: 50 # + 12.5 # = 62.5#. The remaining 38.5 pounds of fertilizer in the 2 nd bag can be stored somewhere dry and used next year. See pages 151-153 for more info.
Slide 69 Fertilizer application methods: Drop Spreader The drop spreader will drop the fertilizer straight down only to the width of the wheel-base of the spreader. Therefore, it usually takes longer to fertilize with a drop spreader, but it is more accurate then its broadcasting counterparts. The pattern you should use to apply is much the same as the broadcast spreader except that, since the spread width is narrowed, it's a good idea to slightly overlap the wheelbase while making a pass to assure even coverage. It's also a good idea to make two passes perpendicular to each other to insure an even spread. However, make sure that you only apply half of the recommended fertilizer on each pass when you do so.
Slide 70 Fertilizer application methods: Drop spreader Broadcast Broadcast spreading has become one of the most popular ways to apply fertilizer to your lawn. A walkbehind rotary spreader has two wheels that help spin the rotary spreader at the bottom to quickly release the fertilizer and spread it out over a larger area (typically 3-5 feet in width). Most types can hold a relatively large amount of fertilizer in the holding bin and make a fairly even distribution of fertilizer while moving at a constant rate. Additionally, most of the spreaders have a release control lever at the handle (much like the throttle on a mower) that controls the amount of fertilizer released during spreading.
Slide 71 Fertilizing Pattern With the rotary walk-behind versions, it is best to start with the edges of the lawn and proceed back and forth until your lawn is completely covered. Make sure on the first pass that you determine the spreading width so you can make parallel passes without excessive overlap. Always make sure that if you stop or pause during the spreading, that the control lever is turned off so no excess fertilizer will leak onto the lawn and burn it. Some gardeners will apply 1/2 rate going 1 way (north/south), and the other half at right angles (east/west).
Slide 72 Fertilizer application methods: Broadcast Drop spreader Spikes Fertilizer spikes are a slow-release form of nitrogen. Fertilizer is concentrated in pellets. Fast, easy to use. Expensive. Can cause root burn, if the spike is placed directly over small feeder roots. With trees, can miss feeder roots altogether, because you don t know where the roots are. Dissolved nutrients tend to flow downward with soil moisture, don t go sideways looking for roots.
Slide 73 Fertilizer application methods: Broadcast Drop spreader Spikes Sidedressing Sidedressing is a way to add supplemental fertilizer during the growing season. Fertilizer is put to side of row or plants. Avoid getting dry fertilizer on the foliage! It will cause chemical burning of the leaves.
Slide 74 Fertilizer application methods: Broadcast Drop spreader Spikes Side dressing Starter fertilizer Starter fertilizer is high in phosphorus, important for early root growth in cold soil. This is often used in the first watering after a transplant has been placed into the soil.
Slide 75 Fertilizer application methods: Broadcast Drop spreader Spikes Side dressing Starter Foliar Foliar feeding putting fertilizer on leaves. Absorbed quickly, corrects deficiencies temporarily. Does not correct soil deficiency. So, you re only masking the symptoms, not actually fixing the problem (a lack of that nutrient in the soil). Easy to cause chemical burn on the leaves of sensitive plants. Difficult to know how much actual fertilizer you are applying per 1000 square feet.
Slide 76 Fertilizer application methods: Broadcast Drop spreader Spikes Side dressing Starter Foliar Root feeders/injectors Root feeders inject fertilizer solution under pressure into root zone of trees, shrubs. Gets fertilizer below surface, usually doesn t provide nutrients to turf. Not really recommended, but is popular with people who want to fertilize their shrubs/trees, without fertilizing the lawn and needing to mow more. In theory, the fertilizer solution should move outwards in a cloud of nutrients from the applicator wand.
Slide 77 Pattern for soil injection: every 2-3 feet, starting 4-5 feet from trunk. LOTS of holes. In theory, the fertilizer solution should move outwards in a cloud of nutrients from the applicator wand. In reality, in heavy clay soils, fertilizer solution can NOT spread outwards. Usually shoots straight upwards out of the hole, up your pant legs, turning your socks a lovely shade of blue. The excess fertilizer then spills back onto the lawn in small splotches. Lawn looks like army of poodles marched across the yard and piddled ever 2 feet. Looks ridiculous
Slide 78 Organic Fertilizers Manures: cow, horse, poultry Animal by-products: blood meal, fish meal Green Manures: mustard, vetch, peas, barley, rye Good minerals : greensand, rock phosphate Organic fertilizers give their nutrients when they break down into their elemental forms in the soil. This can be done rather quickly, like bloodmeal, or it can take years as the humus or sawdust breaks down and gives off nitrogen and trace amounts of other fertilizers (potash and sulphur to name a few). Some organic, like green manures, are actually grown as a cover crop or the previous planting season and then plowed into the grounds to give off nutrients as they decompose.
Slide 79 Basic difference between organic and inorganic fertilizers. Chemical fertilizers (Miracle Gro, 10-10-10) provide the minerals that are required for plant. Some organic fertilizers (manures) provide not only the needed minerals, but bulk organic matter. This organic matter slowly breaks down by being eaten by soil microorganisms (fungi, bacteria) and macroorganisms (earthworms). The action of these living organisms improves soil structure, drainage, and aeration.
Slide 80 Nutrient value of some organic fertilizers (% by weight) Material N P 2 O 5 K 2 O Compost (Yard Waste)** Amount Needed (lbs/a)* Availability 1.0 0.25 1.0 4400 Slow Cow manure, dry 1.5 2.0 2.3 2930 Slow Cow manure, fresh 0.5 0.2 0.5 8800 Medium Chicken manure, dry 4.5 3.5 2.0 1000 Med-Fast Horse manure, fresh 0.7 0.3 0.5 6300 Medium Sheep manure, fresh 1.4 0.7 1.5 3150 Medium 10-10-10 fertilizer 10 10 10 440 Fast *Amount needed to supply 44 pounds of N/acre, ~ 1 # N/1000 sq. ft. ** Backyard compost analysis can be variable, based on materials used, time composted, and management practices. Approximate nutrient analysis of some fertilizer materials. Notice the differences between animals, and whether material is fresh or dry. Then compare with processed 10-10-10 fertilizer material.
Slide 81 Manure Best product for amending soil (bulk) May contain weed seeds Odor Bacterial contamination? Large amounts needed (low analysis) Weed seeds: worse in horses because of straw bedding and incomplete digestion of food. Odor: problem with neighbors! Bacterial contamination see next slide. Large amounts needed (tons per acre).
Slide 82 Manure: Food Safety Timing manure application and harvest Incorporate (plow, disk, till) Types of crops Sidedressing? No. Manure tea? No. See page 145 for safe handling. Manure may contain harmful bacterial, such as E. coli. If the contaminated manure touches the edible part of the crop, you could be setting yourself up for food poisoning. Food safety - Timing: 120 days from application of manure until first harvest. Types: Best - Fruit trees and bushes; vegetables to be heat treated (cooked) before consumption. Good: Veggies on stakes; mulch over soil to prevent splatter. If the edible portion has no contact with soil, there s little risk. Worst: Leafy vegetables that touch soil; root crops. These are in direct contact with contaminated soil. No sidedressing: not enough days to harvest Manure tea: No! Still has microbes; extremely low in nutrients; no magic ingredients inside it.
Slide 83 Don t Guess ----Soil Test HO - 71 Every 3 to 5 years unless problems arise Take a good sample Depth of tillage (6-8 inches) 3-4 inches for lawns Use a certified soil test lab Don t guess, soil test. Use a certified soil test lab, such as Farm Bureau Coop. They come up with consistent results, and provide recommendations to fix deficiencies. Home test kits are inaccurate, and they don t provide recommendations.
Slide 84 Soil sampling Soil sampling: Sample each part of garden separately. Most people fertilize the vegetable garden differently than the lawn. The top of the hill may be different than the bottom of the hill. The front yard may be native soil, but the backyard is where the subsoil dug out to make your basement was dumped. Each different site, each different soil, each different crop use may cause differences. Take several representative subsamples from each location. Combine 5 to 7 scoops of soil from each sample area. That way you average out weird anomalies. For example: if a dog peed on one spot last week, and that s the only spot you took a sample, your results are going to be way off
Slide 85 Soil sampling Put plugs of soil in plastic bucket, mix together. Take about 2-3 cups in sample bag and bring to soil test lab. Be sure to accurately label each bag so you know where it came from!
Slide 86 Soil test results. Important points: ph, Phosphorus, Potassium, soil texture. CEC is for soil technician. Magnesium and Calcium: don t worry about. Micronutrients: don t test for unless ph is normal but still seeing deficiencies. See pages 148-150 for explanation.