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424 Cards in this Set
- Front
- Back
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What is a macro nutrient? |
A nutrient required by plants in larger quantities. |
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What is a micro nutrient? |
A nutrient required by plants in smaller quantities. |
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Name the 3 non fertilizer nutrients utilized within the physical plant structure. |
a. Carbon. b .Hydrogen. c. Oxygen. |
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The primary macro nutrients essential for plant nutrition are? |
a. Nitrogen. b. Phosphorus. c. Potassium. |
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The secondary macro nutrients essential for plant nutrition are? |
a. Calcium. b. Magnesium. c. Sulfur. |
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the micro nutrients essential for plant nutrition are? |
a. Iron. b. Boron. c. Copper. d. Chlorine. e. Mangenese. f. Molybdenum. g. Zinc. h. Cobalt. i. Nickel. |
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What are the functions of nitrogen in plants |
1.Found inchlorophyll, nucleic acids and amino acids; component of protein and enzymes. 2. N is responsible for increasing protein content in plants and grains. 3. Necessary for chlorophyllsynthesis. 4. Nitrogen as a part of chlorophyllmolecules is involved in in photosynthesis. 5. Promotes new plant growth. |
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What are the common symptoms associated with nitrogen deficiency in plants |
1. Leaves will take on a yellow (chlorotic) appearance down the middle of the leaf. 2. Stunted growth 3. Plants and grains have low protein content 4. Reduction in protein results in stunted growth and dormant lateral buds. 5. Flowering, fruiting and starch contents are reduced. |
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What are the common symptoms associated with phosphorus deficiency in plants |
1. Essential partof the components of DNA and RNA. 2. Promotes root development andseedling growth. 3. Component of the ATP system, the "energy currency“ of plants. 4. Improves seed production and flower formation |
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What are the common symptoms associated with potassium deficiency in plants |
1. Yellowing of the leaf margins andveins 2. Crinkling or rolling of the leaves |
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What are the symptoms associated with zinc deficiency in corn |
1. White bands in younger leaves. 2. Abnormal ear and tassel development. |
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What are the symptoms associated with zinc deficiency in flax |
1. Gray-brown spots develop on younger leaves. 2. Short and stunted appearance due to abnormally short internodes along the stem. |
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What are the symptoms associated with zinc deficiency in beans |
1. Overall stunting in plant growth. 2. Leaves develop light yellow blotches between the veins. |
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What are the symptoms associated with manganese deficiency in cereals |
Pale green, white or gray colored between the veins of the leaf. |
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What are the symptoms associated with boron deficiency in canola and alfalfa |
Canola and Alfalfa are more sensitive to boron deficiency than other crops. In canola there is seed abortion and pale yellow discoloration. |
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What are the symptoms associated with boron deficiency in alfalfa |
1. Yellowing or reddening of young leaves. 2. Death of terminal buds. 3. Rosetting |
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What is Rosetting ? |
This is the abnormal formation of short branches near the top of plants. |
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How plant does nutrients needs change as plant growth progresses from germination to maturity |
plant nutrient needs gradually increases during the seedling stage, rapidly increases during vegetative stage and decreases as reproductive growth begins. |
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What is a soil solution? |
The liquid found in the soil. Plantnutrients (solids and gases) dissolved in the soil solution can move into theplant as the water is taken up by the roots |
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What are cations? |
Positively charged ions(Ca2+, K+,and NH4+) which are held on negatively-charged exchange sites in the soil. |
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What is cation exchange capacity? |
This is a measure ofthe amount of cations that can be held by the soil and released into the soilsolution. |
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what is soil organic matter? |
Soil organic matterrefers to hydrocarbon compounds in various stages ofdecomposition. |
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what is a primary soil mineral |
Primary mineralspersist with little change in composition. Examples include: quartz, micas andfeldspars |
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what is a secondary soil mineral |
Secondaryminerals are formed by the breakdown and weathering of primary minerals.Examples include iron, dolomite and calcite |
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Define the term soil texture. |
Soil texture isdefined as the proportion of sand, silt, and clay in the soil. |
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Define the term soil structure. |
Soil structure isdefined as the arrangement of soil particles into aggregates. |
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Define the term mass flow. |
Massflow is the movement ofdissolved nutrients into a plant as the plant absorbs water for transpiration. |
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Describe the process of diffusion during plant nutrient uptake. |
Diffusion isthe movement of nutrients to the root surface in response to a concentrationgradient. When nutrients are found in higher concentrations in one areathan another, there is a net movement to the low-concentration area so thatequilibrium is reached. |
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Describe the process of root interception during plant nutrient uptake. |
Rootinterception occurs when growth of aroot causes contact with soil colloids which contain nutrients. The root thenabsorbs the nutrients. |
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What is nutrient uptake antagonism? |
Nutrient uptake antagonism refers to the competitionbetween nutrients for uptake by plants. The two nutrients, often ionswith the same charge, are said to be antagonistic with regard to theother. |
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Briefly describe the nitrogen cycle. |
Nitrogen Cycle is a continuous sequenceof natural processes by which nitrogen in the atmosphere and nitrogenouscompounds in the soil are converted by nitrification and nitrogen fixation intosubstances that can be utilized by green plants and then returned to the airand soil by denitrification and plant decay. |
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Describe the process of fixation in the nitrogen cycle. |
Fixation byclay refers to association of nitrogen with the soil. Since the soil has anegative charge, the ammonium ion (NH4+) can be bound to the soil particle |
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Describe the process of mineralization in the nitrogen cycle. |
This is the conversion of organic N in manure, crop residues and soil organicmatter to inorganic N. |
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What is nitrification? |
Nitrification isthe process by which microbes use enzymes to convert ammonium (NH4+)to nitrate (NO3-) to obtain energy. |
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Describe the process of denitrification in the nitrogen cycle. |
Denitrification occurs when NO3- isconverted into gaseous forms of N. This is the lossof nitrogen through the conversion of nitrate intovarious gaseous forms. |
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What is volatilization |
Volatilization isthe production and loss of ammonia gas from ammonium. |
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Describe the process of immobiliation in the nitrogen cycle. |
Immobilization is the reverse of mineralization. Microbes tie up crop available N.Microbes compete with crops for NH4+ andNO3- for their own survival;when nitrogen is scarce the microbes convert inorganic N forms into their ownorganic forms, preventing plants from taking the N up. |
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What is leaching |
Leaching is the loss of NO3- fromthe soil with water movement. Nitrate has a negative charge, soit does not attach to soil particlesand easily washes below the root zone. |
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What are the 3 main factors that influence leaching? |
1. Soildrainage 2.Rainfall 3.Amount of nitrate in the soil |
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Describe the process of plant uptake in the nitrogen cycle. |
Plant uptake occurs when plant take in nitrates and ammonium(to alesser extent) to form essential compounds for yield and quality, amino acidsand proteins |
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What is symbiotic fixation |
Symbiotic fixation isthe conversion of nitrogen gas fromthe atmosphere to plant protein. Atmospheric N is fixed in a symbiotic processcarried out by microorganisms, the Rhizobium bacteriawhich form root nodules in legumes |
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What soil factors affect symbiotic nitrogen fixation? |
1. Soil pH 2. Population of Rhizobia species 3. Moisture 4. Nitrogen level |
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How does cropping systems on affect soil fertility levels |
1.The productivity of crops ishigher in crop rotation system than in permanent mono-cropping system. 2. Crop type – different crops havedifferent nutrient requirements. 3. Root system of crops 4.Irrigation with water containingcarbonates increase soil pH |
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What are the types of solid fertilizer application? |
1. Broadcasting 2. Placement 3. Band Placement 4. Pellet Application |
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What are the types of liquid fertilizer application? |
1. Starter solution 2. Foliar application 3. Fertigation 4. Soil injection 5. Aerial application |
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Where are symptoms seen in plants when there is a deficiency in mobile nutrients? |
Symptoms appear inthe older leaves, as the nutrients are transported to new growth from there |
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Where are symptoms seen in plants when there is a deficiency in immobile nutrients? |
Symptoms appear in the new growth asthe plant was unable to take up sufficient amounts to transport them to the newshoots. |
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Describe how nutrientdemands change at different plant growth stages. |
plant nutrient demands increase during seedling stage, rapidly increases during vegetative stage and decreases at reproductive stage. |
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chemical uptake forms of nitrogen |
NO3- NH4+ |
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chemical uptake forms of phosphorous |
HPO42- H2PO4- |
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chemical uptake form of potassium |
K+ |
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chemical uptake form of Sulfur |
SO4- |
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chemical uptake form of calcium |
Ca2+ |
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chemical uptake form of magnesium |
Mg2+ |
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How is an immobile nutrient is placed placed in the soil to ensure plant uptake |
Example: Phosphorus isbanded closeto seeds to make sure it can be reached by starting roots. |
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How is an mobile nutrient is placed placed in the soil to ensure plant uptake |
Example: Sulfur placed 2inches away fromthe seed due to its high mobility in the soil. |
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What is the mobility of nitrogen in the soil? |
Mobileas NO3- immobile as NH4+ |
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What is the mobility of phosphorous in the soil? |
Immobile |
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What is the mobility of sulfur in the soil? |
Mobile |
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What is the effect of moisture on nutrient uptake? |
Low moisture can result in the formation of insoluble nutrient-containing compounds. |
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What are the functions of sulfur in plants |
1. Promotes nodule formation in legumes. 2. Active in the conversion ofinorganic N into protein. 3. Component ofthe compounds that give the characteristic odors and flavors to mustard, onionand garlic |
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Sulfur deficiency in plants results in? |
1.Pale flowers. 2.Thickened twistedpods with aborted seeds. |
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Fall fertilizer application |
If the nutrients remain available over winter, may be advantageous due to labour, equipment, fertilizer availability & price. Fall weather may interfere with application, nutrient losses could occur over winter. |
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Spring Preplant Fertilizer Application |
Plant nutrients are applied near the time that the crop will require them. Can take into account factors such as weather, crop price, and fertilizer price. Requires an additional equipment pass in comparison to side banding or seed-placed fertilizer |
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Planting/Pre-emergence Fertilizer Application |
Nutrients are applied near the time the crop will require them. Planting can be combined with nutrient application. Seedlings may be sensitive to the fertilizer |
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Post-Emergence Fertilizer Application |
Can compensate for changing growing conditions and crop nutrient needs. Adverse weather can limit the timing and effectiveness of applications. More expensive than applying all nutrients early in the season. |
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Split Fertilizer Application |
Can maximize yield, which is advantageous if net income is also maximized |
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Polymer Coated Urea |
Allows water to slowly permeate the porous polymer layer, dissolve urea, then gradually diffuse into the soil through the polymer layer. Soil moisture and temperature are the most important environmental factors controlling rate of urea release and polymer breakdown. |
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Urease Inhibitor |
Mode of action is not clearly defined, thought to be a substrate for the urease enzyme. It allows urea to be retained longer rather than being converted to ammonia. |
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Polymer Additive for P Fertilizers |
Increase P availability in the soil by interfering with other cations or through complexation of P. Reduces P precipitates and increases P solubility. |
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Seed Inoculant Containing Penicillium bilaiii |
Naturally occurring fungus that colonizes root zone. Releases compounds that function in making bound mineral forms of phosphorus applied phosphate fertilizers more available. |
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Plant Growth Promoting Soil Rhizobacteria |
Naturally occurring soil organism that is attracted to root exudates. Sulpher oxidizer that makes sulphur more plant-available. May also stimulate root and root hair development, and out-compete undesirable soil bateria. |
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Nitrification Inhibitor |
Interrupt the nitrification process to slow the conversion of ammonium and nitrite to nitrate. Eliminate the bacteria Nitrosomonas where ammonium is present. |
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Composite Granule |
Multiple macro and micro nutrients combined into one granule. Allows uniform application in the field. |
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Band Fertilizer Application |
Fertilizer placed slightly below and to the side of the seed, slightly below the seed, or between the rows. |
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Broadcast Fertilizer Application |
Fertilizer is spread across the top of the soil. Can be surface, incorporated, or top-dressed |
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Seed Placed Fertilizer |
Fertilizer is placed in the same position as the seed. |
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Injection |
Application of liquid or gaseous fertilizer in a zone beneath the soil surface. Requires specialized equipment, but allows for precise placement. |
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Fertigation |
Application of dissolved or suspended fertilizer by injection into an irrigation system. Requires an injection pump. Application rates can be precisely determined, but spray drift can cause non-uniformity. |
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Foliar Fertilizer |
Used to apply small amounts of nutrients in liquid form to a growing crop, usually a row crop. |
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Manure moisture Content |
Impacts NH4+ losses and decomposition of stored manure. Dry manures are resistant to decomposition, moist manures are not. |
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Manure percent solids |
Directly affects actual manure applied for a given volume or weight of manure |
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Manure incorporation |
Reduces NH3 losses and optimizes organic N mineralization compared to surface-applied. Other nutrients may or may not be more available. |
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State of manure decomposition |
More decomposition --> less organic N, remaining organic N is resistant to mineralization |
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Manure composting |
Reduces availability of nutrients bound in manure organic compounds as those organic compounds decompose very slowly compared to the original manure |
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Timing of manure applications |
Timing application to take advantage of nutrient availability and minimize losses to the environment maximizes nutrients available to the crop. |
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Manure application method |
Incorporated manures exhibit minimal NH3 volatilization and mineralize N more rapidly than surface application. Nutrients such as P and K are subject to losses through runoff and erosion in surface application. |
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Anhydrous ammonia |
NH3 82-0-0 Liquid under pressure, gas at reduced pressure |
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Urea |
(NH2)2CO 46-0-0 Solid |
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UAN |
Urea plus ammonium nitrate solution 28-0-0 to 32-0-0 Liquid |
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Ammonium nitrate |
NH4NO3 33.5-0-0 or 34-0-0 Solid |
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Ammonium sulfate |
(NH4)2SO4 21-0-0 Solid |
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Calcium nitrate |
Ca(NO3)2 2H2O 15.5-0-0 Solid |
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Aqua ammonia |
NH4OH 20-0-0 Liquid |
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Calcium ammonium nitrate |
(CAN), NH4NO3 plus lime 27-0-0 Solid |
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How many years of production can yield goals be estimated from? |
5-10 |
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Crop Nutrient Requirement |
the product of the crop weight and nutrient concentrations |
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What are 2 ways crop rotation impacts crop nutrient needs? |
1. fertilization of one crop may also provide sufficient fertility for other crops in the rotation 2. the portion of a crop returned to the soil can increase or decrease the need for a nutrient by a succeeding crop |
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The P Index |
Gives a relative measure of the potential for a given tract of land under a given set of management conditions to contribute P to an aquatic system |
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what are the 4 factors that the P Index is based off of? |
1. P Source 2. P Transport 3. Rainfall 4. Best Management Practices |
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What is the ratio of total N to total P in most manures? |
3:1 |
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What are 2 major disadvantages of P-based manure applications? |
1. more area is needed for land application as manure application rates are smaller than N-based approach 2. supplemental N must be added for adequate crop growth |
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Environmentally Sensitive Area |
from a nutrient standpoint is an area which can be degraded by the addition of excess nutrients like N and P |
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Erosion |
soil particles which are transported to a surface water carry nutrients, pesticides, metals and other potentially hazardous materials |
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Runoff |
runoff can carry dissolved nutrients, pesticides, metals and other potentially hazardous materials to a surface water |
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What is an Animal Unit |
one animal unit (AU) is 1000 lbs of live animal |
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what calculations is an Animal Unit used for? |
estimating manure production, determining how much land is needed for manure application, what best management practices should be employed, and evaluating whether or not feed rations should be changed. |
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What feeding management options do you have to reduce excess nutrient production in manure? |
phase feeding, amino acid supplemented low crude protein diets, low phytin P grain and enzymes, such as phytase |
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Biosolid |
any organic material, such as livestock manure, compost, sewage sludge, or yard wastes applied to the soil to add nutrients or for soil improvement |
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N-based nutrient application |
the rate of application of a nitrogen containing material so the desired amount of nitrogen is applied, regardless of the amounts of other nutrients being applied in the material |
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P-based nutrient application |
the rate of application of a phosphorous containing material so that the desired amount of phosphorous is applied, based on balancing the agronomic rate or crop removal rate of the crop with the amount of phosphorous contained in a material |
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What are the 4 aspects to every fertilizer application outlined by the 4R Nutrient Management Stewardship? |
1. Source 2. Rate 3. Time 4. Place |
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What are the 3 benefits to having an efficient fertilizer management application system as outlined by the 4R Nutrient Management System? |
Environmental, Economic, Social |
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What are the 2 ways the P Index impacts a nutrient management plan? |
1. sets minimum separation distances for nutrient application close to surface water 2. determines maximum phosphorous application rates in the vicinity of surface water |
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What happens when manure is applied to soil based on N? |
much larger amounts of P are added than can be used by crops |
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What are the 3 steps to calculating manure application rates? |
1. Determine nutrients added in one ton of manure 2.Determine actual plant available amounts of nutrients 3.Determine how much manure would be needed to meet your nutrient needs |
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When is the recommended time to sample manure? |
Right before application |
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The net contribution of nitrogen from legumes is going to vary with what? |
- type of legume-lifecycle (perennial or annual) -growing conditions -portion of the plant harvested |
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Which legume contributes the largest and most consistent nitrogen benefit? |
Field peas |
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Monoammonium Phosphate |
NH4H2PO4 12-51-0-2 or 11-55-0 Granular |
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Diammonium Phosphate |
(NH4)2HPO4 18-46-0 Granular |
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Ammonium Polyphosphate |
10-34-0 Solution form |
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Organic matter |
As soil organic matter decomposes, nutrients (primarily N, P, S) are mineralized. Soil organic matter retains cations in available forms. Plant residues are sources of nutrients as they decompose (N, P, S and all others). In some cases (high C:N) they will temporarily immobilize N. Soluble nutrients (eg. nitrate, chloride) can be leached out of plant residues prior to decomposition. |
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Irrigation water |
Commonly contains calcium, magnesium, potassium, sulfate, and chloride, an may contain appreciable levels of metals like iron and manganese. |
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Inorganic/Organic fertilizer |
Nutrients that remain in available forms (soluble, exchangeable cation, adsorbed anion) from fertilizer additions are nutrient sources for current and subsequent crops. |
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Soil minerals |
Soil minerals slowly dissolve to release nutrients. |
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Animal manure/Processed waste water |
Animal and human wastes are sources of nutrients as they decompose (e.g. N, S) and contain readily available forms of other plant nutrients (e.g. P, K). Some animal wastes contain relatively high levels of metals (e.g copper). |
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Urban/Industrial waste |
This is a broad category and, so, plant nutrients in these wastes are quite variable. Some mineralize N, others cause N immobilization depending on the C:N ratio. These wastes may contain high levels of metals (e.g. copper, zinc). |
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Crop residue |
Plant residue contains the essential elements that are returned to the soil system as the plant residue decomposes and rainfall leaches soluble nutrients from the plant residue. |
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Residual soil nutrients |
There is a carryover of nutrients from fertilizer and manure applications. A portion of these nutrients may be available for subsequent crops if they remain in the soil in available forms. |
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Shallow groundwater |
If plant roots reach shallow groundwater or groundwater moves to the root zone during evapotranspiration, nutrients soluble in that groundwater can be a nutrient source. |
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Potassium Chloride |
KCl, (aka Potash) 0-0-62 or 0-0-60 Granular or crystal |
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Ammonium Sulphate |
(NH4)2SO4 21-0-0-24 or 20-0-0-24 Granular or crystal |
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Ammonium Thiosulphate |
12-0-0-26 Solution |
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Elemental Sulphur |
S 0-0-0-90 Typically granular, may be liquid suspension |
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NO3-Nitrate |
Mobile |
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NH4+ Ammonium |
Immobile |
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H2PO4- Phosphate |
Immobile(Except where P absorption capacity has been exceeded) |
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SO4 2- Sulfate |
Mobile in most soils |
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Ca2+ |
Immobile in CEC Mobile in soil solution |
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Mg2+ |
Immobile in CEC Mobile in soil solution |
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K+ |
Immobile in CEC Mobile in soil solution |
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Boron |
Mobile |
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Copper |
Immobile |
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Manganese |
Immobile |
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Zinc |
Immobile |
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Soil pH |
the negative logarithm (base 10) of the hydrogen ion activity in water according to equation pH = -log base 10 (H+) |
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Buffer pH |
a buffer is a solution that contains weak acids, bases and salts that cause that solution to resist a change in pH. when a soil is mixed with a buffer solution, the solution pH changes because the buffer reacts with acidity on soil colloids and in the soil solution. |
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Acidic soil |
two kinds of acidity contribute to total acidity in a soil. salt-replaceable which is acidity that can be removed by an unbuffered salt solution and residual which is acidity that reacts with a buffer. |
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Alkaline soil |
soils with a pH greater than 7. |
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Lime requirement |
the amount of lime needed to change the pH of a oil to the desired value. |
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Ammonium |
A form of nitrogen that is available to plants from fertilizer and organic matter decomposition |
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Anhydrous ammonia |
Fertilizer in pressurized gas form, made by compressing air and natural gas under high temperature and pressure in the presence of a catalyst |
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Anion |
an ion with a negative charge |
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Anion exchange capacity |
The sum total of exchangeable anions that a soil can absorb |
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Aqua ammonia |
20% anhydrous ammonia dissolved in water |
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Available nutrient |
A nutrient in a form that a plant can absorb |
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Calcium Carbonate equivalent (CCE) |
the liming potential of a material as compared to CaCO3 |
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Cation |
An ion that has a positive electrical charge |
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Cation Exchange Capacity (CEC) |
the amount of exchangeable cations that a soil can adsorb at a specific pH |
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Cation Exchange Sites |
negative charged sites on the surfaces of clays and organic matter |
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Dolomitic Lime |
a naturally occurring liming material composed chiefly of carbonates of magnesium and calcium |
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Elemental sulphur |
sulfur in the elemental form that must be oxidized by soil microbes to the sulfate form for plant uptake |
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Green manure |
plant material incorporated into the soil while green or at maturity, for soil improvement |
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Gypsum |
calcium sulfate used to supply calcium and sulfur and to improve sodic soils |
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Lime fineness |
the particle size of limestone determined by the fineness of grinding. The finer the grind, the more reactive the material is in neutralizing acidity |
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Lime material |
a material capable of neutralizing soil acidity |
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Nitrate |
an inorganic nitrogen form that is very soluble, easily leached from soils, and readily available to plants |
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Nitrite |
a form of nitrogen that is the result of the first step in nitrification in soil as microbes convert NH4 to NO2. |
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Remote Sensing |
Uses spectral sensors that detect specific chemical and material bonds from satellite and airborne sensors. Detect geographical and man-made structures. |
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Electrical Conductivity |
Electrodes make contact with the soil to measure electrical conductivity. |
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Topographic Position |
Elevation changes within the field can be used to develop soil management zones.Different land forms have different properties and can be managed differently. |
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Yield Maps |
Yield variations within a field can be tracked by yield monitors. Part of the yield variation can be attributed to soil variation, so soil management zones can be derived. |
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Optical Sensors |
Measure the amount of red visible radiation and near infrared radiation reflected by the crop canopy and soil. An indirect measure of the crop's above ground biomass and nutrient uptake. |
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What information (techniques) are used to develop a soil sampling plan? (5) |
1. Yield map 2. Aerial imagery 3. Soil survey map 4. Landscape positioning 5. Land use history |
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What is random/composite soil sampling approach? |
Randomly collecting 15-20 cores per field & avoid biased areas during collecting |
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What is zone soil sampling approach? |
Dividing the field into soil management zones according to soil properties. Taking sample & fertilize each zone separately |
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What is benchmark soil sampling approach? |
Select a quarter acre as benchmark. Taking samples at the benchmark to represent the whole field (or soil management zone) |
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What is grid soil sampling approach? |
The field is sampled in a regular, geometric grid pattern. Nutrient variation within the field can be well detected Very costly |
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What factors cause variability in soil test analysis? (5) |
1. Time of sampling 2. Depth of sampling 3. Extraction chemistry and detection method 4. Methods of preparing and shipping samples 5. Number of cores per composite sample |
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What is a composite soil sample? |
A composite soil sample consists of several sub samples that are thoroughly mixed together to create one sample for analysis |
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The most practical soil sampling time in Alberta is ? |
Fall. Usually at the beginning of October |
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Summer soil sampling is usually used for ? |
Crop diagnosis |
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What is the common soil sampling depths for soil mobile nutrients? |
0-60 cm (0-24in) |
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What is the common soil sampling depths for soil immobile nutrients? |
0-15cm (0-6 in) |
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When the number of cores per composite sample increases, sample's representativity _____? |
Increases |
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In soil testing, what is extractable nutrient levels? |
Concentration of nutrients that can be extracted by chemical in a soil test |
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In soil testing, what is plant-available nutrient levels? |
The portion of any nutrient in the soil that can be absorbed and assimilated by growing plants |
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In soil testing, what is total nutrient levels? |
Total concentration of all forms of nutrient in soil, including plant available and plant unavailable forms |
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Approaches for making nutrient recommendations (4) |
1. Soil buildup/drawdown 2. Maintenance/crop removal 3. Sufficient level 4. Base saturation/nutrient balance |
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In soil testing, what is critical value |
The soil test value where yield reaches 95-97% of maximum |
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What is soil buildup/drawdown approach for making nutrient recommendations? Is it suitable for soil mobile or immobile nutrients? |
Bringing soil test value to critical value through increased fertilization (buildup) or decreased fertilization (drawdown)Soil immobile |
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What is maintenance/crop removal approach for making nutrient recommendations? |
Applying the amount of nutrients that crop remove from the soil. The soil nutrient level is maintained |
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What is sufficient level approach for making nutrient recommendations? |
This method estimates the nutrients a crop will remove from the soil to reach the target yield and subtracts the available soil nutrients as determined in the soil test. Fertilizer is only recommended if the available soil nutrients is less than the amount the crop will remove |
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What is base saturation approach for making nutrient recommendations? |
This approach is used only for Ca Mg and K recommendation. It recommends applying fertilizer to reach a specific ratio of these cations in order to achieve maximum yield |
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What factors affect soil analysis interpretation for crop management ? (5) |
1. Probability of crop response to added nutrients 2. Reported nutrient sufficiency level 3. Units used to report results 4. Within field variability 5. Environmental risk |
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When the environmental risk is high, soil test recommendation for a particular nutrient may be _______ than in situations where environmental risk is low |
Lower |
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In plant tissue nutrient analysis, what is deficient? |
Concentration of a nutrient associated with visible deficiency symptoms |
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In plant tissue nutrient analysis, what is toxic level? |
Concentration of nutrient that causes reduced growth or impaired development |
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In plant tissue analysis, what is sufficient range? |
The concentration of nutrient between critical value and toxic level. Optimal for plant growth and production. |
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What factors affect plant tissue analysis results? (7) |
1. Crop species 2. Growth stage 3. Plant part sampled 4. Crop stress level 5. Time of day sampled 6. Sample handling/preparation 7. Method and timing of nutrient application |
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What is EC? What does it indicate? |
Soil electrical conductivityIt indicates soil salinity |
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What are plant root stimulator (PRS) probes? |
They are probes made from ion exchange membranes that mimic plant root membranes. They are used to measure plant available nutrient level |
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Wheat yield is ______ correlated with protein content. As yield increases, grain protein content usually ______ . |
Negatively; decreases |
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Chlorophyll absorbs ______ and ________ colours while reflecting ______ and _______ |
Blue; red; Green; NIR (near infrared) |
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What methods can achieve non-destructive plant nutrient test? |
1 Proximal sensing 2 Chlorophyll meters 3. Remote sensing |
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What is the mechanism of chlorophyll meters? |
It measures leaf transmittance in red and infrared spectral bands and relates it to the N status in the plant |
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What is the mechanism of proximal sensing and remote sensing devices? |
They capture canopy reflectance in certain wavelengths and come up with plant nutrient status from the reflectance data |
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What is Fertilizer Act? |
The legislative authority under which the Department of Agriculture monitors and controls fertilizers and supplements sold or imported into Canada |
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What is soil amendment according to the Fertilizer Act? |
Agricultural materials, other than traditional fertilizers, that may be added to soil to improve crop growth.Ex: rock phosphate, manures, bone meal, garbage tankage etc. |
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What is mixed fertilizer according to Fertilizer Act? |
All fertilizers other than fertilizers consisting of a single material or one chemical compound |
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1 ppm = ______ lb/ac |
2 |
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What is a macro nutrient?
|
A nutrient required by plants in larger quantities.
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What is a micro nutrient?
|
A nutrient required by plants in smaller quantities.
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Name the 3 non fertilizer nutrients utilized within the physical plant structure.
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a. Carbon. b .Hydrogen. c. Oxygen.
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The primary macro nutrients essential for plant nutrition are?
|
a. Nitrogen.b. Phosphorus.c. Potassium.
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The secondary macro nutrients essential for plant nutrition are?
|
a. Calcium.b. Magnesium.c. Sulfur.
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the micro nutrients essential for plant nutrition are?
|
a. Iron.b. Boron.c. Copper.d. Chlorine.e. Mangenese.f. Molybdenum.g. Zinc.h. Cobalt.i. Nickel.
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What are the functions of nitrogen in plants
|
1.Found inchlorophyll, nucleic acids and amino acids; component of protein and enzymes.2. N is responsible for increasing protein content in plants and grains. 3. Necessary for chlorophyllsynthesis. 4. Nitrogen as a part of chlorophyllmolecules is involved in in photosynthesis. 5. Promotes new plant growth.
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What are the common symptoms associated with nitrogen deficiency in plants
|
1. Leaves will take on a yellow (chlorotic) appearance down the middle of the leaf. 2. Stunted growth3. Plants and grains have low protein content4. Reduction in protein results in stunted growth and dormant lateral buds.5. Flowering, fruiting and starch contents are reduced.
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What are the common symptoms associated with phosphorus deficiency in plants
|
1. Essential partof the components of DNA and RNA.2. Promotes root development andseedling growth.3. Component of the ATP system, the "energy currency“ of plants. 4. Improves seed production and flower formation
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What are the common symptoms associated with potassium deficiency in plants
|
1. Yellowing of the leaf margins andveins 2. Crinkling or rolling of the leaves
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What are the symptoms associated with zinc deficiency in corn
|
1. White bands in younger leaves.2. Abnormal ear and tassel development.
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What are the symptoms associated with zinc deficiency in flax
|
1. Gray-brown spots develop on younger leaves.2. Short and stunted appearance due to abnormally short internodes along the stem.
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What are the symptoms associated with zinc deficiency in beans
|
1. Overall stunting in plant growth.2. Leaves develop light yellow blotches between the veins.
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What are the symptoms associated with manganese deficiency in cereals
|
Pale green, white or gray colored between the veins of the leaf.
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What are the symptoms associated with boron deficiency in canola and alfalfa
|
Canola and Alfalfa are more sensitive to boron deficiency than other crops. In canola there is seed abortion and pale yellow discoloration.
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What are the symptoms associated with boron deficiency in alfalfa
|
1. Yellowing or reddening of young leaves.2. Death of terminal buds.3. Rosetting
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What is Rosetting ?
|
This is the abnormal formation of short branches near the top of plants.
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How plant does nutrients needs change as plant growth progresses from germination to maturity
|
plant nutrient needs gradually increases during the seedling stage, rapidly increases during vegetative stage and decreases as reproductive growth begins.
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What is a soil solution?
|
The liquid found in the soil. Plantnutrients (solids and gases) dissolved in the soil solution can move into theplant as the water is taken up by the roots
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What are cations?
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Positively charged ions(Ca2+, K+,and NH4+) which are held on negatively-charged exchange sites in the soil.
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What is cation exchange capacity?
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This is a measure ofthe amount of cations that can be held by the soil and released into the soilsolution.
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what is soil organic matter?
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Soil organic matterrefers to hydrocarbon compounds in various stages ofdecomposition.
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what is a primary soil mineral
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Primary mineralspersist with little change in composition. Examples include: quartz, micas andfeldspars
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what is a secondary soil mineral
|
Secondaryminerals are formed by the breakdown and weathering of primary minerals.Examples include iron, dolomite and calcite
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Define the term soil texture.
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Soil texture isdefined as the proportion of sand, silt, and clay in the soil.
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Define the term soil structure.
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Soil structure isdefined as the arrangement of soil particles into aggregates.
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Define the term mass flow.
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Massflow is the movement ofdissolved nutrients into a plant as the plant absorbs water for transpiration.
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Describe the process of diffusion during plant nutrient uptake.
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Diffusion isthe movement of nutrients to the root surface in response to a concentrationgradient. When nutrients are found in higher concentrations in one areathan another, there is a net movement to the low-concentration area so thatequilibrium is reached.
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Describe the process of root interception during plant nutrient uptake.
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Rootinterception occurs when growth of aroot causes contact with soil colloids which contain nutrients. The root thenabsorbs the nutrients.
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What is nutrient uptake antagonism?
|
Nutrient uptake antagonism refers to the competitionbetween nutrients for uptake by plants. The two nutrients, often ionswith the same charge, are said to be antagonistic with regard to theother.
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Briefly describe the nitrogen cycle.
|
Nitrogen Cycle is a continuous sequenceof natural processes by which nitrogen in the atmosphere and nitrogenouscompounds in the soil are converted by nitrification and nitrogen fixation intosubstances that can be utilized by green plants and then returned to the airand soil by denitrification and plant decay.
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Describe the process of fixation in the nitrogen cycle.
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Fixation byclay refers to association of nitrogen with the soil. Since the soil has anegative charge, the ammonium ion (NH4+) can be bound to the soil particle
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Describe the process of mineralization in the nitrogen cycle.
|
This is the conversion of organic N in manure, crop residues and soil organicmatter to inorganic N.
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What is nitrification?
|
Nitrification isthe process by which microbes use enzymes to convert ammonium (NH4+)to nitrate (NO3-) to obtain energy.
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Describe the process of denitrification in the nitrogen cycle.
|
Denitrification occurs when NO3- isconverted into gaseous forms of N. This is the lossof nitrogen through the conversion of nitrate intovarious gaseous forms.
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What is volatilization
|
Volatilization isthe production and loss of ammonia gas from ammonium.
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Describe the process of immobiliation in the nitrogen cycle.
|
Immobilization is the reverse of mineralization. Microbes tie up crop available N.Microbes compete with crops for NH4+ andNO3- for their own survival;when nitrogen is scarce the microbes convert inorganic N forms into their ownorganic forms, preventing plants from taking the N up.
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What is leaching
|
Leaching is the loss of NO3- fromthe soil with water movement. Nitrate has a negative charge, soit does not attach to soil particlesand easily washes below the root zone.
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What are the 3 main factors that influence leaching?
|
1. Soildrainage 2.Rainfall 3.Amount of nitrate in the soil
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Describe the process of plant uptake in the nitrogen cycle.
|
Plant uptake occurs when plant take in nitrates and ammonium(to alesser extent) to form essential compounds for yield and quality, amino acidsand proteins
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What is symbiotic fixation
|
Symbiotic fixation isthe conversion of nitrogen gas fromthe atmosphere to plant protein. Atmospheric N is fixed in a symbiotic processcarried out by microorganisms, the Rhizobium bacteriawhich form root nodules in legumes
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What soil factors affect symbiotic nitrogen fixation?
|
1. Soil pH2. Population of Rhizobia species3. Moisture4. Nitrogen level
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|
How does cropping systems on affect soil fertility levels
|
1.The productivity of crops ishigher in crop rotation system than in permanent mono-cropping system.2. Crop type – different crops havedifferent nutrient requirements.3. Root system of crops4.Irrigation with water containingcarbonates increase soil pH
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|
What are the types of solid fertilizer application?
|
1. Broadcasting2. Placement3. Band Placement 4. Pellet Application
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What are the types of liquid fertilizer application?
|
1. Starter solution2. Foliar application3. Fertigation4. Soil injection 5. Aerial application
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Where are symptoms seen in plants when there is a deficiency in mobile nutrients?
|
Symptoms appear inthe older leaves, as the nutrients are transported to new growth from there
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Where are symptoms seen in plants when there is a deficiency in immobile nutrients?
|
Symptoms appear in the new growth asthe plant was unable to take up sufficient amounts to transport them to the newshoots.
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Describe how nutrientdemands change at different plant growth stages.
|
plant nutrient demands increase during seedling stage, rapidly increases during vegetative stage and decreases at reproductive stage.
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chemical uptake forms of nitrogen
|
NO3- NH4+
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chemical uptake forms of phosphorous
|
HPO42- H2PO4-
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chemical uptake form of potassium
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K+
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chemical uptake form of Sulfur
|
SO4-
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chemical uptake form of calcium
|
Ca2+
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chemical uptake form of magnesium
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Mg2+
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How is an immobile nutrient is placed placed in the soil to ensure plant uptake
|
Example: Phosphorus isbanded closeto seeds to make sure it can be reached by starting roots.
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How is an mobile nutrient is placed placed in the soil to ensure plant uptake
|
Example: Sulfur placed 2inches away fromthe seed due to its high mobility in the soil.
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What is the mobility of nitrogen in the soil?
|
Mobileas NO3- immobile as NH4+
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What is the mobility of phosphorous in the soil?
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Immobile
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What is the mobility of sulfur in the soil?
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Mobile
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What is the effect of moisture on nutrient uptake?
|
Low moisture can result in the formation of insoluble nutrient-containing compounds.
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What are the functions of sulfur in plants
|
1. Promotes nodule formation in legumes. 2. Active in the conversion ofinorganic N into protein. 3. Component ofthe compounds that give the characteristic odors and flavors to mustard, onionand garlic
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|
Sulfur deficiency in plants results in?
|
1.Pale flowers. 2.Thickened twistedpods with aborted seeds.
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Fall fertilizer application
|
If the nutrients remain available over winter, may be advantageous due to labour, equipment, fertilizer availability & price. Fall weather may interfere with application, nutrient losses could occur over winter.
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Spring Preplant Fertilizer Application
|
Plant nutrients are applied near the time that the crop will require them. Can take into account factors such as weather, crop price, and fertilizer price.Requires an additional equipment pass in comparison to side banding or seed-placed fertilizer
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Planting/Pre-emergence Fertilizer Application
|
Nutrients are applied near the time the crop will require them. Planting can be combined with nutrient application. Seedlings may be sensitive to the fertilizer
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Post-Emergence Fertilizer Application
|
Can compensate for changing growing conditions and crop nutrient needs. Adverse weather can limit the timing and effectiveness of applications. More expensive than applying all nutrients early in the season.
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Split Fertilizer Application
|
Can maximize yield, which is advantageous if net income is also maximized
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Polymer Coated Urea
|
Allows water to slowly permeate the porous polymer layer, dissolve urea, then gradually diffuse into the soil through the polymer layer.Soil moisture and temperature are the most important environmental factors controlling rate of urea release and polymer breakdown.
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Urease Inhibitor
|
Mode of action is not clearly defined, thought to be a substrate for the urease enzyme.It allows urea to be retained longer rather than being converted to ammonia.
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Polymer Additive for P Fertilizers
|
Increase P availability in the soil by interfering with other cations or through complexation of P.Reduces P precipitates and increases P solubility.
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Seed Inoculant Containing Penicillium bilaiii
|
Naturally occurring fungus that colonizes root zone.Releases compounds that function in making bound mineral forms of phosphorus applied phosphate fertilizers more available.
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Plant Growth Promoting Soil Rhizobacteria
|
Naturally occurring soil organism that is attracted to root exudates.Sulpher oxidizer that makes sulphur more plant-available. May also stimulate root and root hair development, and out-compete undesirable soil bateria.
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Nitrification Inhibitor
|
Interrupt the nitrification process to slow the conversion of ammonium and nitrite to nitrate. Eliminate the bacteria Nitrosomonas where ammonium is present.
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Composite Granule
|
Multiple macro and micro nutrients combined into one granule. Allows uniform application in the field.
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Band Fertilizer Application
|
Fertilizer placed slightly below and to the side of the seed, slightly below the seed, or between the rows.
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Broadcast Fertilizer Application
|
Fertilizer is spread across the top of the soil. Can be surface, incorporated, or top-dressed
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Seed Placed Fertilizer
|
Fertilizer is placed in the same position as the seed.
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Injection
|
Application of liquid or gaseous fertilizer in a zone beneath the soil surface. Requires specialized equipment, but allows for precise placement.
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Fertigation
|
Application of dissolved or suspended fertilizer by injection into an irrigation system. Requires an injection pump. Application rates can be precisely determined, but spray drift can cause non-uniformity.
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Foliar Fertilizer
|
Used to apply small amounts of nutrients in liquid form to a growing crop, usually a row crop.
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Manure moisture Content
|
Impacts NH4+ losses and decomposition of stored manure. Dry manures are resistant to decomposition, moist manures are not.
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|
Manure percent solids
|
Directly affects actual manure applied for a given volume or weight of manure
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|
Manure incorporation
|
Reduces NH3 losses and optimizes organic N mineralization compared to surface-applied. Other nutrients may or may not be more available.
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State of manure decomposition
|
More decomposition --> less organic N, remaining organic N is resistant to mineralization
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Manure composting
|
Reduces availability of nutrients bound in manure organic compounds as those organic compounds decompose very slowly compared to the original manure
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|
Timing of manure applications
|
Timing application to take advantage of nutrient availability and minimize losses to the environment maximizes nutrients available to the crop.
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Manure application method
|
Incorporated manures exhibit minimal NH3 volatilization and mineralize N more rapidly than surface application. Nutrients such as P and K are subject to losses through runoff and erosion in surface application.
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Anhydrous ammonia
|
NH3 82-0-0 Liquid under pressure, gas at reduced pressure
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Urea
|
(NH2)2CO 46-0-0Solid
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UAN
|
Urea plus ammonium nitrate solution28-0-0 to 32-0-0Liquid
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Ammonium nitrate
|
NH4NO333.5-0-0 or 34-0-0Solid
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Ammonium sulfate
|
(NH4)2SO421-0-0Solid
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Calcium nitrate
|
Ca(NO3)2 2H2O15.5-0-0Solid
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|
Aqua ammonia
|
NH4OH20-0-0Liquid
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Calcium ammonium nitrate
|
(CAN), NH4NO3 plus lime27-0-0Solid
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|
How many years of production can yield goals be estimated from?
|
5-10
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|
Crop Nutrient Requirement
|
the product of the crop weight and nutrient concentrations
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|
What are 2 ways crop rotation impacts crop nutrient needs?
|
1. fertilization of one crop may also provide sufficient fertility for other crops in the rotation2. the portion of a crop returned to the soil can increase or decrease the need for a nutrient by a succeeding crop
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|
|
The P Index
|
Gives a relative measure of the potential for a given tract of land under a given set of management conditions to contribute P to an aquatic system
|
|
|
what are the 4 factors that the P Index is based off of?
|
1. P Source2. P Transport3. Rainfall4. Best Management Practices
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|
What is the ratio of total N to total P in most manures?
|
3:1
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|
What are 2 major disadvantages of P-based manure applications?
|
1. more area is needed for land application as manure application rates are smaller than N-based approach2. supplemental N must be added for adequate crop growth
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|
Environmentally Sensitive Area
|
from a nutrient standpoint is an area which can be degraded by the addition of excess nutrients like N and P
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|
Erosion
|
soil particles which are transported to a surface water carry nutrients, pesticides, metals and other potentially hazardous materials
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Runoff
|
runoff can carry dissolved nutrients, pesticides, metals and other potentially hazardous materials to a surface water
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|
|
What is an Animal Unit
|
one animal unit (AU) is 1000 lbs of live animal
|
|
|
what calculations is an Animal Unit used for?
|
estimating manure production, determining how much land is needed for manure application, what best management practices should be employed, and evaluating whether or not feed rations should be changed.
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|
What feeding management options do you have to reduce excess nutrient production in manure?
|
phase feeding, amino acid supplemented low crude protein diets, low phytin P grain and enzymes, such as phytase
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Biosolid
|
any organic material, such as livestock manure, compost, sewage sludge, or yard wastes applied to the soil to add nutrients or for soil improvement
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|
N-based nutrient application
|
the rate of application of a nitrogen containing material so the desired amount of nitrogen is applied, regardless of the amounts of other nutrients being applied in the material
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|
P-based nutrient application
|
the rate of application of a phosphorous containing material so that the desired amount of phosphorous is applied, based on balancing the agronomic rate or crop removal rate of the crop with the amount of phosphorous contained in a material
|
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|
What are the 4 aspects to every fertilizer application outlined by the 4R Nutrient Management Stewardship?
|
1. Source2. Rate3. Time4. Place
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|
What are the 3 benefits to having an efficient fertilizer management application system as outlined by the 4R Nutrient Management System?
|
Environmental, Economic, Social
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|
|
What are the 2 ways the P Index impacts a nutrient management plan?
|
1. sets minimum separation distances for nutrient application close to surface water2. determines maximum phosphorous application rates in the vicinity of surface water
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|
What happens when manure is applied to soil based on N?
|
much larger amounts of P are added than can be used by crops
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|
|
What are the 3 steps to calculating manure application rates?
|
1. Determine nutrients added in one ton of manure2.Determine actual plant available amounts of nutrients3.Determine how much manure would be needed to meet your nutrient needs
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|
When is the recommended time to sample manure?
|
Right before application
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|
|
The net contribution of nitrogen from legumes is going to vary with what?
|
- type of legume-lifecycle (perennial or annual)-growing conditions-portion of the plant harvested-weather and soil conditions
|
|
|
Which legume contributes the largest and most consistent nitrogen benefit?
|
Field peas
|
|
|
Monoammonium Phosphate
|
NH4H2PO4 12-51-0-2 or 11-55-0 Granular
|
|
|
Diammonium Phosphate
|
(NH4)2HPO418-46-0 Granular
|
|
|
Ammonium Polyphosphate
|
10-34-0Solution form
|
|
|
Organic matter
|
As soil organic matter decomposes, nutrients (primarily N, P, S) are mineralized. Soil organic matter retains cations in available forms. Plant residues are sources of nutrients as they decompose (N, P, S and all others). In some cases (high C:N) they will temporarily immobilize N. Soluble nutrients (eg. nitrate, chloride) can be leached out of plant residues prior to decomposition.
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|
|
Irrigation water
|
Commonly contains calcium, magnesium, potassium, sulfate, and chloride, an may contain appreciable levels of metals like iron and manganese.
|
|
|
Inorganic/Organic fertilizer
|
Nutrients that remain in available forms (soluble, exchangeable cation, adsorbed anion) from fertilizer additions are nutrient sources for current and subsequent crops.
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|
Soil minerals
|
Soil minerals slowly dissolve to release nutrients.
|
|
|
Animal manure/Processed waste water
|
Animal and human wastes are sources of nutrients as they decompose (e.g. N, S) and contain readily available forms of other plant nutrients (e.g. P, K). Some animal wastes contain relatively high levels of metals (e.g copper).
|
|
|
Urban/Industrial waste
|
This is a broad category and, so, plant nutrients in these wastes are quite variable. Some mineralize N, others cause N immobilization depending on the C:N ratio. These wastes may contain high levels of metals (e.g. copper, zinc).
|
|
|
Crop residue
|
Plant residue contains the essential elements that are returned to the soil system as the plant residue decomposes and rainfall leaches soluble nutrients from the plant residue.
|
|
|
Residual soil nutrients
|
There is a carryover of nutrients from fertilizer and manure applications. A portion of these nutrients may be available for subsequent crops if they remain in the soil in available forms.
|
|
|
Shallow groundwater
|
If plant roots reach shallow groundwater or groundwater moves to the root zone during evapotranspiration, nutrients soluble in that groundwater can be a nutrient source.
|
|
|
Potassium Chloride
|
KCl, (aka Potash)0-0-62 or 0-0-60Granular or crystal
|
|
|
Ammonium Sulphate
|
(NH4)2SO4 21-0-0-24 or 20-0-0-24 Granular or crystal
|
|
|
Ammonium Thiosulphate
|
12-0-0-26Solution
|
|
|
Elemental Sulphur
|
S 0-0-0-90 Typically granular, may be liquid suspension
|
|
|
NO3-Nitrate
|
Mobile
|
|
|
NH4+ Ammonium
|
Immobile
|
|
|
H2PO4- Phosphate
|
Immobile(Except where P absorption capacity has been exceeded)
|
|
|
SO4 2- Sulfate
|
Mobile in most soils
|
|
|
Ca2+
|
Immobile in CECMobile in soil solution
|
|
|
Mg2+
|
Immobile in CECMobile in soil solution
|
|
|
K+
|
Immobile in CECMobile in soil solution
|
|
|
Boron
|
Mobile
|
|
|
Copper
|
Immobile
|
|
|
Manganese
|
Immobile
|
|
|
Zinc
|
Immobile
|
|
|
Soil pH
|
the negative logarithm (base 10) of the hydrogen ion activity in water according to equation pH = -log base 10 (H+)
|
|
|
Buffer pH
|
a buffer is a solution that contains weak acids, bases and salts that cause that solution to resist a change in pH. when a soil is mixed with a buffer solution, the solution pH changes because the buffer reacts with acidity on soil colloids and in the soil solution.
|
|
|
Acidic soil
|
two kinds of acidity contribute to total acidity in a soil. salt-replaceable which is acidity that can be removed by an unbuffered salt solution and residual which is acidity that reacts with a buffer.
|
|
|
Alkaline soil
|
soils with a pH greater than 7.
|
|
|
Lime requirement
|
the amount of lime needed to change the pH of a oil to the desired value.
|
|
|
Ammonium
|
A form of nitrogen that is available to plants from fertilizer and organic matter decomposition
|
|
|
Anhydrous ammonia
|
Fertilizer in pressurized gas form, made by compressing air and natural gas under high temperature and pressure in the presence of a catalyst
|
|
|
Anion
|
an ion with a negative charge
|
|
|
Anion exchange capacity
|
The sum total of exchangeable anions that a soil can absorb
|
|
|
Aqua ammonia
|
20% anhydrous ammonia dissolved in water
|
|
|
Available nutrient
|
A nutrient in a form that a plant can absorb
|
|
|
Calcium Carbonate equivalent (CCE)
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the liming potential of a material as compared to CaCO3
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Cation
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An ion that has a positive electrical charge
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Cation Exchange Capacity (CEC)
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the amount of exchangeable cations that a soil can adsorb at a specific pH
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Cation Exchange Sites
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negative charged sites on the surfaces of clays and organic matter
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Dolomitic Lime
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a naturally occurring liming material composed chiefly of carbonates of magnesium and calcium
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Elemental sulphur
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sulfur in the elemental form that must be oxidized by soil microbes to the sulfate form for plant uptake
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Green manure
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plant material incorporated into the soil while green or at maturity, for soil improvement
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Gypsum
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calcium sulfate used to supply calcium and sulfur and to improve sodic soils
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Lime fineness
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the particle size of limestone determined by the fineness of grinding. The finer the grind, the more reactive the material is in neutralizing acidity
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Lime material
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a material capable of neutralizing soil acidity
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Nitrate
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an inorganic nitrogen form that is very soluble, easily leached from soils, and readily available to plants
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Nitrite
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a form of nitrogen that is the result of the first step in nitrification in soil as microbes convert NH4 to NO2.
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Remote Sensing
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Uses spectral sensors that detect specific chemical and material bonds from satellite and airborne sensors. Detect geographical and man-made structures.
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Electrical Conductivity
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Electrodes make contact with the soil to measure electrical conductivity.
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Topographic Position
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Elevation changes within the field can be used to develop soil management zones.Different land forms have different properties and can be managed differently.
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Yield Maps
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Yield variations within a field can be tracked by yield monitors. Part of the yield variation can be attributed to soil variation, so soil management zones can be derived.
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Optical Sensors
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Measure the amount of red visible radiation and near infrared radiation reflected by the crop canopy and soil. An indirect measure of the crop's above ground biomass and nutrient uptake.
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What information (techniques) are used to develop a soil sampling plan? (5)
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1. Yield map2. Aerial imagery3. Soil survey map4. Landscape positioning5. Land use history
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What is random/composite soil sampling approach?
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Randomly collecting 15-20 cores per field & avoid biased areas during collecting
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What is zone soil sampling approach?
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Dividing the field into soil management zones according to soil properties. Taking sample & fertilize each zone separately
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What is benchmark soil sampling approach?
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Select a quarter acre as benchmark. Taking samples at the benchmark to represent the whole field (or soil management zone)
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What is grid soil sampling approach?
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The field is sampled in a regular, geometric grid pattern. Nutrient variation within the field can be well detected Very costly
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What factors cause variability in soil test analysis? (5)
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1. Time of sampling2. Depth of sampling3. Extraction chemistry and detection method4. Methods of preparing and shipping samples5. Number of cores per composite sample
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What is a composite soil sample?
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A composite soil sample consists of several sub samples that are thoroughly mixed together to create one sample for analysis
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The most practical soil sampling time in Alberta is ?
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Fall. Usually at the beginning of October
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Summer soil sampling is usually used for ?
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Crop diagnosis
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What is the common soil sampling depths for soil mobile nutrients?
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0-60 cm (0-24in)
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What is the common soil sampling depths for soil immobile nutrients?
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0-15cm (0-6 in)
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When the number of cores per composite sample increases, sample's representativity _____?
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Increases
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In soil testing, what is extractable nutrient levels?
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Concentration of nutrients that can be extracted by chemical in a soil test
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In soil testing, what is plant-available nutrient levels?
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The portion of any nutrient in the soil that can be absorbed and assimilated by growing plants
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In soil testing, what is total nutrient levels?
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Total concentration of all forms of nutrient in soil, including plant available and plant unavailable forms
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Approaches for making nutrient recommendations (4)
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1. Soil buildup/drawdown2. Maintenance/crop removal3. Sufficient level 4. Base saturation/nutrient balance
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In soil testing, what is critical value
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The soil test value where yield reaches 95-97% of maximum
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What is soil buildup/drawdown approach for making nutrient recommendations? Is it suitable for soil mobile or immobile nutrients?
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Bringing soil test value to critical value through increased fertilization (buildup) or decreased fertilization (drawdown)Soil immobile
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What is maintenance/crop removal approach for making nutrient recommendations?
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Applying the amount of nutrients that crop remove from the soil. The soil nutrient level is maintained
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What is sufficient level approach for making nutrient recommendations?
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This method estimates the nutrients a crop will remove from the soil to reach the target yield and subtracts the available soil nutrients as determined in the soil test. Fertilizer is only recommended if the available soil nutrients is less than the amount the crop will remove
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What is base saturation approach for making nutrient recommendations?
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This approach is used only for Ca Mg and K recommendation. It recommends applying fertilizer to reach a specific ratio of these cations in order to achieve maximum yield
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What factors affect soil analysis interpretation for crop management ? (5)
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1. Probability of crop response to added nutrients2. Reported nutrient sufficiency level3. Units used to report results4. Within field variability5. Environmental risk
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When the environmental risk is high, soil test recommendation for a particular nutrient may be _______ than in situations where environmental risk is low
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Lower
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In plant tissue nutrient analysis, what is deficient?
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Concentration of a nutrient associated with visible deficiency symptoms
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In plant tissue nutrient analysis, what is toxic level?
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Concentration of nutrient that causes reduced growth or impaired development
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In plant tissue analysis, what is sufficient range?
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The concentration of nutrient between critical value and toxic level. Optimal for plant growth and production.
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What factors affect plant tissue analysis results? (7)
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1. Crop species2. Growth stage3. Plant part sampled4. Crop stress level5. Time of day sampled6. Sample handling/preparation 7. Method and timing of nutrient application
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What is EC? What does it indicate?
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Soil electrical conductivityIt indicates soil salinity
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What are plant root stimulator (PRS) probes?
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They are probes made from ion exchange membranes that mimic plant root membranes. They are used to measure plant available nutrient level
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Wheat yield is ______ correlated with protein content. As yield increases, grain protein content usually ______ .
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Negatively; decreases
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Chlorophyll absorbs ______ and ________ colours while reflecting ______ and _______
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Blue; red; Green; NIR (near infrared)
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What methods can achieve non-destructive plant nutrient test?
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1 Proximal sensing2 Chlorophyll meters3. Remote sensing
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What is the mechanism of chlorophyll meters?
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It measures leaf transmittance in red and infrared spectral bands and relates it to the N status in the plant
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What is the mechanism of proximal sensing and remote sensing devices?
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They capture canopy reflectance in certain wavelengths and come up with plant nutrient status from the reflectance data
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What is Fertilizer Act?
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The legislative authority under which the Department of Agriculture monitors and controls fertilizers and supplements sold or imported into Canada
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What is soil amendment according to the Fertilizer Act?
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Agricultural materials, other than traditional fertilizers, that may be added to soil to improve crop growth.Ex: rock phosphate, manures, bone meal, garbage tankage etc.
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What is mixed fertilizer according to Fertilizer Act?
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All fertilizers other than fertilizers consisting of a single material or one chemical compound
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1 ppm = ______ lb/ac
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2
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