Term
|
Definition
smallest unit of matter that maintains the distinguishing features of an element.
Example: N (nitrogen) |
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|
Term
|
Definition
| smallest unit of compound or element with stable, independent existence.
Example: N2 (N gas), NH3 (ammonia) |
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Term
|
Definition
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|
Term
|
Definition
|
|
Term
|
Definition
| Number of protons in the nucleus of an atom |
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|
Term
|
Definition
| 1/12 mass of the nucleus of carbon (amu) |
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|
Term
|
Definition
mass of atom in amu
Example:
C → 12 amu
N → 14 amu
H → 1 amu |
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|
Term
|
Definition
|
|
Term
|
Definition
| mass of a molecule in amu |
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|
Term
|
Definition
| 6.02 x 1023 particles (atoms, molecules) |
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|
Term
| the weight of 1 mole of atoms |
|
Definition
| atomic weight of the atom |
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Term
|
Definition
| Number of positive or negative charges on an ion |
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Term
|
Definition
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|
Term
|
Definition
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|
Term
|
Definition
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|
Term
|
Definition
|
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Term
|
Definition
| Quantity that will release, react with, or be equivalent to 6.02 x 1023 hydrogen ions (H+) |
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|
Term
|
Definition
| (moles of solute)/(liter of solution) |
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|
Term
|
Definition
| (equivalents of solute)/(liter of solution) |
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|
Term
|
Definition
| percentage of weight made up by element or compound of interest |
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|
Term
| depth of 1 acre furrow slice |
|
Definition
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|
Term
| predicted increase in cereal consumption for food over the next 4 decades |
|
Definition
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|
Term
| predicted increase for meat consumption over the next 4 decades |
|
Definition
|
|
Term
| why it might be costly for agriculture to expand into new areas |
|
Definition
-poor soil fertility
-shallow soil depth
-low rainfall
-etc. |
|
|
Term
| great risks caused by agricultural expansion |
|
Definition
-biodiversity
-soil erosion
-other factors impacting ecosystem health |
|
|
Term
| why per capita cropland assessments are misleading |
|
Definition
| because of the changing distribution of human populations in urban and rural areas |
|
|
Term
| current estimates state that ______% of future crop production increases will come from ______ compared to ______. |
|
Definition
90%
intensification
expansion of cropland |
|
|
Term
| the primary causes of soil degradation |
|
Definition
|
|
Term
| why undeveloped and developing nations will continue to rely on food imports |
|
Definition
| because this is where the majority of future population growth is gonna be and the soil in these areas that could be converted to cropland is substantially less productive than current croplands |
|
|
Term
| why using corn for ethanol is not sustainable |
|
Definition
| because using it for ethanol makes it harder for undeveloped and developing countries to meet their basic food needs |
|
|
Term
| using ethanol as fuel in the future will require this |
|
Definition
| use of lignocellulose feedstocks, such as crop residues, forest products, etc. |
|
|
Term
| why there are limits to using field crop residues for ethanol |
|
Definition
| because organic residues returned to soils are critical to sustaining soil and crop productivity |
|
|
Term
| meeting future food and fiber demand, while protecting environmental health, will require this |
|
Definition
|
|
Term
| why meeting future food and fiber demand, while protecting environmental health, will require ag intensification |
|
Definition
-decreasing available land for cultivation
-maintaining and enhancing natural land areas is critical to sustaining ecosystem diversity and health |
|
|
Term
| this is critical to sustaining ecosystem diversity and health |
|
Definition
| maintaining and enhancing natural land areas |
|
|
Term
| why advances in ag production technologies must occur |
|
Definition
| to enhance productivity per unit of cropland to ensure world food security |
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|
Term
| the principal factors contributing to higher crop yields |
|
Definition
include:
-development of improved varieties and hybrids
-nutrient and pest management
-soil and water conservation
-cultural practices |
|
|
Term
| why the continued growth of N fertilizers will increase demand for fossil fuel |
|
Definition
| because natural gas (CH4) is a primary ingredient in the manufacture of N fertilizers |
|
|
Term
| why improved nutrient management technologies are needed |
|
Definition
| to reduce the impact of nutrient use on environmental quality and ecosystem health |
|
|
Term
| one important nutrient management principle discussed throughout the book |
|
Definition
| the importance of maximizing crop productivity to increase the quantity of applied nutrient recovered by the crop |
|
|
Term
| why it's important to maximize crop productivity to increase the quantity of applied nutrient recovered by the crop |
|
Definition
| because it reduces the quantity of applied nutrient in the soil after harvest and, thus, reduces the impact of nutrient use on the environment |
|
|
Term
| Carl Sprengel and Justus von Liebig |
|
Definition
| 19th century scientists who developed the Law of the Minimum |
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Term
|
Definition
| states that crop yield is proportional to the amount of the most limiting nutrient |
|
|
Term
| some climate factors that affect crop yield potential |
|
Definition
| -precipitation
-air temp
-relative humidity
-light
-altitude
-latitude
-wind
-CO2 concentration |
|
|
Term
| some soil factors that affect crop yield potential |
|
Definition
-organnic matter
-texture
-structure
-CEC
-pH
-base sat
-slope and topography
-soil temp
-soil management factors
-depth (root zone)
-nutrient supply (soil test)
-element toxicity |
|
|
Term
| some soil management factors |
|
Definition
|
|
Term
| some crop factors that affect crop yield potential |
|
Definition
-crop species
-variety
-seeding rate
-geometry
-seed quality
-evapotranspiration
-water availability
-nutrition
-pests
-harvest efficiency
-crop sequence or rotation
-
- |
|
|
Term
| some pests that can affect crop yield potential |
|
Definition
|
|
Term
| the order in which limiting factors should be minimized |
|
Definition
1: the most limiting factor
2: the 2nd most limiting factor
3: so on and so forth |
|
|
Term
| an element is considered essential to plant growth and development if... |
|
Definition
-the element is directly involved in the nutritionof the plant
-a deficiency makes it impossible for the plant to complete its life cycle, and
-a deficiency is specific to the element and can only bee prevented or corrected by supplying the element |
|
|
Term
| why you must use caution when evaluating a visual symptom on a plant |
|
Definition
| because there's lots of things that can cause the visual sumptoms |
|
|
Term
|
Definition
| when the concentration of an element is low enough to severely limit yield and distinct deficiency symptoms are visible |
|
|
Term
|
Definition
| the nutrient concentration in the plant below which a yiield response to added nutrients occurs |
|
|
Term
| where critical range occurs |
|
Definition
| somewhere between deficient and sufficient |
|
|
Term
|
Definition
| the nutrient concentration range in which added nutrient will not increase yield but can increase nutrient concentration |
|
|
Term
|
Definition
| absorbtion by the plant that does not influence yield |
|
|
Term
|
Definition
| when the concentration of essential or other elements is high enough to reduce plant growth and yield |
|
|
Term
| excessive nutrient concentration can cause this, which can also influence yield |
|
Definition
| an imbalance in other essential nutrients |
|
|
Term
|
Definition
| when under severe deficiencyrapid increases in yield with added nutrient cause a small decrease in nutrient concentration |
|
|
Term
| what causes the Steenberg effect? |
|
Definition
| dilution of the nutrient in the plant by rapid plant growth |
|
|
Term
| when the concentration of nutrient reaches this range, plant yield is generally maximized |
|
Definition
|
|
Term
| how excessive quantities of elements can reduce plant yield directly |
|
Definition
|
|
Term
| how excessive quantities of elements can reduce plant yield indirectly |
|
Definition
| reducing concentrations of other nutrients below their critical ranges |
|
|
Term
| essential macronutrients in order of abundance in plants |
|
Definition
1: H
2: C
3: O
4: N
5: K
6: Ca
7: Mg
8: P
9: S |
|
|
Term
| essential micronutrients in order of abundance in plants |
|
Definition
1: Cl
2: Fe
3: B
4: Mn
5: Zn
6: Cu
7: Ni
8: Mo |
|
|
Term
| plant nutrients that are not considered mineral nutrients |
|
Definition
|
|
Term
| The p'synth process in green plants converts ______ into ______. |
|
Definition
| CO2 and H2O
simple carbohydrates |
|
|
Term
| organic compounds that can be synthesized from simple carbohydrates |
|
Definition
-amino acids
-sugars
-proteins
-nucleic acids
-other organic compounds |
|
|
Term
| 4 additional elements that have been established as beneficial micronutrients in some plants |
|
Definition
|
|
Term
|
Definition
|
|
Term
| the ash left over from burning plant dry matter contains all the elements except ______ because ______. |
|
Definition
C, H, O, N, & S
they are volatilized as gases |
|
|
Term
| why plants do not absorb all of the nutrients applied |
|
Definition
| because many biological and chemical reactions occur w/ nutrients in soils |
|
|
Term
| external factors plants have to deal with |
|
Definition
| -CO2 c'tration
-light
-heat
-water
-nutrients |
|
|
Term
| wheat the external factors of water, nutrients, heat, light, and CO2 c'tration do to the plant |
|
Definition
| regulate plant growth and development |
|
|
Term
| where most of the water and nutrients a plant uses comes from |
|
Definition
|
|
Term
| why plant roots are in very close association w/ the soil |
|
Definition
| because most of the water and nutrients comes from the soil |
|
|
Term
|
Definition
| Capacity of a soil to support the production of a specific crop |
|
|
Term
| how soil productivity is measured |
|
Definition
| in terms of yield/biomass |
|
|
Term
| soil productivity depends on... |
|
Definition
| adequate moisture and soil nutrients, as well as favorable climate (temperature, rainfall) |
|
|
Term
|
Definition
| Soils’ capacity to supply elements essential for plant growth |
|
|
Term
| how soil fertility is measured |
|
Definition
- directly (concentration of nutrients)
- indirectly (productive capacity) |
|
|
Term
| how soil fertility is measured directly |
|
Definition
|
|
Term
| how soil fertility is measured indirectly |
|
Definition
|
|
Term
| soil fertility is relative to... |
|
Definition
| the plant being considered, that is, how the plant interacts with the nutrients |
|
|
Term
| how soil fertility can be improved |
|
Definition
|
|
Term
| soil fertility is a component of... |
|
Definition
|
|
Term
| why you can, to an extent, manage soil productivity |
|
Definition
| because soil fertility is a component of soil productivity |
|
|
Term
| Importance of Soil Fertility |
|
Definition
-Agriculture depends on soil productivity
-Soil productivity depends in part on soil fertility |
|
|
Term
| agriculture depends on... |
|
Definition
|
|
Term
| soil productivity depends in part on... |
|
Definition
|
|
Term
| population could be ______ by 2060 |
|
Definition
|
|
Term
| population could be 9billion by ______ |
|
Definition
|
|
Term
| this led to an increase in farming |
|
Definition
|
|
Term
| mechinazation led to an increase in... |
|
Definition
|
|
Term
| Green Revolution was part of the ______ inprovement of ag. |
|
Definition
|
|
Term
| some things the Green Revolution brought to ag |
|
Definition
-fertilizers
-high yielding varieties
-pesticides |
|
|
Term
| what pesticides did for ag |
|
Definition
|
|
Term
| the fertilizer consumption that seems to be going up the quickest |
|
Definition
|
|
Term
| recent trend in global fertilizer use |
|
Definition
|
|
Term
| trend in U.S. fertilizer use |
|
Definition
| might be increasing, but might be leveling off |
|
|
Term
| the largest source of N inputs into the Mississippi River basin |
|
Definition
|
|
Term
| the fastest growing source of N inputs into the Mississippi River basin |
|
Definition
|
|
Term
| such a large amount of N going into the water so quickly can lead to... |
|
Definition
|
|
Term
| artificial sources of N cause this |
|
Definition
| increased growth of plants, algae, and other stuff |
|
|
Term
| after the excessive growth of plants, algae, and other stuff due to such excessive N, this leads to depleted oxygen supply |
|
Definition
| microbes later lead to depleted oxygen supply |
|
|
Term
| how long it naturally takes eutrophication to occur |
|
Definition
|
|
Term
| how long it takes eutrophication to occur with such excessive N inputs |
|
Definition
|
|
Term
| how microbes help in the causing of hypoxia |
|
Definition
| they use oxygen to feed on stuff |
|
|
Term
| when the hypoxic zone on the Louisiana coast shows up |
|
Definition
|
|
Term
| can phosphate and potash resources get depleted? |
|
Definition
|
|
Term
| yearly production of phosphate |
|
Definition
|
|
Term
| yearly production of phosphate |
|
Definition
|
|
Term
| yearly production of phosphate |
|
Definition
|
|
Term
| total reserves of phosphate |
|
Definition
|
|
Term
| life of phosphate reserves |
|
Definition
|
|
Term
|
Definition
|
|
Term
| life of US phosphate reserves |
|
Definition
|
|
Term
| the bulk of the phosphate reserves are in... |
|
Definition
|
|
Term
| yearly production of potassium |
|
Definition
|
|
Term
| total reserves of potassium |
|
Definition
|
|
Term
| life of potasium reserves |
|
Definition
|
|
Term
| factors affecting plant growth and yield |
|
Definition
|
|
Term
| climate factors that affect plant growth and yield |
|
Definition
-rain
-temp
-light
-wind
-etc. |
|
|
Term
| crop factors that affect plant growth and yield |
|
Definition
-variety
-planting date
-pests
-etc. |
|
|
Term
| soil factors that affect plant growth and yield |
|
Definition
-fertility
-structure
-texture
-etc. |
|
|
Term
| Leibig’s Law of the Minimum |
|
Definition
| The level of plant production can be no greater than that allowed by the most limiting growth factor |
|
|
Term
|
Definition
| nutrient needed to complete life cycle |
|
|
Term
| how to do the water in hydroponics |
|
Definition
| mix specific amounts of nutrients in solution with water |
|
|
Term
| how hydroponics can be used to determine which nutrients are essential |
|
Definition
| eliminating one nutrient at a time helps identify essential nutrients |
|
|
Term
| criteria for importance of nutrients in plant life cycle |
|
Definition
1: importance in plant growth and development
2: involved in the a plant’s biochemical or physiological process |
|
|
Term
| how plants get most of their carbon |
|
Definition
| carbon being fixed in the form of CO2 |
|
|
Term
| these nutrients are not considered mineral nutrients |
|
Definition
|
|
Term
| distribution of nutrients in plants |
|
Definition
| may differ among different parts of the plant |
|
|
Term
| where silicon is in plants |
|
Definition
| can sometimes accumulate in the leaves, as much as 10% |
|
|
Term
| one hypothesis about silicon |
|
Definition
| says that silicon provides mechanical strength to the plants |
|
|
Term
| does hydroponics use silicon? |
|
Definition
|
|
Term
| yearly production of phosphate |
|
Definition
|
|
Term
| total reserves of phosphate |
|
Definition
|
|
Term
| life of phosphate reserves |
|
Definition
|
|
Term
|
Definition
|
|
Term
| life of US phosphate reserves |
|
Definition
|
|
Term
| the bulk of the phosphate reserves are in... |
|
Definition
|
|
Term
| yearly production of potassium |
|
Definition
|
|
Term
| total reserves of potassium |
|
Definition
|
|
Term
| life of potasium reserves |
|
Definition
|
|
Term
| factors affecting plant growth and yield |
|
Definition
|
|
Term
| climate factors that affect plant growth and yield |
|
Definition
-rain
-temp
-light
-wind
-etc. |
|
|
Term
| crop factors that affect plant growth and yield |
|
Definition
-variety
-planting date
-pests
-etc. |
|
|
Term
| soil factors that affect plant growth and yield |
|
Definition
-fertility
-structure
-texture
-etc. |
|
|
Term
| Leibig’s Law of the Minimum |
|
Definition
| The level of plant production can be no greater than that allowed by the most limiting growth factor |
|
|
Term
|
Definition
| nutrient needed to complete life cycle |
|
|
Term
| how to do the water in hydroponics |
|
Definition
| mix specific amounts of nutrients in solution with water |
|
|
Term
| how hydroponics can be used to determine which nutrients are essential |
|
Definition
| eliminating one nutrient at a time helps identify essential nutrients |
|
|
Term
| criteria for importance of nutrients in plant life cycle |
|
Definition
1: importance in plant growth and development
2: involved in the a plant’s biochemical or physiological process |
|
|
Term
| how plants get most of their carbon |
|
Definition
| carbon being fixed in the form of CO2 |
|
|
Term
| these nutrients are not considered mineral nutrients |
|
Definition
|
|
Term
| distribution of nutrients in plants |
|
Definition
| may differ among different parts of the plant |
|
|
Term
| where silicon is in plants |
|
Definition
| can sometimes accumulate in the leaves, as much as 10% |
|
|
Term
| one hypothesis about silicon |
|
Definition
| says that silicon provides mechanical strength to the plants |
|
|
Term
| does hydroponics use silicon? |
|
Definition
|
|
Term
| the majority of plant nutrient uptake is thru... |
|
Definition
|
|
Term
|
Definition
| longitudinal section of the root |
|
|
Term
| longitudinal section of the root |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| endodermis w/ casparian strip |
|
|
Term
|
Definition
|
|
Term
|
Definition
| region of rapid cell division |
|
|
Term
|
Definition
| quiescent center (few cell divisions) |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| meristematic region helps the root do this |
|
Definition
|
|
Term
| 2 purposes of the root cap |
|
Definition
-helps protect the tip of the root
-helps it stay lined up with the force of gravity |
|
|
Term
| in the elongation zone, there’s less ______ and more ______ |
|
Definition
|
|
Term
| what happens in the maturation zone? |
|
Definition
| cells taking up specific nutrients |
|
|
Term
| cells in the maturation zone no longer do this |
|
Definition
|
|
Term
|
Definition
|
|
Term
| parts of the plant that take up nutrients |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| the parts of the roots that don't do very much nutrient and water uptake |
|
Definition
|
|
Term
| the parts of the roots that do the bulk of the nutrient and water uptake |
|
Definition
| maturation zone and younger |
|
|
Term
| characteristics of root morphology and architecture that can have effect on nutrient uptake |
|
Definition
-Root length, thickness
-Branching |
|
|
Term
| how variations in root architrture can affect nutrient uptake |
|
Definition
| increasing root surface area |
|
|
Term
| Factors affecting root surface area |
|
Definition
-Thinner, multiple roots have more surface area per unit volume
-Root branching, which can be influenced by lateral roots
-Root hairs
-Association with mycorrhizae |
|
|
Term
| Lateral roots increase... |
|
Definition
| root mass and surface area |
|
|
Term
| lateral root develop from the... |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| outgrowths of epidermal cells |
|
|
Term
|
Definition
| short, rarely reaching lengths of 1mm |
|
|
Term
| how much of the root surface area is root hairs? |
|
Definition
|
|
Term
| primary points where roots absorb nutrients |
|
Definition
|
|
Term
| growth of root hairs affected by... |
|
Definition
|
|
Term
| when plants may make more root hairs |
|
Definition
|
|
Term
| mycorrhizae do this for plants |
|
Definition
-contribute greatly to nutrient uptake in most plants (>80% of plants)
-increase surface area |
|
|
Term
| amountof plants that form mycorrhizal associations |
|
Definition
|
|
Term
| when mycorrhizae are most effective |
|
Definition
| under low nutrient conditions |
|
|
Term
| deveolpment of mycorrhizae can be inhibited by some nutrients such as... |
|
Definition
|
|
Term
| how mycorrhizae can make more nutrients available to plants |
|
Definition
| by using organic forms of nutrients and converting them to inorganic forms, thus making more nutrients available to plants |
|
|
Term
| the 2 types of mycorrhizae that plants form associations with |
|
Definition
-Ectomycorrhiza
-Endomycorrhiza |
|
|
Term
|
Definition
sheath around root tip, hyphae do not penetrate plant cells (mainly trees of temperate zones)
-these act kinda like root hairs |
|
|
Term
|
Definition
|
|
Term
|
Definition
extends surface area of roots; penetrates plant cells (widespread)
-hemps move the nutrients inside the cell |
|
|
Term
| what hemps do inside plant cells |
|
Definition
| move nutrients inside plant cells |
|
|
Term
| when plants don't make many mycorrhizal associations |
|
Definition
| when there's lots of nutrients available |
|
|
Term
| illustration of the importance of mycchorizae to corn |
|
Definition
[image]
-left w/ mycorrhizal associations
-right w/o mycorrhizal associations |
|
|
Term
| some anatomical features roots have to regulate nutrient uptake |
|
Definition
-root hairs (epidermis)
-cortex
-endodermis
-pericycle
-phloem
-xylem |
|
|
Term
| function of the root hairs (epidermis) |
|
Definition
|
|
Term
|
Definition
| nutrients can be taken up into the symplast |
|
|
Term
| function of the endodermis |
|
Definition
barrier for uncontrolled uptake; kinda limits the uptake of unneccessary substances
also limits leakage of nutrients |
|
|
Term
| function of the pericycle |
|
Definition
|
|
Term
|
Definition
| transport from the shoot (flows down) |
|
|
Term
|
Definition
| transport to the shoot (flows up) |
|
|
Term
| location of the vascular tissue (xylem and phloem) in the root |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| anatomy of a monocot root |
|
Definition
|
|
Term
|
Definition
| anatomy of a monocot root |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| why nutrient supply to plant roots is a very dynamic process |
|
Definition
| because plants adsorb cations and anions and exude H+, OH-, and HCO3- |
|
|
Term
| how plants get nutrients from the soil |
|
Definition
| by absorbing them from the soil solution by plant roots |
|
|
Term
| what plant roots release into the soil solution |
|
Definition
| small quantities of H+, OH-, and HCO3- |
|
|
Term
| what nutrient uptake by plants causes to happen in the soil |
|
Definition
| several chemical and biological rxns to buffer or resupply these nutrients to the soil solution |
|
|
Term
| what happens to ions adsorbed to the surface of clay minerals when the soil solution needs to be buffered? |
|
Definition
| they desorb from these surfaces to resupply the soil solution |
|
|
Term
| what fertilizer does to the soil solution |
|
Definition
| increases ion concentration in the soil solution |
|
|
Term
| what can happen to ions from fertilizers if they don't remain in solution? |
|
Definition
| some get adsorbed to mineral surfaces and some precipitate as solid minerals |
|
|
Term
| some soil components that influence nutrient concentration in the soil solution |
|
Definition
-nutrient uptake
-soil air
-OM/microbes
-rainfall evaporation/drainage management
-mineral solubility
-surface exchange (that is, in the surface of soil particles) |
|
|
Term
| microbial activity is dependent on... |
|
Definition
-adequate energy supply from organic C, such as crop residues
-inorganic ion availability
-numerous environmental conditions |
|
|
Term
| why CO2 concentration in the soil air is greater than in the atmosphere |
|
Definition
| because plant roots and sil organisms use O2 and respire CO2 |
|
|
Term
| ion exchange in soil occurs where? |
|
Definition
| on the surfaces of clay and other minerals, organic matter (OM), and plant roots |
|
|
Term
| why cation exchange capacity is generally considered to be more important |
|
Definition
| because the CEC is much larger than the AEC |
|
|
Term
| why it's essential to understand the origin of the surface charge of soil minereals and OM |
|
Definition
| because ion exchange rxns are very important to plant nutrient retention and availabvility in soil |
|
|
Term
| why nutrient supply to plant roots is a very dynamic process |
|
Definition
| because plants adsorb cations and anions and exude H+, OH-, and HCO3- |
|
|
Term
| the composition of aluminosilicate minerals |
|
Definition
| sheets of layers of silica tetrahedra and alumina octahedra |
|
|
Term
| the structure of a silica tetrahedra |
|
Definition
| one Si+4 cation bonded to 4 O-2 anions |
|
|
Term
| the structure of the Al octahedra |
|
Definition
| one Al+3 cation bonded to 6 OH- anions |
|
|
Term
| forns that clay minerals exist in |
|
Definition
|
|
Term
| the most common type of 1:1 clay |
|
Definition
|
|
Term
| the composition of 2:1 clays |
|
Definition
| Al octahedral layer between 2 Si tetrahedral layers |
|
|
Term
| the most common 2:1 clays |
|
Definition
-mica (aka illite)
-smectite (aka montmorillonite)
-vermiculite |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| a type of 2:1:1 clay mineral |
|
Definition
|
|
Term
| composition of 2:1:1 clay minerals in acid soils |
|
Definition
| interlayer Al hydroxide sheet in addition tho the 2:1 structure |
|
|
Term
| composition of 2:1:1 clay minerals in basic soils |
|
Definition
| interlayer Mg hydroxide sheet in addition tho the 2:1 structure |
|
|
Term
|
Definition
cation replacement in minerals, predominantly in 2:1 minerals and very little in 1:1 minerals
occurs during the formation of these minerals |
|
|
Term
| the type of isomorphous substitution that contributes to montmorillonite having such a high CEC ad the ability to readily expand and contract based on moisture |
|
Definition
isomorphous substitution in the octahedral layer instead of the tetrahedral layer
this is the only isomorphous substitution that occurs in montmorillonite |
|
|
Term
| in chlorite, the interlayer space is occupied by... |
|
Definition
| Mg(OH)x in basic soils and Al(OH)x in acid soils |
|
|
Term
| why isomorphous substitution occurs in both the octahedral and tetrahedral layers in the 2:1 vermiculite |
|
Definition
| because it's commonly weathered from micas |
|
|
Term
| why vermiculite has a higher CEC, but lower interlayer expansion compared to smectites |
|
Definition
| because although isomorphic substitution (Al+3 for Si+4) is less than in mica, the tetrahedral charge attracts hydrated cations (Ca+2, Mg+2), which limits expansion of the interlayer compared to smectites |
|
|
Term
|
Definition
| chlorite w/ a Mg hydroxide layer |
|
|
Term
|
Definition
| chlorite w/ an Al hydroxide layer |
|
|
Term
| why the CEC of chlorites is extremely low |
|
Definition
| because the surface of the hydroxide layers is + charged and is attracted to the - charged tetrahedral surface |
|
|
Term
| description of intergrade 2:1 minerals |
|
Definition
-similar to smectites and vermiculites except the interlayer area contains discontinuous "islands" of chlorite
-non-expansive and exhibit a much lower CEC than than vermiculites and smectites |
|
|
Term
| the charge on clay minerals that's unaffected by solution pH |
|
Definition
|
|
Term
| the pH-dependent charge on clay minerals |
|
Definition
|
|
Term
| why the edge charge of clay minerals is + under low pH |
|
Definition
| because of the excess H+ ions associated with exposed SiOH and Al-OH groups |
|
|
Term
| why the edge charge becomes more negative when the pH increases |
|
Definition
| because some of the H+ on the clay particles is neutralized |
|
|
Term
| what inbcrteasing the soil pH above 7 does to the charges on the clay particles |
|
Definition
| nearly completely removes the the H+ ions from the Al-OH and Si-OH groups |
|
|
Term
| the amount of - charge on 2:1 clays that's pH dependent |
|
Definition
|
|
Term
| the amount of negative charge on 1:1 clays that's pH dependent |
|
Definition
|
|
Term
| 2 sources of pH dependent charge |
|
Definition
| broken edges on clay minerals and soil OM |
|
|
Term
| where most of the pH dependent - charge from soil OM comes from |
|
Definition
-carboxylic acid
-to a lesser extent, phenolic acid groups |
|
|
Term
| why the CEC of soil OM increases as pH increases |
|
Definition
| because some of the H+ ions are neutralized, increasing the - surface charge |
|
|
Term
|
Definition
| estimated to be 100-300 meq/100g soil |
|
|
Term
| the CEC of the whole soil is strongly affected by... |
|
Definition
| the nature and quantity of clay minerals and OM in the soil |
|
|
Term
| which type of clay mineral tends to have a higher CEC? 1:1 or 2:1? |
|
Definition
|
|
Term
| the CEC of most SE soils (ultisols) is mostly ______ while the CEC of most MW soils (mollisols) is mostly ______ |
|
Definition
pH dependent
permanent charge |
|
|
Term
| 3 rxns from which pH dependent CEC originates |
|
Definition
| -neutralization of H+ on sesquioxide (Al, Fe(OH)x) by way of liming
-neutralization of H+ associated with the interlayer Al(OH)x as pH increases
-neutralization of Al3+ and Al(OH)x+n as pH increases with liming |
|
|
Term
| most of the exchangeable cations in soils are plant nutrients except for... |
|
Definition
|
|
Term
| the principal cations in acid soils |
|
Definition
| -Al3+
-H+
-Ca2+
-Mg2+
-K+ |
|
|
Term
| the predominant cations in neutral and basic soils |
|
Definition
|
|
Term
| this influences the ease with which cations can be replaced or exchanged with other cations |
|
Definition
| cations being adsorbed to the CEC with different adsorption strengths |
|
|
Term
|
Definition
| series that shows cations in order of how strongly they are adsorbed onto CEC sites
Al3+ > H+ > Ca2+ > Mg2+ > K+ = NH4+ > Na+ |
|
|
Term
| the strength of adsorption is directly proportional to... |
|
Definition
| the charge on the cations (>charge>adsorption strength)
exception: H+ |
|
|
Term
| what makes the H+ ion unique? |
|
Definition
| its very small size and high charge density |
|
|
Term
| the adsorption strength of cations with similar charges is determined by... |
|
Definition
| the size or radii of the hydrated cation |
|
|
Term
| why smaller cations of different charge are adsorbed more strongly |
|
Definition
| because larger hydrated cations can't get as close to the exchange surface as smaller cations |
|
|
Term
| some factors that affect which cations are preferentially adsorbed onto mineral surfaces |
|
Definition
-mineral type
-solution pH
-dominant anions present
-electrical potential of the charged surface
-other factors beyond the scope of this text |
|
|
Term
|
Definition
represents the total quantity of - surface charges on minerals and OM available to attract cations in solution
expressed in meq/100g oven dried soil |
|
|
Term
| why meq is used for CEC instead of mass |
|
Definition
| CEC represents both the meq/100g of - charge and the total meq/100g of cations adsorbed to the CEC |
|
|
Term
|
Definition
| % of total CEC occupied by Ca2+, Mg2+, K+, and Na+ |
|
|
Term
| soil factors that may affect %BS |
|
Definition
-BS of cultivated soils higher for arid than for humid regions
-BS of soils formed from limestone or basic igneous rock is greater than that of soils formed from sandstone or acidic igneous rock |
|
|
Term
| the relation betwen BS and cation availability is modified by... |
|
Definition
| the nature of the soil colloids |
|
|
Term
| soils with ______ can supply nutrient cations to plants at a much lower BS than soils with ______ |
|
Definition
large amounts of OM or 1:1 clays
2:1 clays |
|
|
Term
|
Definition
| BS increases with increasing soil pH |
|
|
Term
| why the influence of pH on CEC is highest in soils high in OM |
|
Definition
| because increasing pH has a greater effect on increasing CEC in the OM fraction in soil compared to montmorillonite, which exhibits little pH dependent charge |
|
|
Term
| why weathered, acidic soils containing hydroxyl-Al vermiculites (ultisols) exhibit strong pH-dependent CEC |
|
Definition
| because of the large quantity of Al(OH)x in the interlayer space of these clays |
|
|
Term
| this displacement mechanism in soil is an important mechanism for anion exchange |
|
Definition
| displacement of OH from hydrous Fe and Al oxides |
|
|
Term
|
Definition
| AEC incereases as soil pH decreases |
|
|
Term
| soils where AEC is greatest |
|
Definition
acid soils containing 1:1 clays and those containing Fe and Al oxides
exception: soils that contain hydroxyl-Al vermiculites common to the SE US |
|
|
Term
| the order of adsorption strength for anions |
|
Definition
| H2PO4- > SO4-2 > NO3- > Cl- |
|
|
Term
| the primary anion adsorbed in most soils |
|
Definition
|
|
Term
| how Al and Fe oxide minerals can adsorb H2PO4- |
|
Definition
| thru rxns that result in chemical bonds that are non-electrostatic |
|
|
Term
|
Definition
-Carbon
-Hydrogen
-Oxygen
-Nitrogen
-Phosphorous
-Potassium
-Calcium
-Sulfur
-Magnesium |
|
|
Term
|
Definition
-Iron
-Zinc
-Boron
-Molybdenum
-Copper
-Manganese
-Chloride
-Nickel |
|
|
Term
| types of solute transport mechanisms |
|
Definition
|
|
Term
| Passive transport occurs along... |
|
Definition
| concentration and electrical (electrochemical) gradients |
|
|
Term
| Active transport can occur against... |
|
Definition
| electrochemical gradients |
|
|
Term
| passive vs. active transport |
|
Definition
-Passive transport occurs along concentration and electrical (electrochemical) gradients
-Active transport requires energy, and can occur against electrochemical gradients. |
|
|
Term
| types of proteins that can facilitate passive transport |
|
Definition
| channel and carrier proteins |
|
|
Term
| types of active transport |
|
Definition
|
|
Term
| mechanisms of Primary active transport (PAT) |
|
Definition
-ATP hydrolysis generates energy
-Energy used for ion/solute transport |
|
|
Term
| mechanisms of Secondary active transport |
|
Definition
-Special proteins (Integral membrane proteins)
-Co-transport involved
-Energy indirectly derived from PAT |
|
|
Term
| depiction of primary active transport in plants |
|
Definition
| see slide 7 of the powerpoint titled "Nutrient Uptake - II", but be sure to remove that white block |
|
|
Term
| how plants bring Pi into the cell |
|
Definition
| using ATP to send protons outside of the cell so they can bind with Pi so the Pi can come into the cell
this is an example of a symporter |
|
|
Term
| how plants get Na+ out of their cells |
|
Definition
| pumping protons out of their cells so they can reenter and cause the Na+ to leave |
|
|
Term
|
Definition
| pumps hydrogen ions across the plasmalemma |
|
|
Term
| Nutrient transporters are present in these zones of roots |
|
Definition
| uptake related zones of roots |
|
|
Term
| Two possible routes for apoplastic uptake |
|
Definition
-Elongation zone
-Emerging laterals |
|
|
Term
| examples of Adaptations in Nutrient Uptake |
|
Definition
-Adaptations in Nutrient Uptake
-Regulation of Nutrient Uptake
-Increase in nutrient transporters in roots under nutrient deficiency |
|
|
Term
| ways roots can modify themselves |
|
Definition
-Altered root hair density
-Proteoid root formation |
|
|
Term
| mechanisms nutrient uptake may follow |
|
Definition
| single- or a multi-phasic mechanism |
|
|
Term
| Rate of uptake dependent on... |
|
Definition
|
|
Term
| when plant uses Low Affinity Transport System (LATS) |
|
Definition
| high nutrient concentration |
|
|
Term
| when plant uses High Affinity Transport System (HATS) |
|
Definition
| low nutrient concentration |
|
|
Term
| when plants may Increase the number of nutrient transporters in roots |
|
Definition
| under nutrient deficiency |
|
|
Term
| depiction of the difference between roots under nutrient deficiency and roots not under nutrient deficiency |
|
Definition
| see slide 16 of the powerpoint titled "Nutrient Uptake - II" |
|
|
Term
| why a plant root may form proteoid roots |
|
Definition
|
|
Term
| examples of regulation of uptake in plants |
|
Definition
-High N uptake rates result in high N levels in the leaves
-Leaves contain high levels of amino acids
-Amino acids are transported back to the roots
-Amino acids inhibit nitrogen uptake by the roots |
|
|
Term
| Two separate long distance transport systems in plants |
|
Definition
|
|
Term
| what the xylem transports |
|
Definition
-water
-nutrients
-some amino acids |
|
|
Term
| what the phloem transports |
|
Definition
-water
-sugar
-many nutrients |
|
|
Term
| what nutrients can be transported in the xylem? |
|
Definition
|
|
Term
| direction of transport in the xylem |
|
Definition
| unidirectional (roots to shoots for nutrients) |
|
|
Term
|
Definition
-Bidirectional, although mainly from leaves to growing plant parts (roots, fruits, meristems, young leaves)
-From old, senescing leaves to younger plant parts (retranslocation)
-Mobility of nutrients in the phloem varies |
|
|
Term
| plants remobilize nutrients thru the... |
|
Definition
|
|
Term
| when plants remobilize nutrients |
|
Definition
|
|
Term
| where nutrients in plants go when remobilized |
|
Definition
| Many nutrients are removed from senescing leaves and transported to younger leaves or fruits |
|
|
Term
| where nutrients can be stored if not used right away |
|
Definition
|
|
Term
| the older part of the roots don’t do very much... |
|
Definition
| nutrient and water uptake |
|
|
Term
| these parts of the roots do the bulk of the nutrient and water uptake |
|
Definition
| maturation zone and younger |
|
|
Term
| these factors have an effect on nutrient uptake |
|
Definition
-Root morphology and architecture
-Root surface area |
|
|
Term
| factoirs of Root morphology and architecture that have an effect on nutrient uptake |
|
Definition
-Root length, thickness
-Branching |
|
|
Term
| root branching can be influenced by... |
|
Definition
|
|
Term
| lateral roots start forming from ______, not the ______ |
|
Definition
the inside of the pericycle
epidermis |
|
|
Term
| how much root surface area is in the root hairs? |
|
Definition
|
|
Term
| how Mycorrhizae can make nutrients more available to plants |
|
Definition
| by using organic forms of nutrients and converting them to inorganic forms, thus making more nutrients available to plants |
|
|
Term
| plants don’t make many mycchorrizal associations when... |
|
Definition
| there’s lots of nutrients avilable |
|
|
Term
| some functions of the cortex |
|
Definition
-nutrients can be taken up into the symplast
-can also act as storage; nutrients can be stored in the vacuoles of cortical cells |
|
|
Term
| what the endodermis limits |
|
Definition
-kinda limits the uptake of unnecessary substances
-also limits the leakage of nutrients |
|
|
Term
| why pericycle can generate lateral roots |
|
Definition
| has new cells that can make lateral root |
|
|
Term
|
Definition
| space outside plasma membrane, even the space costituted by dead functioning xylem tissue |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| all the plant cells are connected by... |
|
Definition
|
|
Term
| something inside plasmodesmata that might help regulate traffic thru them |
|
Definition
| plasmodesmata have some amount of endoplasmic reticulum in there and plasmodesmata are pretty tightly controlled; there’s regulatory mechanisms inside plasmodesmata |
|
|
Term
| depiction of cells in the endodermis |
|
Definition
|
|
Term
| casparian strip found in... |
|
Definition
|
|
Term
| casparian strip is (hydrophobic or hydrophilic) |
|
Definition
|
|
Term
|
Definition
| movement of ions from one side of the membrane to the other |
|
|
Term
| this happens when ions bind to carrier proteins |
|
Definition
| they change shape to bind to ions |
|
|
Term
| these proteins have a higher transport rate |
|
Definition
|
|
Term
| these proteins have to undergo more changes than channel proteins |
|
Definition
|
|
Term
| these proteins can be gated |
|
Definition
|
|
Term
| what ATPase does with hydrogen |
|
Definition
| pumps hydrogen ions across the plasmalemma, against normal gradient and uses energy |
|
|
Term
| normal charge outside cell |
|
Definition
|
|
Term
| normal charge inside cell |
|
Definition
|
|
Term
| the only known proteins that directly use primary active transport |
|
Definition
|
|
Term
| depiction of Primary Active Transport in Plants |
|
Definition
|
|
Term
| what happens in 2ndary active transport |
|
Definition
| carrier proteins couple the transport of protons with other ions from outside the cell to inside the cell; energy used by proton pump, not nitrogen pump, for example |
|
|
Term
| depiction of 2ndary active transport |
|
Definition
|
|
Term
| an important function of antipiorters in plant cells |
|
Definition
| can help mitigate toxicities inside the cells |
|
|
Term
| depiction of a Sodium-proton antiporter |
|
Definition
|
|
Term
| phosphate transporter mostly in these zones of the root |
|
Definition
| mesomatic and elongation zones |
|
|
Term
| regulation of calcium inside plant cells |
|
Definition
| the c’tration of Ca in the plant cells is tightly regulated and kept pretty low |
|
|
Term
| what plants do to their carbohydrates when they don't put out root hairs |
|
Definition
| they partition more of the carbohydrates towards the shoots |
|
|
Term
| this might stunt plant growth |
|
Definition
| severe nutrient deficiency |
|
|
Term
| at the cellular level, plants can do this in response to nutrient deficiencies |
|
Definition
| make more of certain kinds of transporters and increase the concentration of them, such as the specific one for P when there's a shortage of P |
|
|
Term
| plants make this in response to Pi defficiency |
|
Definition
|
|
Term
| plants make proteoid roots in response to... |
|
Definition
|
|
Term
| some details about proteoid roots |
|
Definition
-they are dense clusters of lateral roots, but very short, about 1-2mm long
-they can form tertiary roots
-these roots can send out certain enzymes to change rhizosphere and increase P uptake |
|
|
Term
| how plants respond to nutrient excess |
|
Definition
| plants respond to nutrient excess by slowing down uptake or storing it |
|
|
Term
| an example of regulation of nitrogen uptake |
|
Definition
-High N uptake rates result in high N levels in the leaves
-Leaves contain high levels of amino acids
-Amino acids are transported back to the roots
-Amino acids inhibit nitrogen uptake by the roots |
|
|
Term
| what happens to leaves before they fall off |
|
Definition
| N from leaves goes back into plants for next season |
|
|
Term
| the difference between storage and sequestration |
|
Definition
| storage is when it’s intended to be used later, but sequestration is dead end for it |
|
|
Term
| how well boron is stored in plants |
|
Definition
| boron typically doesn’t get stored very well |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| HCl + H2O <--> H3O+ + Cl-
HCl is the acid and H2O is the base |
|
|
Term
|
Definition
| mix of equal amounts of conjugate acid and conjugate base that resists pH changes; this is the important concept for soil |
|
|
Term
| what buffer does when the pH is too low |
|
Definition
| some of the conjugate base becomes part of the conjugate acid, making the conjugate acid increase and the conjugate base decrease |
|
|
Term
| what buffer does when the pH is too high |
|
Definition
| some of the conjugate acid becomes part of the conjugate base, making the conjugate acid decrease and the conjugate base increase |
|
|
Term
|
Definition
|
|
Term
| Regions with predominantly acidic soils |
|
Definition
|
|
Term
| some sources of soil acidity |
|
Definition
1. Acids in Precipitation
2. Dissociation of H+ from Soil Organic Matter
3. Dissociation of H+ from broken edges
4. Al and Fe hydrolysis
5. Microbial respiration
6. Nutrient Transformations |
|
|
Term
| the rxn that causes water to become more acidic after being exposed to air |
|
Definition
| H2O + CO2 ←→ H2CO3 ←→ H+ + HCO3- |
|
|
Term
|
Definition
|
|
Term
| where the rainfall is <4.3 |
|
Definition
|
|
Term
| Natural Causes of Acid Rain |
|
Definition
-Lightning
-Volcanoes
-Decomposing plant biomass |
|
|
Term
| Man-Made Causes of Acid Rain |
|
Definition
-Exhaust from cars, trucks, and buses
-Power plants that burn coal
-Pollution from industry |
|
|
Term
| when organic matter releases H+ |
|
Definition
| when the soil is a certain pH |
|
|
Term
| when the H+ on broken edges starts to come off |
|
Definition
|
|
Term
| series of rxns of aluminum hydrolysis |
|
Definition
| Al3+ + H2O → Al(OH)2+ + H+
Al(OH)2+ + H2O → Al(OH)2+ + H+
Al(OH)2+ + H2O → Al(OH)3 + H+
Al(OH)3 + H2O → Al(OH)4- + H+ |
|
|
Term
| how hydroxy Al ions reduce CEC |
|
Definition
| bvy combining to form large polymers, which are so big, that they're non exchangeable |
|
|
Term
| a type of soluble Al that's toxic |
|
Definition
|
|
Term
| the equation of microbial respiration |
|
Definition
| CO2 + H2O → H2CO3 ←→HCO3- + H+ |
|
|
Term
| the pHa of microbial respiration |
|
Definition
|
|
Term
|
Definition
| the pH where half of the acid is dissociated |
|
|
Term
| some transformations of N that cause soil acidity |
|
Definition
| -immobilization
-nitrification
-volatilization
-NH4+ uptake |
|
|
Term
| a transformation of S that causes soil acidity |
|
Definition
|
|
Term
|
Definition
| ammonium being converted to organic form |
|
|
Term
| effect of immobilization of N on soil pH |
|
Definition
| pH decreases 1 unit for each mole of N |
|
|
Term
|
Definition
| ammonium being converted to nitrate |
|
|
Term
| effect of nitrification of N on soil pH |
|
Definition
| pH decreases 2 units for each mole of N |
|
|
Term
|
Definition
| ammonium being converted to ammonia |
|
|
Term
| effect of volatilization of N on soil pH |
|
Definition
| pH decreases 1 unit for each mole of N |
|
|
Term
|
Definition
| to me, it seems to be a type of immobilization |
|
|
Term
| effect of ammonium uptake on soil pH |
|
Definition
| pH decreases 1 unit for each mole of N |
|
|
Term
|
Definition
| organic S being converted to inorganic S |
|
|
Term
| effect of mineralization of S on pH of soil |
|
Definition
| pH decreases 1 unit for each mole of S |
|
|
Term
| effect of a rxn consuming H+ |
|
Definition
|
|
Term
| N rxn that produces the most acidity |
|
Definition
|
|
Term
|
Definition
|
|
Term
| how active acidity is measured |
|
Definition
| measured by pH in soil-water mixture |
|
|
Term
| methods by which to measure active acidity |
|
Definition
-Electrometric method (pH meter)
-Dye methods (pH indicator)
-Test probe (not reliable) |
|
|
Term
| the most reliable pH meter |
|
Definition
|
|
Term
| what dilution does to soil pH |
|
Definition
|
|
Term
| what suspended particles do to soil pH |
|
Definition
-decrease soil pH (negatively charged soil)
-increase soil pH (positively charged soil) |
|
|
Term
| how the probe can affect the pH reading |
|
Definition
| because the soil particles interact with how the probe works |
|
|
Term
|
Definition
-decrease soil pH (negatively charged soils)
-increase soil pH (positively charged soils) |
|
|
Term
| this might cause seasonal variations in the soil's pH |
|
Definition
|
|
Term
| the UGA method for measuring pH avoids... |
|
Definition
| the seasonal variation in pH caused by differences in the soil’s salt content |
|
|
Term
| an advantage of the UGA method for measuring soil pH |
|
Definition
| this gets you close to the true pH, no matter how much salt |
|
|
Term
|
Definition
|
|
Term
| some sources of potential acidity |
|
Definition
| - Al3+ in soil solution (all species)
- Hydroxy-Al polymers
- H+ and Al3+ in exchange sites
- H+ in broken edges of clays, oxides
- H+ in organic matter (ROOH, ROH) |
|
|
Term
| when undissociated acids release H+ |
|
Definition
| when you try to increase the pH |
|
|
Term
| diagram of potential and active adidity in soil |
|
Definition
|
|
Term
| amount of potential acidity vs. rate of change in active acidity |
|
Definition
the more potential acidity, the slower the change in active acidity
the less potential acidity, the faster the change in active acidity |
|
|
Term
| potential acidity vs. lime requirement |
|
Definition
| the higher the potential acidity, the higher the lime requirement |
|
|
Term
| why midwest soil has high potential acidity |
|
Definition
| because it has high buffering capacity and has organic matter that has hydrogen attatched to it |
|
|
Term
| part of the acidity tolerance is... |
|
Definition
|
|
Term
| some plants with very low acidity tolerance |
|
Definition
-Alfalfa
-Cotton
-Soybean
-Spinach |
|
|
Term
| some plants with moderate acidity tolerance |
|
Definition
-Peanut
-Rice
-Strawberry
-Watermelon |
|
|
Term
| some plants with high acidity tolerance |
|
Definition
-Azalea
-Blueberry
-Cranberry
-Rhododendron |
|
|
Term
| above the critical pH, you don’t see much... |
|
Definition
|
|
Term
| do this to the critical listed pH |
|
Definition
|
|
Term
| why we now recommend pH 6 instead of pH 6.5 |
|
Definition
| because there’s the chance of overshooting the target pH |
|
|
Term
| chart showing pH related to nutrient supply |
|
Definition
|
|
Term
|
Definition
|
|
Term
| methods of determining lime requirement |
|
Definition
1. Titration
2. Buffer Solution |
|
|
Term
|
Definition
| add a base and measure pH |
|
|
Term
|
Definition
| Add Ca(OH)2 in 1:1 mix
-20 g soil (0.02 kg)
-20 mL 0.01 M CaCl2 (measure pH1)
-this is shaken for 30 minutes because you need that reaction time
I think 1:1 means 1mg/mL |
|
|
Term
| why it's not a good idea to use Ca(OH)2 as lime |
|
Definition
| because it's caustic such that it burns plants |
|
|
Term
| why lime requirement (LR) is often multiplied by 1.5 |
|
Definition
| because they assume you’re not using pure calcium carbonate |
|
|
Term
| buffer solution method of determining lime requirement |
|
Definition
|
|
Term
| this determines how much the pH goes up |
|
Definition
|
|
Term
|
Definition
-Ca
-Mg oxides
-hydroxides
-carbonates
-silicates |
|
|
Term
| H+ must be neutralized by... |
|
Definition
|
|
Term
| liming materials have to produce... |
|
Definition
|
|
Term
|
Definition
| because it reacts very fast |
|
|
Term
| why soil tersting lab uses Ca(OH)2 |
|
Definition
| because it reacts so fast |
|
|
Term
|
Definition
|
|
Term
| how long it takes to see the effect of calcium carbonate |
|
Definition
| about 6 months after application |
|
|
Term
| this isn used to express the purity of liming material |
|
Definition
| Calcium Carbonate Equivalent (CCE) |
|
|
Term
| in Georgia, you need at least ______% Calcium Carbonate equivalent to sell it as lime |
|
Definition
|
|
Term
| is fgineness factor measured in Georgia? |
|
Definition
no
not even given a weight |
|
|
Term
| why repeated applications of lime are needed in Southeastern soils |
|
Definition
| to maintain appropriate chemical balances in the soil |
|
|
Term
| the recommended pH is usually... |
|
Definition
|
|
Term
| the main process that acidifies soil |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| apply lime how long in advance? |
|
Definition
|
|
Term
| do this with lime for a faster rxn |
|
Definition
|
|
Term
| why you can't mix lime with the soil in pasture |
|
Definition
| because it ruins your pasture |
|
|
Term
| rxn of elemental S that acidifies soil |
|
Definition
| S + H2O + 3/2 O2 → 2H+ + SO4-
-biological rxn
-Thiobacillus sp.
-sulfur oxidizes and forms sulfuric acid
-you need the bacteria for this reaction to occur |
|
|
Term
| how sulfuric acid has been used to acidify soil |
|
Definition
| has been used in midwest where there are some very calcareous soils |
|
|
Term
| how alum (Al2(SO4)3) can be used with poultry litter |
|
Definition
| can be mixed in with poultry litter to tie up the phosphorus so that it don’t run off |
|
|
Term
| preferred pH for blueberries |
|
Definition
|
|
Term
| how manures can contribute to soil being salty |
|
Definition
| manures have a lot of salt, so if there’s little or no rain with the manure there, the soil could become saline |
|
|
Term
| this can cause soils to become saline or sodic |
|
Definition
-Water evaporation
-salt accumulation |
|
|
Term
| come cations in saline and sodic soils |
|
Definition
|
|
Term
| some anions in saline and sodic soils |
|
Definition
|
|
Term
| salt content of sodic soils |
|
Definition
| sodic soils don't have much salt |
|
|
Term
|
Definition
| sodic soils tend to be very basic |
|
|
Term
| when the pH of soil is above 8.5 or 9, this happens to the dissolved organic matter |
|
Definition
| the dissolved organic matter is deposited on the surface |
|
|
Term
| chart showing some details of normal, saline, sodic, and saline-sodic soils |
|
Definition
|
|
Term
| how EC and exchangeable Na affect plant growth |
|
Definition
|
|
Term
|
Definition
| the dissolved organic matter |
|
|
Term
| what saline soils can do to plants |
|
Definition
-water imbalance in the plant
-ionic imbalance |
|
|
Term
| how to remediate the effects of saline soils on plants |
|
Definition
| leach with low-salt water |
|
|
Term
| water in soils moves from ______ negative to ______ negative |
|
Definition
|
|
Term
| why too much salt in the soil is bad for plants |
|
Definition
| -too much salt in the soil draws water away from plant roots because salt has so much negative charge on it
-toxic levels of Na+ and Cl- |
|
|
Term
| why saline and sodic soils have bad physical properties |
|
Definition
| poor structure, resulting in dispersive clay |
|
|
Term
| why the clay in saline and sodic soils is dispersive |
|
Definition
| because some of the negative charge on the clay pushes against each other |
|
|
Term
| amount of exchangeable sodium vs. dispersiveness of the clay |
|
Definition
| the more exchangeable sodium, the more dispersive the clay |
|
|
Term
| dispersiveness of the clay vs. hydraulic conductivity |
|
Definition
| the more dispersive the clay, the less the hydraulic conductivity |
|
|
Term
| why more dispersive clay has lower hydraulic conductivity |
|
Definition
| when the clay is more dispersive, the hydraulic conductivity declines because small particles clog pores in the soil |
|
|
Term
| how to fix dispersiveness of clay in saline and sodic soils |
|
Definition
| by replacing the sodium with calcium |
|
|
Term
| how calcium fixes clay dispersiveness in saline and sodic soils |
|
Definition
| by neutralizing the negative charges and causing aggregation |
|
|
Term
| problems with saline and sodic soils |
|
Definition
| -bad physical properties
-dispersed clay
-toxic levels of Na+ and Cl- |
|
|
Term
| how to remediate saline and sodic soils |
|
Definition
| add gypsum (CaSO4) and leach |
|
|
Term
| how gypsum remediates saline and sodic soils |
|
Definition
|
|
Term
| some transformations of N that increase soil pH |
|
Definition
| -mineralization
-denitrification
-urea hydrolysis
-NO3- uptake |
|
|
Term
|
Definition
| organic N being turned into NH4+ |
|
|
Term
| effect of N mineralization on soil pH |
|
Definition
| 1 mole N increases pH 1 unit |
|
|
Term
|
Definition
|
|
Term
| effect of denitrification on soil pH |
|
Definition
| 1 mole N increases pH 1 unit |
|
|
Term
|
Definition
| urea turning into nitrate |
|
|
Term
| effect of urea hydrolysis on soil pH |
|
Definition
| 1 mole N increases pH 1 unit |
|
|
Term
|
Definition
|
|
Term
| effect of NO3- uptake on soil pH |
|
Definition
| 1 mole N increases pH 1 unit |
|
|
Term
| a transformation of S that increases soil pH |
|
Definition
|
|
Term
| effect of SO4-2 uptake on soil pH |
|
Definition
| 1 mole S increases pH 2 units |
|
|
Term
| why fertilizing can be inefficient |
|
Definition
| because plant roots are always competing w/ microbes and minerals for nutrients |
|
|
Term
| how nutrients can get out of soil other than by plant uptake |
|
Definition
|
|
Term
| Nutrients in solution controlled by |
|
Definition
-Microbial processes (N, S, etc.)
-Chemical processes (P, K, etc.)
-Physical processes (P, etc.) |
|
|
Term
| Microbial processes control these nutrients |
|
Definition
|
|
Term
| Chemical processes control these nutrients |
|
Definition
|
|
Term
| Physical processes control these nutrients |
|
Definition
|
|
Term
| one form in which organic nitrogen can occur |
|
Definition
|
|
Term
| why our soils here in Georgia don’t expand and contract very much based on wetness |
|
Definition
| because of the H bonds between the sheets of kaolinite |
|
|
Term
| 2 Origins of Charge in clay minerals |
|
Definition
-Isomorphic substitution
-Broken edges |
|
|
Term
| example of isomorphic substitution in the tetrahedral layer |
|
Definition
|
|
Term
| example of isomorphic substitution in the octahedral layer |
|
Definition
| Mg2+ or Fe2+ replacing Al3+ |
|
|
Term
| why clays that undergo isomorphic substitution have charges on them |
|
Definition
| because each link tries to compensate half a charge |
|
|
Term
| when the charge on clays disappears |
|
Definition
| when it breaks down into its elements |
|
|
Term
| the part of clay charge that's pH dependent |
|
Definition
| the charge along the broken edges |
|
|
Term
| why the point of no charge is bad |
|
Definition
| because it means no nutrient retention |
|
|
Term
| one reason it's important to maintain pH |
|
Definition
| because the pH at which there's no charge means no nutrient retention |
|
|
Term
|
Definition
| the pH at which there's no charge on the clay particles |
|
|
Term
| when gibbsite develops negative charge |
|
Definition
|
|
Term
| the charge on our soil here in Georgia |
|
Definition
| here in Georgia, we have lotta positive soil in the profile |
|
|
Term
| for which type of clay is pH more important? 1:1 or 2:1? |
|
Definition
|
|
Term
| amount of charge on 2:1 clays that's permanent due to isomorphic substitution |
|
Definition
|
|
Term
| amount of charge on 1:1 clays that's permanent due to isomorphic substitution |
|
Definition
|
|
Term
| amount of charge on 2:1 clays that's pH dependent due to broken edges |
|
Definition
|
|
Term
| amount of charge on 1:1 clays that's pH dependent due to broken edges |
|
Definition
|
|
Term
| the point of zero charge for our soils |
|
Definition
|
|
Term
| you need this to retain cations |
|
Definition
|
|
Term
|
Definition
|
|
Term
| the types of clays in oxic soils |
|
Definition
|
|
Term
| how organic matter adds negative charge to soil |
|
Definition
dissociation of carboxylic acid and phenolic acid
each acid has its own dissociation constant |
|
|
Term
| pH of soil vs. negative charge |
|
Definition
| increasing the pH of the soil causes more negative charge |
|
|
Term
| amount of organic matter vs. places for nutrient retention |
|
Definition
| increasing organic matter increases places for nutrient retention |
|
|
Term
| how roots add negative charge to the soil |
|
Definition
| carboxylic acid dissociation |
|
|
Term
|
Definition
| what’s actually working in the soil |
|
|
Term
| change in CEC of clay vs. change in CEC of organic C as pH increases |
|
Definition
| CEC of OM increases faster than the CEC of clay with increasing pH |
|
|
Term
| why organic matter is critical to increasing CEC |
|
Definition
| because its CEC increases with pH at a faster rate than the CEC of clay does |
|
|
Term
| this part of soil contributes the most in terms of increasing CEC |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| CEC of Sphagnum peat moss |
|
Definition
|
|
Term
|
Definition
|
|
Term
| what determines the CEC of the roots? |
|
Definition
| the amount of negative charges in the roots; the more negative charges in the roots, the higher the CEC |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| these 2 factors affect how strongly an ion is held |
|
Definition
|
|
Term
| which type of clay, 1:1 or 2:1, can supply nutrients to plants at a lower pH? |
|
Definition
|
|
Term
| anion exchange capacity (AEC) |
|
Definition
| Total amount of positive charges |
|
|
Term
| important mechanism for AEC in many soils of tropics and subtropics |
|
Definition
| displacement of OH-, often from Al and Fe hydroxides |
|
|
Term
| pH where you start developing CEC |
|
Definition
| above the point of zero charge |
|
|
Term
| pH where you start developing AEC |
|
Definition
| below the point of zero charge |
|
|
Term
| why oxisols have lots of AEC, but not much CEC |
|
Definition
| because all they have left is Fe oxides with lots of positive charge |
|
|
Term
| the key to oxisols and why |
|
Definition
| increasing organic matter because it increases the CEC |
|
|
Term
| pH vs. depth here in Georgia |
|
Definition
|
|
Term
|
Definition
|
|
Term
| at this depth, you retain nitrate |
|
Definition
|
|
Term
| why you want a soil that's well buffered |
|
Definition
| so the pH don’t change much when you drain it |
|
|
Term
| Mechanisms of nutrient movement to roots |
|
Definition
1: Mass flow
2: Diffusion
3: Root Interception |
|
|
Term
|
Definition
| soluble ions move to root with soil water |
|
|
Term
| mass flow vs. transpiration |
|
Definition
| mass flow increases as transpiration increases |
|
|
Term
| diffusion as a mechanism of nutrient movement to roots |
|
Definition
| low solubility ions move only by random thermal motion |
|
|
Term
| speed of diffusion as a mechanism of nutrient movement to roots |
|
Definition
| very slow, only 1-2cm/season |
|
|
Term
|
Definition
| root hair grows until it can reach ions and exchange then takes place |
|
|
Term
| in soil, Ca can accumulate here |
|
Definition
|
|
Term
| why temp is critical for diffusion of water |
|
Definition
| because the diffusion coefficient for water is temp dependent |
|
|
Term
| why lots of of the early corns show purplish color |
|
Definition
| because of P deficiency due to the temp being insufficient for diffusion of nutrients |
|
|
Term
|
Definition
| basically the difficulty of a path; length can be a factor |
|
|
Term
| buffering capacity vs. nutrient adsorption |
|
Definition
| when you have a bigger buffering capacity, you have more nutrients being adsorbed onto the soil particles |
|
|
Term
| how much the P moves in soil |
|
Definition
| in most soils, not much more than an inch |
|
|
Term
| diffusion of K vs. diffusion of P |
|
Definition
| -potassium diffuses much faster than phosphorus |
|
|
Term
| key nutrient uptake mechanism for corn |
|
Definition
|
|
Term
| Root interception can be enhanced by... |
|
Definition
|
|
Term
|
Definition
| sheath around root tip – do not penetrate plant cells (mainly trees of temperate zones) |
|
|
Term
|
Definition
| extends surface area of roots – penetrate plant cells (widespread) |
|
|
Term
| depiction of ectomycchoriza |
|
Definition
|
|
Term
| depiction of endomycchoriza |
|
Definition
|
|
Term
| corn does better on fumigated or unfumigated soil? |
|
Definition
|
|
Term
| the biological N fixation by legumes |
|
Definition
|
|
Term
| how much of the world's N the U.S. uses |
|
Definition
|
|
Term
| the N-P-K nutrients in order of greatest consumption to least consumption |
|
Definition
|
|
Term
| how much of our atmosphere is N? |
|
Definition
|
|
Term
| microbes tend to prefer ______ for immobilization |
|
Definition
|
|
Term
| lightning's role in nitrogen |
|
Definition
| fixing it, which later comes down as rain |
|
|
Term
| what happens when urea decomposes in the soil? |
|
Definition
| raises the pH of the soil |
|
|
Term
| why terrestrial systems are getting enriched with nitrogen |
|
Definition
| because the rate of fixation turns out to be greater than the rate of denitrification |
|
|
Term
| soils contain how much N? |
|
Definition
|
|
Term
| How much of the soil N is organic? |
|
Definition
|
|
Term
| types of organic N in soil |
|
Definition
-amino acids
-proteins
-complex compounds |
|
|
Term
| how much of the soil N is inorganic? |
|
Definition
|
|
Term
| types of inorganic N in the soil |
|
Definition
| -NH4+ (ammonium)
-NO2- (nitrite)
-NO3- (nitrate) |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Org N --> NH4+
organic N turning into ammonium |
|
|
Term
| the 2 steps of N mineralization |
|
Definition
-Aminization
-Ammonification |
|
|
Term
|
Definition
| Org N --> R-NH2 (amines)
organic N turning into amines
R is organic residue |
|
|
Term
|
Definition
| R-NH2 + H+ + H2O --> R-OH + NH4+
amines turning into ammonium |
|
|
Term
| the plant leaves with the most cumulative N mineralized after 160 days |
|
Definition
|
|
Term
| Nitrogen mineralization from broiler litter varies depending on... |
|
Definition
|
|
Term
| 2 N compounds that are in broiler litter |
|
Definition
-Water-soluble organic N
-Uric acid |
|
|
Term
| why it's good to know the amount of N Mineralized in all parts of the field |
|
Definition
| because if you can estimate these numbers, you can use precision ag |
|
|
Term
|
Definition
| ammonium turning into organic N
NH4+ + R-OH --> R-NH2 + H+ + H2O |
|
|
Term
| Nitrogen Immobilization is controlled by... |
|
Definition
|
|
Term
| C/N ratio that leads to immobilization |
|
Definition
|
|
Term
| C/N ratio that leads to mineralization |
|
Definition
|
|
Term
| the C/N ratio is based on... |
|
Definition
|
|
Term
| most residues contain this much C |
|
Definition
|
|
Term
| C:N ratio is an indicator of... |
|
Definition
| the stability of the soil supplement |
|
|
Term
| what a lower C:N ratio means for plants |
|
Definition
| Lower ratios mean the supplement is very stable and will not draw down nutrients from the soil that plants need to grow. |
|
|
Term
|
Definition
|
|
Term
| what residue with a high C:N ratio does |
|
Definition
| soaks up water and nutrients, robbing plants of what they need |
|
|
Term
| compost has a 30:1 ratio, but what's the disadvantage? |
|
Definition
| it breaks down quickly in the soil |
|
|
Term
| peat moss, being 50:1, draws down a small amount of nitrogen fertilizer such that it won't hurt the plant, but what's an advantage of it? |
|
Definition
| it lasts for years in the soil |
|
|
Term
| why the ideal C:N ratio isn't always 30:1 |
|
Definition
| because the C:N ratio of 30 is a rule of thumb; it really depends on where the N is in the material |
|
|
Term
| why you gotta know the C:N if you want to use compost |
|
Definition
| because not all compost will give you the desired N |
|
|
Term
| how much the N immobilizes depends on |
|
Definition
| the microbial biomass that’s there |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| microbial efficiency refers to... |
|
Definition
|
|
Term
|
Definition
| ammonium turning into nitrite that then turns into nitrate
NH4+ + 3/2 O2 --> NO2- + 2H+ + H2O
NO2- + ½ O2 --> NO3-
only the first rxn acidifies soil |
|
|
Term
| you usually don’t have accumulation of nitrite unless... |
|
Definition
| something inhibits the second rxn, such as lots of ammonia |
|
|
Term
| the strain of bacteria that works best at any given pH |
|
Definition
| the strain that’s best adapted to that pH |
|
|
Term
| Optimum pH for nitrification |
|
Definition
|
|
Term
| Applying fertilizer in a band can lead to... |
|
Definition
| bacteria being dehydrated |
|
|
Term
|
Definition
|
|
Term
| aluminum starts to appear in the exchangeable process at this pH |
|
Definition
|
|
Term
| in soils with too much ______, nitrification stops |
|
Definition
|
|
Term
| nitrification is very sensitive to... |
|
Definition
|
|
Term
| if you don’t control the ______, nitrification stops |
|
Definition
|
|
Term
| problem in soils with 2:1 clay minerals |
|
Definition
| fixed NH4+
this is called ammonium fixation |
|
|
Term
| some minerals that can fix ammonium |
|
Definition
|
|
Term
| how much of the ammonium in fertilizer can be fixed in certain soils? |
|
Definition
|
|
Term
| heating soil does this to the edges of 2:1 minerals |
|
Definition
|
|
Term
| how 2:1 minerals fix ammonium |
|
Definition
| ammonium gets stuck in between the sheets of 2:1 minerals binding to the CEC sites |
|
|
Term
|
Definition
-nitrate leaching
-denitrification
-runoff and erosion
-ammonia volatilization
-crop harvest |
|
|
Term
| amount of nitrate leaching depends on... |
|
Definition
- Rate, timing of N fertilization
- Nitrification inhibitors; some fertilizers come with these and they last for about 2 weeks
- Crop uptake; reduces nitrate leaching
- Soil characteristics
- Precipitation patterns |
|
|
Term
| why we have negative charges in the lower levels |
|
Definition
|
|
Term
| if you have this soil, you’ll have leaching |
|
Definition
|
|
Term
|
Definition
| nitrate turning into nitrogen gas or nitrous oxide
2NO3- + 2H+ --> N2 + 21/2 O2 + H2O |
|
|
Term
| pH effect of denitrification |
|
Definition
| 1 mole of N raises the pH by 1 unit |
|
|
Term
|
Definition
- Nitrate or intermediate product
- Carbon source
- Anoxic conditions (no oxygen)
- Temperature |
|
|
Term
|
Definition
| amount of N gas increases as you become more alkaline |
|
|
Term
| there’s bacteria that have the ability to switch to nitrification when... |
|
Definition
|
|
Term
| bacteria can also use this for reduction |
|
Definition
|
|
Term
| other than soil, denitrification can occur in... |
|
Definition
|
|
Term
| the majority of global emissions of non-CO2 GHGs are from... |
|
Definition
| nitrous oxide from soils and methane from enteric fermentation and livestock |
|
|
Term
|
Definition
| ammonium turning into ammonia that gets into the air |
|
|
Term
| if there’s lotta ammonium in ______, there’s lotta ammonium in CEC |
|
Definition
|
|
Term
| the pKa of the ammonia volatilization rxn |
|
Definition
| about 9.3; above it, you got mostly ammonia, below it, you got mostly ammonium |
|
|
Term
|
Definition
| nitrogen in the form of ammonium and ammonia; can be used to determine pH |
|
|
Term
| this form of N can be used to determine pH |
|
Definition
| ammoniacal nitrogen (ammonium and ammonia) |
|
|
Term
| the direction the ammonia volatilization rxn goes at higher temperatures |
|
Definition
|
|
Term
| some factors that affects ammonia volatilization |
|
Definition
|
|
Term
| best conditions for ammonia volatilization... |
|
Definition
|
|
Term
| pH effect of ammonia volatilization |
|
Definition
|
|
Term
| some conditional details about ammonia volatilization |
|
Definition
-Important at pH > 7.5 and surface application
-Slow at < 5 oC
-N source (contains or generates NH4+)
-Increases with temp
-Increases with wind speed |
|
|
Term
| you get more denitrification from these ecosystems |
|
Definition
|
|
Term
| why ammonia can get absorbed by the water |
|
Definition
| because it has a very high affinity for water |
|
|
Term
| other than water, ammonia can also be absorbed by... |
|
Definition
|
|
Term
| how ammonia can lead to soil acidification |
|
Definition
| ammonia gets into the atmosphere, reacts with water, becomes ammonium, and acidifies soil |
|
|
Term
|
Definition
| resistant to decomposition |
|
|
Term
| what compost will do to soil |
|
Definition
| improve the physical conditions of the soil, but won’t give you much N |
|
|
Term
| how much N legume residues can cupply to soil |
|
Definition
|
|
Term
|
Definition
-manure
-compost
-legume residues
-sewage sludge
-feather meal
-blood meal
-bone neal |
|
|
Term
| one use of composted sludge |
|
Definition
|
|
Term
| why too much nitrate is bad |
|
Definition
|
|
Term
|
Definition
-Ammonia
-Urea
-Ammonium Nitrate
-Ammonium Sulfate |
|
|
Term
| the world's largest fertilizer N consumer |
|
Definition
| east Asia, followed by S. Asia and N. America |
|
|
Term
| the principal N fertilizer used in most of the world |
|
Definition
|
|
Term
|
Definition
| international fertilizer association |
|
|
Term
| the primary N fertilizer in the US |
|
Definition
| urea ammonium nitrate (UAN) solutions |
|
|
Term
| N loss pathways and cropping systems around the world |
|
Definition
|
|
Term
| how management to improve crop N recovery and to reduce the risks of environmental loss will vary |
|
Definition
-geographically
-site-specifically
-the N source used |
|
|
Term
| NH3 is compatible with... |
|
Definition
- Carbon steel
- Stainless steel
- Fiberglass, rubber, PVC, polyethylene |
|
|
Term
| NH3 is not compatible with... |
|
Definition
| - Aluminum [Al(OH)3]
- Copper [Cu(NH3)4]2+
- Zinc [Zn(NH3)4]2+
because it binds with these materials and forms a precipitate |
|
|
Term
| Fertilizers containing NH3 |
|
Definition
|
|
Term
| some details about Anhydrous NH3 |
|
Definition
- 82% N
- about 6% of world N fertilizer use |
|
|
Term
| some details about Aqua NH3 |
|
Definition
- 20 to 25% N
- not used much in Midwest |
|
|
Term
| Overall Effect of NH3 on soil pH |
|
Definition
| 1 mole of NH3 decreases pH by 1 unit |
|
|
Term
| why ammonia is bad for plants |
|
Definition
| because it's toxic to roots |
|
|
Term
| management of Anhydrous NH3 and Aqua NH3 |
|
Definition
- Knife into the soil
- Preferably moist soil
- Apply several weeks before planting
- Observe safety recommendations |
|
|
Term
| toxic contaminant in urea fertilizer |
|
Definition
|
|
Term
| amount of biuret that can be tolerated |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| why the urea usually has to go to the clays |
|
Definition
| because most of the urease is bound to the clays |
|
|
Term
|
Definition
| critical relative humidity |
|
|
Term
| critical relative humidity (CRH) |
|
Definition
| relative humidity at which urea dissolves |
|
|
Term
| surface application of urea can result in loss of... |
|
Definition
|
|
Term
| how to avoid ammonia loss after applying urea |
|
Definition
| Irrigate (0.5 to 1 inch) after surface application to incorporate and avoid NH3 losses; this much irrigation needed to make it go down and make it not volatilize |
|
|
Term
| N content of ammonium nitrate |
|
Definition
|
|
Term
| how much of the world's fertilizer use is ammonium nitrate? |
|
Definition
|
|
Term
| when ammonium nitrate causes ammonia loss |
|
Definition
|
|
Term
| Behavior of Ammonium Nitrate in Soil |
|
Definition
| NH4NO3 --> NH4+ + NO3-
NH4+ + 2O2 --> NO3- + H2O + 2H+ |
|
|
Term
| this is a big problem in ammonium nitrate |
|
Definition
|
|
Term
| why you should not stack many bags of ammonium nitrate in hot weather |
|
Definition
|
|
Term
| why it's hard to sell ammonium nitrate |
|
Definition
| because it can be used to make bombs |
|
|
Term
| N content of ammonium sulfate |
|
Definition
|
|
Term
| ammonium sulfate is how much of world's fertilizer usssssssseeeee? |
|
Definition
|
|
Term
| why ammonium sulfate is a very convenient fertilizer |
|
Definition
| because it has a significant amount of fertilizer |
|
|
Term
| Behavior of ammonium sulfate in soil |
|
Definition
| (NH4)2SO4 --> 2NH4+ + SO42-
2NH4+ + 4O2 --> 2NO3- + 2H2O + 4H+ |
|
|
Term
| when ammonium sulfate doesn't cause any ammonia loss |
|
Definition
|
|
Term
| N content of ammonium chloride |
|
Definition
|
|
Term
| how much of world fertilizer use is ammonium chloride? |
|
Definition
|
|
Term
| pH effect of ammonium chloride |
|
Definition
| 1 mole N causes pH to decrease by 2 units |
|
|
Term
| why you have to wash your equipment after using ammonium chloride |
|
Definition
|
|
Term
| why P and K are expressed on an oxide basis in fertilizer grades |
|
Definition
| because back in the day, they had to precipitate it and go a gravimetric measure |
|
|
Term
| ammonium phosphates account for how much of world N fert use? |
|
Definition
|
|
Term
| Monoammonium phosphate (MAP) |
|
Definition
|
|
Term
| N content of Monoammonium phosphate (MAP) |
|
Definition
|
|
Term
| pH effect of Monoammonium phosphate (MAP) on soil pH |
|
Definition
| 1 mole N causes soil pH to decrease 2 units |
|
|
Term
| pH at which Monoammonium phosphate (MAP) has no ammonia loss |
|
Definition
|
|
Term
| Diammonium phosphate (DAP) |
|
Definition
|
|
Term
| N content of Diammonium phosphate (DAP) |
|
Definition
|
|
Term
| why Diammonium phosphate (DAP) is a very commonly used fertilizer |
|
Definition
because it provides lotsa N and lotsa P
Raises the pH pretty high |
|
|
Term
| pH effect of Diammonium phosphate (DAP) on pH of the soil |
|
Definition
| 1 mole N makes pH go down 1.5 units |
|
|
Term
| what Diammonium phosphate (DAP) can do to seeds |
|
Definition
| Can cause seed germination damage because of high pH (NH3 damage) |
|
|
Term
| amount of Diammonium phosphate (DAP) that should be used with seed |
|
Definition
| Use < 10 kg N/ha with seed |
|
|
Term
| some Fertilizers containing only nitrate |
|
Definition
-calcium nitrate
-potassium nitrate
-sodium nitrate |
|
|
Term
| advantage of Fertilizers containing only nitrate |
|
Definition
|
|
Term
| how Urea-Ammonium nitrate (UAN) is produced |
|
Definition
| Dissolve ammonium nitrate and urea in water |
|
|
Term
| what Urea-Ammonium nitrate (UAN) does in soil |
|
Definition
| behaves as ammonium nitrate and urea |
|
|
Term
| UAN solutions are corrosive to these materials |
|
Definition
| Cu and Zn alloys, and to an extent, Al alloys |
|
|
Term
| UAN soluytions are OK with these substances |
|
Definition
-PVC
-fiberglass
-stainless steel
-carbon steel |
|
|
Term
| why UAN must not be used with brass nozzles |
|
Definition
| because it'll complex with the copper, leading to plugging up |
|
|
Term
| this may happen when UAN ius applied to surface |
|
Definition
|
|
Term
|
Definition
| leaves a yellow streak where it burned it, but didn‘t kill it; disappears soon after |
|
|
Term
|
Definition
| about half urea and half ammonium nitrate |
|
|
Term
| use of Slow release N fertilizers |
|
Definition
| mainly used by turf industry, horticulture, high-value crops |
|
|
Term
| advantages of Slow release N fertilizers |
|
Definition
-release rate more closely matches plant requirements
-no extra N in soil (less leaching)
-less frequent applications |
|
|
Term
| disadvantage of Slow release N fertilizers |
|
Definition
|
|
Term
| particle size vs. release rate |
|
Definition
| the bigger the particle size, the lower the release rate |
|
|
Term
| solubility vs. chain length |
|
Definition
| Solubility increases with decrease in chain length |
|
|
Term
| the reason urea releases N so quickly |
|
Definition
| because the bond in urea between the C and the ammonium is a single bond |
|
|
Term
| why N release from Triazone compounds is slow |
|
Definition
| because of closed-ring structure |
|
|
Term
| why Triazone compounds have lower N loss |
|
Definition
|
|
Term
|
Definition
| Sulfur shell around each urea granule |
|
|
Term
| Sulfur-coated urea (SCU) designed to... |
|
Definition
| reduce leaching and denitrification |
|
|
Term
| Polymer-coated compounds (Osmocote) |
|
Definition
| Coated N-P-K fertilizer granules |
|
|
Term
| how Polymer-coated compounds (Osmocotes) release fertilizer |
|
Definition
by osmotic exchange with moisture from the soil
-Water moves in, dissolves N, N goes into soil
-Bacteria decompose the plastic coat |
|
|
Term
| uses for Polymer-coated compounds (Osmocote) |
|
Definition
| Used in turf, floriculture, high-value crops |
|
|
Term
| the Most common nutrient limiting crop growth and yield |
|
Definition
|
|
Term
| why N is Applied in greater amounts than any other nutrient |
|
Definition
| becaus it's used in such large quantities |
|
|
Term
| dry weight content of plants |
|
Definition
|
|
Term
| the primary inorganic forms of N in most plants |
|
Definition
|
|
Term
| how urea is often taken in to plants |
|
Definition
|
|
Term
| some organic forms of N that can be taken up |
|
Definition
| amino acids; small proteins (peptides) |
|
|
Term
| how plants can take in organic forms of N |
|
Definition
| some microbial enzymes help the plant do this |
|
|
Term
| what mycchorrizae help plants access |
|
Definition
| more nutrients than just P; they can help turn organic N into inorganic form |
|
|
Term
| plants seem to be able to take up this form of organic N from the soil by themselves |
|
Definition
|
|
Term
| primary mechanism by which nitrate is taken in |
|
Definition
| 2ndary active trrransport, in the form of a symporter |
|
|
Term
|
Definition
|
|
Term
| the force used to bring nitrate into the cell |
|
Definition
|
|
Term
| how symporter creates proton motive force |
|
Definition
| using energy from the ATP to move protons across the membrane to create a proton motive force |
|
|
Term
| Nitrate transport mechanisms in plants |
|
Definition
| low affinity transport system (LATS) and high affinity transport system (HATS) |
|
|
Term
|
Definition
|
|
Term
|
Definition
| at high nitrate c'tration |
|
|
Term
|
Definition
|
|
Term
| Multiple nitrate transporters needed for nitrate movement... |
|
Definition
|
|
Term
| plants that have both HATS and LATS |
|
Definition
| so far, this is all plants that have been categorized |
|
|
Term
| an example of N remobilization within plants |
|
Definition
| some N stored within older leaves gets remobilized to where it's needed |
|
|
Term
| one possible use of fluorescence in plants |
|
Definition
| to detect where a particular protein is present |
|
|
Term
| is it easier for ammonia or ammonium to get into plant cells? |
|
Definition
|
|
Term
|
Definition
| type of transporter that is specifically for ammonium; this is a passive process based on e'chem gradient |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| where ammonium transporters are found in plants |
|
Definition
| some present in the root hairs and some functional in the roots |
|
|
Term
| the type of gradient ammonium toxicity can affect |
|
Definition
| can dissipate pH gradients |
|
|
Term
| parts of the plant that can have high pH |
|
Definition
|
|
Term
| parts of the plant that can have low pH |
|
Definition
-lumen
-intermembrane space
-vacuole |
|
|
Term
|
Definition
|
|
Term
|
Definition
| because it helps with the movement of ions and keeps hundreds of enzymes working properly |
|
|
Term
|
Definition
|
|
Term
| the transition of ammonium to ammonia depends on... |
|
Definition
|
|
Term
| when ammonia in the cytoplasm turns into ammonium... |
|
Definition
| after it gets into the vacuole |
|
|
Term
| ammonium gets taken up thru... |
|
Definition
|
|
Term
| do animals have mechanisms to manage ammonium? |
|
Definition
|
|
Term
| lots of plants tend to do better on (ammonium or nitrate) |
|
Definition
|
|
Term
| why do lots of plants do better on nitrate than on ammonium? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| the direction in which the xylem transports nutrients |
|
Definition
|
|
Term
| this usually happens to ammonium before transport |
|
Definition
| generally incorporated into organic molecules before transport |
|
|
Term
| plant can do this with nitrate |
|
Definition
| transport it or assimilate it in the roots |
|
|
Term
| some organic forms of N plants can take up |
|
Definition
-Amino acids
-Amides
-Ureides |
|
|
Term
| how nitrate uptake increases the pH of soil |
|
Definition
| Nitrate is taken up together with H+
This increases the pH of the soil or growing medium. Ammonium has the opposite effect |
|
|
Term
| Nitrate reduction requires... |
|
Definition
|
|
Term
| some plants that seem to prefer ammonium over nitrate |
|
Definition
| -Ericaceous plants, such as blueberries, azaleas, rhododendron
-rice
-Chenopodium album (lambsquarters) |
|
|
Term
| the biologically active form of N |
|
Definition
|
|
Term
| Nitrate needs to be ______ before it can be used |
|
Definition
|
|
Term
| reduction of nitrate depends on... |
|
Definition
|
|
Term
| enzyme used to reduce nitrate |
|
Definition
|
|
Term
|
Definition
| because nitrate reductase contains Mo. Without Mo, this enzyme does not function, and nitrate cannot be reduced and incorporated into biological molecules. |
|
|
Term
| function of nitrate reductase (NR) |
|
Definition
| Catalyzes the reduction of nitrate to nitrite |
|
|
Term
| nitrate reduction occurs in... |
|
Definition
|
|
Term
| activity of nitrate reductase depends on... |
|
Definition
-nitrate
-light
-carbohydrates |
|
|
Term
| what happens in plants w/o Mo? |
|
Definition
| nitrate reductase (NR) does not function, and nitrate cannot be reduced and incorporated into biological molecules |
|
|
Term
| nitrate reductase (NR) activated by... |
|
Definition
|
|
Term
| why there's no nitrate reduction under low light conditions |
|
Definition
|
|
Term
| where nitrate can be stored for later use |
|
Definition
|
|
Term
| function of nitrite reductase (NiR) |
|
Definition
| Catalyzes the reduction of nitrite to ammonium (light dependent) |
|
|
Term
| nnnnitrite reductase (NiR) is dependent on... |
|
Definition
|
|
Term
| why ammonium has to be incorporated into amino acids (or other compounds) immediately |
|
Definition
| because it's highly toxic to plants |
|
|
Term
| this cycle used to incorporate ammonium |
|
Definition
|
|
Term
| function of the GS-GOGAT cycle |
|
Definition
| used to incorporate ammonia |
|
|
Term
| Summary of nitrate Assimilation |
|
Definition
|
|
Term
| plants that use GS-GOGAT cycle |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| Glutamine: 2-oxo-glutarate amido transferase (Glutamate synthase) |
|
|
Term
| GS-GOGAT uses how many ATP? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| ammonium can be incorporated into various amino acids, such as... |
|
Definition
-glutamate
-aspartate
-glutamine
-asparagine |
|
|
