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Flashcards do conjunto (70)
- 1Passive UptakeNo respiratory Energy
Entry in apoplastic flow
Along electrochem gradient - 2Active UptakeLow affinity uptake
Charge inblance
Cation comp - 3Nutrients influenced by OM mineralisationNPS
- 45 compounds of OMPlant Material
Biomass
Resistant plant material
Physical Stable OM
Chemical stable OM - 5Rapid Compounds in OMSugars + Starches
- 6Moderate Compounds in OMCellulose
- 7Slow in OMLignins, waxes
- 8Humic Materials in OMFulvic Acid, humin, humic acid
- 9Carbon content in soil58%
- 10Non humic soil subatancesCarbs, ammino acid, 10% SOC
- 11How does soil retain AmmoniumInterlayer of clay minerals 2:1
- illite - 12Inhibitors of nitrificationAlk soils
Water logged
Inhib of bacteria
high concentration of fert - 13What N state flows with mass flowNO2-
- 14Which N moves freely with irrigation + rainfallNO3
- 15Which forms of N volatiliseN20, N2
- 16High N20 production is caused by?High temp, soil water increasesv
- 17What are some attributes of Primary Minerals- Elevated temp reactions
- Derived from ingenious or metamorphic rock
- Dom sand/silt fraction - 18What are secondary mineralsgypsum, silicate minerals, dolamite
- 19Attributes of secondary mineralsFormed via low temp reactions
Sedimentary rock
- Formed via weathering
-Dom dry fraction - 205 Major mineral classesHalides, Sulfates
- Silicates
- Oxides, hydrocide
- Sulfides - 21What are oxides (mineral class)- Common but small impact of physical + chem properties
- low CEC
- Highly weathered
Low fertility - 22Calcium reach plants and impact- Mass flow + root interception
- .Benefits cell membrane structure
- Defends plants from toxins - 23How does Mg travelMass flow carries it to surface
- 24Mg plant benefits- Crtitical for chlorophil
- Photosynthesis
- Depeleted by cropping and leaching - 25What will interfer with Mg uptakeBase saturation
- pH
- K, NH4 highly exchangable (competition)
- When CA: MG is wrong - 26Natural sources of Sulfur- OM
- soil minerals
- S gases
- Fert - 27Attributes of Sulfate and sulfur- Sulfate ions released via weathering
- highly mobile
90% is organic - 28What is organic SHydriodic acid
- Reducable S
- Reduced by Hi (H2S) - 29C:S needed for mineralisation and immbolisation<200 for mineral
>400 immboile - 30Inorganic S in Acid Soils (SO42-)Prone to leaching
- Specifically absorbed
- Highly absorbed in variable charge
- Perm charge = low absorption
- Variable -= Low ph soil only - 31Sulfur def symptomsYellow
- growth slowdown
- photosynthesis - 32How to calc WUEtranspiration ratio + losses
- 33Compents for total water potential- Matric potential + gravimetric potention
- 34What component doms sat soilsGravimetric component
- 35What component doms dry soilMatric component
- 36What indicates gravimetric reading = 0No height diff between two points
- 37What happens when Matric potential is same between 2 pointsgradient = 1
- 38How does centripedal translocation workGoes from soil solution to cortex tissue to xylem
- 39How does vert transport happenXylem to leaves
- Into atmosphere - 40What causes vertilicle movement- Weak root pressure and capillary forces
- Cohesion - 41How to calc available water capacilyFC-PWP
- 42Major salts that cause salinityMg, Nah, OH
- 43How does alkalinity accumulateFrom carbonates and biocarbonates (MgCO3)
- 44High Na has what impact on soilIncrease pH
- 45What is classified as a saline soil (EC)>4%
- 46What determines Sodic (ESP)>15%
- 47What is ECConcentration of dissovled salts
- 48What is SAR- Sodium adsorption ratio
- determines what happens to esp of soil after irrigation - 49What is ESP- Exchangable sodium percentage
-% of CEC occupied by Na
- - 50WHat is RSCResidual sodium carbonate
- If CA or Mg are present pH is limited to 8 or 9
- Precipiation of CuCO will occur
- measure of alkalinity of water
- RSC <1.25 safe - 51Impact of salt to plant- Reduces solute suction if salts are soluble
- water intake decreases - 52Effect of removing salt when high Na present- Dispersion, unstable
- 53SOlution to fix saline, non sodic soilReduce water table
- 54What if soil is sodic non salineIncrease irr water quality by adding Ca salts, Ca, Mg carbonates
- 55How to tackle saline sodic soil- Apply gypsum then leach salts to minimise dispersoin
- Sodium displaced by Ca - 56Nutrient effects of acidic pH-Al, Mn, H+ toxic
- Ca, Mg, K def
- Low P, low OM, low microbes
- Al toxic ph <5 - 57Are all forms Al toxic- No, exchangable Al3 used to determine Al toxicity
- hydration of Al (OH)
- toxicity vaties - 58WHat is the effect of H+Stunts plant growth above ground
- deteriorates membrane
reduce root growth
only toxic below 4 - 59what is the stern layerInternal layer of double layer
ions are immoble - 60what is diffuse layer- Distance between charged surface and counter ions
- 61what is the isomporphic substitution on tetrahedral layerAl3 for Mg
- 62Isomorphic substitution on octo layerMg for Al
- 63where is variable charge in minerals- Edges of crystals
- - 64What are the metal nutrientsFe, Al, Mn, Ti
- 65Metal exhange components- Exchange with OH and H20
- Charges developed through sorption of H and OH
- Highly weather soils and CEC and AEC - 66What happens at neutral charge- H+ on surface creates positive charge on low pH soil
- H+ creates negative charge high pH - 67Problems from too much Na- DIspersion, microaggregets, clay particle attraction
- 68What balances surface charge- Cation excess
- anion deficit - 69What effect does balanced repulsion and attraction haveDispersion
- 70How do you reduce repolsion- Thickness of diffuse layer reduced
- Ca uses half as many ions than if it is balanced by Na
-Concentration of cations if ionic strength high = tight diffuse layer
Informações
- Descrição
- FlashCards sobre Sem título, criado por alexbrugs em 18-06-2015.
- Criado por
- alexbrugs · jun 2015
- Atualizado
- 19 fev 2016
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