MAJOR SOILS + LAND MANAGEMENT Flashcards
Histosols
= Soils with thick organic layers
SOC can be lost upon land conversion & by drainage!! The formation of these peats can take thousand of years, they have a very large carbon store.
- tropics: extremely fertile soils (plantations + fruit and vegetable cropping smallholders)
RESULTS DRAINAGE
- CO2 and CH4 emissions (GHG)
- subsidence and instability
- enhanced wild fire risk
To counter these emissions there are laws in place for protection and restoration of peatlands, overall reduction in emissions
Anthrosols
= Soils with strong human influence, with long and intensive agricultural use.
LM: Agriculture
Technosols
= Soils with strong human influence, containing significant amount of artefacts.
LM: Restricted use for fear of toxic substances
used for land-files or bio-remidation
afforestation, urbanparcs.
Cryosols
= Soils with limitations to root growth, permafrost affected.
landuse/cover: Tundra & Taiga
- Building of houses can lead to melting of permafrost, houses can collapse.
- Very short growing seasons, so only short season crops
- Bad management: resulting badlands, wildfires thawing the permafrost, …
Leptosols
= Soils with limitations to root growth, thin or with many coarse fragments.
Land use: forest & pastures
Occurence: mountains and dry regions
Solonetz
= Soils with limitations to root growth, high content of exchangeable Na.
- leaving land to nature
- watch out with extensive grazing (livestock densities)
- reducing excessive alkalinity (adding gysium (CaSO4), adding organic matter, …
- organic matter management
- Salt and drought tolerant vegetation & crops
- Implications on irrigation & drainage!! Watch out for water sources which are high in sodium, leaching with clean water
- reversing sodium hazard through exchange reactions
1. Exchange sodium on the clay complex by calcium from gypsum or equivalent
Na2-clat + SO4(2-) + Ca(2+) <-> Ca-clay + Na2SO4
2. Leaching of Na2SO4 - crust formation, hard to get water into the soil
vertisols
= Soils with limitations to root growth, alternating wet-dry conditions, shrink-swell clays
- difficult soils with high potential
- gilgai relief: causes localized flood problems, moisture induces differences
- water logging (subsequent due to ploughing), frequent low applications of water (irrigation)
=> best: shallow and infrequent tillage - consequences
instability + gully erosions enhanced by cracks
NUTRIENT MANAGEMENT
N and P need special attention
- farmyard manure => soil structure, acidity & supply of N&P
- legumes => Nfix, contribution to organic matter
PHYSICAL MANAGEMENT
conservation agriculuture!!
- drainage + evacuation exces surface water
raised beds & furrows, contour , cultivation & bunds, tied ridges
- improved rooting conditions
surface drainage & organic manure - gully control
grassed waterways - water harvesting
small ponds & micro dams
Solonchaks
= Soils with limitations to root growth, high concentrations of soluble salts.
Land use: salt mining (Tanzania & Vietnam) + pastures
- drainage canals to flush out salts
- flocculated soils, not as serious physical properties as solonetz (sodic soils)
- improper management can lead to sodic soils
Gleysols
= Soils distinguished by Fe/Al chemistry, Groundwater-affected, underwater & tidal areas.
- Grassland, pastures when drained
- WET: suldifes dominate the soil profile
- DRY: ocidation to acid sulphate (There is an oxidation proces after drainage)
ACID SULPHATE SOILS
- low pH, aluminium toxicity, acidification of surface waters, corrosion of construction works => liming
- salinity => leaching
- iron toxicity => K-fertilisation
- H2S toxicity after flooding of sulfuric horizon
RECOMMENDATIONS
- avoid disturbance/ drainage iron sulfide layer, shallow drainage without disturbance
- liming: neutralization but costly
- covering with water to prevent further oxidation, keep water on the affected area
Andosols
= Soils distinguished by Fe/Al chemistry, Allophanes or Al-humus complexes.
Vulnerability to erosion by for example extensive grazing
Podzols
= Soils distinguished by Fe/Al chemistry, subsoil accumulation of humus and/or oxides
liming + high input of fertilisers
- Low nutrient status
- Low level of available
moisture - Low soil-pH
- Aluminium toxicity and
phosphorus deficiency - Dense illuviation horizon or
hardpan
=> unnattractive soils for arable farming
plinthosols
= Soils distinguished by Fe/Al chemistry, Accumulation and redistribution of Fe
Poor natural soil fertility, water logging in lowlands and drought on shallow and/or skeletal Plinthosols in uplands pose serious limitations, notably to root growth. The occurrence of petroplinthite hinders agriculture, the land is best left for grazing.
- preventing hardening with strong protection against erosion of the overlying layers
- soft plinthite, carefully managed to avoid irreversible hardening upon wetting and drying
- road construction material + stable foundations for buildings + brick mining
Planosols
= Soils distinguished by Fe/Al chemistry, stagnating water, ABRUBT textural difference
drainage limitations
- dry seasons too dry
- wet seasons too wet
Land use: Mostly pastures, sometimes forests (low diversity), few cases of afgriculture
Stagnosols
= Soils distinguished by Fe/Al chemistry, stagnating water, structural difference and/or moderate textural difference
COMPACTATION OF SOIL
- decreased pH
- leaching base cations
- poor aeration & water saturation (winter)
remediation
- reduced tillage and compost to counteract soil degradation
- compost: positive effect on pH
- cover crops
- non-inversion tillage, reducing leaching base cations & organic compounds
Nitisols
= Soils distinguished by Fe/Al chemistry, low activity clay, P fixation, many Fe oxides, strongly structured
fertile tropical soils BUT:
- low P availability
- low base status
- deep stable soils with favorable physical properties
Ferralsols
= Soils distinguished by Fe/Al chemistry, dominance of kaolinite and oxides
- in beginning reasonable yields, then gradual decline, many years needed for restoring
- traditional: no-tillage agriculture
- high input of fertilizers needed in PC, close to housing (higher input of organic material)
MANAGEMENT
- topsoil conservation
- addition organic matter, macro + micro nutrients
- minimal tillage
- crop residue management
- good crop rotations
Chernozems
= Pronounced accumulation of organic matter in the mineral topsoil, very dark topsoil, secondary carbonates
Among best arable soils, high fertility rates lead to very high crop yields
gully erosion due to intense land-use & cultivation
- tree windbreaks
- manure & mulching
- crop rotation
- restoring grass vegetations
=> more reliable carbon sinks than trees
- less impacted by droughts and wild fires
- sequestering of carbon underground, in forest this is in woody biomass
Kastanozems
= Pronounced accumulation of organic matter in the mineral topsoil, dark topsoil, secondary carbonates
land use: natural grasslands or dry forests
- agriculture mostly rainfed
Phaeozems
= Pronounced accumulation of organic matter in the mineral topsoil, dark topsoil, no secondary carbonates (unless very deep), high base status
high agricultural potential due to prominent reserves of organic carbon in topsoil
Umbrisols
= Pronounced accumulation of organic matter in the mineral topsoil, dark topsoil, low base status
Fertilization needed for agriculture
- low base saturation => acidic soils that lak nutrients for optimal plant growth
- liming
- preventing leaching by mulching & cover crops (P > ET in these regions)
durisols
= Acculumulation of moderate soluble salts or non saline substances, accumulation of and cementation by, secondary silica
Problems
- serious subsurface erosion
- exposing the duripan
solutions
- arable cropping only when irrigation water is available
- duripan must be broken to remove barrier for root and water penetraition
gypsisols
= Acculumulation of moderate soluble salts or non saline substances, accumulation of secondary gypsium
Occurance: hot desert areas
- xerophytes and ephemeral grasses & herbs
tunneling
- irregular subsidence of the land surface and overal instability due to dissolution of gysium
solution : very localize irrigation systems
calcisols
= Acculumulation of moderate soluble salts or non saline substances, accumulation of secondary carbonates
occurance: dry climates almost all year + short rainy period
mostly extensive grazing (nomadic herdings)
- water deficit is major problem
=> tree planting in peepholes to last water accumulate & infiltrate
Retisols
= Soils with clay enriched subsoil, inter fingering of coarser-textured, lighter colored material into a finer-textured, stronger coulourd layer
- stagnic properties & reducing conditions, N loss, …
- subsurface drainage lowers the water table of the saturated soil
- Not always effective, but purpose was to take away the stagnic properties
acrisols
= Soils with clay enriched subsoil, low activity clays, low base status
problems
- low CEC and low base-saturation, acidification, prone to aluminium
toxicity
- nutrient availability is limited
- liming, organic matter, slow release N-fertilizers, erosion control, rotation with N-fixators, acid tolerant crops, …
lixisols
= Soils with clay enriched subsoil, low activity clays, high base status.
low CEC, but high base saturation
- occur in drier parts of the tropics & subtropics
- organic matter additions (crop residues, green manuring, cover crops, …)
- fertilizer application needed for agriculture
- limited capacity to retain additional nutrients, applying fertilizers carefully (leaching risk)
alisols
= clay enriched subsoil, high activity clays low base-status
high CEC and low base saturation
- good capacity to hold cations, lack of base cations
- high concentrations of Al3+ and H+, acidity
- liming needed, calcium and potassium are likely to be deficient
- problem of Al toxicity and P deficiency
luvisols
= clay enriched subsoil, high activity clays high base-status
Among the most productive soils in the world
- loess: string erosion by wind and water
cambisols
= soils with little or no profile differentiation, moderately developed
Broad range form high yielding to low productive. Management dependent on qualifiers.
Fluvisols
= soils with little or no profile differentiation, stratified fluviatile, marine and lacustrine sediments
Climate change:
Sea Level Rise
- Salt Water Intrusion from normally one month to four months
- Threat to local rice based farming systems and fisheries
- Fresh water supplies are a major problem
- Technology for desalinating brackish river water
=> flood control is needed
Arenosols
= soils with little or no profile differentiation, sandy
only agriculture with high input of fertilizers and irrigation (not that sustainable)
- low plant available water, low residual water contents, but high drainage water contents
- revegetation with drought tolerant, fire resistant savanna species, cashew trees (combating desertification)
- high evaporation rates, drought and heat stress, …
- addind LNC = liquid natural clay
regosols
= soils with little to no profile differentation, no significant profile development
- Low moisture holding capacity, Irrigation is costly (frequency!)
- Dry farming practices
Vineyards; Olive plantations
Extensive grazing in arid areas
