feature result management prescription sandy topsoil poor plant...

Baxter & Robinson (2001). A Land Resource Assessment of the Glenelg Hopkins region. Agriculture Victoria – CLPR.

Feature Result Management PrescriptionSandy topsoil •Poor plant available

water holdingcapacity

•Poor nutrientholding capacity

•Increased risk ofwind erosion

•Potential forhydrophobicity

•Establish wind protection barriers

•Maintain vegetative cover

•Increase frequency of fertiliser (e.g.side dressings) and irrigations

•Dryland cropping - minimum tillageand stubble retention, improve organicmatter through maintenance ofvegetative cover and growing greenmanure crops


Feature Result Management PrescriptionDeep sandy profile •Poor plant available


•Poor nutrientholding capacity

•Increased risk ofwind erosion

•Potential forhydrophobicity

•Rapidly drained

•Grow appropriate species

•Maintain vegetative cover

•Improve organic matter throughmaintenance of vegetative cover andgrowing green manure crops

•Establish wind protection barriers

•Increase frequency of fertiliser (e.g.side dressings) and irrigations


Feature Result Management PrescriptionHydrophobic topsoil •Poor infiltration of

water into the soil

•Increased risk ofwater and winderosion

•Poor seedgermination

•Maintenance of surface vegetativecover

•Claying (clay spreading) ifappropriate

•Reducing wetting/drying cycledifferential


Feature Result Management PrescriptionStrong texturecontrast betweentopsoil and subsoil

•Strong texture andstructure differencebetween the topsoiland the subsoil

•Can result inimpeded internaldrainage

•Can restricted rootgrowth if subsoilclose to the surface


•Reduce tillage

•Optimise plant growth throughregular balanced fertiliser program

•Consider sub-surface drainage (ifappropriate) if subsoil has impededdrainage is restricting root growth

•Deep ripping if not dispersive


Feature Result Management PrescriptionShallow topsoildepth

•Reduced water andnutrient holdingcapacity

•Reduced rootgrowth

•Potential forwaterlogging

•Water and winderosion potential


•Reduce tillage to protect against waterand wind erosion

•Optimise plant growth through aregular and balanced fertiliser program

•Consider sub-surface drainage (ifappropriate) if the subsoil has impededdrainage and is restricting root growth


Feature Result Management PrescriptionBleached A2 horizon •Indication of

waterloggedcondition (impededinternal drainage)

•Poor soil structure(often massive)

•Low organicmatter, waterholding capacity andnutrition within thehorizon

•Optimise plant growth through aregular and balanced fertiliser program


•Install subsoil drainage if subsoil hasimpeded drainage (if appropriate)

•Dryland cropping - include deeprooted crops in the rotation, minimumtillage and stubble retention. Applygypsum if the topsoil is dispersive


Feature Result Management PrescriptionSodic subsoil •Subsoil often has

poor structure thatcan reduce watermovement and plantgrowth

•Poor water and airmovement into thesubsoil resulting inwaterlogging(impeded internaldrainage)

•Poor root growthinto the subsoilreducing the volumeof the soil able to beexploited

•Very difficult tocultivate particularlyif topsoil is shallow

•Limited workingtime (sets hard)

•Apply gypsum if the subsoil isdispersive and close to the surface andtopsoil textures are light

•Dryland cropping - include deeprooted crops in the rotation, minimumtillage and stubble retention


Feature Result Management PrescriptionMottled subsoil •Indication of

periodicwaterlogging,particularly if greyand yellow mottlespredominate

•Consider sub-surface drainage (ifappropriate)

•Apply gypsum if subsoil is dispersiveand close to the surface and topsoiltextures are light


Feature Result Management PrescriptionSubsoil dispersivewhen worked whenwet

•Indication of soilsodicity. Soilstructure collapsesfollowing tillage andwetting Results inpoor soil structure(hardpans, surfacesealing) that reduceswater movement andplant root growth(see sodic subsoil).

•Increases watererosion hazard.

•Raindrop impact onbare soil is likely toresult in structuraldegradation.

•Don’t cultivate wet soil

•Apply gypsum if growing high valuecrops and subsoil is close to the surfaceand topsoil textures are light


Feature Result Management PrescriptionAlkaline subsoil •Potential nutrient

imbalance.

•Unsuitable foralkaline intolerantplants.

•Grow shallow rooted species.

•Grow alkaline tolerant plants.


Feature Result Management PrescriptionCalcium carbonatenodules

•Potential fornutrient imbalance

•Unsuitable foralkaline intolerantplants

•Possible drainagerestrictions if dense

•Grow alkaline tolerant species

•Grown shallow rooted species ifcarbonate close to the surface

•Supply trace elements ie zinc


Feature Result Management PrescriptionSoil salinity at depth •Poor or no plant

growth for deeperrooted species

•Indication ofwaterlogging(impeded internaldrainage) or highwater table

•Grow shallow rooted species

•Increase plant water use throughoutthe catchment

•Install subsoil drainage (ifappropriate)

•Minimise irrigation water loss belowthe root zone (improve irrigationefficiency)


Feature Result Management PrescriptionVery low and lowPlant AvailableWater HoldingCapacity (PAWC)

•Poor plant availablewater holdingcapacity

•Indication of lightsoil texture orshallow effectiveplant rooting depth(ie presence ofrestrictive layers,salinity, pH orstructure)


•Increase effective rooting depth byreducing the effect of the restrictivelayer

•Addition of finer material (claying)on deep light textured soils


Feature Result Management Prescription•Ferromanganiferousnodules

•Restricted rootpenetration

Limit availablewater holdingcapacity

•May be anindication of periodwaterlogging

•Select shallow rooted species ifnodules are close to the surface

•Improve topsoil by increasing organicmatter and nutrition

•Consider subsoil drainage (ifappropriate) if subsoil has impededdrainage


Feature Result Management Prescription•Ferruginousnodules•Ferric horizon

•Restricted rootpenetration

•Limit availablewater holdingcapacity

•May be anindication of periodwaterlogging

•Select shallow rooted species ifnodules are close to the surface

•Improve topsoil by increasing organicmatter and nutrition.

•Consider subsoil drainage (ifappropriate) if subsoil has impededdrainage


Feature Result Management Prescription•Ferruginous pan•Ferromangaiferouspan•Petroferric pan

•Restricted rootpenetration into thesubsoil.

•May be anindication ofperiodicwaterlogging.

•Select shallow rooted species

•Improve topsoil by increasing organicmatter and nutrition

•Ripping may assist if pan iscontinuous and close to the surface,include gypsum if subsoil is sodic

•Consider subsoil drainage if subsoilhas impeded drainage (if appropriate)


Feature Result Management PrescriptionAcidic topsoil •Potential nutrient

imbalance

•Unsuitable for acidintolerant plants

•Potential foraluminium andmanganese toxicity

•Highly sensitivespecies (such asbarley, lucerne,medics, phalaris andsome wheatvarieties) may beaffected

•Deficiencies inmolybdenum,calcium, andpotassium may alsooccur

•Apply lime. Raising the pH level ofthe surface soil will help reducealuminium and manganese toxicity. Alime test (sampled at paddock level)may be appropriate to determine howmuch lime is needed to raise the pHlevel. Also raises the availability ofnutrients


Feature Result Management PrescriptionAcidic subsoil •Potential nutrient

imbalance

•Unsuitable for acidintolerant plants

•Potential foraluminium andmanganese toxicity

•Highly sensitivespecies (such asbarley, lucerne,medics, phalaris andsome wheatvarieties) may beaffected

•Deficiencies inmolybdenum,calcium, andpotassium may alsooccur

•Grow acid tolerant species or varietiesif acidic subsoil is deep

•If the acidic subsoil is close to thesurface apply lime. Raising the pHlevel of the surface soil will helpreduce aluminium and manganesetoxicity. A lime test (sampled atpaddock level) may be appropriate todetermine how much lime is needed toraise the pH level.


Feature Result Management PrescriptionLimestone •Highly alkaline

layer. Can restrictroot growth ofsensitive plantspecies

•Potential fornutrient imbalance;some nutrients moreavailable, some lessavailable

•May restrict watermovement if layer ishard rock

•Grow alkaline tolerant species.

•Grow shallow rooted species iflimestone is close to the surface

•Supply trace elements ie zinc

•Considered sub-surface drainage (ifappropriate) if limestone causinginternal waterlogging


Feature Result Management PrescriptionHardsetting topsoil •Possibly clay

texture

•Possibly sodic

•Poor seedgermination andseedlingestablishment

•Poor root growthand exploration ofthe topsoil

•Poor infiltration ofwater into the topsoiland air movementthrough the topsoil

•Apply gypsum if the topsoil isdispersive

•Build up organic levels and greenmanure



Feature Result Management PrescriptionShallow soil •Poor plant available


•Poor nutrientholding capacity.Restriction for rootgrowth

•Select shallow rooted species

•Improve organic matter throughmaintenance of vegetative cover andgrowing green manure crops toincrease the available water andnutrient holding capacity


Feature Result Management Prescription‘Coffee rock’ layer •The ‘coffee rock’

layer may restrict thedownwardmovement of plantroots and water.

•If ‘coffee rock’ is deep, plant deeprooted species. In some situations, thetemporary build up of water on top ofthis less permeable layer may bebeneficial for deeper rooted plants inthat it prevents deep drainage of wateraway from plant roots.

•If ‘coffee rock’ is shallow selectshallow rooted species.


Feature Result Management PrescriptionCracking soil •Uneven levels of

infiltration that ishighly permeablewhen dry and almostimpermeable whensaturated.

•Cracking soils areoften prone tostructuraldegradation (e.g.compaction,smearing) whenworked in moistconditions

•Soil is oftenstrongly alkaline,particularly at depth

•Variation in soilproperties can oftenoccur over a shortdistance due to gilgaimicrorelief

•Tillage of cracking clay soils shouldbe avoided if the soil is wet. At suchmoisture conditions excessive tillage,trafficking or overstocking can resultin structural degradation. Ideally,tillage and trafficking should takeplace when the soil is drier than theplastic limit.


Feature Result Management PrescriptionClay throughout •Almost

impermeable whensaturated. Internaldrainage may bepoor. These soils aretypically Crackingsoils

•Tillage of clay soils should beavoided if the soil is wet. At suchmoisture conditions excessive tillage,trafficking or overstocking can resultin structural degradation. Ideally,tillage and trafficking should takeplace when the soil is drier than theplastic limit.


Feature Result Management PrescriptionTopsoil dispersivewhen worked whenwet

•Possibly claytexture

•Possibly sodic.Soil structurecollapses followingwetting resulting inpoor structure thatreduces watermovement and plantgrowth




•Avoid cultivation and tillage of thissoil if wet

•Apply gypsum



•Horticulture – maintain optimumplant growth in between the rows.Minimum tillage and surfacevegetative cover


Feature Result Management PrescriptionSubsoil dispersivewhen dry

•Indication of soilsodicity. Soilstructure collapsesfollowing wettingresulting in poor soilstructure thatreduces watermovement and plantroot growth (seesodic subsoil).

•Increases watererosion hazard.

•Dryland cropping - apply gypsum, ifsubsoil is close to the surface andtopsoil textures are light. Include deeprooted crops in the rotation, minimumtillage and stubble retention.

•Horticulture - apply gypsum,maintain optimum plant growth inbetween the rows. Minimum tillageand surface vegetative cover.


Feature Result Management PrescriptionCoarse fragments •Restricted root

penetration into thesubsoil, if above thesubsoil.

•Restricted waterand nutrient holdingcapacity of the soil

•Select shallow rooted species.

•Improve topsoil by increasing organicmatter and nutrition.

•Ripping may assist if coarsefragments are small and close to thesurface, include gypsum if subsoil issodic.


Feature Result Management PrescriptionTopsoil dispersivewhen dry

•Possibly claytexture

•Possibly sodic.Soil structurecollapses followingwetting resulting inpoor structure thatreduces watermovement and plantgrowth




•Apply gypsum



•Horticulture – maintain optimumplant growth in between the rows.Minimum tillage and surfacevegetative cover


Feature Result Management PrescriptionSodic topsoil •Potential for topsoil

to becomehardsetting




•Increases watererosion hazard

•Apply gypsum



feature result management prescription sandy topsoil poor plant...

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