Soil and Water Best Management Practices for Nsw Banana Growers

8/2/2019 Soil and Water Best Management Practices for Nsw Banana Growers

1/20


2/20

Soi & Wtr Bst Mngmnt Prctics for

NSW Bnn GrowrsArthur Akehurst, Peter Newley & Mark Hickey

NSW Department of Primary Industries


3/20

Title: Soil & Water Best Management Practicesfor NSW Banana Growers.

Authors: A Akehurst, P Newley & M Hickey

Published by NSW Department of PrimaryIndustries

State of New South Wales (2008).

You may copy, distribute, display, downloadand otherwise freely deal with this publicationfor any purpose, provided that you attributethe department as the owner. However, youmust obtain permission if you wish to chargeothers for access to the publication (other than

at cost); include the publication in advertisingor a product for sale; modify the publication; orrepublish the publication on a website.

First published June 2008

ISBN 978 0 7347 1914 0

About this guide

These guidelines have been developed byNSW DPI in consultation with NSW bananagrowers and the Northern Rivers CatchmentManagement Authority. Other relatedpublications include Banana Growing Basics forNSWand Banana Growing Guide CavendishBananas, both published by NSW DPI areavailable from the NSW DPI website

www.dpi.nsw.govau. Updated versions of thisdocument and other publications covering pestand disease management will also be found atthis web address.

Current contacts are listed below.

NSW Department of Primary Industries

Alstonville Office Mark Hickey

Coffs Harbour Office Peter NewleyMurwillumbah Office Arthur Akehurst

Disclaimer

The information contained in this publication isbased on knowledge and understanding at thetime of writing (June 2008). However, becauseof advances in knowledge, users are reminded ofthe need to ensure that information upon whichthey rely is up to date and to check currency ofthe information with the appropriate officer ofNSW DPI or the users independent adviser.

The product trade names in this publication aresupplied on the understanding that no preferencebetween equivalent products is intended and that

the inclusion of a product name does not implyendorsement by NSW DPI over any equivalentproduct from another manufacturer.

jn 8690


4/20P | 1

T a B l e O F C O N T e N T S

so mngement 13

Managing nutrients: 13

Managing soil pH: 13

Fertilising young plants: 13

Fertilising established crops: 13

Irrigation: 14

Managing soil biology: 15

Use of mulches: 15

inrtruture mntenne 16

Road maintenance: 16

Drainage maintenance: 16

Irrigation system maintenance: 16

Dam maintenance: 16

further redng 17

aknowedgment 2

introduton 3

Industrybackground: 4

Pnnng 5Site selection: 5

Slope: 5

Aspect: 5

Gullies, watercourses and ridgelines: 5

Pntton yout/degnonderton 6

Roads: 6

Plantation design: 7

Drains: 7

lnd preprton 8

Clearing the land : 8

Panama disease management : 9

Re-planting an existing plantation: 10

cover rop 11

Planting bananas into a cover crop: 11

Managing cover crops in youngplantations: 11

Managing cover crops in establishedplantations: 12

Cover crop options for bananaplantations: 12

s o i l & w at e r b e s t m a n a g e m e n t P r a c t i c e s f o r n s w b a n a n a g r o w e r s


5/20


6/20P | 3

A comprehensive approach to naturalresource management on horticulturalfarms extends further to considerissues of water and air quality, weedmanagement, impacts of pesticide use,management and retention of remnant

vegetation, recognition of protectedspecies and biodiversity. However, thepurpose of this document is to provideguidance to industry on current bestpractice to protect and improve thequality of soils on banana plantationsand to manage water flows within andthrough the plantation to minimiseerosion and off site transport of soil,nutrients and organic matter.

I N T R O D U C T I O N

This publication focuses on bananaplantations on steep lands on theNSW north coast where high seasonalrainfall is a regular event. Landmanagers on similar landscapes areencouraged to consider the on andoff farm effects of their managementdecisions. The aim of this publicationis to provide practical guidelinesto help growers and land managersdevelop whole farm practices thatlead to a stable, productive andsustainable system. These practiceswill also have off farm benefits tothe wider community such as cleanwaterways and improved soil healthand biodiversity. However the generalprinciples will apply equally to otherhorticultural enterprises with similar

intensive systems.

Apart from the on and off farmeffects of soil loss on the steep landsof the north coast, improvement ofsoil health is critical to maintenanceof healthy and productive bananaplantations. Use of organicmulches (including banana trash),composts and cover crops are morecommonplace these days in northcoast banana production. There is

also some evidence to suggest thatmaintaining a biologically diversesoil through use of various forms oforganic matter and maintenance of awell aerated, well structured soil, canhelp suppress soilborne diseases ofbananas.

Some of the best practices describedin this publication add to the cost ofgrowing bananas. However, with mostit is a oneoff investment which notonly adds value to the farm, but canenhance productivity. So, if attemptinglarge scale changes involving biginvestment dollars is not feasible, agradual approach over a number ofyears can spread the cost, and theworkload.

A double row system at Ian Simpsonsallows extra light penetration, access formachinery and a buildup of mulch aroundthe plants.

i n t r o D U c t i o n


7/20P | 4

Industry bckground

The NSW banana industry isconfined to the coastal strip fromthe Queensland border south to theKempsey Shire. Bananas are grownon hillsides to enable them to be

above the frost line. This creates manyproblems for the growers, making thework backbreaking and limiting theamount of machinery that can be used.It also limits banana production tosloping sites which are highly proneto erosion. Prior to the advent of fourwheel drive vehicles, elaborate flyingfox systems were used to deliver thebunches from the plantations to thepacking sheds.

The introduction of four wheel drive

vehicles necessitated the constructionof road systems throughout theplantations. These road systemscreated new challenges for growers asthey can concentrate water which maycause extensive soil erosion. Roadstherefore need to be planned andconstructed correctly. Road batters canalso create erosion problems and needto be well planned and constructed tominimise erosion risk.

Early in the history of bananaproduction it was mandatory tokeep the banana plantation free ofweeds and other vegetation. This wasnecessary to permit Banana BunchyTop Virus inspectors access to theplantation and inspect each plantfor possible infection with the virus.This regulation has now been relaxedand vegetation within one metre ofthe base of banana plants must bekept below 30 centimetres. This nowpermits growers to grow low growingcover crops in the interrow area.

These days growers are able to manage their plantation to minimise the risksof erosion and maximise the benefits of organic material on the soil surface.Table 1 below summarises the best management practices outlined in thispublication.

Table 1. Natural Resource Management summary

ManageMent area goal Process growers can

Planning Minimise on and off

farm impacts of erosion

and runoff water

Use a whole farm

planning approach to

water management

Involve specialists at the

design phase

Plantation layout and

design

Catch and divert runon

water and manage on

farm drainage

Design roads, drains

and culverts to control

water

Ensure roads are

effectively diverting

water to drains

Good land preparation Minimise soil

disturbance

Maintain ground covers

where possible to

mitigate erosion

Supervise all aspects

(e.g. contract dozer

operations)

Us ing cover crops Minimising soi l loss and

improving soil health

Establ ish crops early Manage the cover

crop for maximum soil

coverage

Managing fert il isers Minimise nutrientrunoff

Match applications toplant nutrient demands

Use regular soil, leaf andwater tests.

Apply regular small

doses of fertiliser

Effective irr igation Apply water to satisfy

crop needs

Schedule irrigation to

match water use

Monitor soil moisture

and apply the correct

amount

Infrastructure

maintenance

Maintain water

diversion and control

structures

Incorporate

maintenance into farm

management routine

Conduct regular

inspections of all

structures

I N T R O D U C T I O N



8/20P | 5

Site selection

The ideal site has a gentle slope facingnorth to north east, above frost leveland protected from prevailing winds.Very seldom will ideal conditions beavailable over the entire property and

normally a compromise will have to bemade. Variations within the propertycan assist in spreading the farmoperations out and help spread thework load.

Slope

The slope of the plantation willaffect productivity. If a section of theproperty is obviously too steep, seriousconsideration should be made notto plant the area and if it is plantedalready then maybe the area shouldbe retired and revegetated. Clearing ofland on slopes in excess of 18 degreesis restricted under State regulations,and such land should also be avoidedfor banana cultivation.

Steep land will have manydisadvantages:

erosion will be more difficult tocontrol

water flows will be more damaging all operations will be harder to

undertake

the cost of production will be higher

roads will be steeper which willimpact on safety for farm workers

road batters will be higher

fruit is more liable to be damagedduring harvesting

overall bunch yield may be lower

plants may be more susceptible tofalling over.

aspect

The aspect of the plantation will affectwinter temperatures and exposure tocold winds. North east to north slopesare ideal. Flat land is suitable providedit is sheltered from strong winds.

However sites exposed to cold winds,with temperatures regularly fallingbelow 12 C cycle more slowly andproduce inferior fruit.

Areas that are open to cold winds, aretoo low or have the wrong aspect willbe too cold and less viable. It will befound that:

fruit will have a higher incidenceofDeightoniella and other skinblemishes

fruit will be a dull grey in winter/spring

P l a N N I N G

fruit will be slower ratooning

more frequent treatment for fruitpests and diseases may be required

the plantation will have lowerproduction

less leaf mulch will be producedresulting in less soil protection

leaves will become shredded and lessefficient

some varieties will choke in winter.

Gullies, wtercourses nd ridgelines

Any gullies and watercourses on theblock should not be disturbed and

vegetation along ridge lines should bekept as windbreaks.

Bananas in NSW are grown on hillsides,requiring growers to implement steps toreduce soil erosion.

P l a n n i n g


9/20

Good road design andmaintenance is critical tominimise erosion as well asreduce fruit damage duringharvest operations.

If a section of an existing plantationis being replanted the option to startreroading the plantation should beconsidered. When the plantationroads were originally constructed, itis possible the plantation was alreadyestablished and the roads wereconstructed between existing bananarows. This may have resulted in aroad system that was a compromisebetween the ideal design and notlosing too many plants or opening theplantation up to damaging winds.

Rods

When replanting, the option tocompletely redesign the road systemshould be considered. A good road

system will:

allow efficient movementthroughout the plantation

collect and divert drainage waterinto natural or constructedwaterways

be designed to permit harvesting offruit with the minimum of walkingup and down the slope

have roads spaced so there is a

minimum of walking back to thevehicle to refil l during fertiliserapplications

P l a N T aT I O N l a yO U T / D e S I G N C O N S I D e R a T I O N S

have roads spaced to enable the useof large spray equipment if these areto be used for leaf spraying

be designed to provide safe accessto the plantation for vehicles,equipment and people

be designed for roads to run acrossthe slope or up and down the slope.

Roads across the slope:

must be well designed andmaintained otherwise they canconcentrate water which could causesevere soil erosion

may have steep batters on theuphill side which can make farmoperations difficult

need to be grassed or protectedwith rocks on the banks to preventerosion

can be constructed as inslopingroads with a 3% gradient to collectand divert water to natural orconstructed drains

can be constructed as outslopingroads which will allow rainfall tocontinue down the slope providedthey are well maintained; however,

maintenance is difficult as even thesmallest wheel rut will concentratewater.

Roads running up and down theslope:

permit vehicles to be parked whereharvested bunches and fertiliser canbe carried across the slope

permit rows to be planted up and

down the slope where appropriateutilising tramline configurationand permitting the use of machineryfor farm operations such as weedcontrol, fertilising

have been known to allow damagingwinds into the plantation

can be grassed if they can be slashed

will concentrate some water in thewheel ruts or between the concretetracks

can be sealed or concreted to protectagainst soil erosion

depending on the plantation, crossdrains may be required to divertwater out of the plantation.

P | 6



10/20P | 7

P l a N T aT I O N l a yO U T / D e S I G N C O N S I D e R a T I O N S

Sealed roadways in t he plantation:

provide added safety for farmvehicles

are ideal on corners

improve vehicular access in all

weather conditionshelp prevent the spread of panamadisease

require a minimum of maintenance

should be well planned andconstructed to minimiseconcentration of high velocity waterflows. Concrete strips with diversiondrains can slow and spread waterbefore it becomes damaging.

Plnttion designCavendish bananas are usuallyplanted to have one plant per sevensquare metres, while ladyfingersare planted at about twelve squaremetres each. Consideration should begiven to choosing a plantation designthat incorporates ease of access forharvest and farm operations withfavourable conditions for cover cropestablishment. One system whichprovides such benefits is use of doublerows with grassed interrows, or tramlining. This system can be used whereslopes are gentle and has the followingadvantages:

trash can be concentrated betweenthe rows, allowing nutrient recycling, and a build up of soilorganic matter

grassed interrows enable easy accessfor harvest aids and machinery

wider spacing of the interrowsallows better air circulation to allowthe plantation to dry out quicklyafter rain, minimises leaf disease andmaximises light penetration

grassed rows and mulch beds

running across the slope slowdown water movement, resulting inminimal soil losses.

Drins

A well designed drainage systemis essential if soil erosion is to becontrolled. Water from above theplantation should be diverted ifpossible and water that collects withinthe plantation needs to be controlled.

Grassed inter-rows help to slow watermovement through internal drains. Bananatrash also remains undisturbed enablingnutrient recycling, and soil protection.

drainage water from above theplantation (runon water) needs tobe directed away from the plantationor into natural or constructed drains

water that collects within aplantation needs to be controlled

and slowed by a well designed andmaintained road and drainagesystem

ideally drains should be vegetated orprotected with rocks to reduce soilerosion.

Gully lines should not be disturbed,and can be protected with vegetationor rocks if needed.

P l a n t at i o n l a Yo U t / D e s i g n c o n s i D e r a t i o n s


11/20

Clearing native vegetation is highly regulated in NSW. Consult withthe regional CMA and local government prior to clearing existing

vegetation. For clearing of exotic or dead native trees on slopes over18 degrees DECC must also be consulted.

P | 8

Clering the lnd

Bananas will normally be establishedinto one of three situations:

newly cleared land which is to beplanted to bananas for the first time

planting into former bananaplantations where the bananashave been removed and significantregrowth has occurred

replanting an existing plantation.

A soil test should be taken beforeland preparation starts so that soilamendments such as lime can bespread mechanically if possible.Consider using compost or mulch toimprove soil physical, chemical and

biological fertility.Depending on the situation thereare a range of land preparationoptions. These include the use ofheavy machinery, the use of handheld machinery, i.e. brush cutters andspray equipment, and the injection ofexisting banana plants with herbicide.

Fire has been used in the pastto prepare sites, but it is not arecommended practice because it

destroys all vegetation which wouldhave protected the soil from erosion

destroys soil organic matter

can escape, damaging neighbouringproperties.

When using heavy machinery toclear the site

Where the site has never been cleared,or has significant regrowth vegetationrequiring large scale dozer operations,consider:

Soil that is left bare is prone tosevere erosion.

Remnant vegetation should beretained along natural drainage linesand gullies running through theplantation.

Timing should avoid periods ofheavy rainfall (June to October is thebest time to avoid heavy storms).

MayJune is the best time to startsite preparation. This allows timefor a cover crop to establish prior to

planting bananas in the spring.

Logs and rocks can be removedwhich can later interfere withplantation operations and harbourrats.

Roads and drains should beconstructed at this stage.

Immediate establishment of a covercrop will save the soil from erosionand build up the soil.

Having a clear plan for the dozer iscritical. The plan should show whereroadways, drainage lines and runonwater diversion structures are to go.

When using brush cutters andherbicide

if the regrowth vegetation is low

growing it may be possible to clearwith brushcutters and herbicides ifit is economical. This method willminimise soil disturbance and ispreferable to using machinery.

the cover crop should be establishedas soon as possible after the landis cleared. This will reduce thepossibility of soil erosion prior to thecover crop establishing.

l a N D P R e P a R aT I O N



12/20P | 9

Pnm disese mngement

Panama disease is a fungal diseaseFusarium oxysporum that is spreadin water, soil and planting material.Once Panama gets established ina plantation it is there for ever. At

present there is no chemical controlavailable. The only control is to plantresistant varieties.

To keep Panama out of a plantationand limit its spread in a plantationgrowers need to:

control the access of visitors

use a footbath before entering theplantation

limit vehicle access to the plantationduring wet weather

wash farm vehicles with a truckwash containing quaternaryammonia compound

only use contract machinery as a lastresort

if contractors are used, ensure theirmachinery is thoroughly cleanedbefore entry

use your own planting material ortissue cultured plants

use cover crops in the plantation tolimit the movement of soil

ensure drainage water from bananasdoes not enter the irrigation dam

have the footvalve of the irrigationpump as close to the water surface aspossible

seal roads with gravel or concrete

dont return bunch stalks to theplantation.

Young bananas in molasses grass mulch at Jim Voiseys plantation.The molasses grass was planted three years ago, when the previous

plants were destroyed, and sprayed off a few months before theseyoung bananas were planted.


l a n D P r e P a r at i o n


13/20

Under no circumstances should the plants be pushed out with a dozerand piled into windrows because this will:

loosen the soil and make it prone to erosion

result in a heap of banana plants that will be hard to kill at a later date

remove large quantities of top soil containing organic matter andnutrients.

P | 1 0

Re-plnting n existing plnttion

Planning for replanting commencesbefore the original bananas aredestroyed.

Prior to killing the old bananas acover crop should be planted. This

can then establish as the bananaplants are dying.

The best method of killing thebanana plants is to inject them witha systemic herbicide. Do not cutdown plants before injecting themwith herbicide as the leaves need toremain on the stool for the herbicideto work. This will clear the old cropwhile causing a minimum of soildisturbance.

The banana plants can also beslashed with a heavy duty slasheror trampled with a dozer. Bothmethods will rid the area ofbananas but will cause considerablesoil disturbance making the areaprone to soil erosion. Bringing anymachinery into a plantation alsoruns the risk of introducing panamainto the plantation.


The existing plants need to beremoved at least six months BUTpreferably 24 months before thenew planting. This ensures theelimination of banana weevil borerand nematodes, which can persistin the needled corms of plants formany months. This time out ofbananas ensures that all plants andsuckers are dead and that bunchytop will not be carried over to thenext crop.

A dozer may then be brought in toredesign or repair roads. Bananaplanting lines can be ripped at thisstage, limiting the rip line to a singletyne along banana rows. Under nocircumstances rip up and down the

hill.



14/20P | 1 1

Use of grasses or legumes in bananasas cover crops have been shown toprovide a range of benefits, including

reducing the effect of raindropimpacts on soil

slowing water movement throughthe plantation and minimising soilerosion

provision of root channels in the soilwhich improve water infiltration andair movement into the soil

consolidation of the soil surface toallow easy access of machinery intothe plantation.

The requirements of an ideal covercrop include:

adapted to lower light environments

ground hugging

not too invasive or competitive withplants

do not harbour nematodes

persistent and doesnt requirereseeding.

Plnting bnns into cover crop

Regardless of whether the bananas arebeing established into newly clearedland or former banana plantationswhere significant regrowth hasoccurred, or replanting an existingplantation, it is recommended thata cover crop is established prior toplanting the bananas.

C O v e R C R O P S

Once a cover crop is established,the management procedures aroundplanting time are as follows:

4 8 weeks before planting thebananas, spray out a 1 m wide circleat each planting site or 1 m wide

strip along the row. If using molassesgrass spray out the entire block inMay, before it flowers.

After planting backfill the hole andpull mulch back around the plant.

Mnging cover crops in youngplnttions

Spot spray around plants with anonsystemic herbicide for weedcontrol if required.

No interrow weed control should beneeded for at least six months if thecover crop is well established.

Progressively increase the width ofthe sprayed strips; by 12 monthsthere should be about a metre stripof cover crop left along the middleof each row. Allow this to reseedto keep the cover growing back intosprayed area. Spray back after lateautumn.

Haifa white clover established in two yearold bananas.

c o V e r c r o P s


15/20

Cover crops protect soil againsterosion, protect waterways andhelp keep weeds down withoutconstant spraying.

P | 1 2

Mnging cover crops in estblishedplnttions

The use of a nonsystemic herbicideto reduce competition for waterfrom grass strips may be necessaryin spring and summer if the

plantation is not irrigated.

An alternative is to spray out the covercrop and weeds and then broadcastlow growing turf varieties of ryegrassin late summer. These grow wellthrough the winter and will lastthrough until the following season.This reduces herbicide applicationsand improves soil health.

Cover crop options for bnn

plnttionsoPtion 1

Turf varieties of ryegrass (Lolium perenne)

Turf varieties of r yegrass are low growing

and do not run to seed as readily as pasture

varieties.

They establish best in autumn.

Broadcast the ryegrass seed after any weeds in

the plantation have been sprayed out.

When planted thickly the ryegrass will block

the light and inhibit germination of other

weeds.

C O v e R C R O P S

oPtion 2

Broadleaf paspalum (Paspalum dilatatum)

Takes two years to get a full establishment so

plan ahead and plant in summer.

No interrow weed control needed for at least

six months.

Spot spray around plants for weed control if

required.

Spray back after late autumn seeding.

Excessive growth of weeds or paspalum can

be sprayed with a light spray of a nonsystemic

herbicide without killing the paspalum.

If paspalum is being used for replant areas:

Plant the cover crop before the old bananas are

destroyed.

Annual weeds in the first year will be

smothered next winter.

oPtion 3

Molasses grass (Melinis minutiflora)

While molasses grass is similar to broadleaf

paspalum up to early crop establishment, it

wont persist in long term plantations in the

same way that paspalum does. Therefore

molasses grass is good for establishment but

not as good for a long term cover crop.

Molasses grass planted into a patch that is to

be spelled will provide a good mulch layer

when sprayed out for planting the new crop.

It takes two years to get a full

establishment plan ahead and plant in

summer.

It will harbour burrowing nematodes so it

is not the best choice in areas where these

nematodes are a problem. If in doubt about

burrowing nematodes use a different cover

crop.

Spray out the entire block in May prior to

planting the bananas. (After it seeds it is

uncomfortable to work in.)

Annual weeds from the first year will be

smothered in winter.

oPtion 4

Other cover crops

There are undoubtedly other cover crops that are

not excessively competitive or unmanageable.

Check what your fellow growers are doing.

Some other crops that have been used are listed

below:

Spring:

Millet is cheap and easy to establish and

manage, or better still a mixture of millet and

paspalum.

Autumn:

Oats is cheap and easy to establish and

manage.

Follow up the autumn cover crop with planting

of paspalum; however it is better to sow oats

and paspalum together in autumn.

Some growers have also successfully used

Namoi woolly pod vetch.

Smothergrass (Dactyloctenium australe)has been successfully used in macadamia

plantations on the north coast, and is well

adapted to a medium shaded environment.

It is suitable for protecting road batters and

within plantations that can be mown.

Haifa white clover (Trifolium repens) can be

established in young bananas and will persist

within the plantation.



16/20P | 1 3

Once the plantation is established, thesoil should be managed to providethe best environment for the plantroots. This will involve the applicationof fertilisers and soil additives aimedat improving the physical, chemicaland biological properties of the soil tobenefit crop growth.

Mnging nutrients

A well managed nutritional programwill help keep the soil healthy andthe plantation growing vigorously. Asoil test should be taken to establishan effective, economical fertiliserprogram. Bananas perform bestin soils with a pH of 5.0 (calciumchloride) or above. The table below

provides a guide to preferred levels forbananas from a typical soil test.

recoMMended MiniMuM nutrient levels

Phosphorous (P) 80 ppm

Potassium (K) 0.5 meq/100 g

Calcium (Ca) 4 to 10 meq/100 g

Magnesium (Mg) 1 to 3 meq/100 g

Electrical conductivity (EC) < 0.15 ds/m

Zinc and boron levels are likely to

be low in north coast soils so theseshould also be checked when the soiltest is done.

Excessive application of fertilisers,particularly during the storm season,can result in massive nutrient lossesin runoff water, or with topsoil duringsevere erosion events. Leaching lossesthrough the soil profile should also beavoided. These nutrient losses wasteinputs and pollute the surroundingenvironment. Cover crops also need tobe fertilised to maintain good groundcover.

Mnging soil pH

Increased soil acidity reduces thecation exchange capacity of the soil,which can result in deficiencies ofcalcium and magnesium, leading topoor productivity. Regular use of

ammonium based nitrogen fertiliserscan increase soil acidity, so considerswitching to alternatives such ascalcium nitrate if soil tests indicatedecreasing pH (increasing acidity).Lime or dolomite are also used toincrease pH if acidity is becominglimiting to plant growth.

Deciding when to apply fertilisers

The preferred approach is to apply alittle fertiliser often. Once you have

a recommendation for the amountof fertiliser needed, calculate howmuch you need to apply in five orsix applications per year to reach theannual target. Do not apply fertiliserin a few big applications as fertiliserapplications are prone to being washedaway if a storm occurs, and more liableto losses through volatilisation.

Generally, for banana crops,the application rates for majornutrients should be in theregion of: Nitrogen: 100 kg/ha,Phosphorous: 60 90 kg/ha andPotassium: 220 kg/ha. This will replacethe nutrients used by the crop over ayear. If manures are being used as analternative to chemical fertiliser, soiland leaf testing should also be used todetermine if additional nutrients arerequired.

Fertilising young plnts

Apply the fertiliser within a circle lessthan 15 cm from the plant (keep awayfrom the funnel leaf to avoid burns).

Continue applying fertiliser eachmonth, widening the circle out each

time to keep slightly ahead of rootgrowth until you start broadcastingover all the interrow area from6 months onwards.

Aim to apply small doses every warmmonth but remember, it can take upto 30 mm of rain for fertiliser to bewashed in. So in practice you wouldapply 5 or 6 applications per year.

Fertigation is an ideal method ofapplying precise amounts of nutrients.

Automated systems deliver nutrientat the correct time and match thecrop needs, and allows for the littleand often approach. However,the distribution uniformity of theirrigation system must be high (85%plus) to ensure even application acrossthe block.

Fertilising estblished crops

Take soil and leaf samples for analysis

in April/May each year once theplantation is in production. Thiswill allow for the annual fertiliserrequirements to be calculated andallow time for any lime or dolomiteapplications to be applied duringwinter before the fertiliser programcommences in the next spring. Itis best to broadcast fertiliser overthe whole interrow in establishedbananas.

S O I l M a N a G e M e N T

s o i l m a n a g e m e n t


17/20

Tensiometers give an easy indication of soilmoisture in the root zone. These two showwet soil at both 300 mm (12'') and 450 mm(18'') after 50 mm of rain.

Irrigtion

Bananas grow more consistently andcycle faster if they are well irrigated.Bananas have a relatively high wateruse in the heat of summer but onlyhave a shallow root system, with most

of the roots in the top 30 cm. At thepeak of the season bananas can useup to 50 mm a week. This means soilmoisture reserves are used up veryquickly, particularly in light or gravellysoils. An actively growing cover cropwill require additional irrigation,otherwise it will compete with thebanana crop.

To get the best performance, irrigationmay need to be applied at 30 mm atime twice a week in November andDecember in soils with low waterholding capacity. An irrigation systemshould be designed to allow for anirrigation schedule which can achievethis.

P | 1 4


Irrigations should be scheduled toapply enough water to refill theroot zone as regularly as possible.These decisions are best made afterchecking either evaporation data orsoil moisture levels. A range of soilmoisture monitoring devices areavailable from simple tensiometers tohightech computerised systems. (Allof these tools are more accurate thankicking the soil!)



18/20

As the plantation matures, thetrash from harvested plants,de-suckering and deleafing willprovide additional soil protection,and increase soil organic matter.

P | 1 5

Concreted roadways stop the formation oferosion ruts and make the plantation morestorm proof.

Mnging soil biology

Bananas will grow better where thesoil is well structured and has a buildup of organic matter. A well structuredsoil will have better aeration at depthwhich gives roots a greater volume

of soil to grow into. Soil structureis improved by increased levels oforganic matter which is know toencourage soil dwelling organisms,which in turn help retain and recycleplant nutrients.

Use of mulches

A mulch is organic matter applied tothe soil surface in a layer up to 10 cmthick, and designed to:

protect soil from raindrop impact

reduce erosion improve soil microbial and soil

invertebrate (i.e. worms) activity anddiversity

reduce soil temperature variations

increase root growth, which helps tocounteract nematode damage


improve the nutrient holdingcapacity of the soil

improve the structural stability ofthe soil by adding organic matter

improve infiltration and waterholding capacity of the soil

suppress weed growth

reduce moisture loss from the soil.

Banana trash is an ideal mulchfor banana plantations, allowingrecycling of nutrients, and reducingthe reliance on applied fertilisers.Cover crops that are either slashedroutinely or sprayed off can also actas an effective mulch and are a goodsource of organic matter.

s o i l m a n a g e m e n t


19/20

P | 1 6

Rod mintennce

Even well designed roads needadequate maintenance to preventwater being concentrated which canthen break out and cause erosion. Wellmaintained roads are also important to

reduce damage to fruit during harvest.Ensure road batters have cover cropsplanted to minimise soil erosion.

Check that drainage water is directedto natural or constructed drains.

Check that drains are not eroding.

Ensure diversion banks, also knownas whooups and culverts areworking.

Repair wheel ruts before theydevelop into major problems.

As Panama disease can be spread insoil and mud, concrete or gravel roadswill reduce its spread around theplantation.

Roads across the slope used as drainscan divert contaminated water out ofthe plantation instead of it runningthrough the plantation.

Dringe mintennce

Keep drains protected from erosionwith vegetation, rocks or structuresto slow down water if required.

Ensure natural watercourses remainwell grassed.

I N F R a S T R U C T U R e M a I N T e N a N C e

Reduce impact of waterfalls withrocks.

Inspect culverts on a regular basisfor blockages.

Repair any minor damage before itbecomes major.

Irrigtion system mintennce

Check for leaks and blockages.

Check for uniformity of coverage,especially if using fertigation.

Dm mintennce

Keep the spillway well vegetated orreinforced.

Install a silt trap upstream from thedam and keep it cleared of debris asnecessary.

Even a small rock wall, like this one at IanSimpsons can slow down water f low andstop gullies eroding through a plantation.



20/20

F U R T H e R R e a D I N G

Banana Growing Basics for NewSouth Wales, Newley P, Akehurst A,Campbell B and Treverrow N. NSWDepartment of Primary Industries,May 2008.www.dpi.nsw.gov.au/agriculture/horticulture/tropical/bananas/

growing-basics

Banana Growing Guide CavendishBananas, Newley P and Akehurst A.NSW Department of PrimaryIndustries, June 2008.www.dpi.nsw.gov.au/agriculture/horticulture/tropical

Soil Erosion Solutions Helping NorthCoast landholders reduce soil erosion,Jenkins A and Alt S. Department ofPrimary Industries, June 2007

Also see the following websites:

The Northern Rivers CMA website www.northern.cma.nsw.gov.au

NSW DNR Soils publication website www.waterwise.nsw.gov.au/care/soil/soil_pubs/index.html

Landcare website www.daff.gov.au/natural-resources/landcare

NSW DPI website www.dpi.nsw.gov.au/agriculture/horticulture

f U r t h e r r e a D i n g

Soil and Water Best Management Practices for Nsw Banana Growers

Documents