Post on 03-Feb-2022
Introduction
Crop production in (sub)tropical areas was heavily influenced by European developments
Introduction of machinery without critically testing and validating them
Under tropical circumstances the destructivepotential of ploughs and particularly discs is increased
Traditional land preparation
Clearing of the land(Burning of fallow vegetation or residues)Primary tillageSecondary tillageCrop management activities: weeding, ridging, breaking crusts, etc.
Reasons for soil tillage
TraditionPreparation of the seedbedControl of weeds and pestsEnhancement of soil water storage and retentionWarming-up of the soil
Functions of soil tillage
Prepare seedbedManage crop residuesIncorporate fertilizers and agro-chemicalsControl weedsDecompact dense layersIncrease water infiltrationShape the soil surface (levelling, ridging)
Effects of badly chosen tillage practices
Tillage system
Reduction of vegetative cover
Compaction of underlying layerPulverization of
surface layer
Reduction of water infiltration
Bad root development
Low yieldsIncrease in run-off
ErosionInefficient use of
water and fertilizers High production costs
Winderosion
Pollution
Residues left with different land preparation activities
Residues after harvest 80-95 %
Mouldboard plough 0-15 %
Plough and chisel 0-10 %
Discs (2 operations) 15-20 %
Chisel (2 operations) 30-40 %
Cultivator (2 operations) 40-50 %
Cultivator (1 operation) 50-70 %
Direct seeding 80-95 %
Disadvantages of tillage
Loss of soil moistureLimits water infiltration through surface sealingDestroys the soil structureIncreases erosion riskIncreases operational costHigh demand on power, time and equipment
Conservation Agriculture
Alternative to conventional tillage, through
permanent soil coverno mechanical soil disturbancecrop rotation and cover crops
Functions of Conservation Agriculture
Conserve the soilSoil moisture retentionImprove the soil’s productivityReduce machinery costsReduce time input
Advantages of Conservation Agriculture
Increases organic matterIncreases water Improves soil structureIncreases crop yieldsAllows more time off for other activitiesMore cost-effective
Tools and equipment used in Conservation Agriculture
Ploughs, chisels and subsoilersCover crop and weed managementDirect seeding
Plough
Mainly used for primary tillage
DisadvantagesNeeds high powerCreates plough panLoss of soil moistureBrings weed seeds to the surface
No regular use under CA
Chisels or rippersTool for minimum or reduced tillage
DisadvantagesPoor weed controlClogging up with residuesNeeds proper soil moisture (crumbling point or dryer)Lifting stones/clods
SubsoilerTo break hard or compacted soil layers
DisadvantagesNeeds lot of powerWorn points reduce effectWater infiltration will not improve a lot when used improperlyTo be used in dry soils only
SubsoilerUnder Conservation Agriculture
Subsoilers should:work under crop residues (have cutting disks)Not lift clods to the soil surface requiring subsequent tillage (shanks bent to the side)Be only considered as exceptional repair tool
Cover crop and weed management
Mechanical managementKnife rollersMowers and choppersMechanical weeding
Chemical management
Mechanical managementKnife rollers or chopping rollers
To flatten and crush the weed or cover crop
AdvantagesSimple and relatively cheap
DisadvantageNeeds proper management to avoid regrowth
Mechanical managementMower/Shredder
To cut or chop residues
AdvantageAvoids clogging up of the seeding equipmentControls pests
DisadvantageRapid decompositionPossible resprouting
Mechanical managementStraw management
Straw choppers on a combine:
AdvantageAvoids clogging up of the seeding equipmentGood spreading
DisadvantageHigh power demandPossible “hairpinning”
Mechanical managementStraw management
Straw choppers on a combine:
AdvantageLow power demandSlow decompositionLess “hairpinning”
DisadvantageFew commercial productsDifficulties in spreading
Mechanical weed Management
Weeders for residue coverHave a cutting discHave few hoes with wide blades
orare of rolling type
Chemical management
Use of herbicides to desiccate or kill the vegetation
AdvantageEasy and quick
DisadvantageSometimes expensiveHealth and environmental risks - needs proper training
Different sprayers
Hydraulic nozzleRotary nozzle/low volume
Point sprayer(single nozzle)
Boom sprayerShieldedsprayer/row crops
Direct seeding
Broadcast seeding
Planting stick or hand jab planter
Animal traction direct planters
Tractor direct seed-drills and planters
Direct seeding- broadcast -
Broadcasting using a fertilizer spreaderused for small grain and cover crops:Seed is “walked” through mulch coverusing disk harrows set straight
Direct seeding foranimal traction and tractorsBasic design Row cleaner
Cutting discFertilizer coulter
hoedisc
Seed coulterdischoepunch
Seed fixing wheelPress wheel
Cutting disc
Soil conditions: texture, resistance to penetration, humidity and porosityStraw and residue condition: resistance to be cut, humidity, quantity and managementSeeder: weight and dynamicsDisc: size/shape/profile
To get a good result
Work during the warmest hours of the dayWork when the straw is either green or completely dryOperate when soil is friableWith animal traction never try to seed when you have more than 5 tons of dry matter as soil cover
Insufficient cutting of the residues
Accumulation of residues between different parts of the seederIrregular spacing or complete absence of seedsIrregular germinationFertilizer deposition problems
Furrow openers
Punch type injection
chisel tine or hoe
single discs at an angle to the furrow
double discs, either the same diameter or not and placed in an angle forming a "V" to each other
Three basic slot / furrow shapes
V-shaped slot(double disc)U-shaped slot(Single disc, hoe,rotating knifeopeners)Inverted T-shaped slot
(Baker-Boot, hoes)Cross slot
Daily moisture loss from different slots:V 3.7%U 2.4%Inverted T 1.7%
Double disc coulter
Create V-shaped furrowsAngle about 10 degreesResidue handling easySimple construction and maintenance freeImproved action with different disc-diameters and offset discs (better cutting, self cleaning)
Double disc coulter
Disadvantages
Needs high penetration forcesIntolerance to sub-optimal soil conditionsTendency to ‘tuck’ residues into the slot(hairpinning)Concentration of seeds and fertilizers
Single disc coulter
Produce U-shaped slotSimple and robustCompact (often used for small grain seeddrills)Good residue handling
Single disc coulter
DisadvantageHigh penetration force requiredConsiderable soil movement (depending on angle)
Hoe openers
AdvantagesLow costLess affected by forward speedGood penetration, thus ideal for animal traction and dry soilNo “hairpinning”
Hoe openers
DisadvantagesProblems with stones and obstaclesRequires good cutting disc for long residues Considerable soil movement depending on shape and width
Strip till
Create U-type slots; used for strip tillage for transplanting or for some no-till seeddrillsProblems with long straw (depend on design)Considerable soil movement
Inverted T-opener
AdvantagesNo compaction of the soilSelf-closure of the slotConstant seeding depthExcellent for grassland
Inverted T-opener
DisadvantagesConsiderable wear on sandy soilsNo proper furrow opening onloose soilsDifficult residue handling(requires cutting disc)
Cross slot
AdvantagesIdeal germinationconditions for seedEffective separation ofseed and fertilizerLow draft requirementGood residuehandling, nohairpinning problem
Metering/Seedplates
Different sizes for small and big seedsActivated by the movement of one of the wheelsDifferent systems: seed plates with holes, chambers, spoons, mechanic release, pneumatic
Metering
Interesting feature: combined metering systems for drill seed and precision planting on the same machine