soil cultivation and seasonal management
DESCRIPTION
Soil Cultivation and Seasonal Management. Chris Thoreau March 3, 2012. Outline. Introducing Soil Cultivation What is cultivation? Cultivating Machines Hand Tools Cultivation for Small-Scale Farmers Consistency and Plasticity Mycorrhizal fungi - PowerPoint PPT PresentationTRANSCRIPT
Chris ThoreauMarch 3, 2012
Soil Cultivation and Seasonal Management
Introducing Soil Cultivation What is cultivation?Cultivating MachinesHand ToolsCultivation for Small-Scale Farmers
Consistency and Plasticity Mycorrhizal fungi
Effect of Cultivation and Loss of Soil Structure Challenges in Cultivation Reduction No-till soil management
Outline
Soil Cultivation:
Any intentional mechanical disturbance of the soil using machinery or hands tools
With a broad range of implements:Digging Fork Broad Fork Rototiller Plough
For a broad range of purposes:Weeding Bed Prep. Cover Crops Break
Ground
Soil Cultivation
Soil Cultivation:
Any intentional mechanical disturbance of the soil using machinery or hands tools
Our Focus: Soil conditioning implements which
Condition soil for plantingIncorporate cover cropsAlleviate compaction
Soil Cultivation
Why Do We Cultivate?Breaking groundIncorporate manure, compost, plant residues,
amendmentsBuilding soil tilth/structureReduce compactionSeed bed preparationWeed/vegetation control
Soil Cultivation
Cultivation needs change over time and space
Cultivation changes throughout the seasonCultivation changes through the life of a farm
Change in cropping areaChange in cropsChange in growing methods
Cultivation changes with farmer experience
Soil Cultivation
Cultivation ConsiderationsCultivation is a tool to manage and improve soil
conditionsStructureDrainageSoil Depth
Cultivation methods need to correspond with sustainability goals
No cultivation activity does just one thingCultivation goal: reduce cultivation!
Soil Cultivation
Cultivation ConsiderationsCultivating for one purpose can be counter
productive towards anotherSeed bed tillage can increase compaction and
affect drainageAll cultivation can increase weed pressure by
bringing weed seeds to the soil surface to germinate
Soil Cultivation
Mouldboard/Furrow Plow Inverts the soil
DiscingSlices/Inverts the soil
RotovatorGrinds up the soil
Chisel PlowDeep cultivation
Spading ToolGentler cover crop incorporation
Cultivation Methods
These implements require a machine/tractor to power them so choose the implements that are best for your scale of operation
Not sure what is best? Hire someone to do your primary cultivation (breaking ground/incorporating cover crops) for you.
Cultivation Methods
Methods are often used together
Mouldboard Plow Discing
Spading Rotovator
Mouldboard Plow Chisel Plow Disc/Rotovator
Rotavator/Spading Roller
Cultivation Methods
Small-scale farmers tend to use:Spading machine on tractorRotavator on tractorWalk behind tractorRototillerHand tools (e.g., Broadfork)Often combine machines with hand tools for prepping seed
bed
A small tractor is a very versatile machine that can perform a multitude of tasks, but can be pricey and require care!
The rototiller and walk-behind tractor are popular machines for small-scale farmers due to their smaller size and lower cost
Cultivation Methods
RototillerFront and rear tine modelsRear tine models preferred for larger scale
Cultivation Methods
Walk-behind TractorLarger version of rototillerBut has variety of implement attachments
Cultivation Methods
Hand Tool CultivationLow cost soil cultivation solutionEffective but physically demandingTime consumingLess impact on soil structureLess risk of compactionOnly practical on smaller scale
Cultivation Methods
Digging Fork
Cultivation Methods
Broad Fork
Cultivation Methods
MattockGreat for breaking new ground; compact soil
Cultivation Methods
Considerations when choosing tools/machinery BudgetOverall farms needsPhysical capability of operator
This changes as you age!Effect on soilEffect on environmentEase/cost of repair and maintenance
Cultivation Methods
ConsistencyStrength with which soil particles are held
togetherRelated to texture and water content
PlasticityDescribes the response of a soil to change in
moisture content.
Both are very important when considering soil cultivation
Soil Consistency and Plasticity
Soil Consistency and Plasticity
Cultivating soil when too dryBreaks aggregates into small pieces
De-aggregatesCan result in dust
Very damaging to soil structure
The drier the soil – the more it acts like powder
Soil Consistency and Plasticity
Cultivating soil when too wetWhere to start?!
CompactionRisk and depth of compaction increases in wet
soil
Soil Consistency and Plasticity
Cultivating soil when too wet
The wetter the soil - the more it acts like water
Soil Consistency and Plasticity
Soil Consistency and Plasticity
Soil Consistency and Plasticity When to Cultivate?
Soil moisture needs to be just rightShould be able to handle soil without water dripping
outShould be friable and plastic feeling (if not too sandy)Soil water levels need to be considered at greater
depthsDry Soil clodding; lost nutrients through dustWet Soil compaction, loss of structureDecomposition time needs to be consideredSowing or transplanting to follow?
Hyphal soil fungi Forms symbiotic relationships with plant
roots80-90% of terrestrial plantsImproves plant uptake of phosphorus and
water in return for sugarsActs as expansion of plant root zone
Contribute to soil aggregation and improved soil structure
Mycorrhizal Fungi
Cultivation destroys hyphal networksSome species are killed by tillageRedistribution of fungal spores to lower soil
profiles reduces root infection
And…
Cultivation and Mycorrhizal Fungi
The loss of soil structure limits regrowth of the fungiReduction pore space
Fungi require air and waterReduced pore space limits air and water
movementCompaction makes hyphal regrowth difficult
Cultivation and Mycorrhizal Fungi
Fungal loss = Disadvantage for plants
Less P uptakeLess water uptakeReduced Disease immunity
Loss of microbial diversityReduces aggregation
Fungal Loss and Plant Growth
Remember: goal is to reduce cultivation over time
Reducing cultivation is difficultDifficult to manage large areas; especially
organicallyMost low-till systems herbicide dependentDisease pressure can be higher in some no-till
systems
What to do? What to do?
Strategies to Reduce Cultivation Impact on Soil
Choose methods carefully!Use spader over rotovator for cover cropsSlow down rotation speed on rotovator
Separate growing beds and pathsReduces compaction risk in growing areasTractor wheels can go in pathways
Design beds around tractor width
What to do? What to do?
Strategies to Reduce Cultivation Impact on Soil
Stay on top of weedsReduces temptation to cultivateReduces weed pressure less weed seeds
Incorporate no-till methods into your systemEasier to do at smaller scale
What to do? What to do?
No-till goals:Maintain overall integrity of soilReduce risk of compactionReduce risk of structure damagePromote sustained biological presenceReduce use of machineryMimicking natural soil processes
No-till Soil Management Strategies
No-till goals in relation to why we cultivate :
Why Do We Cultivate?Improve soil tilth/structureWeed controlReduce compaction
No-till Soil Management Strategies
Rodale Institute developed crimping methodEffective for cover crops
Perennial wheatUse of winter killed cover cropsNo-till is a viable small-scale option
Looking Forward with No-till
Most cultivation happens early in season Often gives instant results Main cultivation uses:
Breaking ground Add amendments at this time Follow with cover crop
Incorporating cover crops Weed/vegetation control
Effcieitn vegetation control Seed Bed Prep
Ensures fine soil texture for ease of seeding
Cultivation through the Season
Early SeasonMost cultivation happens early
Incorporating winter cover cropsPrepping seed beds
Be patient! Watch soil water levelsSeason length depends on soil and locationAssess need for cultivation
Can you utilize no till methods?Transplanting into winter killed stubble
If using no till methods get an early start
Cultivation through the Season
Mid-SeasonCultivation more about weed controlCould be incorporating cover cropsCould be incorporating amendments for later
crops
Good time for no-till cover crop managementWarm weather = rapid decomposition
Cultivation through the Season
Late SeasonCash crop growing usually priorityCover crops can be more easily sown into less-
than-ideal conditions – no cultivation neededIf no cover crop being sowed, or it’s too late to
sow, beds should be mulchedMakes early season prep easierRemove mulch, add compost, sow or transplant
Cultivation through the Season
No Till Cropping Sequence – Small Scale
Starting with:Fall Rye cover crop – well established due to
early sowing
Cultivation through the Season
No Till Cropping Sequence – Small Scale
1. Cover crop cut in mid-late February2. Mulched…
Heavily with organic materialSynthetic material
Mulch smothers the crop – reducing light, encouraging biological activity
Cultivation through the Season
No Till Cropping Sequence – Small Scale
3. Mulch removed in April - MayCover crop absentArea now ready to plant
4. Top with compost, transplant:TomatoesLong season – in ground until SeptemberUndersow with legume
Cultivation through the Season
No Till Cropping Sequence – Small Scale
5. Tomatoes removed in September/OctoberManage weeds carefully to keep soil cleanMulch lightly in summer to reduce evaporation
6. Amend bed with compost – plant garlicMulch garlic heavily with straw/leavesIf planted early may be able to interplant Asian
greens
Cultivation through the Season
No Till Cropping Sequence – Small Scale
7. Harvest garlic in following JulyRemove mulch and amend with compost
8. Transplant overwintering broccoli and mulch
9. Harvest broccoli in early spring
Cultivation through the Season
No Till Cropping Sequence – Small Scale
10. Summer cover crop – buckwheat, phacelia, legume
Cultivation through the Season
Cultivation can both improve and damage soil Soil water is indictor of when to till Using appropriate method
Like all human activity:Tillage does more than just one thing
No-till is feasible on smaller scales Limited examples of sustainable, large-scale, no-
till systemsThough reduced tillage is possible
New no-till methods need to be developed Perennial crop development and expansion
reduces soil impact
In Closing
The future or the past?