Land Preparation

1. Land Preparation
Crop Science 2
Alminda M. Fernandez, Ph.D.
University of Southeastern Philippines
Tagum – Mabini Campus

2. Land preparation
• is a combination of tillage practices that
places the soil in the best physical condition
for plant establishment and crop growth.
• covers a range of soil disturbances from zero-
tillage, which minimizes soil disturbance
through to a totally ‘puddled’ soil, which
actually destroys soil structure.

3. Aims of Land preparation
• Loosen the soil to facilitate the penetration of
plant roots
• Improve aeration (N, O)
• Increase infiltration of water
• Reduce evaporation
• Destroy or control weeds and soil pests
• Incorporate crop residues and manures into
the soil

4. Aims of Land preparation
• Prepare the site for seeds and seedlings
• Repair soil compaction caused by previous
activities
• Decrease ped or clod size
• Reduce wind and water erosion by leaving a
rough surface
• Stimulate microbial activity

5. What is the appropriate tillage system,
pattern and equipment for your field?
Dry and level field Wet and level field

6. Dry tillage – manual, animal, mechanical?

7. Wet tillage – manual, animal, mechanical?

8. Types of Tillage Operations
• Primary tillage
• Secondary tillage
• Seedbed preparation
• Inter tillage

9. Primary tillage
• the most aggressive tillage operation
• undertaken when the soil is wet enough to allow
the field to be ploughed and strong enough to
give reasonable levels of traction
• after the crop harvest or at the beginning of the
next wet season
• includes the ploughing operation which is
opening of the compacted soil with the help of
different ploughs

10. Ploughing

11. objectives of primary tillage
• Open the hard soil
• Separate the top soil from lower layers
• Invert the soil whenever necessary
• Till the soil to attain a reasonable depth (10-
15cm ) with varying clod sizes
• Kill weeds by burying or cutting and exposing
the roots
• Soil aeration and water accumulation
• Chop and incorporate crop residues

12. Primary Tillage Implements
• Moldboard plough
• one-way disc plough
• Tine disc plough
• Offset disc plough

13. Moldboard plough
• causes total inversion of the
soil sod and relies on the
digging point for penetration
• throws the soil in one
direction
• least damage to soil structure
• works well in very hard soil
conditions but no built stump
or obstacle protection

14. One-way disc used
with 4-wheel tractor
• causes total inversion of the soil sod and relies
on the ploughs in built weight for penetration
• throws the soil in one direction
• works well in hard soil and heavy trash
conditions and can ride over stumps or
obstacle in the soil
• Power requirement is less than a moldboard

15. Offset disc for 4-wheel
tractor
• capable of operating offset
from the tractor
• throws the soil in different
direction
• very versatile and can be
operated in any ploughing
pattern
• widely used in upland situations

16. Tine plough
• most versatile
• used in secondary tillage
• modified to be used as a seed drill
• dry working situations
• cut the soil rather than invert the soil
• kill weeds by cutting and lifting the weeds to
the surface
• lower power requirements

17. Secondary Tillage
• any working completed
after primary tillage
• shallower and less
aggressive
• includes the operations
performed after ploughing
such as leveling, discing,
harrowing etc.

18. Secondary Tillage Implements
• peg tooth harrow
• disc harrow
• tined cultivator
• rotary tiller
• inter row cultivator

19. Peg tooth harrow
• used in animal and 2-
wheel tractor powered
systems
• for second workings,
soil puddling and land
leveling

20. Disc cultivator
• used in dry fields and
upland situations
• very aggressive action
of the plough gives
good weed control and
cuts and buries crop
residues

21. Tined cultivator
• used for secondary tillage
and as a seed drill
• dry working situations
• cut the soil rather than
invert the soil
• kill weeds by cutting and
lifting the weeds to the
surface

22. Rotovator
• for secondary workings
and especially seedbed
preparation
• Upland and flooded fields
• very aggressive action,
which pulverizes the soil
and buries weeds and
crop residues

23. Upland Tillage
• aerobic soil conditions
• non-puddled soils
• no freestanding water in the fields
• too dry soils will not till easily, in clay soils large
clods may be formed
• very wet, near soil saturation, smearing and
soil sealing can become problems
• water erosion can be a problem and ploughing
on the contour is recommended

24. Seedbed Preparation
• for germination of seeds
& growth of crops, called as SEEDBED
• includes harrowing, leveling, compacting the
soil, preparing irrigation layouts such as
basins, borders, rides & furrows etc.
• carried out by using hand tools or implements
like harrow, rollers plank, rider etc.

25. Inter tillage
• carried out in the standing crop
• after sowing or planting and prior to the
harvesting of crop plants
• includes gap filling , thinning , weeding ,
mulching, top dressing of fertilizers, hoeing,
earthling up etc.

26. Tillage Patterns
• reduces the time spent in non-productive
work
• minimize the number of turns and maximize
the length of the tillage runs
• circuitous, up and back or headland and
working in lands

27. Circuitous pattern
• used with moldboards,
discs and offset discs
• most animals are
accustomed to working
• ends up with a large cut
out furrow in the center –
difficult to drain and get an
even depth of cultivation

28. Up and back or headland pattern
• runs parallel to each other
• used for tined implements,
rotovators, harrows and
reversible ploughs
• most field efficient system
and if equipment is correctly
set up and operated should
not leave furrows in the field.

29. Land system
• ploughing to begin in the
center of the field and
works out to the edges
• Requires measurement of
the field to establish the
center point
• used with all types of
ploughs

30. The use of animals
The advantages of using animals include:
• cheap to maintain
• multi-purpose use for meat and milk,
• self-replacement and
• manure production

31. The use of animals
Disadvantage of using animals include:
• have limited daily working hours
• need feeding
• need protection against pests and disease.
• slow
• high person to power ratio
• limited range of working conditions
• require training

32. The use of human power
Tasks undertaken include:
• land preparation including ploughing, soil
leveling and constructing levees and drains
• plant establishment
• pest control
• crop harvesting and transporting
• grain processing

33. Human Power

34. The use of Machines
The advantages
• multi-purpose vehicle
• operate in harder
conditions than animals
or humans
• operate in both wet and
dry conditions
• fairly simple mechanical
design
The disadvantages
• cost of owning
and operating
• operator fatigue,
although ride-on
versions are now
available.

35. Use of Machines

36. CONSERVATION VERSUS CONVENTIONAL TILLAGE
Conventional tillage:
• Mechanized
systems
• Traditional tillage
Conservation tillage:
• no-tillage (slot planting),
• mulch tillage,
• strip or zonal tillage,
• ridge till (including no-till
on ridges)
• reduced or minimum
tillage.

37. Conventional tillage system
Mechanized system
• mechanical soil
manipulation of an
entire field,
• by ploughing
followed by one or
more harrowings
Traditional tillage
• manual labour, using
native tools (cutlass
and hoe )
• clearing is non-
exhaustive, leaving
cover on the soil and
the root system

38. No tillage
• one-pass planting and fertilizer operation
• soil and the surface residues are minimally
disturbed (Parr et al. 1990)
• eliminate all preplanting mechanical seedbed
preparation
• only opening of a narrow (2-3 cm wide) strip or
small hole in the ground for seed placement to
ensure adequate seed/soil contact

39. No tillage
• Weed control thru herbicides and crop
rotation
• soil surface is covered by crop residue mulch
or killed sod
• appropriate for Luvisols in the humid tropics
• Wheat, coffee, others in some parts of USA
• Slow adoption

40. No tillage
Advantage
• more effective control
of soil erosion
• increased water
storage
• lower energy costs per
unit of production
• higher grain yields
Disadvantage
• chemical fallow
• heavy use of
herbicides for weed
control

41. Mulch tillage
• causing least soil disturbance
• leaving the maximum of crop residue on the
soil surface
• obtaining a quick germination, adequate stand
and a satisfactory yield (Lal 1975, 1986)
• chisel plough can be used in the previously
shredded crop residue to break open any hard
crust or hard pan in the soil
• Coffee, banana, wheat, barley in USA

42. Strip or zonal tillage
• seedbed is divided into a seedling zone and a
soil management zone (Lal, 1973, 1983)
• the seedling zone (5 to 10 cm wide) is
mechanically tilled to optimize the soil for
germination and seedling establishment
• interrow zone is left undisturbed and
protected by mulch
• also achieved by chiselling in the row zone to
assist water infiltration and root proliferation.

43. Ridge till
• soil is left undisturbed prior to planting
• one-third of the soil surface is tilled at planting
with sweeps or row cleaners
• planting of row crops is done on preformed
cultivated ridges
• weeds are controlled by herbicides
• maize and soybean production in the USA
(Parr et al. 1990)

44. Reduced or minimum tillage
• tillage and cultivation systems not covered
above but meets the 30% residue requirement
(Laryea et al. 1991)
• Africa

45. Till or not to Till?
Tillage
• Improves aeration
• Incorporates crop
residues
• Facilitates root
penetration
• Suppresses weeds
Zero-tillage
• Improves soil
structure
• Maintains soil organic
matter
• Supports soil
organism
• Prevents soil erosion

46. Lesson to be learnt
• Soil cultivation can have positive or negative
impact on soil fertility
• Frequent tillage can lead to decrease of soil
organic matter, nutrient losses, and soil
erosion
• Soil cultivation should aim on a minimum
disturbance on soil life…….

48. How to control Soil Erosion?
1. COVER methods
– Mulching
– Green manure
– Mixed cropping and intercropping
– Early planting
– Crop residues
– Agroforestry
– Minimum cultivation

49. How to control Soil Erosion?
2. BARRIER methods
– Man-made terraces
– Contour ploughing
– Contour barriers
– Natural terraces
– Medias lunas

50. Medias lunas
• This is a helpful system for reclaiming badly
eroded land which has been used successfully
in Bolivia.
• Medias lunas or crescent shaped depressions
are built on sloping land.
• The crescent shapes are built at the end of the
rainy season so the ridges made can be
compacted well.

51. Medias lunas
• The crescent collects the rainwater and soil.
• Trees - usually legumes - are planted when the
next rainy season begins and protected by
thorn branches from grazing animals.
• After 3 or 4 years each media luna will be
covered with vegetation.
• Later, as the soil continues to improve, crops
may be grown in the medias lunas.