TILLAGE & TILTH, OBJECTIVES AND TYPES OF TILLAGE, EFFECT OF TILLAGE ON SOIL PROPERTIES
Jetho
Tull – Father of tillage
TILLAGE:-
The word tillage is derived from ‘Anglo-Saxon’ words Tilian and Teolian,
meaning ‘to plough and prepare soil for seed to sow, to cultivate and to raise
crops.’
“.It
is the physical manipulation of soil with tools and implements to result in
good tilth for better germination and subsequent growth of crops.”
TILTH:-
It is the physical condition of soil resulting from tillage.
CHARACTERISTICS OF GOOD TILTH
- A soil should be mellow, friable, crumbly and adequately aerated.
- A soil in good tilth is porous.
- Capillary and non capillary pores are equal. Tilth facilitates free movement of air and water.
- Tilth can be coarse or fine. For sandy soils fine kind of tilth is required and for heavy black soils rough cloddy conditions or coarse tilth is enough.
Objectives
of Tillage:-
- The main objectives of tillage are:-
- To prepare a good seed bed which helps the germination of seeds.
- To create conditions in the soil suited for better growth of crops.
- To control the weeds effectively.
- To make the soil capable for absorbing more rain water.
- To mix up the manure and fertilizers uniformly in the soil.
- To aerate the soil.
- To provide adequate seed-soil contact to permit water flow to seed and seedling roots.
- To remove the hard pan and to increase the soil depth.
Types of Tillage:- Tillage operations may be grouped into 2 portions:-
1.
On-season Tillage:- Tillage operations that are done for
raising crops in the same season or at the onset of the crop season are known
as on-season tillage.
They may be Preparatory Cultivation and After Cultivation.
A.
Preparatory Tillage:- This refers to tillage operations that
are done to prepare the field for raising crops. It consists of deep opening
and loosening of the soil to bring about a desirable tilth as well as to
incorporate or uproot weeds and crop stubble when the soil is in a workable
condition.
Types
of preparatory tillage:-
a. Primary Tillage:- The tillage operation that is done after the harvest of crop to bring the land under cultivation is known as primary tillage or ploughing. Country plough, Mould board plough, Bose plough, tractor and Power Tiller drawn implements are used for primary tillage.
b. Secondary Tillage:- The tillage operations that are performed on the soil after primary tillage to bring a good soil tilth are known as secondary tillage. Harrows, Cultivators, Guntakas and Spade are used for secondary tillage.
c.
Layout of Seed Bed:- This is also one of the components of
preparatory tillage. Leveling board, Buck scrapers etc. are used for leveling
and markers are used for layout of seedbed.
B.
After cultivation (Inter-tillage):- The tillage operations
that are carried out in the standing crop after the sowing or planting and till
to the harvesting of the crop plants are called After Cultivation Tillage. This
is also called as Intercultivation or Post Seeding/ Planting Cultivation. It
includes Harrowing, Hoeing, Weeding, Earthing Up, Drilling or Side dressing of
fertilizers etc. Spade, Hoe, Weeders etc. are used for inter cultivation.
2.
Off-season Tillage:- Tillage operations done for conditioning
the soil suitably for the forthcoming main season crop are called off-season
tillage. Off season tillage may be, Post Harvest tillage, Summer tillage, Winter tillage and Fallow tillage.
Special
Purpose Tillage:- Tillage operations are done to perform
special purposes is called Special Purpose Tillage.
They are classified below:-
a. Sub-soiling:- To break the hard pan beneath the plough layer, special tillage operation (chiseling) is performed to reduce compaction. Sub-soiling is essential and once in four to five years where heavy machineries are used for field operations, seeding, harvesting and transporting.
b. Clean Tillage:- It refers to working of the soil of the entire field in such a way no living plant is left undisturbed. It is practiced to control weeds, soil borne pathogen and pests.
c. Blind Tillage:- It refers to tillage done after seeding or planting the crop or pre-emergence stage of the crop plants or while they are in the early stages of growth so that crop plants (sugarcane, potato etc.) do not get damaged, but, extra plants and broad leaved weeds are uprooted.
d. Dry Tillage:- Dry tillage is practiced for crops that are sown or planted in dry land condition having sufficient moisture for germination of seeds. This is suitable for crops like broadcasted rice, jute, wheat, oilseed crops, pulses, potato and vegetable crops.
e. Wet Tillage or Puddling:- Puddling operation consists of ploughing repeatedly in standing water until the soil becomes soft and muddy. Puddling creates an impervious layer below the surface to reduce deep percolation losses of water and to provide soft seed bed for planting rice.
Modern Concepts in Tillage:- With the introduction of herbicides in intensive farming systems, the concept of tillage has been changed. Continuous use of heavy ploughs create hard pan in the subsoil, results in poor infiltration.
To avoid those bad effects, modern concepts on tillage is in rule.
1.
Minimum Tillage:- It aims at reducing tillage operations
to the minimum necessity for ensuring a good seed bed.
- The advantages of minimum tillage over conventional tillage are:-
- The cost and time for field preparation is reduced by reducing the number of field operations.
- Soil compaction is comparatively less.
- Soil structure is not destroyed.
- Water loss through runoff and erosion is minimum.
- Water storage in the plough layer is increased.
2. Zero tillage (No tillage):- In this, new crop is planted in the residues of the previous crop without any prior soil tillage or seed bed preparation and it is possible when all the weeds are controlled by the use of herbicides.
Advantages:-
- Zero tilled soils are homogenous in structure with more number of earthworms.
- Organic matter content increases due to less mineralization.
- Surface run-off is reduced due to presence of mulch.
Disadvantages:-
- Higher amount of nitrogen has to be applied for mineralization of organic matter in zero tillage.
- Perennial weeds may be a problem.
- High number of volunteer plants and buildup of pests.
3. Stubble Mulch Tillage or Stubble Mulch Farming:- Soil is protected at all times either by growing a crop or by leaving the crop residues on the surface during fallow periods. Sweeps or blades are generally used to cut the soil up to 12 to 15 cm depth in the first operation after harvest and depth of cut is reduced during subsequent operations.
Disadvantages
of Stubble Mulch Farming:-
- The residues left on the surface interfere with seed bed preparation and sowing operations.
- The traditional tillage and sowing implements or equipments are not suitable under these conditions.
4. Conservation Tillage:- It is a system of tillage in which organic residues are not inverted into the soil such that they remain on surface as protective cover against erosion and evaporation losses of soil moisture.
Advantages:-
- Energy conservation through reduced tillage operations.
- Improve the soil physical properties.
- Reduce the water runoff from fields.
EFFECTS OF TILLAGE ON SOIL PHYSICAL
PROPERTIES
1.
Soil Structure:- Tillage improves soil structure
when done at optimum soil moisture level. Tilling a soil when it is too wet
spoils the structure. Ploughing a dry soil is difficult and will not help in
improving structure.
2.
Soil Texture:- Relative proportion of different soil
particles namely sand, silt and clay.
Coarse sand - 2.0 - 0.2mm.
Fine
sand - 0.2
- 0.02mm.
Silt - 0.02
- 0.002mm.
Clay - <0.002mm.
3.
Pore Space:- When the soil is in good tilth the
capillary and non capillary pores would be roughly equal. This facilitates free
movement of air and moisture in soil.
4.
Bulk Density:- BD of Clay soils is low (1.05 m3 and
that of sandy soils is high (1.25 – 1.30 m3 ) and Bulk density of tilled soil
is less than that of untilled soil. Particle density is always more than BD.
5.
Particle Density:- Particle density is not altered by
tillage.
6.
Soil Colour:- Tillage
increases oxidation and decomposition of organic matter resulting in fading of
colour.
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