Tillage-An Overview

Tillage operations in various forms have been practiced from the very inception of growing plants.Primitive man used tools to disturb the soils for placing seeds. The word tillage is derived from the Anglo-Saxon words tilianand teolian, meaning to plough and prepare soil for seed to sow, to cultivate and to raise crops. Jethrotull, who is considered as Father of tillagesuggested that thorough ploughing is necessary so as to make the soil into fine particles.

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DEFINITION

Tillagerefers to the mechanical manipulation of the soil with tools and implements so as to create favourable soil conditions for better seed germination and subsequent growth of crops. Tilth is a physical condition of the soil resulting from tillage. Tilth is a loose friable (mellow), airy, powdery, granular and crumbly condition of the soil with optimum moisture content suitable for work-ing and germination or sprouting of seeds and propagules i.e., tilth is the ideal seed bed.

CHARACTERISTICS OF GOOD TILTH

Good tilth refers to the favourable physical conditions for germination and growth of crops. Tilth indicates two properties of soilviz., the size distribution of aggregates and mellowness or friability of soil. The relative proportion of different sized soil aggregates is known as size distribution of soil aggregates. Higher percentages of larger aggregates with a size above 5 mm in diameter are necessary for irrigated agriculture while higher percentage of smaller aggregates (1–2 mm in diameter) are desir-able for rainfed agriculture. Mellowness or friability is that property of soil by which the clods when dry become more crumbly. A soil with good tilth is quite porous and has free drainage up to water table. The capillary and non-capillary pores should be in equal proportion so that sufficient amount of water and free air is retained respectively.

OBJECTIVESTillage is done:
• To prepare ideal seed bed favourable for seed germination, growth and establishment;
• To loosen the soil for easy root penetration and proliferation;
• To remove other sprouting materials in the soil;
• To control weeds;
• To certain extent to control pest and diseases which harbour in the soil;

• To improve soil physical conditions;
• To ensure adequate aeration in the root zone which in turn favour for microbial and biochemical
activities;
• To modify soil temperature;
• To break hard soil pans and to improve drainage facility;
• To incorporate crop residues and organic matter left over;
• To conserve soil by minimizing the soil erosion;
• To conserve the soil moisture;
• To harvest efficiently the effective rain water;
• To assure the through mixing of manures, fertilizers and pesticides in the soil;
• To facilitate water infiltration and thus increasing the water holding capacity of the soil, and
• To level the field for efficient water management

TYPES OF TILTH

Fine Tilth refers to the powdery condition of the soil.
Coarse Tilth refers to the rough cloddy condition of the soil.
Fine seedbed is required for small seeded crops like ragi, onion, berseem, tobacco.
Coarse seedbed is needed for bold seeded crops like sorghum, cotton, chickpea, lab-lab etc.

TYPES OF TILLAGE
1. On Season Tillage:It is done during the cropping season (June–July or Sept.–Oct.).
2. Off Season Tillage:It is done during fallow or non-cropped season (summer).
3. Special Types of Tillage:It is done at any time with some special objective/purpose.

On Season Tillage
Tillage operations done for raising the crops in the same season or at the onset of the crop season are called as on season tillage. They are,
A. Preparatory TillageIt refers to tillage operations that are done to prepare the field for raising crops. It is divided into three types viz., (i) primary tillage, (ii) secondary tillage, and (iii) seed bed preparation.
(i) Primary tillage - The first cutting and inverting of the soil that is done after the harvest of the
crop or untilled fallow, is known as primary tillage. It is normally the deepest operation performed during the period between two crops. Depth may range from 10–30 cm. It includes ploughing to cut and invert the soil for further operation. It consists of deep opening and loosening the soil to bring out the desirable tilth. The main objective is to control weeds to incorporate crop stubbles and to restore soil structure.
(ii) Secondary tillage - It refers to shallow tillage operation that is done after primary tillage to bring a good soil tilth. In this operation the soil is stirred and conditioned by breaking the clods and crust, closing of cracks and crevices that form on drying. Incorporation of manures and fertilizers, leveling, mulching, forming ridges and furrows are the main objectives. It includes cultivating, harrowing, pulverizing, raking, leveling and ridging operations.
(iii) Seed bed preparation - It refers to a very shallow operation intended to prepare a seed bed or make the soil to suit for planting. Weed control and structural development of the soil are the objectives.

B. Inter Tillage/Inter Cultivation
It refers to shallow tillage operation done in the filed after sowing or planting or prior to harvest of crop plants i.e.,tillage during the crop stand in the field. It includes inter cultivating, harrowing, hoeing, weeding, earthing up, forming ridges and furrows etc. Inter tillage helps to incorporate top dressed manures and fertilizers, to earth up and to prune roots.

Off Season Tillage
Tillage operation is done for conditioning the soil during uncropped season with the main objective of water conservation, leveling to the desirable grade, leaching to remove salts for soil reclamation reduc-ing the population of pest and diseases in the soils. etc. They are:
(a) Stubble or Post harvest tillage - Tillage operation carried out immediately after harvest of crop to clear off the weeds and crop residues and to restore the soil structure. Removing of stiff
stubbles of sugarcane crop by turning and incorporating the trashes and weeds thus making the soil ready to store rain water etc., are the major objectives of such tillage operations.
(b) Summer tillage - Operation being done during summer season in tropics to destroy weeds and soil borne pest and diseases, checking the soil erosion and retaining the rain water through
summer showers. It affects the soil aggregates, soil organic matter and sometimes favour wind erosion. It is called as Kodai uzavu in Tamil Nadu state.
(c) Winter tillage -It is practiced in temperate regions where the winter is severe that makes the field unfit for raising crops. Ploughing or harrowing is done in places where soil condition is optimum to destroy weeds and to improvethe physical condition of the soil and also to incor-porate plant residues.
(d) Fallow tillage - It refers to the leaving of arable land uncropped for a season or seasons for various reasons. Tilled fallow represent an extreme condition of soil disturbance to eliminate all weeds and control soil borne pest etc. Fallow tilled soil is prone to erosion by wind and water and subsequently they become degraded and depleted.

A. M. Awan (Author)

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A M Awan Currently working as Marketing Executive at Oasis Agro Industries Pakistan, and hobbies to read about agriculture, share latest information with others