Tillage is the most important operation, in which physical manipulation of soil is done with tools and implements in order to obtain favourable conditions for plant growth. The harder surface soil is dug out to a certain depth, and the resulting big clods are broken down to make the soil fne, smooth and compact. This facilitates weed eradication, removes crop residues, helps in water infltration, promotes aeration, and permits root penetration and development.
Different operations, such as ploughing and levelling of feld soil, harrowing, etc. are also performed under tillage operation. In soil, a tilth appears when it is soft, friable and aerated. All these activities involve the use of different tools and equipment. The selection of an equipment depends on its effciency and size of
IMPLEMENTS USED FOR LAND PREPARATION
Ploughing is the initial operation that involves breaking of hard soil surface, uprooting previous crop residues and pulverising the soil. Different type of ploughs can be used for ploughing. Mouldboard, disc, rotary and sub‑soil ploughs are some of the implements designed for breaking soil.
It is made up of carbon steel or steel alloy, whose base is of a right-angle triangle. The size of a mouldboard plough is measured by the width of the furrow that is opened by the plough. Generally, it can open a furrow of about 20 cm and above. It may throw furrow slices only on one or two sides of the motion.
It consists of moving circular steel discs of varying sizes. The size of discs includes its diameter and thickness. Discs in different ploughs used are 50-90 cm in diameter. The thickness of the discs may be 2.5 cm at the cutting edge and up to 40 cm towards the centre.
Some discs are 7.5 cm at the edge, which are thickened to 20 cm towards the centre. Discs cut, turn and break furrow slices. The plough can work in sticky, as well as, hard and dry soils. It cannot be used when the soil surface is covered with weeds and bushes.
Sub-soil single arm (Patashi) plough
This plough is useful for heavy soils and consists of a single adjustable arm, having shear at the base. It breaks the hard pan developed below the soil surface. It improves drainage in water stagnant soils. It can be inserted up to 50 cm deep in the soil and is most suitable for making a trench of
5 to 7 cm wide.