Tillage is a technique in which soil is prepared for crop production through a mechanical process. It involves cutting, milling, crushing, beating, and rebound. Mainly, tillage promotes soil aeration, gaseous exchange between seed and root region, seed and soil contact, and controls pests and pathogens.
But too much tillage often destroys the soil structure. Recently, new tillage practices have been introduced in organic farming such as minimum or zero tillage. These practices can effectively control the runoff and soil erosion, and also maintain the yield of crops.
Minimum tillage means a reduced manipulation of soil necessary for crop production. Unlike intensive tillage, It doesn’t involve soil inversion. In this practice, a high level of surface residue is maintained for crop production. It reduces primary tillage and involves only secondary tillage practice. The main objective of minimum tillage is to provide a favorable growing soil medium to the seeds with reduced tillage.
The benefits of minimum tillage are:
- Improves soil structure by decomposition of crop residue.
- Minimizes resistance to root growth.
- Unlike conventional tillage, it reduces soil compaction due to the minimum movement of heavy tillage vehicles.
- Promotes infiltration rate of the soil as the decomposition of dead roots make channels in the soil.
The common methods of minimum tillage practice are;
Row Zone Tillage: Primary tillage is done by using a mouldboard plough. The disking and harrowing are minimized. Tillage is done only in the row zone.
Plough plant tillage: After plowing, only the row zone is crumbled by using a specific planter. The next step is seed sowing.
Wheel Track Planting: The seeds are sown with the help of a tractor after normal plowing, the tractor wheels are used to crush the soil of the row zone.
Zero tillage is also known as no-till, direct drilling, or transplantation. This practice completely skips primary tillage. Only the seedbed preparation step of secondary tillage is applicable in the zero tillage. The zero tillage technique is effective in reducing the erosion of sandy and dry soil in sloppy lands.
One common method of practicing zero tillage is:
Till planting: In till planting, machinery is used to clean the area before sowing seeds. After cleaning the strip, the land is prepared for seed insertion. The wide sweep and trash bars of the machine clear a single row over the previously planted crop. The seed is sown with the help of a planter shoe and covered with soil. All of these tasks are done by a single machine.
However, the conventional no-till practice involves the use of herbicides to kill the remains of previous vegetation. In organic farming, the remains of cover crops are mechanically killed by mowing, undercutting, and rolling. In this way, the terminated cover crop remains under the soil. This mulch helps in suppressing the weeds and retains the moisture of the soil. By using this practice, the crops of corn, soybean, and vegetables can be planted successfully.