Difference between zero tillage and minimum tillage
Answers
Minimum and zero tillage systems are very similar in that the ground is worked very little or not at all before the seed is sown. This approach has increased in use over recent years with, for example, 8 million hectares in Brazil and a major swing towards the technology in Asia.
The most important advantage of minimum tillage is that crops can be sown almost immediately the previous crop has been harvested and commonly approaching the optimum sowing time This is not possible with conventional tillage as that is time consuming. So it is highly suited to areas where two or more crops are rotated on the same land within the year. In much of south Asia yield in wheat reduces rapidly as sowing time is delayed beyond the optimum date for the area (see Hobbs et al., 1997 for details). So delay costs yield. Minimum tillage in addition to shortening turn-around time between crops can be much cheaper than conventional tillage.
Conventional tillage on smallholdings in some parts of Asia can be very exhausting and slow. A common practice in Bangladesh is six ploughings with cattle and 11 plankings, or two passes with a rototiller and four plankings. Only then is the crop sown. Using a minimum till approach the land can be tilled and seeds sown directly in one pass. In that pass, using accessories for example to the Chinese Hand Tractor, a 2” (5 cm) deep seedbed is tilled, the seed is sown and then covered with soil (CA Meisner pers comm.). An even less demanding single pass system is ‘strip till’, which is close to zero tillage, only tilling strips 10 cm wide and 5 cm deep.