By Doug McClymont
The minimum required for tillage operations is to;
1. Make a suitable seedbed.
2. Cultivate out any initial weeds.
3. Promote maximum soil moisture penetration.
4. Prevent wind and water erosion on the surface.
5. Save fuel by making minimum passes over the field with smallest suitable tractor.
6. Reduce soil compaction to the minimum.
Always use Gypsum for softening the soil and promoting earth worms. Tilling when the soil is at the correct moisture content is important .
Plough a green crop in every five years. Deep rip with a ripper and trailed roller every year if necessary. Use a crop residue freeway where necessary to plant maize and other crops. Leave surface crop residues as much as possible. Ripping results in soil shatter and roming results in a reasonable seedbed; it is a very popular method because its operation uses minimal diesel. It can be modified as situations dictate and should not be used willy-nilly. For proper conditions answer the following questions correctly:
– Is the whole root profile friable (i.e. can roots grow there without restriction?
– Is there a surface seedbed that will allow the seeds to germinate?
Deciding on the tillage methods to use – The very important principle with all tillage methods is to budget for a “system” not a collection of methods each with its own cost. The whole system must be costed and compared “system for system,” not just “method for method”.
Decide which of the following is most economical for you:
– Is my root zone friable?
– Have I a plantable seedbed for the crop to be grown?
– Can I reduce the operations to as few as possible?
– What other costs are involved (e.g extra seed for broadcasting)?
– What are the negative aspects (e.g compaction, over working of the soil)?
Soil, Weeds, Pests, and diseases – Soil tillage has a major effect on pests, diseases, and weeds. Plant residues left in or on the soil followed by planting the same crop into that land is a recipe for disaster. That is why rotation is so important with conservation or reduced tillage. With tight rotations, purple nutsedge is a growing problem under irrigation with tight rotations. Expensive herbicides can control purple nutsedge where desiccation can remove 80% of the problem. As a part of crop rotation, tillage is the best“herbicide” here if the soil is deep ripped and allowed to dry out completely.
First Published on ZiMunda Farming Magazine issue 3