Some Practical Pointers
When one starts to talk about tillage, it seems that whoever you are talking to thinks that their programme is the best and everything else is irrelevant or is a fanatic on a particular system such as “ban the plough or disc harrow”. In both cases, common sense is hardly common.
There are three main routes to proper tillage:
1. Proper soil acidity, soil texture and nutrient status is essential.
2. The tillage operations should aid the above but still be as economic.
3. Minimum economic use of pesticides for pest and disease problems.
SOIL CONDITION IMPROVEMENT
A. Soil acidity is vitally important. pH values for the soil should be 5.5 – 6. In lighter soils, pH values in the range 3.8 – 4.8 are not on. Annual liming is compulsory.
B. The calcium to magnesium ratio in the soil of 3.0 – 5.0 is essential. Calcium is the plant cell building block. Low calcium equals weak plants and lodging before harvest. Various enzyme processes necessarily require the correct amount of magnesium.
C. Major deficiencies of boron and zinc lead to poor quality crops. The photos show typical symptoms in maize and wheat. The yield of grass crops (maize/wheat/pasture) are devastated by Zinc deficiency.
TILLAGE OPERATIONS
The minimum required tillage operation should:
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. To 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 common sense.
Plough a green crop in every five years. Deep rip with a ripper and trailed roller every year if necessary. Use a trash freeway where necessary to plant maize and other crops. Leave surface trash as much as possible. Ripping to get soil shatter and roming to get a reasonable seedbed is very popular and 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 (ie can roots grow there without
restriction?
– Is there a surface seedbed that will allow the seeds to germinate?
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 (eg extra seed for broadcasting)?
– What are the negative aspects (eg compaction, over working of the soil)?
SOIL WEED PEST AND DISEASE PROBLEMS
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.
The whole cost structure and gross margin return on all crops depends on correct tillage. Significant savings, yield improvement and improving soil condition rely on common sense tillage.
Article and images by: Doug McClymont