Root growth under conventional tillage practices
Tillage which inverts and mixes soil:
-Kills weeds by smashing, mixing and inverting soil.
-Creates fine soil aggregates for seedbed.
-Fine soil gives surface sealing and water run-off.
-Breaks down & depletes organic matter (humus levels)
-Fine soil reduces aeration (denser soil structure)
-Reduced worm & microbe activity
-Soil fines and tillage create hard pans
-Vehicle and stock cause soil compaction
-Restricted root growth & smaller root volume
-Restricted water penetration, less water stored
-More soil disturbance and degradation
Benefits of Direct Drilling
Direct drilling prevents the soil from being exposed to wind and water erosion and the effect of reduced traffic minimises soil compaction. Zero cultivation avoids degradation of soil structure.
The primary reason for cultivation is to kill vegetation that consumes moisture from the soil. This can now be achieved by alternative methods.
A big advantage of direct drilling is that it allows soils to improve and become more friable with time. As increased organic matter is retained and broken down, it is combined with the soil as humus. Soil structure is improved by this organic matter, making it more porous for better aeration and water infiltration.
The reduction of soil compaction (due to less traffic and soil degradation) allows full moisture retention to be achieved. The plant can then use the soils full potential of stored moisture, and can pursue water and nutrients deep into the soil.
Studies have shown that earthworms level have increased by using this method. Soil microbes are also returned to the soil and these beneficial organisms aerate the soil. This further helps to break down organic matter and make nutrients available.
Utilising chemicals and livestock, modern farming is able to control weeds and maintain a good ground cover. Erosion is therefore reduced and evaporation is kept to a minimum.
As the cost of farming continues to rise over the next decade any increase in margins is an advantage to farmers. Compared to conventional cultivation, direct-drilling will save time and money, and also reduce replacement expenditure on plant and equipment.
Look at the advantages enjoyed by farmers who have adopted direct-drill and minimum-tillage techniques:
-Reduction of capital costs by up to 40%.
-Greater length of grazing time (between two and four months), allowing
-Carrying capacity to be lifted in mixed enterprises.
-Flexibility in cropping programs.
-Yields superior to conventional cultivation.
-Reduced labour requirements - less time is spent on the tractor.
-More control over timing of sowing and related activities.
-Reduced costs of production.