Purpose of ground engaging equipment :
- Promote water infiltration throughout the soil profile
- Reduce water runoff and take full potential of rainfall
- Create a friable seedbed
- Reduce the effects of wind erosion and provide a good soil / organic material mix
Goal: To provide the plant with a growing medium or environment with favourable root development zones to ensure the intake of water, minerals and nutrients.
Result: A favourable soil environment will ensure a better chance of yielding greater crops.
Note: No-till applications do not fall within the scope of the article.
A popular enemy of the modern farmer is soil Compaction… Currently, ground preparation applications are based on traffic-intensive processes, which in turn creates higher soil compaction.
- Address the specific depth of the compaction zone. Use a penetrometer, a simple penetration tool like a t-bar or by digging a profile hole approx 600mm deep, depending on the crop to be planted and the rooting requirements respectively.
- Study the profile of the soil and look for indications of soil compaction and the depths that they occur. Also, look at the soil profile within the top 10cm for organic material breakdown and constitution. This will give you an idea of what type of tillage will work best to get a better friable topsoil profile or a better soil-to-organic material mix. Many of these variables can be addressed by the choice of implement and share sizes that are more suited to either soil mixture or deep profile ripping.
Top Profile compaction
- Normally associated with post-plant rainfall and water runoff creating a crust or compaction top layer. This could pose a problem to emergence of seed, but if the occurrence takes place before planting the situation is a lot less serious and can be rectified by a simple seedbed preparation. If seeding or planting of crop has already taken place a rotary harrow can be used to break and aerate the top profile without disturbing soil unnecessarily.
Upper Root profile up to 100mm
This usually occurs due to equipment traffic and can be addressed by using a shallow working tined implement or more recently a high speed disc harrow able to penetrate 100mm. Many Farmers have reverted to working these traffic zones at 40 degree angles to effectively combat these compaction issues, while leaving an even seedbed and not perpetuate traffic compaction. This profile zone is of major importance as it will be the environment where seed germination, initial root formation and most nutrient absorption occurs. Furthermore it is advisable to note the importance of a well aerated profile to facilitate water penetration rate and holding capacity, while reducing the probability of water runoff and erosion.
Lower Root Profile 200mm and more
Commonly associated with Equipment choices like ploughs where the continued use creates a compaction zone due to clay content, water content and repetition. This compaction zone is quite detrimental to the overall health of plants, it slows the tempo of water infiltration which could lead to water logged spots. Furthermore root development past the 200mm will be strained as the compaction zone is not conducive to unobstructed root proliferation. Equipment used to lift the compaction layer would be done by using a shank type ripper that can loosen depths of 150mm to 600mm depending on soil conditions and clay content.
Summary: Soil Preparation and Ground Engagement
There are many benefits and risks associated with ground engaging equipment as a means of soil preparation. Some benefits however include better aeration of the soil profile, less water runoff and erosion, better water infiltration tempo, better root growth distribution and better usage of the total soil profile for nutrient absorption. Some disadvantages are costs, soil structure breakdown, and organic material breakdown acceleration.
The balancing act of soil preparation versus conservation of organic material in the soil is a mammoth task and one that needs to be addressed for the future sustainability of agricultural practices.
Recognition to Dr Rio van Antwerpen (full article here https://sagrainmag.co.za/2019/08/01/voor-en-nadele-van-grondvoorbereiding-in-bewaringsboerdery/)
For more information regarding ground engaging equipment visit our website and make contact with our product experts.