What is aeration for? It is the European Turfgrass Specialists' belief that aeration is a critical component that contributes to the correct PATH for success
Provide more available oxygen and pore space within the soil.
To improve the natural biological processes taking place within the soil. For example hydraulic conductivity, critical tension, nutrient uptake, growth, water potential tension, natural breakdown of elements etc.
Help to create the best possible soil properties within your soil structure.
How do you calculate how often you should aerate?
The answer to this question depends on a variety of different factors that need to be clearly understood. Firstly, you require a detailed knowledge of your grass type, and its growth method, to enable you to know the limits and requirements of your turfgrass for healthy growth purposes. Grass selection should be dependant on your usage requirements, local weather patterns, economical restraints and your own expectations.
Your aeration programme should, therefore, be engineered to create a favourable growing environment that suits your favoured grass selection. It is critical not to over aerate or to under aerate turfgrass, and this matter is therefore worth taking time over.
It is also especially important that a detailed understanding of your soil type is recognised in order to produce a purpose designed aeration programme.
A primary starting point is, therefore, to take a physical assessment of your soil. This would represent an excellent precautionary measure to help you classify your soil in line with your own expectations for your playing surface, e.g. a clay based soil will not benefit from the same frequency of aeration as a sand profile that contains a variety of different particle sizes.
Once you understand the type of soil you are working with, i.e. clay, silt, peat, sand, or perhaps a loam, the next important detail to be aware of is...
What condition is your soil in?
There exists numerous laboratory tests, agronomy tools and support that can help you understand the existing condition of your soil. Some laboratory tests are based on the resultant effect of aeration availability within the soil, such as the hydraulic conductivity factor that exists within the soil. This test describes the ability of a soil to transmit water flow and is usually measured in mm h-1. Water movement is reliant on pore spaces within the soil and can, therefore, be improved if the correct pore space is made available.
Oxygen diffuses considerably quicker through air than it does through water. Therefore, it is particularly important to maintain air filled porosity because it will help you to enable roots to grow more comfortably and allow more micro-organisms to respire aerobically.
One particularly useful agronomy tool, called a penetrometer, will also help you to determine the actual density of the soil and other materials. This tool can be useful to identify any individual compaction layers that exist within the soil, and provide you with an overall indication of the level of compaction that exists within your soil.
A visual examination will also help you recognise common features in your soil:
• Greyish coloured clay may suggest that water exists for prolonged periods in the soil, often visible at depth
• Shallow rooting structures may indicate stress associated with limited oxygen in the soil or, perhaps, even other factors
• An unusual smell could also highlight stagnation and, therefore, anaerobic conditions
Aeration will help to prevent the formation of anaerobic processes and stagnation, which can potentially reduce nitrogen availability if allowed to develop, resulting in the formation of phytotoxic products.
The soil structure itself could even reveal different layers and features throughout. This would certainly suggest that further investigation is required in order to appreciate the actual soil profile's full potential for growing healthy turfgrass.
Once you have established a good understanding of your soil type and its current condition, an appropriate aeration programme can then be created, aimed at producing better properties within the soil.
Are there any negative aspects associated with aeration?
In our opinion, yes there are. It is difficult to admit, but nobody really truly enjoys the actual act, or the initial effects, of aeration. The work itself is often time consuming, it can be both costly and very labour intensive. It is often required, at times in the year, when resources aren't available and it is likely to disrupt the playing surfaces condition on a short term basis.
Any disruption that is caused through aeration activities on the playing surface can put an increasing amount of pressure on the turfcare professional also. For example, an amateur may consider this disruption to be destroying the playing surface in the short term. This is potentially correct, as the playing surfaces do tend to become affected initially. Several different measurements can be undertaken to detail the extent of this disruption. These tests are useful because they help everyone to appreciate the full effects of aeration clearly, and acceptable limits can be created between the players and the groundsman or greenkeeper for working standards.
There are several ways to help offset any short term disruption caused by aeration. To start with, players that use the playing surfaces should be engaged with to help them understand why the work needs to be undertaken. The players must learn to appreciate that the professional groundsman or greenkeeper should be given support and time to plan when this crucial work can be undertaken, like in any successful business.
Ideally, aeration work should fit smoothly into the sporting diary. This can be agreed between all parties annually, with allowances for variance in weather conditions. Communication between the groundstaff and the players is, therefore, critical and this is an especially important aspect for all groundstaff to initiate.
This communication will help all parties concerned. In reality, our sports have possibly exceeded all of our wildest expectations, in part thanks to the media. Consequently, our level of expectation has, potentially, surpassed our capability.
It is, therefore, important that we recognise our current position and set achievable goals that we can aim to achieve and deliver. This task can sometimes be difficult. However, we will support anyone willing to take these important steps. This process requires excellent communication, patience and a sound knowledge between all interested parties. The potential rewards of this process cannot be underestimated.
There is a solution to any problem, but recognising the problem in the first place is critical. To offset aeration disturbance plenty of options are available. Timing and cost implications must be considered from a practicality view point.
A good example of this is if aeration work was undertaken on a heavy soil in wet conditions. This, too, can sometimes be detrimental as it could effect the structure of the soil. When a soil is wet it can become considerably unstable and may restructure as and when it dries out in a variety of different ways in its own time. This could produce a permeable layer that is impenetrable.
How do you aerate?
This is certainly an interesting question which has been covered before by many different people. This question does intrigue us all since the answer seems to change, constantly.
Traditionally, all aeration practices have been implemented through the use of hand tools or machinery that inserts tines into the ground and heaves. In more recent times we have seen vast arrays of equipment that use different sized and shaped tines aimed at providing a multitude of different effects.
The use of compressed air being injected into the ground is now becoming increasingly popular. This successful treatment method is proven in the agricultural world and is commonly being used to improve tree growth conditions for the tree roots.
Compressed air is injected into the ground at varying depths and levels of pressure. The soil fissures that are created are less uniform than traditional measures and can be far reaching and hugely advantageous.
High compression injections of water, fertiliser and other soil amendment products are now also available on the market to aid with the aeration process.
Another type of machine was readily available at Pinehurst Golf Resorts ten years ago in case of sudden downpours and extreme weather patterns. The Sub-air is connected to a pipe drainage system and it sucks or blows air into the rootzone for various benefits.
Aeration can even be provided by inserting soil amendments into the ground to enhance pore space and soil structures. Several of these new products allow you to enhance the oxygen in the soil in different ways. Many of these products state on their label that they offer advantages, and research certainly shows us this too.
Perhaps a demonstration is the safest bet if you would like to consider any new options such as these. Also, try using the manufacturer's support network. You could even consider using an independent agronomist for additional support.
Recently, we have started to recognise that it is not just air alone that restructures soils but that aeration is one facet of a larger picture. We must, however, still focus on getting this aspect correct and the right amount of pore space is certainly necessary.
This will partly depend on your original decision behind soil selection and grass selection. If you inherit your site, then testing to benchmark and identify the different traits that you have is certainly sensible.
There are numerous methods available to you but, crucially, you must ensure that you have a fine balance of aeration, drainage, thatch control, nutrient balance and recognise all the relevant stresses that the playing surface is under. This will help to achieve the ultimate goal of producing a suitable playing surface for the customers. This aim is surely what we all strive towards, but finding the right balance for your aeration programme is not to be dismissed lightly.
There is very little reliable research available that compares the different effects of one aerator to another and, so, this information is currently very contentious. More research of this nature is certainly required to help us all appreciate the best possible methods to create more pore space within the soil.
In our experience, any aeration equipment that creates fissures in the soil will provide an excellent remedy. The natural contraction of the soil due to the earth drying out will also help us all as well, but this cannot truly be relied upon alone anymore.
Several tests are available to help benchmark your soil's existing condition, and this is the direction that more and more turfcare professionals seem to be going down. Each of the individual tests mentioned earlier in this article will help you to learn more about the condition of your soil.
Once you have collated this information, you will then be able to recognise, more clearly, the advantages that you get from different aeration practices within your soil profile. Tests can be repeated at any time to help you see these improvements and monitor any unforeseen changes that may naturally occur, perhaps through environmental changes or changes in maintenance strategies.
This information must always be collated in a tidy documented fashion so that you can recognise any problems that may occur in advance. This process really does represent a pro-active method towards growing healthier turfgrass in today's increasingly technological industry.
In summary, once you know your own soil's balance, you can then start to produce tailor made maintenance programmes with the sound knowledge that you are being the most efficient and effective for your turfgrass.
For further information or assistance with any of the items discussed, or any other agronomic matters, please contact The European Turfgrass Specialists on firstname.lastname@example.org or telephone 08442 259614.