Managing Soil Biota - anyone for tea?

"Whatever method you decide to use, there is clear evidence that breeding beneficial biology in a controlled environment and applied to your turf will benefit turf health and vigour"

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I have been asked why, after so many years, I decided to follow the path of brewing micro biology? Well, I did not wake up one morning thinking "I had been doing it all wrong for the last thirty-five years and that brewing soil biology was the answer to all my woes!"

It all started with the realisation that my very lean operating budget meant it was not possible to implement any course improvements on an annual basis, without reducing my maintenance costs elsewhere.

I am no different from any other manager, I have always been driven by results and I need to see improvements on a regular basis. Without positive results, I lose any semblance of motivation; without motivation, it would be difficult to get out of bed in the morning, and I have never had that problem.

So, when faced with the dilemma of tight resources, I looked to where my annual maintenance costs were going, and noticed one area in particular was my pesticide usage. I was applying, on average, eight fungicide applications per year and was staggered when I saw how much was spent on pesticides and realised significant savings could be made if I were able to reduce disease incidence.

Before I go any further, I should give you an insight into my management regime and the history of Staverton Park, which is a parkland course, approximately thirty-five years old, with reasonable USGA greens.

I arrived in the autumn of 2005 to discover the greens had several active diseases, including fusarium, anthracnose and Rhizoctonia cerealis whilst, beneath the surface, the typical signs of black layer could be clearly seen alongside a root-break some 40mm below the surface. Trying to resolve all of these conditions was paramount and obviously the reason why so much money had been spent on pesticides.

The first three years, I carried out an intensive slitting and spiking programme, with rather rudimentary equipment, which entailed using either a slitter or tined drum spiker. In that first autumn, I hired a Sisis Javelin Aer-Aid, which proved to be a worthy tool and was probably the key to resolving the black layer issue so quickly. Each year after, I hired a Verti-Drain in both the spring and autumn. I was then fortunate enough to be able to purchase a Toro Pro-core 648 in 2010 which, in my opinion, is the best aerator on the market.

My greens are now aerated mostly by the Pro-core, using both 9mm or 15mm solid tines, and the occasional Verti-Drain on hire. There is no need to hollow core since I have never had a thatch issue.

In those early days, it soon became apparent that the rootzone lacked little in terms of soil life. The rootzone was stagnant and predominantly anaerobic with poor root structure that really needed a kick-start to bring life back to the growing medium. My lack of resource had me looking back to my earlier years as a course manager working on a heathland course in East Sussex, where I followed the advice of the renowned Jim Arthur, by implementing a programme of regular aeration on push-up greens, with judicious nutrition and irrigation.

Over a four year period, my greens lost their poa dominance and saw a natural ingress of indigenous bentgrass. I say natural since overseeding was never a consideration. During that time, I would apply a homemade concoction of mostly organic fertilisers, applied both in the spring and autumn, and only needed to apply one preventative fungicide in the autumn, and that was it. How simple things were then!

Even after thirty-five years of managing turf, I have to be honest and admit that it never really occurred to me just how important soil biology and its relationship with plants were; yes, I know I touched on it during my adult education, but it was a subject that seemed to get less time than it actually deserved.

On top of that, USGA spec greens were becoming fashionable and the opposite of what I was taught at college. We are also bombarded with literature and sales pitches that are directed towards inorganic fertilisers and other magic potions, the options and promises of which are endless. Perhaps if we paid more attention to just how much effect some of these products have on plant health, some as low as 2%, we would soon realise that most are not good value for money.

Inorganic versus organic fertilisers

In most cases, inorganic fertiliser is manufactured to give precise applications of nutrition, usually with a portion of fast and slow release and in a uniform coated prill. It does what it says on the bag, i.e. feed the sward and very little else! However, organic fertilisers do more than just feed the sward since they also feed the biology.

Soil biology (micro-organisms) are essential in breaking down organic matter, which is critical in controlling thatch and, if left unmanaged, could lead onto moss issues and/or dry-patch. They also aid in suppressing pests and disease as well as degrading chemicals and similar toxins.

This symbiotic relationship didn't happen by chance, but has evolved over millions of years. If you look at the way ecosystems evolve, it starts with annual weeds and grasses that require minimum support from the soil biology, which can, in fact, grow in a near sterile environment and are generally limited to bacterial support only. This means all the energy from that annual plant is directed towards surviving long enough to produce seed and little else.

However, perennial plants flourish year after year and do not rely on seed alone to proliferate. This is why as much as 50% of the energy produced by perennial grasses is channelled towards feeding soil biology; this includes bacteria, fungi, protozoa, nematodes and larger soil life, such as arthropods and worms. It has taken millions of years to evolve into a diverse ecosystem, then man comes along and, in the blink of an eye, works against these processes without considering the consequence!

I am confident in stating, most people do not realise the importance of healthy soil biology, also known as the Soil Food Web.

Like most, my knowledge is very basic, but it is clear soil biology plays an integral part in providing plants with nutrients in various ways, such as preventing nutrient leech loss to groundwater, fixing atmospheric nitrogen, producing ammonium, which is converted into nitrates. Other roles include increased infiltration by improving soil aggregation and porosity. By-pass soil biology and its association with plant life and the impending results have become all too obvious today.

I am not quite sure when or how it happened but, not too long after the general introduction of inorganic fertilisers, we saw an increase in hydrophobic conditions and, consequently, have seen a steady increase in the use of wetting agents. These wetting agents are designed to rehydrate hydrophobic soils.

Soil hydrophobicity is thought to derive primarily by the coating of long-chained hydrophobic organic molecules on individual soil particles. These substances may be released from decaying organic matter, soil fauna and micro-organisms. We should be asking ourselves; is it not possible these products have brought about a reduction in biological diversity which, in normal circumstance, would digest these conditions and is it not possible that these wetting agents might strip out some of the beneficial secretions associated with soil biota?

All hypothetical, but why are we seeing these types of products used with more regularity and as part of our annual maintenance programme today? I certainly did not use them, or need to, thirty years ago!

Looking back on the successes in Sussex all those years ago had me thinking and researching ways of producing a healthy environment for grasses to thrive naturally.

I came upon the research work of Dr Elaine Ingham who has been studying the soil food web for many years. I was soon reading about compost tea applications, soil biology, its diversity and the important role it plays in plant health. The more I read into this subject, the more I realised this could be my "Get out of Jail" card!

The key point in maintaining a healthy soil biology is quite simple, but most of us have been ignoring this fact and relying on inorganic fertilisers to supply nutrients or applying wetting agents or pesticides at the first signs of dry-patch or disease, all of which either bypass or harm the soil biology and results in a downhill spiral of plant health and vigour.

Soil biology and its role.

Like all living organisms, the soil biology that we are interested in has basic requirements, i.e. air, water, temperature and a food source. The ones we commonly associate with grass plants are bacteria, protozoa, nematodes and beneficial fungi, and there are thousands of species of each, all having their own niche in this extraordinary terrestrial world beneath our feet.

The size and composition of these microbial populations are influenced by management practices affecting the soil environment, for example, cultural practices that decompact or aerate, creating aerobic conditions, or the lack of these operations or compaction-causing agents that result in anaerobic conditions.

This diverse and complex community is constantly at battle, consuming each other as a source of energy. Damage to any part of this complex community has long-term consequences for the remaining communities and could inflict imbalances that provide opportunities for pests and diseases.

However, with this realisation, and what I have learnt in recent years, I am aware that Poa annua is dominating our swards all too easily and the main reason given is the increase in traffic, not just golf traffic but maintenance traffic. My golf rounds per year have increased from 35,000 to 40,000. Unfortunately, that additional golf traffic is predominantly the occasional golfer created by cut-price green fees, who hack their way around the golf course and lack even basic golf etiquette!

Yet, my Poa annua populations are in decline, whilst the perennial grasses, i.e. fescue and bent, are increasing. How could this be? I have always aerated on a regular basis, my maintenance programmes have changed very little, yet there is a noticeable increase in perennial grass populations.

I mentioned earlier that annual plants require little association with soil biology and are usually interrelated with bacterial dominant soils. When you consider that, if we provide Poa annua with food and water, it will flourish, it is also well documented that bacteria populations, however small, will generally survive/recover in a fairly toxic environment. By toxic, I refer to the use of pesticides and, to a degree, inorganic fertilisers.

Artificial fertilisers with a high salt index are harmful to all soil biology, however, bacteria can recover from such applications, but they are always getting knocked back, resulting in low population numbers. This is why managers who are on high nutrient programmes, which bypass the biology, will generate higher volumes of thatch, what I term as grass factory management! And, since, we have caused the reduction in microbial decomposition and, therefore, reduced Mother Nature's means of decomposition; this results in excessive thatch, creating more work in terms of thatch removal by hollow coring and/or additional dressings of sand to dilute that thatch, both of which disrupt play.

We then get into that downhill spiral and finish up managing predominantly Poa annua by applying more nutrients, more pesticides, producing shallow root systems and applying more wetting agents to control thatch hydrophobicity. And, whilst all this is going on, we are seeing the desirable perennial grasses smothered because they cannot survive in a bacterial dominant environment.

For years, I gave up on overseeding my greens, since I assumed the competition by the mature grasses too high, but now I realise the perennial seedlings could not survive in a bacteria dominant environment that favoured annual grasses.

It is important to remember that perennial grasses cannot survive without a diverse biology, one that contains beneficial fungi. Equal amounts of bacteria and fungi would see perennial grasses compete against annual grasses and, assuming the rootzone received regular aeration and suitable food sources, the appropriate biology would proliferate.

In a healthy soil, as much as 95% of plant species have a symbiotic relationship with soil fungi. Some of the fungi will send hypha (roots) for many metres, whilst other beneficial fungi are much smaller and live in close proximity to roots. They all live in close association with plants, searching for moisture and nutrients, digesting organic matter and even protecting plants against disease by producing antibiotics in exchange for sugars and carbohydrates.

Unfortunately, beneficial fungi are more delicate and easily damaged by pesticides, which is why we are seeing an increase in bacterial dominant soils and, sadly, dominance in Poa annua. I now overseed my greens and see seedlings maturing, and my sward is gradually changing to one of perennial dominance.

Some managers would consider brewing as too expensive and I admit there is an element of truth in this, but I think this is largely down to some suppliers making the process more expensive by recommending unnecessary add-ons. Some managers are of the opinion it is too time consuming and messy and, again, this can be true, but there are various choices out there, some I have used and some I would never consider using.

Brewing methods

The common description for compost tea brewing is based upon extracting microbiology and nutrients from compost, aerated in a suitable container, fitted with a constant fine air bubble aerator and using clean water (chlorine removed) for a specific period of time. Every brew will finish differently since the actual brewing time, compost used, pH, food source, water source and temperature will all have an effect on the resultant biota.

A question I am constantly asked is, why is there so little data published about compost teas? We must assume part of the reason is that each microbe in a sample would have to be isolated and identified, then scientifically tested to see whether it is an effective coloniser and competitor, as each batch would be different and contain a variety of microbes at varying concentrations.

We would need to know how these microbes interact. Do different combinations have the same, improved or lesser effect than those isolated? The possible results are vast and, with so many possible variables, this naturally leads to inconclusive testing.

Compost teas usually consist of suitable compost; some suppliers have this made in a controlled environment and guarantee its content. Some use what is termed as hedge compost, which is gathered from a suitable area on your own site, but each sample should be tested before use since there are no guarantees of its content.

Homemade compost can be used, but care has to be taken to ensure no food or animal waste/manure is used, which could result in brewing pathogens such as E-coli etc. Again, this should be tested and the compost should be mainly of a woody nature.

Surprisingly, some do not use compost at all, but supply specific colonies of bacteria and fungi bred in laboratory conditions which are increased using similar methods, but without compost.

In the five years I have been brewing, I originally used either homemade or purpose made compost, but now do not use compost at all.

Whatever assignment I undertake, I always analyse, review the results and simplify the process without diminishing my primary objective. I have applied this to brewing and I am assured by my supplier that I can brew without compost more safely and quickly, with the added bonus of easy cleaning when completed. I have assured myself of these results by inspecting all my brews under the microscope prior to application.

Positives versus negatives when using compost

The positives are:
- More diversity
- Contains bacteria, beneficial fungi, protozoa and beneficial nematodes

The negatives are:
- Compost must be tested to ensure there are no pathogens present
- Compost usually has to be held in a large filtered container or tea bag
- Compost teas have to be left to settle out or filtered into spray tank
- Messy to clean up after brewing

Generally, recommendations for the type of container suitable for brewing compost teas will read something like: "choose a brewer that does not have internal pipes, nooks, crannies or which may harbour biofilm and difficult to clean." The reason behind this is there is no guarantee what is inside any compost, regardless whether it has been tested!

Pathogen inclusion can be limited, but not guaranteed to be pathogen free, since it would have to be manufactured under laboratory condition, in a sterilised environment and then inoculated with the desirable biology - which would kind of defeat the object!

Because I do not use compost in my brewing process, and the fact that I am using pure biology bred under laboratory conditions, I know there are no pathogens present. This also means I am not limited to a purpose built brewer, which often costs a lot of money, since there are no pathogens present that will cause infection.

I use a specially designed aerator that can either be placed in an IBC tank or, in my case, directly into my 750 litre sprayer. I am then able to add my food source and brew for the specified time. It is recommended to include additional organic food sources/bio stimulants to the spray tank to ensure the brew has a good start.

The brew is then applied with the minimum of effort. If I do not have the time to produce a brew, it can be dispensed directly into the spray tank, with the required food sources added and the batch applied directly, either as a drench or folia application. The only downside of not brewing first is you do not get as much for your money! Naturally, hygiene still remains an important part of my programme and all my equipment is cleaned after use.

Why do I prefer to use compost free brews?
- The biology is safer and easier to handle
- The products are cheaper in comparison to other suppliers
- Biology can be applied directly into sprayer without fear of blocking nozzles
- I am seeing similar results with my brews when observed under the microscope

Why are teas integral to my management programmes?
- They have reduced my pesticide budget by 80%.
- They have reduced my fertiliser budget by 50%.
- They have reduced applications of wetting agent by 70%
- They have reduced competition/dominance from Poa annua
- They have increased competition and dominance from fescues and bents

Key products used, each targeting specific areas:
- A combination of over twenty beneficial bacteria and fungi
- A combination of N fixing and companion bacteria able to fix atmospheric nitrogen
- A combination of fungal digesters, targeting difficult to breakdown lignums
- Each product targets specific problems or are part of a broader strategy

Note: Each product requires a small portion of food added to the brewer at start-up, generally as little as 200mls per 200lts water. When the brew is applied, each has the same specified food source added to the spray tank, generally between 5lt -10lt/Ha.

In addition to these products, they are enhanced with the following.
- Liquid oxygen (is an addition to the aeration programme and not designed to replace cultural practices)
- Fulvic acid (a good quality fulvic acid should look like weak tea and is extracted from humic acid)
- Organic seaweed (some seaweed extracts can be quite harsh, depending on extraction method used)

Whatever method you decide to use, there is clear evidence that breeding beneficial biology in a controlled environment and applied to your turf will benefit turf health and vigour. It will also give the desirable perennial grasses improved sward competition and improved resistance to the stresses associated with fine turf management. More importantly, it is more cost effective in this current climate.

It is inevitable that legislation will gradually reduce pesticide availability and choice. There are more organic pesticides being produced, which are less harmful to the environment, but these are costly alternatives. The benefits of brewing is evident in European countries such as Sweden, where pesticides are banned, so why not start that move towards change now, before it is too late!