Specialists in biological services and solutions for healthier soil
11 Feb 2018
Healthy soil = healthy plants and food

When is the right time to sample your soil?

I have written a lot in the past about how to sample soil, what tools you can use to make this process easier and how to plan your sample distribution for representative measurements. But how do you decide when to actually sample in the first place?

In this article I’ve broken down the process in to a series of simple steps or questions that you can reflect upon in order to help you decide when is the right time for you to sample. This means that you will have a (planned) approach ready before you even set foot on soil – making the whole thing easier.

 

To sample or not to sample? That is the question.

 

1) What information do you have about your land, plot or field already?

This will require you to know when you last tested the soil in this area. If it was more than 3 years ago, it is probably worth considering another test and if has been more than 5 years, it’s most definitely time to get that auger out again! If you have no data, how are you going to manage it? I recommend planning the annual budgets to cover soil analysis across an entire estate over a period of 3 or 5 years or in line with the crop rotations.
But, not so fast…

2) If you have already had a test, what did the results show?

If you implemented a programme of treatments or made focused applications due to imbalances or deficiencies (biological as well as chemical), you need to understand if there are sufficient concentrations still available/active or if things remain balanced. Chances are if you had a comprehensive analysis* within the last couple of years AND you have a good understanding of the effects of crop history, husbandry and organic/inorganic fertilisers or amendments you should consider a focused test to ‘sense check’ baseline levels and makes sure that they are in line with your expectations. A focused soil test may be slightly easier on your budget, although I do recommend spending as much as you can afford on soil analysis to ensure the most comprehensive data you can get. You only have one opportunity to collect data on your soil now and who knows what information you wish you knew in 5 years time. Over time this information helps you form a more complete story of your soil which is so valuable to drafting and implementing a long term soil management plan that will sustain the operation well in to the future.

*This would probably include Organic Matter, biology, minor and micronutrient concentrations in addition to major index tests and pH.

Timing

 

Full sample bags ready for testing
Collecting plenty of soil when sampling is always advisable if having multiple analyse performed

3) Sample history

Having established that this year is indeed the year to have your soil tested for a particular plot of field(s), we must then think about the precise time within the year. Data will generally be more helpful if it is comparative and so this means you should consider if repeat testing or scheduled cyclic analysis is it at a same time within the season or stage of crop as previous tests were performed.

4) Activity

If you sample now, will it be convenient to sample at the same date in 1,2,3 or 5 year’s time? It might be that at this moment in time there are exceptional circumstances and lower levels of grower/staff activity means that you have an (untypical) time and the capacity to sample and interpret results now, but actually you will be unlikely to have this opportunity at the same point in the season in coming years. This is so important because as mentioned before, you will want to build up a comparative picture of what is happening in your growing area, over time, by sampling at the same time in the season each time.

 

 

Fungi (zoomed in at 400 x magnification)
Fungi (zoomed in at 400 x magnification)

 

 

5) Active crop management

It may be that there are subsequent tests that you want to perform throughout the growing cycle of a crop – N, P, K, biological activities or mycorrhizal fungi etc. These can be treated as a one-off as they relate to that crop at that time and will inform a immediate and direct intervention, as a response.

Ultimately, managing soil health in the long run, is a ongoing process, a journey, rather than an activity you complete – Especially when intensively cultivating land. By thoroughly measuring your soil’s functional components, you are adding a Chapter to the story of how your soil works, every time you test.

6) Time of day
On an even more basic level, when we talk about the time of day that we should undertake the task of sampling, generally I would recommend earlier in the day wherever possible. The best time will be first thing in the morning, when plant sugar levels are lower and soil activity lower due to cooler night time temperatures and natural dormancy. Also, when collecting material for biological analysis, the Sun’s UV levels are also lower which ensures that microbial life in your sample are less likely to be affected (or destroyed) by the sun’s rays and is easier to protect bags of soil from heat and light whilst sampling other areas.

Conditions

 

7) Climate and weather
Natural and seasonal conditions play a huge role in determining your soil’s ability to function by directly (and also indirectly) affecting the Physical, Chemical and Biological aspects. Seasonal conditions may therefore affect the sampling timing. You definitely do not want to be sampling your soil during the height of a heat wave, monsoon or in middle of the icy, bleak mid winter so avoid any extremes.

Checking your soil temperature with a solid probe is a great way to get an understanding of expected biological activity
Checking your soil temperature with a solid probe is a great way to get an understanding of expected biological activity

 

8) Temperature

Temperature is really key for any kind of microbiology testing and I advise, if possible, to avoid collecting soil material for microbiological analysis when temperatures are continuously < 8 Degrees C. These kinds of low temperatures will affect the activity levels of the different organisms – you will be analysing activity levels at a time when their natural tendency is to be less active. Also, depending on the extent to which soils have cooled and duration, total concentrations levels may also be less then what it is representative level when soil is warmer and fauna and plants and crops are interacting with one another.
The same is true of heat and it will not always make sense to test for soluble nutrient concentrations (those available to plant roots) or microbial activity when the soil is arid and absent of moisture. Both readings are liable to provide unhelpful readings when compared to real-world conditions for plant responses to properties that are critically dependent on soil water content. A more useful test in these circumstances might be soil moisture content itself!

 

 

 

 

9) Rainfall

Speaking of water levels, significant levels of rainfall can affect the amount and extent to which soil processes occur. An absence of water can hinder some key factors by limiting or disabling certain life-processes. The same is often true of excessive H2O, though for different reasons. Some elements can become increasingly (plant) toxic due to higher availability (more dilute in the soil solution) in conjunction with changes to basic biological processes. Oxygen levels are reduced in flooded soil. This can impair plant roots and effectively suffocates many organisms that can work for us, causing them to die or make facultative types (bacteria and certain protozoa) respond by multiplying to very large population numbers creating biological imbalances. You should therefore avoid sampling during and immediately after heavy downpours of rain.

10) Physical activities

Sometimes, our own interventions will affect conditions too and make it unsuitable to take soil samples for testing straight away. Examples of these times range from the application fertilisers, including organic amendments (compost, FYM etc) and inorganic substances such as herbicides, pesticides or fungicides. In almost all cases this will probably skew readings taken immediately after their application with effects ranging from incorrect soil organic matter % levels, overly optimistic soluble element concentrations and low concentrations of soil micro-organisms such as fungi. In all but a very few cases, including trial work or product tests, it would be more appropriate to wait until conditions settle first and this could mean waiting from between 2 days to 2 weeks** before entering the area to gather material for testing. This includes ploughing which by nature will turn the soil upside down, shaking up your data too.

** Refer to the product label or contact the manufacturer for guidance.

What you are testing for?

 

These days if you are not changing that makes you static. With the current economic and environmental pressures this static middle-ground is, in my opinion, a dangerous place to be. Many growers have already identified the threat and very real possibility of going backwards (in production) due to a decline in soil health and are more open than ever before to look at new (and old) ways of restoring and regenerating tired land.

There are so many different properties that you can test for, so it is worth some thought as to the value of what you choose to measure
There are so many different properties that you can test for, so it is worth some thought as to the value of what you choose to measure

11) Testing something new

Adaption is the key to survival and, hopefully, thriving. But this requires change. Testing the ‘same old things to inform the same old practices’ has already created many problems that we are struggling to resolve. Like Einstein said “We can’t solve problems by using the same kind of thinking we used when we created them.”
Traditionally soil testing has generally always consisted of texture and basic chemical analysis. Our knowledge has grown and we know better than ever before that this is more complex than we can currently comprehend and that Soil is far more than the sum of it’s parts. You can our (simple) take on the Science of Soil here.
If you are always taking (carbon) and never replacing, it makes sense that, at some point, you will run out. How will you know when, if you don’t know how much there was to start with?
So I say, test something new today!

 

12) Think further ahead!

You only get one shot at understanding the soil at a point in it’s and your lifetime. Soil is dynamic and if you are growing plants or crops intensively, conditions will change. Even if you are managing soil perfectly, perfection (if you are lucky enough to achieve this miracle) will have existed for but a brief instant and then cease to exist any longer, until you restore balance or leave the soil alone for nature to run her course.
Therefore, I always recommend having the most comprehensive analyses that you can afford. This means that you will have the widest set of readings to compare “before” and “after” for conditions, after growing something or implementing changes to growing methods and can truly determine the magnitude of impact. Budget will come in to play with this and so prioritise the information that you require first to ensure to help manage the day to day, whilst investing in new data to increase your (long term) understanding of this precious natural resource. An example could be adding soil organic matter and a biological index test to your standard (P K, Mg) soil index test. These nuggets of information might just open the doorway to opportunities within your soil that you never knew were available!

 

The process is mainly common sense, but hopefully by focusing on some of the do’s and don’ts, this article will help you eliminate from your calendar, those handful of times when you might otherwise have considered taking (and paying) for the analysis of soil samples that would otherwise leave you with a costly and less than useful report.

 

– Simon

 

BTW – If you’re looking to move in to a new/sustainable/more natural approach of managing your crops and plants and spoil microbiology is all new to you, you might be interested in checking out the 1:1 Soil Biology – Personal Plan that we’re now offering. This will give you direct access to expert testing and advice to start changing the way you think, use and interact with your soil.

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And, if you have any ideas for subjects that you would like us to cover, feel free to let me know.

12 Jun 2017
Cemetery soil health is a mystery

Soil in church yards

CAUTION! This is seriously outside the box and possibly sensitive, but graveyards are great places to go – if you’re into soil.

As long as you’re not planning on staying indefinitely! 🙂

Think about it. The soil there should be really healthy.

Here’s why.

It is left undisturbed for relatively long periods. Traffic is restricted, mainly on a Sunday and for special events, and generally low volume – primarily limited to foot. And, everyone feels a bit funny walking over a grave don’t they?

Then you have the flora. The grass, hardy shrubs and trees.

Typically there is the odd Yew tree or two, abutting an ancient boundary or hedge or standing soldier-like on sentry on amongst the stone pieces. They are usually quite old and have co-evolved with soil itself, forming symbiotic relationships with the fauna that are too complex to comprehend, though will likely be significantly beneficial for fungi levels. The cover and the protection of the established green landscape and the shade afforded by the steeple tower, provide the first line of defence against climatic extremes.

Graveyards in a grassy swathe with tree
Trees in grave yards can be old, solitary and often have co-evolved with the soil itself

Soil level is frequently elevated in the oldest of these traditional village settings. Contained within a wall, often many feet above other features in and around the site, like paths, gates and roadways. This is great for water drainage and maintaining optimal moisture content. I was led to believe (rightly or wrongly) that ‘coffins drifted underground’. Is this just an old wife’s tale or is the soil really so light, friable and free-flowing at this type of depth? I suppose it may be if it is occasionally being dug up and added to…

Then you’ve got the organic matter! Should be a pretty high %, shouldn’t it? We are made of soil, as we consume it, digest and absorb it in all its different forms. Eventually we are returned to it.

And head stones. Great supply of trace elements! As the granite or marble stone is gently eroded over time, years, centuries, the elements perculate through the soil, feeding it. Fuelling microbial interactions, nourishing plants and grasses.

So how healthy is the soil in a graveyard really?

I feel a soil test coming on though.

If you’ve ever tested soil in a graveyard, I would love to hear your experience. Or, if you have ever pondered this question, and are strange like me, also reach out.

Different I know. But if you enjoyed it, we’d love you support if you can click LIKE below.

02 Jun 2017
Soil consists of physical, biological and chemical aspects

The science of soil is easy!

Well actually, no. That’s not really true. The principles of a healthy, correctly functioning soil are though.


Once you start to consider, even at a very basic level, some of the relationships and manner in which the different components of soil interact with one another, things start to fall in to shape and build your confidence in what you are doing or the new approaches that you are looking to adopt.

Soil consists of physical, biological and chemical aspects
The aspects of soil are intrinsically linked and when balanced plants will generally grow better

You get the soil you’re given.

That much is true and whilst can be very difficult (and costly) to fundamentally alter the texture and manage the PHYSICAL ASPECT of your soil, a great place to start looking in to is the level of organic matter that your soil contains.  Due to intense growing or mono-crop type situations, this is usually one of the first natural resources to decline. As a result, increased levels of nutrition or supplements have to provided in it’s place, often increasing the rate of declining levels of the soil’s ‘power house’ even more rapidly.
Organic matter can means different things to different people, depending on the industry you are in. In sports turf, it can mean thatch and is undesirable. So let’s differentiate here – we are talking about the the core reserves of carbon and organic compounds that drive the natural processes in the soil.

Turf-grass thatch
Thatch in turfgrass is not the same type of organic matter that we are concerned with in terms of soil function, though when degraded and can assist in a similar way

 

 

 

If you are looking to manage your levels of SOM you should understand the importance of the carbon and nitrogen balance necessary to enable efficient function: too high a level of C:N in your SOM and you are likely to rob naturally acquired nitrogen and even some of that which you are paying well earned cash to add to make your crops grow. An exaggerated example of this would be adding raw sawdust! If the levels of carbon too low in the SOM that you are adding then it is likely that you will struggle to support a meaningful level of microbial life – key part of the natural cycle that will make essential nutrients available to plants.

 

 

 

 

 

pH is of primary concern when considering the CHEMICAL ASPECT and nutritional demands of commercial crops and for this reason is often the most frequent and actively managed limiting factors in soil and growing media. It is vital importance that farmers, growers and managers obtain a comprehensive understanding of the different form and concentrations that the essential elements are present in. This requires a detailed soil test. The historic approach to managing limitations around this characteristic of soil has been a direct response using treatments such as liming, granular fertilisers or foliar feeds as the matter of course for dealing with issues surrounding crop nutrition.

 

pH scale
The acidity or alkalinity of you soil will directly influence the availability of elements (foods) to your plants

Which brings us nicely to soil life and the BIOLOGICAL ASPECT.

Where does this fit in?

Well, everywhere actually.

It is neither more or less important than concerns around the physical and chemical aspects of soil. It is neither the start or the end of the cycle, however it is necessary throughout.

Fungi
Fungi are the least common organism in cultivated soil

Whilst we may be some way off fully understanding the many different roles that the different microorganism play in the skin of our planet, we do know that where soil is working well (in a sustainable manner) it is prolific, diverse and BALANCED.

Bacteria help to convert atmospheric nitrogen in to plant available forms, fungi can help mobilise elements like phosphorus to plant roots despite soil tests showing low available levels of P, nematodes help maintain a balance of smaller organisms whilst releasing quantities of soluble foods in to the soil solution and warding off harmful plant feeder types (such as the Potato Cyst Nematode that has vilified this abundance and helpful creature!). Mycorrhizal fungi enhance the complex network of crop roots to help plants scavenge for other essential and micronutrients or obtain water in times of drought. The list of interactions and benefits goes on.

The rhizosphere is the most important area when growing any plant or crop
Plants are the driver behind many if the natural processes that occur in the soil, communicating with the life in the soil to obtain just what it needs, when it needs it.

 

The (micro)biology that we end up with in a field or pot of soil, is no coincidence though. The plant is very much the driver. Unseen to the naked eye, plants are slowly excreting minute traces of sugars and biochemicals (organic compounds, enzymes) that entice ‘just the right’ microscopic workforce for the job.

A well planned cycle of crops can enhance soil life
The order in which crops or plants are grown has a direct relationship to the type and number of microorganisms that will inhabit a soil

 

 

Needless to say, if you don’t consider the plant types that you are growing or cycling between with a crop rotation, and you are trying to develop or maintain a correctly functioning, balanced soil, the consequences could set you back significantly. For example, Brassicas or mustard are prime examples of crop types known to inhibit soil fungi and their introduction at an inappropriate point in a rotation, could alter the biomass and affect the all important ratio of bacteria and fungi in the rhizosphere.

 

 

 

 

This ratio will vary between different plant types. We wrote an article a while ago which explains this in a bit more details. If you want to find out even more get in touch with SoilBioLab.

Organism ratios are vital when working in the biological domain
A balanced ratio between the different types of organisms in soil or growing media will enhance crop performance

 

So there you have, simple – every action has a consequence and the physical, biological and chemical aspects of soil are all intrinsically linked!

We cannot yet fully explain how and why things behave like they do, however we do understand that under intensive agricultural and horticultural methods that we been applying for the majority of the last century and start of this, the long term prospects are not good. It seems that they are fast becoming even more costly in more ways than one.  Any system that relies on the continuous removal of soil matter and the mineral fraction, at the detriment of the life that holds it all together, will ‘yield’ at some point.

So what to do?

Well, with your new found understanding of the simple principles of soil science, find your limiting factor(s) first and develop strategy to resolve or mitigate these.

Quite often this can meaning operating in one of the opposing aspects of the soil environment, such as increasing or balancing the microorganisms to reduce the impact of pathogens or nutrient deficiencies; or modifying chemical applications or introducing natural compounds to enhance effectiveness and build up nutrient holding capacity is another way (humic acid is great for this) or changing tillage practices to reduce the squeeze on the physical structure of soil.

There are more methods available then ever before and new technologies to help you address your limiting factors. This is supported by a rise of experts capable of supporting a Complete Approach to soil management – our core belief.

There are more than one way to cut a cake: understanding the size and number of slices is the first step, so investment in a comprehensive assessment of your soil will pay dividends in the long run.

When did you last test your soil?

 

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18 Apr 2017

Reduced tillage in agriculture and soil microorganisms

Ploughing
For centuries ploughing has been the mainstay of farming however new thinking suggests it could be more damaging then we previously thought

Over the past few decades, farmers have been abandoning the plough in favour of no-till agriculture or conservation tillage, using equipment that only disturbs the soil to a minimal degree.  No-till and conservation tillage are widely accepted to maintain or improve soil quality by preserving soil structure and moisture, increasing soil organic matter, and providing habitat for the soil microbiological communities.

Tillage is used as a method to enhance crop production, control weeds and prepare the seedbed. As with any management practice, tillage influences the soil environment and can have negative effects including soil erosion and degradation of the soil structure. These effect the habitat for the soil microorganisms and therefore often a loss of nutrients.

Whilst no-till soil is generally cooler and moister when compared to a soil under more intensive cultivation, accessibility to organic matter is generally greater when tillage is applied. This is due to organic residues being broken down, increasing the available surface area for microbial colonisation. Whilst this is of direct benefit, it is generally accepted that there is a greater microbial abundance in soils under a no-till regime and that these soils have a more favourable microclimate compared to conventional farming practices.

Tillage can harm the soil biomass and increase erosion

 

 

Until now, most of the studies linking tillage intensity and microbial activity have been performed at individual farm level. Most of these studies do find more soil microbes with no-till management, however the magnitude of biomass varies a lot due to variations in environmental factors, agronomic practices and differences between soil types across fields and farms. Where no-till is compared with tillage, the type of equipment and tillage depth also differs.

 

 

 

 

A recent study, by Zuber and Villamil at the University of Illinois, collected data from peer reviewed scientific studies on the effect of soil management practices on microbial biomass and activity. The data from 62 studies was collated into a database and the effect of the different management practices on soil properties across multiple experimental sites, locations and climactic regimes assessed.

The results of the study showed that microbial biomass is reduced under tillage compared to no-till possibly due to the more favourable environmental conditions under the no-till regime. There was however one exception to this, with microbial biomass not appearing to be diminished under chisel tillage systems.

Overall, the study suggests that since soil microbial biomass and enzymatic activity can stand in as proxies for soil quality, farmers should consider moving toward no-till or conservation tillage systems – as helping the soil function better helps your crops grow better, and can also maintain high quality soil for sustainability purposes.

The original article, “Meta-analysis approach to assess effect of tillage on microbial biomass and enzyme activities,” is published in Soil Biology & Biochemistry.

 

Putting this in to practise…
Working closely with the team at SoilBioLab, I am only too aware that one of the challenges faced when we asked to advise clients, is the lack of (sample) information.

However, recently we experienced one of those rare occasions where we knew much more about the origin, than usual – early this year we undertook the microbiological analysis of samples from two different farms, at precisely the same time.

One farm had been organic for over 30 years, the other had been no-till for just over 3 years.

Notwithstanding the inherent variables that accompany a more robust comparison than this (full history, location, texture etc.) it was very interesting to observe full soil microbiology reports at the end of the process that looked almost identical – both farms with soil assessments that indicated very good levels of microorganisms.  This ‘one-off’ scenario seems to support the findings by Zuber and Villamil and one can speculate that the effect of reducing/ceasing mechanical interventions to fields are as beneficial to microorganisms (like fungi), as a reduction of chemical treatments.

Organic no-till, the ultimate combination(?)

The reality, is that there is this bit in the middle, where we do not fully understand where the interactions between crop, soil chemistry, soil biology and physical structure start and end or where they might receive the largest benefit from our focussed intervention – we’re jumping from ‘A to F’ with wild statements like this.

Our advice, find out for yourself!

What testing or field work are you conducting, to ensure your future success?

 

 

We have developed trials and are involved in experimental projects with many different farmers and growers, so are well placed to help you to test and measure for yourself, the benefits of managing and exploiting the functions of soil life, in a cost effective manner. If you want to understand more about the ‘bit in the middle’ by adopting a more complete approach to soil and crop management, take action and contact us today.