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The undisputed indicator of a “healthy” soil is the earthworm. There are various methods of sampling (or extraction) in order to estimate a level of communities and analyse the different species present. But what is the best of these methods, both chemical or mechanical in nature? In this article we will discuss the methods you can use on your own farms.

Two extraction methods are commonly used in the field: one is chemical with mustard and the other mechanical, simply using a good spade. Mustard contains an active ingredient, allyl isothiocyanate (abbreviated AITC) which has urticating properties. As soon as they feel the presence of the molecule, earthworms have only one desire: to flee! The protocol, clearly defined by the Agricultural Observatory of Biodiversity (see box insert).

The mechanical extraction consists of sampling at several different locations representative of the land parcel, a block of soil corresponding to the dimensions of the spade used, then “delicately” dissecting said block in order to account for the current earthworm community. It could not be simpler.

How Effective are these methods?

Some time ago, we interviewed a number of zero tillers about these methods. This was not a formal survey, but it has allowed us to confirm the importance of the earthworm and the need to monitor the condition of your soils according to the level of the Earthworm population present. Farmers that have tried these methods in general find them effective but are critical of the mustard method saying is more time-consuming than the spade. A question is also raised, although these two methods appear effective, do they allow us to catalogue all the individuals present? In other words: are the worms, disturbed either by the mustard or by the mechanical disturbance of the spade, not fleeing outside the sampled block?

We asked Guénola Pérès, a recognized expert on earthworms at the Agrocampus Ouest agronomy school in Rennes: “Indeed, the addition of the chemical extractant can cause them to flee; for example to push them down further into the soil, instead of bringing them up. From experience, I can say that by reflex, they flee mostly to the top, where oxygen is most present. Regardless of the method, it will always remain a possible approach and should not be assumed to be an exhaustive count of a community at a given location. We cannot achieve 100% accuracy, but we can get close to it and thus have a picture as representative as possible of a community within the soil parcel.

The sampling technique for the chemical method is important to make it possible to find all the species in a population and to have the best analysis of them. Added to this the need for three or even four repetitions of the process. The sampling surface of the mechanical method is smaller, but does risk losing efficiency compared to the chemical technique. “That’s why we have to repeat the extraction here too. With the spade, one can pick a place poor in earthworms whereas at the side, there were more.

That’s why, I advise, when doing the test with the spade, to repeat at least 5 or 6 times” (G. Pérès) Soil vibration due to penetration of the tool can also cause individuals to flee outside the sampling area. “It all depends, in fact, on the force with which the person puts in his spade and the speed with which it extracts its block,” says Guénola. “It is better to do it as quickly as possible so the strength is rather an advantage. Above all, do not “slice” your block slices because it is necessary to avoid cutting worms as much as possible. On the other hand, you really have to take the whole volume of soil: once the block is removed, if there is soil left in the hole (which often happens), you have to have a clean hole with sharp edges. Also some researchers, when using the spade, will still spread in the hole a solution of mustard, or even formalin which traps recalcitrant anecdotes.

Moist soil, Wet and Active Worm

The method depends on the soil conditions. Sampling should not be done in dry soil but in hot and sunny weather. The soil must be sufficiently warmed up. Otherwise, some of your worms will be inactive, rolled in a ball in cavities and they will not go up, even with an extractant. The chemical method is therefore ineffective when the soil is not humid enough. It is better to sample in the autumn or at the end of winter, when the soil is moist but not waterlogged.

When it’s hot, the time of day is also important. Sampling should not take place in direct sun or hot weather! Even if the mustard effect forces them to the surface, as soon as they feel the sun, the anecdics can plunge again. It is therefore advisable to take the samples at the beginning or end of the day.

Finally, G. Pérès insists: you have to know how to take your time. This too will influence the quality of the result you get. For example, if your sampling area is very full of vegetation, you should take the time to mow, also take the trouble to harvest all the worms present in the entanglements of roots. These too count! At this level, cultivation in the autumn does not make it easy for us … We will end with another question about the mustard method: why is it advisable to use the mustard brand Amora Fine and Strong? Not that the researchers are sponsored by Amora but simply because this mustard is everywhere, and it is better to use the same product to have references and make comparisons. When you use another mustard, you can get different results. Finally, the pots are then practical to store the earthworms punctually during the sampling before releasing them. Just like fishermen we identify them, we count them, we weigh them and possibly we take a picture with before releasing them! Editor’s note – although “Aroma fine and strong” maybe common in France we suggest that in the UK Colman’s mustard maybe a more consistently easy to find product!

Mustard is not the only extractant that will bring out earthworms from their galleries. there is formalin, much more effective, still used in scientific experiments but not recommended, because of its toxicity for users. Mustard, less toxic, is much easier to use; it is not expensive, and we find it everywhere. G. Peres and his students went looking for other extractants. “I had hopes for vinegar,” says the scientist. I still have some but for the moment, it’s not conclusive. In high concentrations, vinegar kills earthworms. Among all the tested products, wasabi has been quite interesting, even more effective than mustard. Wasabi, as well as being a condiment used in Japanese cuisine, it is originally a plant of the Brassicaceae family. The condiment is obtained from the stem Eutrema japonicum which is obtained as a green paste. but wasabi is not found at every street corner and it is an expensive product to extract earthworms when compared to mustard!

Mustard is not used pure. It is diluted at the rate of 300 g per 10 L of water. A good dilution is essential to the success of the method. if your mustard solution is not properly mixed, more concentrated solution pockets are formed and the method is biased. So, mix and mix again before spreading! The specialists even recommend shaking the mustard beforehand in a container with a little water like a cocktail barman might!

By James Warne, Soil First Farming

I recently attended the appropriately entitled ‘Calcium Conference’ which served to remind me of the importance to distinguish between calcium and pH balance within our soils, and also the importance of calcium to the dairy cow. How easily we confuse the use of calcium has with the role of pH management within soils simply because we regularly test soil pH and then apply a calcium containing product to correct the pH.

So let me deal with this confusion. pH measures the concentration of hydrogen ions in the soil solution (when the pH is below 7) and adsorbed on the clay colloids (no mention of calcium there!) As the concentration of hydrogen ions in the soil solution rises exponentially the pH falls. For example as the pH drops from pH 6 – pH 5 the concentration of Hydrogen ions increases tenfold and if it drops from pH 6 –pH 4 the concentration of hydrogen ions increases by 100. To neutralise the hydrogen ions we most usually apply lime, or calcium carbonate in its various forms. The neutralising bit here is the carbonate, NOT the calcium. The carbonate disassociates from the calcium in the soil and reacts with the hydrogen to leave carbon dioxide and water while the calcium ion replaces the hydrogen in the soil solution and on the clay colloids. To get scientific for a moment the reaction is

CaCO3 + H2 -> Ca2+ + CO2 + H20

Calcium carbonate in the soil reacts with the hydrogen ions (the acidity) to give calcium ions, carbon dioxide and water. So if the calcium does not neutralise the acidity why should I be worried about my soil calcium levels? Calcium is the sixth most abundant element in plants, and animals for that matter.

It is also the third most abundant metal in the earth’s crust. Historically it has always been assumed that there is generally enough calcium in the soil to supply the crop requirements if the soil is limed to the correct pH. However we also loose calcium from the soil in large amounts every year by a variety of processes. Crop removal via mechanical or animal means removes varying amounts of calcium but these losses is quite small compared to losses caused by inorganic fertilisers and natural leaching.

Work done at Rothamsted has shown that considerable amounts of calcium are lost by leaching, and the amounts lost by leaching double with every unit increase in pH, see the table below.

Similarly calcium can be lost by the use of fertilisers, but why is this? Most inorganic fertilisers are based around sulphates, nitrates or chlorides which are negatively charged anions when disassociated in the soil. They tend to combine with dominant cation calcium in the soil and leach readily in the soil solution. Again work done at Rothamsted suggests that every kg of N as urea and ammonium nitrate needs to be balanced with 2-3 kgs of CaCO3.

Further work needs to be done to establish an ideal model for calcium losses but it is probably somewhere in the region of 50 – 100kg per hectare per year depending upon soil type, drainage etc. You cannot rely on the soil pH to be an indicator of satisfactory soil calcium, the two do not correlate well enough for these days of precision agriculture. I have lost count of the number of times I have heard the following phrase. “I haven’t limed for several years, each time we check the soil pH the results show we don’t need to lime”. But when a cation exchange analysis is undertaken the soil can be very low in calcium. Other factors are keeping the pH at a satisfactory level, which are detrimental to yield and soil health.

So why is calcium so important within the soil?

Firstly as mentioned above calcium is the dominant cation within the soil and as such plays an important role in soil aggregation due to the way its ionic charge, size and hydration acts upon the clay colloids. Soil aggregation or flocculation is the process by which soil colloids and organic matter clump together to form aggregates. It is these aggregates, or crumb structure, which we call tilth. It is this aggregation of the soil that creates pore space within the soil and consequently it is the pore space which allows water and air to move through the soil. As we all seem to be preoccupied with ‘soil health’ at present I always feel that calcium is a good starting point as it drives so many of the other factors which contribute to soil health.

Calcium is essential too for the soil biology (another function of soil health) The beneficial soil biology are generally aerobic (i.e. they need oxygen to function). It is the porosity created as described above by the calcium that allows the movement of oxygen to allow the biology to flourish. Equally the biology also requires large amounts of calcium to support their bodily functions.

Calcium within the plant..

All plants require calcium, it is an essential nutrient along with nitrogen, phosphate, copper etc etc. In fact it is the sixth most important element by concentration within plant tissues. Calcium uptake maybe affected by the presence of other cations in the soil such as potassium, magnesium, ammonium etc. Similarly though excess calcium may reduce the uptake of these cations too, so it’s not simply a case of over applying in the hope that it may do some good. Excess soil calcium can cause as much trouble as deficiency.

Calcium is mainly taken up with the soil water and moves within the xylem stream. Consequently when the transpiration rate is reduced calcium intake may suffer. Parts of the plant with a low transpiration rate may also be low in calcium such as the fruits. Once used within the plant calcium is reasonably immobile, consequently crops require a continuous availability of calcium. Calcium is an important element within the cell wall structure where it forms calcium pectate which give stability and bind cell walls together.

Calcium pectate give the cells walls their structure and strength and gives the plant its standing strength and a higher resistance to fungal infections and aphid borne virus. Many fungi and bacteria secrete enzymes which impair cell wall integrity, calcium can help to reduce this effect. Calcium also plays an important part in fruit quality and starch formation amongst other functions. Being immobile deficiency symptoms show in the younger leaves and plant issues first. Typical symptoms are stunting of plants and lack of leaf expansion.

Useful forms of calcium

In agriculture terms we really only use three forms of calcium containing product, lime, chalk or gypsum. Lime can be further divided into calcitic or dolomitic lime. Calcitic lime contains calcium carbonate, as will chalk, while dolomitic contains calcium and magnesium carbonate. Gypsum contains calcium sulphate. All of these products are crushed and ground from rock and consequently the quality can be very variable depending upon the source. To enable these products to work effectively they need to be very finely ground to dust.

Otherwise the release of calcium cannot be predicted. Dust is particularly difficult to spread accurately unless it is formed into a prill. Calcium carbonate also has a low solubility compared with gypsum, therefore the calcium will be much more readily available from the gypsum compared to the lime. Another overlooked source is CAN, once a widely used fertiliser, but now consigned to horticultural crops it is a useful source of calcium plus the ammonium nutrition which is altogether better for crop health than nitrate.

Finally…

In conclusion, if you are trying to build a healthy soil and grow a healthy crop, calcium should be your first consideration, and just because your pH is correct don’t assume you have the correct level of calcium for your soil. And finally, I don’t sell calcium products but most soil tests I receive do suggest that our soils are in need of calcium.

References
Principles of Plant Nutrition 2001. Mengel
& Kirkby
Crop Nutrition & Fertiliser Use 1996.
Archer

By Olivia Oldham, Farmerama

Do you learn the most talking to other farmers? Don’t always find the time to get out there and hear what’s going on? Well that’s what we are here for.

I am part of Farmerama Radio, an award-winning podcast released once a month sharing the voices of farmers in the UK and around the world. Farmerama is committed to positive ecological futures for the earth and its people, and we believe that the farmers of the world will determine this. Each month we feature recordings of farmers in the UK and further afield, focused on practical tips, innovative ideas and the nitty-gritty of farming today.

We are sharing knowledge of what really works in the field and for farming businesses, from farmer to farmer. Every episode includes three to four different short stories that we weave together. Here we will give you a taster of four stories from four different episodes to whet your appetite. We definitely encourage you to give the episodes a listen because there is lots more to learn than what we cover here, plus it’s always better to hear it from the farmer’s mouth!

You can find the show online at www. soundcloud.com/farmerama-radio/ or farmerama.co, or if you already listen to podcasts then it’s accessible on any podcasting service, just search for Farmerama. Here we go…

Episode 36: Cowpat Lover Greg Judy at Groundswell Conference

In episode 36, we spoke with Greg Judy, a mob grazer based in Missouri, about how mob grazing provides a triplewin by improving soil health, grassland biodiversity, and farm profitability, all with the goal of increasing the longterm viability of a farm. And all this can be achieved even with limited resources. Mob grazing involves putting larger numbers of animals onto smaller areas of land, and moving them around daily, as opposed to giving them access to the whole field continuously.

The mob grazing approach affects the biology, chemistry and physics of the soil. Biologically, it allows different grasses, the seeds of which are already in the soil, to germinate and come up. Mob grazing is also far more effective than continuous grazing at spreading manure across a piece of land. For example, Greg told us that on a farm of 100 acres, it would take 27 years under a continuous grazing management strategy to cover the whole farm with cowpats. With mob grazing, though, the same coverage could be achieved in only one and a half years. This manure coverage improves the chemical and physical composition of the soil by providing extremely good fertilization and creating a better environment for worms.

None of this matters, though, if the farm enterprise isn’t sustainable. Using the cattle’s (or other livestock’s) own natural waste reduces the need for fertiliser inputs, while using livestock to increase the variety of grasses in the pasture reduces the need to buy grass seed, for example. By moving the animals every day and keeping them away from their manure and urine, they are also kept away from the flies which are attracted to fresh waste. This is a simple and free way of keeping animals healthy and reducing the incidence of problems like worms. So, Greg says, “one of the best investments to make to improve farm profitability is in water infrastructure and fencing to be able to implement mob grazing”. 

Speaking of sustainability, Greg emphasised that more than being sustainable, we should be aiming to be regenerative. If we come onto land that has been degraded by unsustainable practices in the past, we don’t want to ‘sustain’ it at its existing levels – we want to regenerate it and make it better for future generations. Mob grazing is one way to do this, using animals to restore soil health. An extended interview with Greg can also be found in this month’s short.

Episode 35: California Paying Farmers to Sequester Carbon with Charles Schembre

In episode 35, we learned about California’s Healthy Soils Program, a scheme which compensates farmers for increasing their soil health – with the goal of sequestering carbon and increasing water retention. For example, one farm is being paid USD50,000 to sequester 345.6 tonnes of greenhouse gases per year. They plan to do this by transitioning to a minimum-tillage approach, planting multi-species legume cover crops, and spreading compost across 70 acres. The quantities sequestered under the scheme are estimated using CARB GHG [carb G-H-G] Quantification Methodology and tools.

This Healthy Soils Initiative is particularly relevant in the UK at the moment as the government considers how farming subsidies will operate after Brexit. We hear an on the ground account of the Healthy Soils Initiative from Charles Schembre, a long-time grower, farm manager and soil conservationist and now a Vineyard Conservation Coordinator at Napa County Resource Conservation District. Charles told us that the Healthy Soils Program is the first time in the United States that it has been recognised at a state-level that soil regeneration is an effective weapon in the climate-change-mitigation arsenal.

Charles pointed out that it can be tempting to look at soil regeneration through a narrow ‘carbonsequestration, climate-change’ lens, but it is important to take a broader view. Regenerative soil management can improve the entire ecological function of the land, including water retention, the reduction of erosion, yield enhancement, and habitat creation. Taking a more holistic view also involves stepping back from the traditional farming lens many of us have had since at least the end of the second world war and begin to question why we do the things we do, why we think things should look a certain way or with a certain technique or approach.

For example, Charles said that as a Californian farmer, he might see a field with long grass and, having been conditioned to think in a certain way, add mowing the field to his list of jobs. But if he stops to think critically and holistically about that task, he might remember that, biologically, chlorophyll is necessary to pull carbon out of the atmosphere and into the soil. In a dry place like California, mowing pretty much kills the plants and eliminates much of that sequestering potential. Additionally, when grass gets quite tall, it captures dew much better and allows the top-soil to stay more moist (anecdotally at least). “If you want to capture carbon,” said Charles, “you’ve got to think like carbon.”

You can hear more about the carbon farm plans Charles has worked on (together with the Carbon Cycle Institute) for 4 vineyards in Napa county, and details of how they monitor soil health and carbon sequestration, in this month’s short.

Episode 28: Using Fungal Innoculants to Foster Perennial Grasses with Joel Williams

Finally, in episode 28, we spoke with Joel Williams of Integrated Soils about using nothing more than the microbial balance of the soil to manage weeds. Although his example related to golf courses rather than pasture, the same principles apply! On golf courses, groundskeepers cultivate certain species of perennial grasses which are best for creating a smooth, fine playing surface. Other types of grasses, like an annual called meadow grass, are difficult to manage, because herbicides cannot be used to manage them. Both are grasses, and so a herbicide would affect not only the unwanted ‘weed’ grass, but also the desirable perennial.

Joel explained that you can apply fungal ‘innoculants’ to do the job instead. Essentially, this means applying beneficial fungi, and food to feed the fungi, to the soil. The soil becomes more fungal-dominated, which is an environment more favourable to the perennials the groundskeepers want, and less favourable to the annual they want to get rid of. The perennials grow with more vigour, while the annual becomes stressed, and within a season or two, the perennial is able to outcompete the annual.

Joel emphasised that it is important to remember that soils are very complex ecosystems, despite our tendency for simplification. Although simplicity is important to make things easier to understand, taking too narrow a view can be detrimental. When trying to improve soil health and anything that flows from that, such as crop yield, we have to take a step back and not box ourselves into one or two parameters in our attempt to make assessments on the health of the system. Soil chemistry is relevant, of course, but so too is soil physics and its structural properties, such as aeration, and soil biology. It is crucial, also, to remember that living plants are another part of the soil picture – they contribute to soil health, for instance, by drawing down carbon from the atmosphere. According to Joel, “soil and plants are one.” If you have a story you want to feature on the show or know someone who we should feature, then please get in touch via our website farmerama. co. You can also find us on facebook, twitter @farmerama__ and instagram @ farmerama_radio. We look forward to hearing from you!

By Dr Niki Rust, Research Associate, Centre for Rural Economy, Newcastle University – December 2018 issue

We all know that some parts of the UK are getting more and more water- and nutrient-stressed over time. With less predictable rainfall, extended periods of droughts or heavy rainfall, and declining nutrients in some soils, it is becoming increasingly difficult for farmers to grow crops in a similar manner to what they had done in the past. To keep up with this changing world, we are finding that we ourselves are having to change.

Historically, when crops have not had enough nutrients, we’ve turned to inputs like fertilisers. However, with increasing costs coupled with more restrictions on their use – and more regulations likely in the future – we’re having to innovate to find ways to improve nutrient-use efficiency of our crops. In terms of water, irrigation is one way to get around lack of water in the soils, but it is harder to deal with too much precipitation from rainfall. Some scientists have predicted that UK weather will become more unstable in the future, with more frequent outbursts of heavy rain followed by extended droughts. How we deal with these challenges whilst keeping farming profitable and productive still remains somewhat of a mystery.

Like farmers, the European Union is concerned about how to continue producing enough food for our population in these uncertain times. It has therefore provided funding for research into methods to improve water-use efficiency (WUE) and nutrient-use efficiency (NUE) for a number of staple European crops. SolACE is such a project, which stands for Solutions for improving Agroecosystem and Crop Efficiency for water and nutrient use. This cross-disciplinary and collaborative research involves natural and social scientists, crop breeders, farming organisations and other agricultural stakeholders from across Europe to develop and test methods that improve crop production in areas of water- and nutrient-stress.

The techniques we are testing include microbial inoculants, cover crops, genotype mixtures, hybrids, fertiliser additives, participatory breeding, decision support tools to improve WUE and NUE, and conservation agriculture based on minimum/no till. We are running controlled experiments at field stations in five countries alongside on-farm trials in seven countries to test how these techniques affect WUE and NUE in durum wheat, bread wheat and potatoes.

As part of the project, we want to learn from crop producers about what they think encourages or discourages uptake of practices that can improve their crop’s WUE and NUE, as well as what methods you currently use to deal with these issues. We are especially interested in hearing what you think will incentivise uptake, such as changes in policies, taxes, subsidies, regulations or education campaigns and knowledge transfer exchanges. We are running a short, 10-minute online survey to collect your views on this. The survey can be accessed here: https://goo.gl/ forms/NX5TkN7F1O5Csv1e2 or by using the QR code below. Please do feel free to share this survey widely with your farming contacts. 

If you’d like more information on the project, you can access our website here: http://solace-eu.net and you can get more involved by joining our Stakeholder’s Forum https://www.solace-eu.net/getinvolved.html If you have any comments or questions on the survey, please feel free to contact me at niki.rust@ncl. ac.uk and I would be more than happy to hear from you.

By Sarah Ferrie, Marketing Manager at Interagro (UK) Ltd

Could amino acids be one of the most overlooked assets in plant nutrition? In this feature we take a look at how supplementing the crop with amino acid biostimulants in-season not only boosts plant health and development, but can also help crops reach their genetic yield potential.

On a cold wet day in summer 2017 we got our first insight into the real power of amino acid biostimulants. A crop of sugar beet on its last legs from a herbicide contaminated spray tank, had totally recovered following a single application of Bridgeway. As the agronomist put it, “it was nothing short of a miracle.” The herbicide damage was so severe that some of the beet didn’t pull through, but in others, Bridgeway had stimulated a new crown to grow. That crop went on to produce larger beet that weighed in 16% heavier than the undamaged beet in the rest of the field, with the same sugar levels.

Eighteen months on, trial upon trial later, working closely with growers and agronomists to really put Bridgeway through its paces, and we are certain that feeding a crop amino acids inseason, not only improves plant health but can produce fitter plants more capable of reaching their yield potential. Deepening our understanding of plant pathology and biochemistry underpins this belief. 

What are amino acid biostimulants and why do they matter?

Biostimulants are incremental technologies to improve yield by improving plant health. They are substances with the exception of nutrients and pesticides, that have the capacity to modify the physiological processes of plants in a way that provides potential benefits to growth, development and relief from stress.

Amino acids are the building blocks of all living cells which combine together in infinite variations to produce countless different proteins critical for healthy growth and development. These proteins play a vital role in virtually every process within the plant – structural components of plant tissue; metabolic enzymes and stimulation; nutrient transport, the list goes on.

Under ideal conditions plants synthesise all 18 L-amino acids they require, which they manufacture from the raw materials carbon and oxygen in the air, hydrogen from water and nitrogen from the soil. Plants therefore depend hugely on soil nutrients. As nitrate / ammonium is one of the main elements of proteins, ag systems use nitrogen / ammonium fertilisers to replenish nutrients in the soil and aid plants in generating the needed proteins. However, these crucial raw materials can become limiting, particularly as nitrogen (and water) can either leach away in the soil or become inaccessible to the crop, as we found in many parts of the UK in 2018.

Protein deficiency in plants has huge consequences on plant health which in turn impacts quality and yield. Incapable of creating reserves, as proteins have a finite lifespan, a continuous supply of amino acids must be translated in order for plant growth and development to continue. When the raw materials to produce amino acids become limited or the crop encounters abiotic stress (such as high/ low temperatures, drought, flooding, disease/pest attacks, phytotoxicity from crop protection products) amino acid production slows and plants start to break down the proteins they have made to gain the amino acids needed to speed up recovery and repair. This occurs because the selfproduction of amino acids is extremely energy expensive and it is much more efficient to self-cannibalise than it is to synthesise amino acids from scratch.

Feeding the crop additional L-amino acids via the roots or leaf tissue inseason before, during or after a stress event ensures the plant has the necessary building blocks to prevent self-destruction and aid repair.

So, what do these amino acids do?

1. Stress defence – During periods of abiotic stress plants increase production of L-Proline to help reduce the effect and speed up recovery time. It primarily strengthens the cell wall and resistance to weather extremes.

2. Photosynthesis – the most important chemical process of plants – carbon dioxide, water and light energy are synthesized into sugars, which the plant uses as an energy source to power all metabolic processes. This process is highly dependent on the amino acids L-Glycine and L-Glutamic Acid. Both amino acids are key components for chlorophyll production which absorb the light energy for photosynthesis. Increasing these amino acids increases light absorption which increases photosynthesis.

3. Enhance nutrient uptake – by increasing the availability of nutrients to plants. Some nutrients are not available to plants due to their molecular structure, ionic charge etc. The amino acids L-Glycine and L-Glutamic acid are able to bond with these nutrients making them available to the plant. These amino acids are tiny molecules allowing them to easily move through cell membranes. Their ability to bind excess metals means they are also able to reduce metal toxicity in plants.

4. Precursors to hormones and growth factors – L-Tryptophan is involved in rooting, its required in auxin synthesis for growth and development; L-Methionine is a precursor to ethylene which stimulates ripening; L-Arginine is a precursor to cytokinin production involved in cell growth, auxiliary bud growth and leaf senescence.

5. Pollination and fruit formation – one of the most important phases of development and extremely energy intensive due to the very high levels of amino acids required. L-Histidine helps with ripening; L-Proline increases pollen fertility; L-Lysine, L-Methionine and L-Glutamic Acid increase germination; L-Alanine, L-Valine, and L-Leucine improve fruit / grain quality.

Only as a stress buster?

If crops can synthesise their own amino acids it could be argued that feeding the crop additional amino acids only makes sense to help the crop through a stress scenario.

However, crops also respond with a supplement at the critical stages of plant development, e.g. vegetative growth, start of reproduction, flowering etc. as the production of amino acids required for these critical stages are extremely energy intensive. Diverting that energy to other processes such as photosynthesis, nutrient uptake, grain fill, etc. will improve the metabolic efficiency of the plant and help the crop towards its genetic yield and quality potential.

So why Bridgeway?

For growers looking to maximise the crop’s income potential, there is no better source of amino acids. Bridgeway is a plant derived biostimulant produced to food grade quality, containing all 18 L-amino acids required by plants with a ready-to-use source of organic nitrogen.  

Feeding a crop Bridgeway guarantees the supply of amino acids for building proteins and provides the most critical amino acids in higher concentration than those biostimulants based on animal sourced protein. For example – 39% higher levels of Glutamic Acid, 33% higher levels of Lysine. Only amino acids sourced from plants can be fully assimilated by crops due to the difference in chemical structure between plant sourced (L-isomer) and animal sourced (D-isomer).

The differences don’t end there. Bridgeway is certified GM free and because it is 100% plant sourced it has full backing from the Soil Association and Organic Farmers and Growers Association for use on organic crops throughout the entire life of the crop. Amino acids sourced from animals could be contaminated with heavy metals, salmonella, E.coli and pose a threat to food chain safety. It is for this reason that animal sourced biostimulants on milling wheat were banned in 2017 by NABIM and are restricted in use by a number of organisations. Bridgeway offers not only peace of mind the crop will be able to utilise all the amino acids, it also gives growers freedom to use at any growth stage, in any crop for all end markets.

Delivering results on farm

With an extensive trial and grower programme in a range of crops, it’s clear that in the right situation Bridgeway has the potential to add in the region of 3 t/ha to a decent winter wheat crop. In 2018, two different wheat crops (Relay and Skyfall) each delivered a +2.3 t/ha uplift in yield from applications at T1, T2 and T3. Both crops were exposed to heat and drought stress after the first application of Bridgeway was applied.

Nutrient analysis carried out by the agronomist on the Skyfall throughout the growing period showed the uptake of most macro and micro nutrients was consistently higher in the Bridgeway treated areas. Sugar levels measured using a digital BRIX refractometer were 23-39% higher in their leaves at every assessment throughout May and June, indicating a healthy plant that is photosynthesising well and producing the carbohydrates in the leaves and stems which ultimately will be crucial components of yield. Despite the difficult season, the treated crop went on to produce a protein sample of 12.8% versus 11.7% in the untreated.

With a range of yield increases in different crops we are working hard to understand when, where and how best to use Bridgeway to deliver the best value to growers. Look out for the next article in Direct Driller where we’ll be sharing the results of our stress and rooting work ongoing at the University of Nottingham and offer in-season advice as spring applications get well underway.

Key takeaways:

• Amino acids are the building blocks of proteins and critical to plant health

• Proteins cannot be stored so a continuous supply of amino acids must be translated for growth and development to continue

• Plants synthesise all 18 L-amino acids in good conditions but stop under abiotic stress or if nitrogen, water or air are limiting

• Feeding the crop amino acids inseason avoids self-cannibalisation & threat to yield

• Bridgeway provides all 18 L-amino acids required by plants

• Bridgeway is approved for unrestricted use in all organic crops

• For best results apply ahead of crop stress and maintain applications at the key stages of crop development

For further information please contact stuart.sutherland@interagro.co.uk