What Stage is Your Oilseed at?
There were different drilling strategies this year for how to best establish oilseed rape – some July drilled and some only drilled within the last week or so. This means there’s a lot of variety in growth stages across the country.
Once oilseed is at the 4-6 leaf stage there is enough leaf area present to apply some key micronutrients. We want to ensure growth isn’t hindered at all going into the winter and micronutrients play their part in that. Oilseed can put a lot of biomass on over a short space of time if autumn conditions are right, which means there is potential for the crop to deplete micronutrient levels in the soil.
For a simple way to apply all the key micronutrients required on OSR this autumn, apply a multi-nutrient, crop-specific product such as YaraVita Brassitrel Pro. This mix contains Mg, Mn, Ca, B and Mo – vital micronutrients for this crop, particularly following autumn establishment.
Yara conducts independently run trials each year and over a 6 -year period the data has shown an average yield response of 0.3t/ha from an application of Brassitrel Pro, both in the autumn and followed up in the spring. This means it is well worth the applications as the return is several times the cost of the investment in the product.
An added benefit from making sure the crop has all the nutrients it requires in the autumn is that, anecdotally, a healthier plant is better able to cope with pest and disease pressure. Think of it as a healthy animal not being as susceptible to illnesses compared to one that doesn’t have a sufficient diet, it is similar for plants. So give your oilseed the best chance going into winter for a healthier crop come spring.
Applying nitrogen and sulphur together just makes sense
Combining nitrogen and sulphur together increases nitrogen use efficiency so means more for your money with less wastage
Using Tech to Time Haulm Destruction
Potato haulm destruction is an important process. It stops the growth of tubers and promotes the hardening or "setting" of the potato skins as they fully mature. A well-set skin is crucial for preventing damage during harvesting/handling and for extending the storage life of the potatoes.
Other important aspects of haulm destruction are to control the spread of disease (late blight in particular) from leaves to tubers and to generally make harvesting easier by reducing the potential for clogging machinery.
Properly timed haulm destruction ensures that the tubers reach their full potential in size and weight without the risk of overgrowth or disease - helping maximise marketable yield. However, if done too early, haulm destruction can have the opposite effect by reducing the potential yield, as the tubers might not have reached their full size.
Quality is also affected by the destruction process with the already mentioned improvements in skin finish, but also improvements in dry matter content and reduction of the risk of certain defects such as hollow heart or internal browning.
With loss of some chemical options a blend of both mechanical and chemical destruction is often required. However, there is increasing concern over chemical residues and environmental impacts, therefore if we can be smarter about how we use them we can help to reduce this.
The Yara N-Sensor can be used to variably apply desiccant to the crop, this will put more on areas that are greener and require a bit more chemical help and less on areas that are already senescing naturally.
If you are flailing then spraying, or you don't have access to an N-Sensor, you can utilise Yara’s Atfarm. Atfarm enables you to see an NDVI+ map to help judge which areas will require more or less chemical, determined by the biomass and colour of the crop. This will enable you, to make a more informed decision than a blanket application across the whole field.
Variable desiccation leads to even destruction of the crop, better use-efficiency of the desiccant and overall evenness of harvest. Overall enabling you to make a more informed decision than a blanket application across the whole field.
Advice For Straw and Grain Nutrient Removal
If you remove straw then you also remove the nutrients that are contained in it, which is fine, but you need to take into account that they won’t be available to the following crop.
Removing both grain and straw with cereal crops removes 8.0-8.5kg/t of P2O5 and 10.5-12kg/t of K2O, therefore is it important to take this into account when calculating next season’s fertiliser plan.
Post-harvest soil sampling will, of course, give a good indication of the P&K levels. If the indices are below 1 then an autumn application of P&K is justified. However, if the indices are 1 or above then autumn P&K applications are not always necessary. At those kind of levels, there will be sufficient P&K in the soil to establish cereal crops and an application of foliar phosphate, such as YaraVita Crop Boost, could be applied with a herbicide spray if required.
The real demand for phosphate comes in the spring from March to May, when a typical crop of winter wheat will require 1-2kg per day for optimum growth. Any phosphate applied in the autumn is unlikely to still be present in the soil in a plant-available form and therefore won’t be able to supply this daily demand.
Therefore, when purchasing P and K products make sure you think about the timing of application to meet the demand from the plant, otherwise you will be feeding the soil and most of the phosphate applied will have been rendered unavailable for the following spring.
For more information on different options for P & K and other nutrient solutions please visit Agronomy Advice.
Get the Most Out of that Little Bag of Soil
Whilst harvest is underway it’s easy to forget about planning soil sampling. Post-harvest is a good time to take soil samples, before you get into drilling the next crop. UK soils have to be tested under the Farming Rules for Water, but don’t let legislation be the only reason to test your soils.
Basic soil analysis will give you P, K, Mg and pH; which is a good start but there are a lot of other important nutrients that can cause issues if deficient. A topic that’s increasingly important is that of soil health, but where do you begin?
Firstly, you need to get the basics right of course, this includes ensuring the correct pH, identifying your P and K indices and organic matter levels. On top of that, knowing the levels of micronutrients will also be useful to plan fertiliser strategies and budgets for the coming year.
By taking a broad spectrum soil sample you’ll get all this data which will help make informed decisions on-farm, but there is still an element that is missing and that’s the microorganisms that live in the soil; which are vital for a number of processes in the soil including enabling nutrient availability and breaking down material into organic matter to name a couple.
There are a few tests that can be carried out in the lab to begin to monitor your soil’s ‘health’. The Solvita Test is a test of how much respiration, and therefore ‘life’, there is in your soil. A low score shows that the soil is lacking something these microorganisms require e.g. oxygen due to lack of soil pores caused by compaction. Whereas a high score shows a good level of organisms present which improve the soil, making it more fertile. Another test is the Labile Amino Nitrogen test (SLAN) which measures the biologically associated nitrogen that is present as amino carbohydrates.
Having these results allows you to judge whether your soils are functioning in a way that enables soil biota to thrive, in turn benefiting the crops you grow. Soil health scores can then monitor over time, showing whether they are generally improving or if specific practices are having a positive/negative effect on your soil.
Grain Analysis, Isn’t it just Hindsight?
Grain sampling has been around for a long time, but it’s not been used as part of a sampling routine on a lot of farms. Whilst grain analysis is a ‘look back’ on the season that’s complete that doesn’t mean hindsight can’t be a useful tool.
Knowing which nutrients were low, or even deficient, can help us alter the nutrient strategy for next season – improving overall nutrient efficiency. Having this data can also confirm what we were doing was right too, helping show you’re already working at optimum nutrient levels – this is also useful to know!
Sulphur is a good example of how to utilise the results you get from the analysis of the grain. An N:S ratio of below 17:1 is the target for wheat; if the ratio exceeds this it is an indication that there wasn’t enough sulphur available to the crop when it required it.
It’s not just the major nutrients that are useful, micronutrients are also measured in grain analysis and are, again, a good way to see whether they were at sufficient levels throughout the season. When we team grain analysis with soil analysis too, we can start to build a picture of the nutrient status of the farm and look at ways to mitigate risks or increase efficiencies where we can.
Keeping Your Potato Canopy Green for Top Yields
There is a general consensus amongst plant physiologists that the potato crop yield is limited by the source of photosynthate as opposed to the size of the ‘sink’ i.e. the number of developing tubers following ‘tuber initiation’. It helps us consider what is important in ensuring we maximise the plant’s ability to fill the ‘tuber sink’ thus producing as many marketable potatoes as possible and improving profitability.
In practical terms we should ensure that plants produce a full canopy of leaves as quickly as possible (rapid early emergence), this full canopy is healthy, maintaining its ‘greenness’, for the duration of the tuber bulking phase and the plant is able to translocate the sugars (sucrose) produced in the leaf down to the developing tubers as they ‘bulk’.
Nutrient deficiencies can be monitored through plant leaf analysis. Data from Yara Analytical laboratories reveals some of the key nutrient deficiencies found in potatoes to be phosphate, potassium and magnesium. Phosphate is of particular importance due to its role in the transport of the sugars from the leaf down to the ‘bulking’ tubers. The transport mechanism is an energy demanding process and the chemical energy is stored by the plant in the phosphate based molecule ‘ATP’. Magnesium, the central component of chlorophyll (leaf greenness), clearly has an important role in keeping the leaf canopy greener for longer. Potassium helps the plant regulate water and nutrient movement from roots, through the plant, to the leaves. Water movement itself is also a necessity in the transport of sucrose down to the ‘bulking’ tubers.
Therefore Yara’s recommendation is one application of YaraVita Magphos K at 10l/ha at tuber initiation to increase tuber number. Or two applications of YaraVita Magphos K at 5 l/ha at tuber bulking (with 14 days between applications) to increase tuber size.
Don’t Buy Straight Nitrogen
With the new season nitrogen market kicked off there is the usual hurry to buy a percentage of fertiliser, but don’t rush into those decisions and end up with too much straight N.
It is well known that soil is deficient in sulphur (S), with over 90% of soils under guideline levels for most crops. This means your nutrition strategy should include sulphur additions, but what source of S should you be considering? Manures are a source of S but the amount in them is quite often lower than RB209 book values when analysed. Nutrient distribution can also be quite varied therefore over all you can’t rely solely on them to provide sufficient sulphur.
Therefore, you are likely to require some mineral fertiliser but again there are factors to consider – is the S in a plant-available form? Is the product going to spread evenly? Does the product increase the number of passes required?
Sulphur should be applied at the same time as your nitrogen applications to get the best efficiency out of both nutrients. Independent trial work shows that applying nitrate and sulphate together at each application increases yields.
Applying a quality compound product where both nutrients are in the same granule ensures an even spread pattern, where each landing site contains the correct analysis. Also, with the nutrients in the same granule it means there is no need for extra passes, saving time and money.
YaraBela Axan (27% N 9%SO3) and YaraBela Sulphan (24% N 15%SO3) are ideal products for use on a wide range of crops, consider these when fulfilling next years’ nitrogen and sulphur requirements so you don’t end up with a shed full of straight N.
How Much Nitrogen is in your Crop?
Atfarm uses satellite imagery to create various maps which have different functionalities. There are the standard NDVI maps that show the variation in biomass in the field, however the range of NDVI alone is limited so there is a lower range of variation (0-9 scale). I’d recommend using the ‘optimised map’, which uses NDVI and teams it with the algorithm from the N-Sensor, to give a range of more than 25 colours - meaning a higher level of variation shown and therefore more accuracy. Another map option is the nitrogen uptake map, which gives you an approximation of the nitrogen uptake by your crop, based on the biomass and colour variation.
If you want to create a variable nitrogen rate application (VRA) map from these it is simple to do so in Atfarm. The system uses the optimised map to create the variability map and assigns different nitrogen rates to the different levels of variation. As the user, you will input your chosen fertiliser product and target rate as well as a minimum and maximum, so the system is very flexible.
Another aspect of Atfarm that will be particularly useful for taking the guesswork out of what rates of nitrogen to use on cereals is the Yara N-Tester BT. The N-Tester BT is a non-destructive handheld device that enables you to analyse how much nitrogen is in your cereal crop and then get a variety-specific recommendation. You can also link the N-Tester BT reading when choosing your target rate for the VRA map for the same field.
So overall, Atfarm enables you to put on what the crop requires and where, rather than blan-ket applications of nitrogen across whole fields. This gives a much better level of nitrogen use efficiency and in turn, better return on your investment.
Well-timed Nitrogen to Hit Protein Spec
In a season with excessive rainfall, ensuring optimal nitrogen levels becomes paramount for meeting premium milling wheat standards. The challenge lies in replenishing depleted soil nitrogen levels with a well-timed application.
When I look back at Yara trial data from 2020, following a wet autumn and winter, it highlights higher nitrogen rates are needed to reach those protein targets. This emphasises the importance of timing, rate and source of nitrogen application.
In order to hit the protein target millers are looking for it requires a separate application of nitrogen after the flag leaf final-dressing. This application needs to be separate to ensure the nitrogen goes towards building up the protein level within the developing grain, rather than utilising it for just yield. As well as timing, nitrogen source and rate are also important when trying to boost the protein, to ensure the nitrogen is utilised correctly in the plant.
Applying about 40-60kgN/ha (e.g. 120kg/ha of YaraBela EXTRAN) at growth stage 51 (which is the start of ear emergence) has been shown to increase grain protein levels by up to 1%. This is possible to achieve without then compromising on yield. Yara trials showed that the separate application later the in the season gave a boost in both yield and protein when applied at end of booting/start of ear emergence. For those on liquid systems, an application of foliar urea (such as Nufol 20) applied later, at milky-ripe stage, is the ideal timing for the same 40-60kgN/ha.
However, if the plant is deficient in certain micronutrients you’re less likely to have a positive impact on protein levels. Manganese and zinc, in particular, are important in the metabolism of nitrogen. If nitrogen metabolism is improved then this increases the amount of nitrogen that is incorporated into the developing protein in the grain. Trials work, again, has shown that an application of zinc at T2 timing can increase grain protein by up to 1.4%! Therefore it is important to ensure there’s no zinc deficiency if aiming for the milling premium - an application of YaraVita Mancozin or YaraVita Zintrac will help prevent this.
Due to excessive rainfall this season, soil N levels were potentially depleted when compared to a more typical year. With the premiums available on milling wheat this year you might be aiming for protein spec, if so the rate and timing of nitrogen is key.
If I look back at Yara trial data from 2020 (following a wet autumn/winter), only the crops with higher N rates reached target proteins, due to the depletion of soil N. In order to hit the protein target millers are looking for it requires a separate application of nitrogen after the flag leaf final-dressing.
The application needs to be separate to ensure the nitrogen goes towards building up the protein level within the developing grain, rather than utilising it for just yield. As well as timing, nitrogen source and rate are also important when trying to boost the protein, to ensure the nitrogen is utilised correctly in the plant.
Cereals crop yields are driven by three key factors
1) the number of ears per square metre, 2) the number of grains per ear, and 3) the size of the grain. All of these can be influences by crop nutrition choices.
The numbers of ears is driven first and foremost by drilling the correct seed rate and having good seedbed conditions to maximise establishment. Early applications of NPKS fertiliser can also help with manipulating tiller numbers. As can conventional practices like rolling
Crops are varied in this growth stages. Those early drilled crops at GS30 (the traditional T0 timing) and those later drilled crops, or second cereals still tillering. Therefore there are two different foliar nutrition strategies to consider.
For the more advanced crop, the number of ears is set. Focus now turns to maximising number of grains per ear. This is where the micronutrients boron, copper and zinc can have a big impact. The time to have an impact is when the ear is being formed (GS30-32). Alongside is the need to maximise photosynthesis to ensure the crop has a healthy plant structure. Both magnesium and manganese play a key role.
YaraVita Gramitrel was developed specifically for the cereal crop. It contains all the above nutrients in an easy to use formulation. A fully replicated trials programme conducted over 6 years (2016 - 2021) showed 2.0 lt/ha applied in the spring between growth stage 30 and 32, delivered an average yield increase of 0.55 t/ha.
In practical terms when should I apply the product? This should be driven by the growth stage and biomass of the crop. For the advanced crops then T0 would work, where you have more leaf than soil. For backward crops then allowing them time to achieve more growth would be wise, then include the Gramitrel at T1.
A proactive approach to nutrition is better than cure and generally more cost effective, however there needs to be sufficient foliage to optimise the product.
Ensuring adequate nutrition of oilseed rape crops is vital to maximise yield and profitability
There are a number of nutrients the crop requires over and above nitrogen, phosphate, potassium and sulphur.
Boron (and Calcium) plays a key role in cell wall biosynthesis, carbohydrate metabolism, cell division and cell elongation. This ensures the crop has a good plant structure. It is therefore critical during periods of rapid growth - particularly important as the crop enters stem extension. Boron also has a role in pollen germination. Adequate boron levels ensure even flowering, which in turn can lead to higher seed set.
Magnesium is well known for its role in photosynthesis, being a central part of chlorophyll. However the majority of magnesium required by the oilseed rape plant is taken up in a short period just prior to flowering. An adequate supply during this time is therefore essential. Recent trials confirm this. Crops showing higher levels of magnesium concentration in the leaves have a tendency to produce the higher yields.
Manganese is also involved in photosynthesis during the growing season. Another important role is the function of carbohydrate metabolism and lipid synthesis. This has an effect on oil production. Crops deficient in manganese are likely to suffer from lower oil content and also lower seed yields.
Molybdenum deficiency in brassica crops is widely known as “whiptail”. It’s primary function in the plant is to improve nitrogen utilisation by metabolising nitrate. If deficiency occurs the leaves become pale and limp. This can reduce the leaf area available for intercepting sunlight. This can lead to reduced photosynthesis, resulting in a lower pod yield. Unlike the majority of other nutrients, molybdenum becomes more available at higher pH so deficiency is often restricted to acidic soils.
YaraVita Brassitrel Pro was developed specifically for the oilseed rape crop. It contains all the above nutrients in an easy to use formulation. A fully replicated trials programme conducted over 6 years (2016 - 2021) showed 3.0 lt/ha applied in the spring just prior stem extension, delivered an average yield increase of 0.27 t/ha, which correlates to a 6.0 % yield increase.
With some crops suffering the effects of Rape Winter Stem Weevil damage then a decision needs to be made. Crops where the main stem has been decimated are unlikely to recover, however others will need some TLC. In these situations is it vital to maintain the focus and marginal gains become very important. With forward OSR prices where they are, a yield increase of 30-40 kg/ha will cover the cost of the Brassitrel Pro application. A 2 t/ha crop with a 6.0 % yield increase means 120 kg extra yield, still an ROI of 3:1.
Cereals Can Look Deceptively Good Despite Waterlogged Soils
With good establishment conditions and mild weather in the autumn, cereal crops are looking good. There is a lot of good, above-ground growth but with recent rainfall in some areas waterlogging will have affected the root system.
Waterlogging has a massive effect on the roots, causing them to lose a significant amount of mass if sustained waterlogging persists. The predicament that this leaves us with is a lot of above-ground growth without the below-ground growth to sustain it; when it comes to spring, the root system won’t be able to provide enough nutrients to the leaves.
But there is a way that we can repair some of the damage from waterlogging and increase the root growth in the spring to ensure that growth isn’t compromised.
Phosphate is a key nutrient for root growth, however getting into the plant, when it has a limited root system, isn’t straightforward. Foliar phosphate uptake is much more efficient when the roots aren’t able to access soil-P, meaning that crops can access it easily.
A micronutrient mixture YaraVita Crop Boost is a particularly useful product for application to cereals in the autumn or at T0. It not only contains P and K but also zinc and magnesium, both of which aid establishment and help reduce levels of disease infection within a plant.
When this is combined with an NPKS compound fertiliser at the first nitrogen timing, such as YaraMila 52S, the crop is getting the best of both sources of phosphate for increasing those lost roots.
For more information please visit Agronomy Advice.
Yara Invests in R&D
Yara is a knowledge-based company and this means that we are always investing back into research and development – this includes a number of field trials.
Yara commissions independently conducted field trials each year, gathering data that is relevant to improving nutrient efficiency on-farm and giving this knowledge to growers to utilise.
Sulphur Response
Each year, Yara invests in trials looking at sulphur response, a very important nutrient that also increases uptake of nitrogen in to the crop. In the wheat trial, we had a yield response of 0.3t/ha from around 50kg SO3 in the AN-based product comparison. If we use £250/t for feed wheat, 0.3t/ha response from sulphur gives you £75/ha. If we use our longer-term average for sulphur response in wheat of 0.85t/ha then it would be £212/ha.
For oilseed we ran a similar trial and got a 0.35t/ha response from 73kg, if we use £516/t for oilseed then this is £180/ha. Longer-term sulphur response data gives an average of 0.5t/ha response; which would be £258/ha.
Micronutrient Trials
Another area where Yara invests in R&D trials is micronutrients. If we look at a wheat trial first, we were comparing YaraVita MAGPHOS K and CROP BOOST in combination with YaraVita GRAMITREL at T1, to see which is the best option at the T0 timing.
CROP BOOST, (containing P, K, Zn and Mg) when used in combination with GRAMITREL, at T1 gave the best increase with 0.6t/ha extra yield which, if we use £250/t feed wheat pricing, is £150/ha benefit - a great 4:1 return on investment!
We also had a trial on potatoes looking at micronutrients +/- biostimulants, here we were looking at MAGPHOS K +/- biostimulants and MANCOZIN alone. The addition of the biostimulant to MAGPHOS K increased the marketable yield by 4t/ha. The biostimulant on its own also had an impressive increase in yield compared to the control.
For more of Yara’s trial results from this season please visit Agronomy Advice
Digital Tools Help Maintain Yield Resilience
With crops, on the whole, looking good as we go towards the end of the year, using digital tools after winter can help keep the crop momentum going in 2023.
Once crops come out of the winter it can be difficult to know how much nitrogen (N) they have taken up, which means the first N application can be a bit of a guess. In order to increase efficiency it would be better to know the crop uptake before we decide on the N rate so that the crop isn’t over or under-fertilised. A quick and easy way to do this for cereals and oilseed is to use the photo analysis part of the Atfarm app.
It works by taking photos within the app of the crop which are then compared to several 100,000 images within our database. From this we can determine how much nitrogen has been taken up by the crop and translate that into a nitrogen recommendation. This then takes the guesswork out of that first application and could save you wasting fertiliser.
As well as monitoring biomass, as mentioned in previous columns, there is the variable rate nitrogen application maps (VRA) within Atfarm, as well as N-Tester functionality. In spring VRA (both N-Sensor and Atfarm) and N-Tester can be invaluable for increasing nitrogen use efficiency, productivity and potentially decreasing overall nitrogen use.
Using Atfarm to Monitor Crop Growth
Satellite imagery is a quick and simple way of looking at your fields, comparing biomass on different areas/soil types or picking up on potential problem areas within a field.
Establishing crops is always a tense time of year, with mild sowing conditions many crops are looking well and enjoying the unusually warm soil temperatures for this time of year. With plenty of things to do on farm it might not always be possible to look round all the crops as regularly as you’d like, which is where Atfarm can help.
Atfarm is a web-based software and app with multiple functionalities, but one that is useful for this time of year is using the satellite images to monitor your biomass. The software uses NDVI, as well as technology that’s used within the Yara N-Sensor, to give a much more accurate scale of variation than NDVI on its own. This means you can pick up more subtle variations in-field in a quick, visual assessment. Because it is fast to carry out it means you can regularly check the growth of the crops that are establishing and pick up on potentially problematic areas that can then be visited on-foot.
This can therefore save you time and increase efficiency as well as picking up on issues sooner, potentially enabling them to be rectified before there are large crop losses. As examples, you might see lower biomass near a wood in a field of oilseed – does this mean that a bird scarer needs moving there? Or if an area within a field is showing slightly lower level of growth/colour difference, this could indicate a nutrient deficiency that needs addressing before if begins to affect yield.
Foliar P on Cereals Averages 1t/ha Yield
Whether you drilled cereals early or late, foliar phosphate is an efficient way of getting the nutrient into the plant to aid root growth.
In particular, later drilled crops don’t have as long to establish much biomass i.e. decent root systems, before the soils cool and the crops slow down growth for the winter. Phosphate is well-known for its role in plant root development, but isn’t plant-available once soil temperatures start to drop. It also easily gets locked up in the soil, with up to 40% of an application of MAP/DAP locked-up 2 weeks after application due to becoming attached to ions (such as Al, Fe, Ca) in the soil.
A more effective method of getting phosphate into the plant, when it has a limited root system, is to apply it as a foliar spray. Foliar phosphate uptake is much more efficient when the roots aren’t able to access soil-P, meaning that the later drilled crops can access it.
A micronutrient mixture, YaraVita CROP BOOST, is a particularly useful product for application to cereals in the autumn. It not only contains P and K but also zinc and magnesium, both of which aid establishment and help reduce levels of disease infection within a plant.
Independent trial work carried out on two sites in 2021 gave an average yield increase of 1.2t/ha from an application of 3.0l/ha CROP BOOST in the autumn, followed by 2.0l/ha YaraVita GRAMITREL in the spring. Another trial in 2022 showed that an application of CROP BOOST at T0 followed by GRAMITREL (same rates as before) gave 0.6t/ha yield increase. Therefore whether you can apply CROP BOOST in the autumn or early in the spring at T0, there are good returns with an average yield increase of nearly 1t/ha, making it well worth the investment.
Digital Tools Help Maintain Yield Resilience
With crops, on the whole, looking good as we go towards the end of the year, using digital tools after winter can help keep the crop momentum going in 2023.
Once crops come out of the winter it can be difficult to know how much nitrogen (N) they have taken up, which means the first N application can be a bit of a guess. In order to increase efficiency it would be better to know the crop uptake before we decide on the N rate so that the crop isn’t over or under-fertilised. A quick and easy way to do this for cereals and oilseed is to use the photo analysis part of the Atfarm app.
It works by taking photos within the app of the crop which are then compared to several 100,000 images within our database. From this we can determine how much nitrogen has been taken up by the crop and translate that into a nitrogen recommendation. This then takes the guesswork out of that first application and could save you wasting fertiliser.
As well as monitoring biomass, as mentioned in previous columns, there is the variable rate nitrogen application maps (VRA) within Atfarm, as well as N-Tester functionality. In spring VRA (both N-Sensor and Atfarm) and N-Tester can be invaluable for increasing nitrogen use efficiency, productivity and potentially decreasing overall nitrogen use.
Managing Risk When Costs Are High
When a lot of aspects of farming are out of our control, we need to focus on what we can manage by minimising any risks coming on to farm.
Certain management decisions bring in yield resilience rather than fragility and this can include a number of things. For example, we need to minimise nutrient loss and application costs whilst maximising application accuracy, all whilst having environmental costs in mind too. Having good quality inputs can address some of the risks so that we are managing risk out and not in.
Dry weather in spring means that crops need to be even more resilient to cope with the lack of moisture and have a root system that is large and deep enough to access water further down the soil profile. We need to maintain growth momentum once crops start growing again in the spring, which can be at quite low temperatures, 5°C for cereals and oilseed. Our first fertiliser application is vital as it gives the crop the best chance of accessing the nutrients applied as they are will have started growing before you’ve been able to get onto the land.
This can affect the fertiliser choice because not all nitrogen-containing fertilisers are plant-available straight away. Nitrates are the most available form for plants to take up immediately, without any conversions needing to occur, therefore ammonium nitrate (AN) products provide immediately available nitrogen to the crop. If we look at urea-based fertilisers they have to undergo a conversion in the soil before they become plant-available and therefore the crop has delayed access to the nitrogen.
Depending on soil conditions this can take 6-8 weeks and therefore we could really be slowing down the crop momentum; which we don’t want to do at that key timing in the spring. So, if you are concerned about this delay stopping crop momentum, apply a nitrate based fertiliser, such as YaraMila 52 S or ACTYVA S, as your first spring top dressing. Aim to apply the first 50-70 kg N/ha with either of these products that will also supply fresh, immediately available PK&S to these crops.
Straw and Grain Nutrient Removal
If you remove straw then you also remove the nutrients that are contained in it, which is fine of course but then they won’t be available to the following crop.
Removing both grain and straw with cereal crops removes 8.0-8.5kg/t of P2O5 and 10.5-12kg/t of K2O, therefore is it important to take this into account when calculating next season’s fertiliser plan.
Post-harvest soil sampling will, of course, give a good indication of the P&K levels. If the indices are below 1 then an autumn application of P&K is justified. However if the indices are 1 or above then autumn P&K applications are not necessary. At those kind of levels there will be sufficient P&K in the soil to establish cereal crops and an application of foliar phosphate, such as YaraVita CROPBOOST, could be applied with a herbicide spray if required.
The real demand for phosphate comes in the spring from March to May when a typical crop of winter wheat will require 1-2kg per day for optimum growth. Any phosphate applied in the autumn is unlikely to still be present in the soil in a plant available form and therefore won’t be able to supply this daily demand.
Therefore when purchasing P and K products make sure you think about the timing of application to meet the demand from the plant, otherwise you will be feeding the soil and most of the phosphate applied will have been rendered unavailable for the following spring.
For more information on different options for P & K and other nutrient solutions please visit yara.co.uk/agronomy-advice/
Simplicity – the Ultimate Sophistication?
When buying fertiliser for spring application, many people fall into the potential ‘trap’ of getting straight nitrogen without thinking about the knock-on effects of this. Whilst nitrogen (N) is the most important nutrient, without sulphur (S), phosphorus (P) and potassium (K) the crop won’t be able to grow effectively.
We know that levels of both N and S in the soil are limited, and therefore the deficit in requirement needs to come from manures or mineral fertilisers. With P and K, we rely on soil indices to tell us how much to apply, but even on index 2 and above, fresh applications give a better use efficiency due to availability in the soil at the time crops require the nutrients.
This leads on to a compound NPKS being a good option for cereals, not only for the first application in February, but all the way through for an easy approach to fertiliser. “Aren’t NPKS a lot more expensive?” I hear you ask. You might be surprised to find out that they are actually more cost effective than urea/straight AN products are, and here’s why.
If we look at straight N then we have to think of applying P, K and S separately into the programme, this means we have 3 extra passes and 6 in total. If we think of the price of fuel at the moment, then this soon adds up to a significant amount - approximately £15/ha each pass.
If we think of the NPKS compound fertiliser then the additional benefits are 0.3t/ha from the spring P&K, 0.77t/ha from applying sulphur little and often and the increased accuracy of spreading is another 0.3t/ha. So, overall the benefit from applying an NPKS compound over straights is approximately 1.37t/ha, which at ~£240/t equates to nearly £330/ha for wheat crops.
Therefore, for a simple and cost-effective approach to nutrition for 2023, then a product such as YaraMila EXTRAGRASS (27-5-5+ 6% SO3) is a really good option.
Well-timed nitrogen to hit protein spec
If you are aiming for protein spec with your milling wheat this year, then the timing of nitrogen is the key. In order to hit the protein target that millers are looking for, then a separate application of nitrogen is required after the flag leaf final dressing.
The application needs to be separate in order to ensure the nitrogen goes towards building up the protein level within the developing grain. As well as timing, nitrogen source and rate are also important when trying to boost the protein, to ensure the nitrogen is utilised correctly in the plant.
Applying about 40kgN/ha (e.g. 120kg/ha of YaraBela Extran) at growth stage 51 (which is the start of ear emergence) can increase grain protein levels by up to 1%. This is possible to achieve without then compromising the yield. Yara trials showed that the separate application later in the season gave a boost in both yield and protein when applied at end of booting/start of ear emergence. For those on liquid systems, then an application of foliar urea (such as Chafer Nufol 20) applied later, at the milky-ripe stage, is the ideal timing for the same 40kgN/ha.
However, if the plant is deficient in certain micronutrients you’re less likely to have a positive impact on protein levels. Manganese and zinc, in particular, are important in the metabolism of nitrogen. If nitrogen metabolism is improved, then this increases the amount of nitrogen that is incorporated into the developing protein in the grain. Trials work, again, has shown that an application of zinc at T2 timing can increase grain protein by up to 1.4%! Therefore, it is important to ensure there’s no zinc deficiency if aiming for the milling premium - an application of YaraVita Mancozin or straight YaraVita Zintrac 700 will prevent this.
Maize needs an efficient form of phosphate
A crop of maize can produce up to 50 t/ha of fresh weight in just 4 months. For this amount of growth over a short timeframe to happen there needs to be a healthy, extensive root system for nutrient uptake from the start.
Phosphate (P) is a very important nutrient, key for growing the root system the crop requires to sustain the rapid growth, as well as being part of the transfer of energy within the plant. Weather plays a role in the availability of P, if soils are cold and wet when the maize is planted then P in the soil will have a very low level of availability, which is why placing some at drilling helps this by providing immediately available forms.
Nutrient availability in general decreases in dry soils, as we’ve had recently, and this will restrict root growth and therefore the ability to support the crop later in the season.
So how do we get around this? A foliar application of phosphate is the best way to overcome these early deficiencies and give the crop a boost in energy levels, both of these will help the crop develop a better root system to support later growth. YaraVita Crop Boost contains foliar phosphate, together with useful amounts of zinc, magnesium and potash. Applying it at the 4-6 leaf stage is effective for fast, efficient uptake through the leaf.
Biostimulants can also help during periods of abiotic stress, such as dry conditions. Trial work carried out in 2021 showed that YaraVita Biotrac, a biostimulant product, increased the yield in maize when applied in combination with YaraVita Crop Boost, by up to 4.4t/ha.
Is sulphur your first thought for new season pricing?
The majority of Irish arable soils are deficient in sulphur which means that most will need to factor this into their fertiliser strategy. It is easy to end up buying straight nitrogen products when new season pricing comes out, but most of the time an NS product is the most efficient way of feeding the crop.
For plants to utilise nitrogen correctly, sufficient sulphur levels are required due to the close relationship between the two nutrients. When applying sulphur it should go on little and often, the same way you would apply your nitrogen, because it has the same leachability characteristics in the soil. The addition of sulphur applied in this way typically increases the yield by an average of 0.50t/ha for wheat and oilseed.
However, the source of sulphur applied also makes a big difference. Elemental sulphur has to undergo an oxidation process before it becomes plant-available, this is weather-dependent and could take up to 6 weeks in the spring. Sulphur in the sulphate form is plant available and therefore the crop can utilise it quickly and efficiently.
The quality of the product is also a key factor for buying decisions and whether it spreads the required distance to give a good, even pattern. Fertiliser is a big investment and therefore buying a product that has a good CV, hard granules/prills (no dust), uniform in size and shape (no segregation), all nutrients in one granule/prill (even nutrition in the field) and has low emissions means an overall reliable return on investment.
YaraBela Axan (27% N + 3.6% S) is a high-quality NS compound which delivers these attributes and more. It is ideal for a multitude of crops when applied throughout the growing season, reducing the requirement of straight nitrogen, for a more efficiently grown crop.
Deciding on final nitrogen rates
When we were first looking at nitrogen applications, back in the winter, it was advisable to review the final N rate once we knew what crops and economics were looking like in the spring. Well, now it is that time!
With current fertiliser prices, the cost of applying nitrogen is still high, however wheat and oilseed prices are also high; which means the economic optimum has shifted back up to more normal levels. If we do the calculations then the economic optimum is now around 190-200kgN/ha, rather than the 160-180kgN/ha when crop prices were lower back at the start of the year.
This means that it is now worth pushing for yields and, on the whole, crops also look like they have good potential. The final dressing rate will of course depend on what you have already applied and also the crop type. If you are growing milling wheat then you will need to have the additional 40kgN/ha for increasing protein levels.
This can be added to the final application however trial work carried out has shown that, when it is applied as a separate dressing at growth stage 51 for solid or milky ripe for liquid, it can increase the protein levels by up to 1%.
YaraBela CAN 27%N is a quality granular fertiliser that spreads to over 40m and is ideal for the final application where straight nitrogen is required.
More arable agronomy advice
What can biostimulants do?
There are many types of biostimulants on the market, each with different purposes. What Yara products focus on is enhancing tolerance to abiotic stresses (e.g. extreme temperatures, drought, pesticide stress). They contain bioactive components such as fucoidan, mannitol, vitamins, organic acids, amino acids and also some of the nutrients that are involved in various mechanisms of the plant.
Ascophyllum nodosum, which is one of the compounds within Yara products, can induce hormone-like activity, improving the plant's hormonal perception and enhancing its effect. The composition of the product can also have an effect on many plant processes that could subsequently result in improved plant growth and yield improvement (e.g. increased photosynthetic efficiency, improved nutrient uptake, mitigation of abiotic stress effects through the mechanisms mentioned above, etc).
YaraVita Biotrac is a complex formulation containing nutrients and bioactive components from Ascophyllum nodosum, organic acids and vitamins. Biotrac can trigger various metabolic processes within the plant due to its composition; which impacts activities such as regulation of water, stress tolerance, stomatal conductance and detoxification of oxygen free-radicals.
This in turn can lead to improvements in the efficiency of plant processes and therefore result in improved plant growth and yield. Work shows that increases in both nutrient use efficiency, uptake and photosynthetic efficiency can be observed.
UK trials data has shown that when in combination with YaraVita micronutrient products, there were increases in yields observed. As an example, in a trial looking at different products on maize, when YaraVita Biotrac was used in combination with Cropboost or Gramitrel, the yield was increased above those products applied alone - showing improvement in the crop’s efficiencies.
Influencing barley grain size, weight and number
Micronutrients have a key role to play in the growth of all crops and have an impact upon crop efficiency and, ultimately, yield. Manganese, copper and zinc are important micronutrients for cereals and can increase the grain size and weight when in sufficient supply.
Of course, the main influencers on grain size are nitrogen and sulphur but, with potential reductions in these macronutrients due to the current situation, we must also focus on which micronutrients can help influence the grain. Don’t forget the number of grains - which we can influence with well-timed micronutrient applications.
Grain size in barley can be reduced by late nitrogen applications. Secondary tillers form ears with small grains, therefore affecting the overall quality of the harvest. Nitrogen applied early will ensure a canopy that is large, containing high levels of stem carbohydrate that is translocated to the developing grain during maturation. If we go back to micronutrients then both manganese and zinc have roles in nitrogen metabolism by the plant and therefore sufficient supply will improve grain weight.
Research has also demonstrated that manganese, copper and zinc have all increased the Thousand Grain Weight (TGW) in barley. When applying these nutrients at the T1 fungicide timing, we see increases in the thousand-grain weight and the number of grains per ear can be positively influenced with copper and zinc in particular. These three micronutrients have also been shown in the literature to improve disease resistance in crops, a healthier plant has improved defence mechanisms against fungal infection and therefore is better able to deal with them.
YaraVita Mancozin contains all three key nutrients and is therefore an ideal product to apply with the T1 fungicide timing on barley
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Cereal spring nutrition is more than just NPKS
Of course the first applications of nitrogen (and sulphur) are a high priority on farm, however, have you thought about micronutrient applications too?
Once crops begin the stem extension phase of growth they require a lot of nutrients to keep up with their rapid rate of development. This means the requirement for major nutrients increases but also the need for micronutrients increases as well. Don’t be fooled by terminology. ‘Micro’ doesn’t mean that these nutrients are less important but that the plant requires them in smaller quantities. A deficiency of any nutrient can cause major problems within the plant. Think of the Law of the Minimum, where any limiting factor will affect the overall yield of the crop – micronutrients can be those limiting factors.
Of particular importance is magnesium. Part of chlorophyll it is therefore vital to efficient photosynthesis and is required by the T1 timing to ensure there is sufficient supply. Think of all the chlorophyll production during the rapid phase of growth once the crops take off – not having enough Mg will mean less light is captured, therefore affecting crop development and eventually yield.
Tissue testing is the only way to see what is in the plant at that moment in time and therefore which micronutrients you will need to apply to keep the crop at optimal levels. However, if tissue analysis isn’t for you then an easy and effective alternative for cereals is to apply a multi-nutrient product such as YaraVita Gramitrel . This foliar product contains all the nutrients required by cereal crops in one can, and can be used to ‘cover all bases’. Long-term independent trial data shows that, on average, there is about a 0.5t/ha yield increase from YaraVita Gramitrel applied in the spring.
Kickstart oilseed growth this spring
Oilseed had favourable establishment conditions and on the whole fields were looking good going into the winter period. Now that regrowth is starting we need to keep that momentum going with spring starter fertiliser and key micronutrient applications.
One thing that could slow that momentum is the availability of phosphate (P) from the soil. When soils are below 8C phosphate availability is less than 10%, this means that when the crop starts to regrow it can’t access the soil-P straight away. P is important for shoot growth and root growth, which can also be compromised after winter if the roots have sat in waterlogged, anaerobic conditions. These factors can slow the development of the crop early-on, until soil temperatures increase.
An application of a compound fertiliser, containing N, P, K and S supplies that fresh P for the crop to take up immediately, whilst soil-P is unavailable. Potash (K) is also key for root systems, particularly those smaller secondary roots, increasing their number and density. Therefore a product such as YaraMila Actyva S (16-15-15 + 6.5% SO¬3) supplies fresh P and K, along with the nitrogen and sulphur, all of which are critical to early regrowth in the spring.
Other key nutrients for oilseed rape in the spring are magnesium, calcium, boron, manganese and molybdenum. All of these are in the crop-specific, foliar micronutrient product YaraVita Brassitrel Pro. Long-term independent trial data shows that an application of 3.0L/ha of YaraVita Brassitrel Pro at the onset of stem extension gives a 0.29t/ha yield increase to oilseed rape, which currently gives a return on investment of more than 8:1. Having all the key micronutrients in one product also makes the application simple and efficient.
These two products cover all the nutrients required to kickstart the growth of oilseed this spring and set the crop up for building yield.
Planning first nitrogen applications
As crops got off to a good start in autumn, with favourable establishment conditions, many were quite advanced heading into winter. But after winter there is a risk that crop root systems have taken a knock by sitting in potentially cold, wet soils towards the end of last year. The last thing we want is to have good above-ground growth without the same below-ground to sustain it, therefore we need to keep the pre-winter momentum going once crops start to actively grow again.
In order to regrow that root system, fresh phosphate (P) and potassium (K) are vital nutrients to go with nitrogen (N) and sulphur (S) at the first nitrogen application timing. Soil-P, in particular, doesn’t become available until soil temperatures are 8oC and above, whereas the crop starts growing at 4-5oC. This means there could be a shortfall in available P. Along with a poor root system, this would be another reason growth could be stalled.
Applying an NPKS product, such as YaraMila Actyva S, at the first nitrogen timing will give the crop the vital nutrients it requires by a) providing immediately available nutrients so that the crop can take them up quickly and efficiently and b) replenish that root system to sustain the top-growth.
The second and/or third dressing(s) should then be an NS product such as YaraBela Axan, as we know that sulphur should be included with nitrogen applications. Split the sulphur into more than one application to get maximum nitrogen uptake and utilisation from sulphur sufficiency.
Read more about improving nutrient efficiency
Knowing your soils for more sustainable farming
January is almost over already and spring is fast approaching; now is a good time to look at your soil results to help plan.
UK soils have changed a lot in the last few decades; whether it’s the 97% sulphur deficiency found in soils sampled or low average organic matter levels across arable land. The importance of taking a soil sample is well-documented, but should you be investing in more than just basic soil analysis?
Identifying Limiting Factors
The basic analysis will give you P, K, Mg and pH; which is a good start but what about micronutrients, organic matter and soil microbial activity? All are important to plant nutrition and you may be unaware that your soils are low in one or more of these elements, a broad spectrum analysis + soil health will give you this information to enable you to manage them.
With more and more emphasis on sustainability, we should start with a farmer’s number 1 asset – soil! In order to be able to monitor your soil and pick up on factors indicative of its health, you have to monitor it in the first place. Organic matter (OM) is a key indicator of soil fertility through the retention of nutrients and the ability to feed beneficial microorganisms in the soil. OM can take a while to build but you need to know your starting point so that you can monitor your progress in building the levels within your soils.
Another important aspect of soil health is the microorganisms within that are key to having a fertile, productive asset to work with. By carrying out a Solvita test you can monitor the level of respiration within the soil; which is an indicator of the amount of microorganisms present.
Once you have baseline levels for OM and microorganisms then you can try different practices to see how they can help increase the levels of each and work towards a more sustainable soil. This will mean better nutrient use efficiency, as well as other key benefits to your crop’s productivity.
Foliar phosphate to kick-start growth
The early spring growth period in cereal crops is an essential phase during which the foundation for high biomass is established. Biomass is a fundamental prerequisite to achieving high grain yields, this biomass is the result of achieving a good population of main shoots and tillers.
The tillering phase commences after leaf 3 is fully expanded and generally finishes when the ‘double-ridge’ stage of development is reached (i.e. just before GS 30.) This growth stage is typically reached by mid-March. The final number of tillers can therefore be manipulated through the appropriate use of inputs. One such input is crop nutrition. Nutrient deficiencies, especially nitrogen and phosphate, will limit early spring growth and development, thus reducing the number of tillers produced – this is then exacerbated even more in waterlogged conditions, such as we have experienced this winter.
The root structure of waterlogged crops will be poor - small and potentially damaged roots means a lower ability to scavenge the limited nutrients from the soil. Phosphate in particular, which is unavailable at low soil temperatures (below 8°C), is important for root growth. With the soils having little to no available P in early spring, fresh applications become even more important. Solid P applications are somewhat inefficient therefore foliar P should be considered as an early option.
A foliar application of phosphate gives an ‘energy boost’ to the crop, stimulating the growth of roots and consequently shoots. Not only does this give an immediate benefit by way of recovery and repair, it builds resilience, enabling the crop to overcome further potential stress points. YaraVita Magphos K is an ideal foliar product for this timing, kick-starting the cereal growth at this early phase.
If you do choose to apply foliar P then do so as soon as you can travel but ensure that you are ready to come back quickly with an application of, ideally, NPKS to ensure the crop doesn’t lose momentum as we don’t want to spark growth off only to let the crop run out of steam once it gets going.
