Grassland advice blog

Two jobs that that will deliver in spades for next year’s growing season are servicing your fertiliser spreader and drawing up a farm nutrient management plan, updating, refining and drawing on previous year’s experiences.

If it’s your first time drawing up a plan, fields with similar management and soil fertility can be grouped together to cut out duplication. There is a regulatory requirement for farmers to prepare a nutrient management plan. If you’re paying someone to prepare a nutrient management plan for you, make sure they’re FACTS qualified.

Now is good time to service your fertiliser spreader for next season. Considering the value of fertiliser and the importance of spreading it accurately, we can’t stress enough how important this job is. The cost of servicing a machine may come to the value of a tonne or two of fertiliser, but the cost can be easily recouped over the course of a season if a faulty machine has been rectified, and regular servicing extends the working life of a machine.

We would encourage all operators of fertiliser spreaders to check that settings are compatible with the fertiliser products being used. The icing on the cake would be to carry out a tray test before you begin spreading fertiliser to ensure that the machine is spreading the product accurately over the chosen spread width. 

The last variable in accurate spreading is the quality of the fertiliser. Remember Yara’s product quality guarantee when buying your fertiliser for the spring ahead! 

Dylan and Wyn Jones, from Castellior, Menai Bridge, Anglesey, were announced as the winners of the British Grassland Society Grassland Farmer of the Year competition for 2024. The announcement was made at an Awards Dinner jointly hosted by BGS and the East of Scotland Grassland Society at The Park Hotel, Peebles on Wednesday 23 October. The competition and the Awards Evening are kindly sponsored by Yara, Germinal, and Nufarm.

Dylan and his father Wyn, who are members of Anglesey Grassland Society, farm just over 330 ha and finish 1,500 beef steers per year. Mainly Holstein, with some dairy crosses are bought in at 16 – 24 months of age weighing 420 – 480 kg. Around 100 – 150 of the cattle are weighed weekly and are sold when daily live weight gain (DLWG) falls towards 1.0 kg. The finishing period is 92 – 140 days with an average DLWG of 1.7 kg/day. They are sold at 630 – 680 kg with carcass weights of 310 – 380 kg.

The farm is self-sufficient with barley and peas grown on the farm. These are crimped and fed to cattle along with silage made from red clover, and Westerwolds in a multi-cut system. A typical rotation on the farm is winter barley, spring barley, followed by two-to-three-year leys.

The competition is always hotly contested, and this year was no exception. The judging panel commented that all the farms were at the top their game and were worthy of being in the final three. The runners-up were Philip and David Clarke from Fermanagh Grassland Club and Peter Done from Cheshire Grassland Society. You can read more about these three farms here.

At some stage over the next couple of months plan to do some soil testing if you haven’t done so already. Once you have the results don’t file them in a drawer! Review them and use them to put together a nutrient management plan (NMP) for 2025. Your NMP is about prioritising how to use organic and mineral nutrients on the farm in the most cost-effective way possible.

Too often organic manures are applied on the same parts of the farm, year after year. There are plenty of reasons why this is done, but it’s not maximising the potential value of this valuable resource. Using umbilical spreading systems may be an option to target other areas of the farm. Target cattle slurry at low K index soils as it’s a cost-effective potash source.

Intensively stocked grassland farms should consider soil testing more regularly. By soil testing every 2 – 3 years you’re in a better position to monitor soil fertility trends. Fertiliser recommendations are not an exact science, hence soil testing more frequently together with measuring grass yields will help you fine tune your NMP for every paddock or field on your farm.

Remember, leys require a continuous and balanced nutrient supply from the soil to achieve its production potential. If a farmer is regularly soil-testing, say every three years, then the €1 ha/year cost is money well spent.

For more information on soil testing this spring search online for “Yara analytical services”

The latest 2023 British survey of fertiliser practice published in July does not paint a good picture for the state of grassland soil fertility in Britain. The overall P & K application rates on grassland, and the percentage area of grassland that receives a fertiliser dressing of P & K has not recovered since 2022, which is a concerning national trend. Only 22% and 24% of grassland receives P and K respectively, down from 37% and 39% in 2021.

On those fields that receive P and K, there was a 1 kg increase in field P rates on both grazing and silage from last year and an increase in K of 2 kg and 3 kg for grazing and silage fields respectively. Grazing will be hit hardest if P applications are forgone, while silage yields are more at risk if K applications are missed or reduced. It should be remembered that K is also lost through leaching, and with above average rainfall comes above average  K leaching losses.

The upshot of declining soil P & K fertility is poorer grass growth, and reduced nitrogen use efficiency which hits both the pocket as grass is the cheapest feed source and potentially water quality and nitrous oxide emissions. If farmers apply the same amount of nitrogen on fields with declining soil P & K fertility, then lower yields capture less nitrogen, leaving more residual soil nitrogen at risk of soil denitrification and leaching.

The cut off point for establishing an autumn ley was generally early September but many are now pushing this date later into September successfully. It’s important that these autumn sown leys are managed adequately to ensure they perform the next year.

The autumn weather can make the timing of the first grazing difficult, but in general the first grazing is left too late. New leys should be grazed as soon as the new roots are strong enough to withstand grazing. We can check for this by using our fingers to see if the root stays anchored in the ground when the plant is pulled.

Early grazing allows light into the base of the ley which will encourage tillering. A light grazing by calves, young stock or sheep is preferable. Bigger animals have more of a tendency to cause sod pull and poaching at this time of year. A first grazing can usually take place when the sward is at 6 – 8 cm’s in height.

Don’t be tempted to allow grass to build up on these new leys for a late cut of silage. This will inhibit tillering, resulting in more open swards which will be more susceptible to weed germination in the spring. Low winter covers will also benefit clover performance come spring.

If soil fertility is not known, then a soil test should be taken. Correcting soil pH and supplying any necessary P & K is a must for the success of a new ley, especially those which include clover.

Growth rates are below average around the country and this will likely result in growth rates dropping below demand earlier than usual in September. Careful autumn grassland management at this point in the year can save money and save on silage. Another key job for September on livestock farms is forage budgeting to identify any potential forage shortfall this winter and spring.

Average farm covers should be hitting 1,000 kg DM/ha by late September and most farms should be out to a 35-day rotation. This means a 35 ha milking platform would be grazing 1 ha per day. If the daily grass allowance based on this rotation length is not enough to meet demand, consider reducing stocking rate or introducing supplement. A minimum 30-day rotation needs to be maintained, to grow and utilise more grass.

Nitrogen applied now is required to grow grass for the last rotation. Where grass demand is high, we recommend YaraBela Nutri Booster at 100 kg/ha in September. Better to take advantage of grass growth now and build covers in September when the fundamentals for growth are better. Applying nitrogen from mid-October onwards is likely to be uneconomical. Apply nitrogen to paddocks that will likely give the best response.  If P & K needs topping up, then a quality NPKS such as YaraMila EXTRA GRASS at 90 kg/ha should be used.

When pre-grazing yields are high, use strip-wires to maintain your target residuals. Try and graze paddocks with heavier, less free draining soil types earlier in the rotation to improve graze-outs.

How effectively can you apply low nitrogen (N) rates on PRG/white clover swards on intensive rotationally grazed platforms using high N fertiliser products like urea and at the same time apply the phosphate (P), potash (K) and sulphur (S) that these swards require? Clover requires very good soil P & K fertility because it hasn’t got the rooting mass of PRG, so is more at risk of transient nutrient deficiencies.

‘Clover is a shallow rooted species with around 15% of the root density of perennial ryegrass making it much less competitive for soil nutrients. Regular applications of a P & K compound fertiliser throughout the growing season are necessary for high levels of clover productivity and biological N fixation.’ - Dr. James Humphrey’s, Teagasc, Solohead Farm

By applying P, K & S little and often during the growing period you are providing clover with the P, K and S it needs to establish and reach a desirable sward content, fix atmospheric N, and remain persistent in the sward. YaraMila ExtraGrass is an ideal solution to low N application rates on these swards, ensuring maximum nutrient coverage of N, P, K & S throughout the season.

YaraMila ExtraGrass is a homogeneous, uniform-sized, compound fertiliser where all the nutrients are contained in every particle. This eliminates any segregation and allows even application and distribution of each nutrient across the whole bout width. The product contains nitrate N for that quick and reliable N response even in drier conditions.

The focus of autumn grazing management is to increase the number of days at grass and animal performance, but also to set the farm up during the final rotation to grow grass over winter and provide grass the following spring.

Because grass remains leafy now, rotation length can be extended from the 2^nd week in August. The focus of this period is to gradually build pre-grazing covers, targeting covers of 2,000kg to 2,200kg DM/ha in mid-September. Be careful not allow covers build beyond 2,500kg DM/ha for grazing, as utilisation is poorer. We want to avoid taking paddocks out for silage after the start of September, as these paddocks won’t have enough time to re-grow to make a significant contribution to the last rotation.

If Autumn nitrogen is going to be spread, it should be spread in August and September. The growth response to October applications is likely to be significantly lower and may not be economical. Our Calcium Ammonium Nitrate based fertiliser YaraBela AXAN with sulphur at 110kg/ha is an appropriate rate for applications during August and into the first half of September. If P & K needs topping up then a quality NPKS such as YaraMila EXTRA GRASS at 110 kg/ha should be used.

Drier or ‘earlier’ paddocks should be grazed from mid-September and then closed off from October onwards. Regrowth on these parts can be carried over the winter months for grazing first in the spring.

The importance of aftermath grass will vary on farms, with a whole range of factors affecting how much grazed grass will be required after the last silage cut is taken. There are two considerations to address when fertilising these aftermaths. Ensuring that the phosphate (P) and potash (K) requirements of the previous silage crops have been met and supplying enough nitrogen (N) and sulphur (S) to grow enough aftermath grass to meet livestock demand.

Unless soil P & K fertility is maintained at current levels on silage fields then it is likely that next year’s silage yields will suffer. On most farms, the N rate remains constant for silage crops from year-to-year, but with deteriorating soil P & K fertility you end up with less grass for every kg of N applied. Calculate what the offtakes and inputs are to see if P & K needs topping up. Use a suitable quality true uniform compound fertiliser, such as YaraMila NK Sulphur or YaraMila ExtraGrass.

The N requirement of aftermaths will depend on grass demand. Where there is high demand, then apply up to 35 kg/ha of N per application in August and September. If P & K are not needed, then use YaraBela Nutri Booster at 140 kg/ha and if they are needed use one of the YaraMila compounds mentioned in the previous paragraph at a N rate of up to 35 kg/ha. It’s important to apply this fertiliser on as soon as possible, to get grass off to a good start.  

Grass mineral analysis can be a useful tool to check nutrient levels, both macro and micro-nutrients levels in grass swards. Silage samples are regularly tested for minerals, but it’s usually with a focus on animal nutrition rather than crop nutrition. So, there is certainly more scope on both grass for grazing and silage to utilise mineral analysis to improve yields and nutrient use efficiency.

A farmer two years ago asked me to have a look at their 1^st cut silage mineral analysis report which highlighted a couple of potential problems. Because it was a composite sample from a number of different fields, it warranted a closer look the following spring, so three silage fields were sampled in May, 10 days before harvest.

The three fields had received the same nutrients, a combination of slurry and YaraMila EXTRAGRASS (27-5-5+6%SO₃) in the spring. Nitrogen, phosphate, potash, sulphur, calcium and magnesium were within the optimum range for two of the fields, while the report on the third field indicated that phosphate, potash, calcium and magnesium were low or very low.

These three fields had the same history of manure applications, and the most recent soil analysis indicated good levels of soil phosphate and potash. The difference was that the field which had the low grass nutrient levels also had a low soil pH (5.4). This makes sense, as soil pH affects nutrient availability. This again highlights the benefit of analysis and in particular acting on soil test results and correcting low soil pH.

If we’re spraying to control grassland weeds in the weeks ahead, spray selection and spraying weeds at the right growth stage are key points for effective weed control. We are also seeing advantages of applying a multi nutrient foliar fertiliser with the herbicide to improve outcomes.

The foliar fertiliser stimulates the growth of both the target (weeds) and non-target species (grass). An actively growing weed will translocate the herbicide around the plant and down into its roots more effectively, than a less active growing weed. It’s important to get the herbicide down into the roots to completely control grassland weeds such as docks and thistles.

Grass herbicides can often ‘check’ grass growth after spraying and especially when growing conditions are not ideal. The application of a foliar fertiliser in combination with the herbicide helps offset this ‘check’ on swards. Also, in newly established leys, foliar nutrition can give grass seedlings a much needed nutrition boost, which promotes tillering, helping to reduce light and space for any new germinating weeds.

We recommend YaraVita Croplift Pro at a rate of 5 kg/ha (2 kg/acre) for inclusion in a tank mix with your chosen grass herbicide. This foliar fertiliser containing multiple nutrients and micronutrients for foliar application on grassland is ideal at times of stress or periods of rapid growth. It has excellent plant absorption properties, giving an immediate and long-lasting feeding effect on grass and herbal leys.

Yara’s maize trials, have demonstrated the positive effect that combining foliar nutrition and biostimulants had on crop performance. In last year’s trial the combination of our crop specific product for Maize - YaraVita CROP BOOST (5 L/ha) and the biostimulant - YaraAmplix Optitrac (2 L/ha) applied at the 5 leaf stage increased dry mater yields by 16%, equal to 2.5 tonnes of dry matter per hectare.

When applied together, YaraAmplix Optitrac complements the nutritional effects of YaraVita CROP BOOST. The unique combination of selected bioactive components and nutrients in YaraAmplix Optitrac activates the plant’s metabolic processes to enhance nutrient use efficiency and tolerance to abiotic stress for example due to the application of a herbicide. The two YaraVita products work in harmony to maximise the ability of YaraVita CROP BOOST to promote root and plant growth and efficiently use the plant’s energy reserves.

YaraVita CROP BOOST is formulated for foliar applications on maize, containing a high concentration of phosphorus, zinc, magnesium and potassium. Yara conducts nutrient specific trials to prioritise nutrients according to their impact on crop growth and development. Once these are established then crop-specific products can be formulated to deliver enough quantities of these specific nutrients.  

The results of two years of maize trials in both the UK and Ireland have demonstrated an economic justification of using YaraVita CROP BOOST and YaraAmplix Optitrac together. There is a very strong case to adopt the YaraVita Maize Programme at the 4 – 6 leaf stage to minimise the risk of nutrient deficiencies and abiotic stress in Maize and maximise yields.

Fertiliser applications for first cut silage have been really hampered by the weather since mid-March. This is a very worrying situation as these first cuts constitute a large part of next winters forage.

Remember grass will start heading out at the same time as usual, so allowing a longer first cut growth period might be okay to increase grass silage yield for some but the quality of this silage will be lower. Also, the second cut regrowth will be slower, so while you might gain extra yield on the first cut, you will lose out on first cut quality and second cut yield.

When it comes to early May, check the base of the sward for dead/decaying leaf and stem. What happens at the base of the sward has as great an effect on feed value as seed head emergence. This dead decaying material might be as a result of water logging or just the wet conditions especially where there were heavier covers of grass on fields and in some cases this grass has lodged whereas in other years it mightn’t have. If there is dead material at the base, then consider cutting sooner rather than later.

There are a couple of first cut scenarios being faced by farmers presently:

1. Fertiliser and slurry have been applied, but the grass looks backward and isn’t a lush green colour.

Grass growth has been affected by wet soil conditions and overcast weather. Nitrogen losses to leaching will have been greater due to the above average rainfall this spring, but putting a figure on this is very difficult. Should more nitrogen be applied in this case? It will depend on when the slurry and fertiliser was applied. If slurry applications were applied in Jan/Feb and fertiliser was applied before the 20^th of March, then an application now of a bag/acre of YaraBela Nutri Booster (25 units N/acre) is justified if the anticipated mowing date is circa 20^th of May.

2. Slurry has been applied but not the nitrogen fertiliser.

If applying nitrogen or an NPK fertiliser, apply as soon as possible. Have the fertiliser in the yard ready for spreading. If slurry was applied a minimum of 2 weeks ago, then the silage crop will utilise 2 units/acre of nitrogen per day from the date of fertiliser spreading to the anticipated harvest date. A nitrogen product such as YaraBela Nutri Booster or an NPK such as YaraMila SulphurCut would be ideal in this situation.

3. Nothing applied to date.

Be very careful applying slurry on first cuts at this late stage. Only apply if there are light grass covers (<750 kg DM/ha) and the slurry is dilute and is being applied by trailing shoe or dribble bar. Otherwise, delay slurry applications until after harvest because of the risk that residues from the slurry will persist on the grass up to harvest or that these residues are picked up off the soil surface at mowing/raking/picking up.

As for the nitrogen rate, calculate the number of days from when the nitrogen fertiliser is applied to the anticipated harvest date and then use the 2 units/acre of nitrogen per day rule. If slurry is being applied, account for the available nitrogen in the slurry when calculating how much nitrogen fertiliser is required. If slurry is not being applied, and soil P & K indices are index 3 or less then use an NPK fertiliser such as YaraMila Sulphur Cut.

Another option that some farmers might be considering for this scenario might be to cut in the next two to three weeks if field conditions allow and then focus on the second cut. If this is the strategy you choose, then only if good ground conditions exist at harvest to minimise soil contamination. This late April/early May mown grass is more likely to have lower sugar levels, so this would need to be considered at mowing. Achieving a good wilt and using a silage inoculant could help counteract sub-optimum sugar levels.

The timing and rate of the first nitrogen (N) application in the spring always sparks debate. Nonetheless, many farmers with dwindling forage stocks will be looking forward to putting stock out to grass this spring as soon as they can. But what can we do to increase the availability of grass this spring on grass farms.

The same principles apply whether its grass for grazing or silage. We know that applying a N source (as slurry or fertiliser) when soil conditions and temperatures are at 5-6^oC and rising and with a favourable weather forecast will increase the supply of grass over the subsequent 6 weeks compared to holding off until later in the spring when growing conditions are more favourable.

N has the effect of stimulating growth earlier than it would otherwise be. The response to this early N will be greatest for more productive ryegrass swards. The exact timing of this initial application will vary across the UK, for the south of England and Wales it is probably early February but for Scotland it may well be a month later.

For silage, tack grazing should have finished in December, as over grazing and grazing into the new year is going to slow grass growth and is shown to reduce 1^st cut silage yields. Slurry is a valuable source of nutrients for 1^st cut silage and often tanks have to emptied in January, but if applications can be delayed till the soil conditions outlined in the second paragraph exist then slurry N utilisation will increase.

As a guide, if slurry is applied in January then any nitrogen, phosphate, potash or sulphur fertiliser that is required should be applied by the end of February/early March. For later slurry applications, then the fertiliser should be applied no later than 6 weeks from the planned cutting date. These 1^st cut silage crops need a sulphur containing fertiliser as there is not enough sulphur in slurry alone.

For grazing, we would recommend applying 80 kg/ha of Nutri Booster when the soil reaches the conditions outlined in the second paragraph and then a second application of 160 kg/ha of Nutri Booster 4-5 weeks later when growing conditions are hopefully improving. In terms of herbage growth, N response and N use efficiency, a recent study by Teagasc, Moorepark demonstrated that the most effective strategy for early spring N applications was to apply total of 60 kg/ha of N by early April, split 20/40 for the first and second application.

Last but not least, don’t leave it till the last minute to buy fertiliser as delivery might not be as prompt as you might like. Not having the fertiliser could cost you more if you’re later applying it. You end up with less grass, making costly fertiliser even more expensive.

A recent study at Teagasc Moorepack investigated the impact of applying 3 rates of spring nitrogen (N) fertiliser (30,60 or 90 kg N/ha) by April 1st, on two N application dates, 3rd Febraury and 19th March, with three different rate strategies (split between Febraury and March); 0:100, 50:50 and 33:66. The highest spring herbage production was reported on the 90 kg N/ha, followed by the 60 kg and 30 kg the lowest (3,026, 2,753 and 2,308 kg DM/ha, respectively). Higher N rates lead to a reduction in N recovery and a lower response to N application. 

The 90 kg N treatment had the lowest N response per kg N applied, followed by the 60 kg N with the 30 kg N the highest (15.7, 18.2 and 21.0 kg DM/kg N). These are all greater than previously reported response figures of 10-13 kg DM/kg N, and greater than the required economic breakeven point. 

The impact of application strategy, across all of the rates of N applied, when zero N was applied in February and all was applied in March (0:100), resulted in a lower spring herbage production of 200 kg DM/ha, compared to either of the 33:66 or 50:50 strategies. The 33:66 strategy (27.3 kg DM/kg N) had the greatest N response compared to the 0:100 or 50:50 (14.3 and 21.1 kg DM/kg N, respectively). High levels of N in a single application in spring, will result in too high a level of available N for the plant to utilise, and does not result in increased levels of herbage production. 

Yara undertook a farm trial this year to investigate the effectiveness of its’ selenium enriched Booster range, by comparing the blood selenium levels of two groups of in-calf dairy heifers - one group having grazed an area that had been fertilized with the selenium fortified YaraMila STOCK BOOSTER S (25-5-5+5%SO3+Na+Se), while the second group had grazed an area fertilised with YaraMila EXTRAGRASS (27-5-5+6%SO3).

The hypothesis is that by enriching the grass with selenium, you therefore increase dietary selenium which will support healthier levels of the nutrient in the animal’s blood. This form of selenium is much more available to the animal, compared to inorganic selenium sources found in concentrates, licks and boluses which are less available to the animal.

The heifers rotationally grazed their respective areas for 3 months (from May until August) and the relevant fertilizer was applied three times during that period. At the end of the trial, blood tests were taken again. The average blood selenium levels in the heifers grazed on the area receiving the selenium fortified fertiliser (Stock Booster S) were 50% higher than the group of heifers grazed on grass fertilised with the standard NPK (EXTRAGRASS).

Herbage analysis also indicated that the group grazing the area where Stock Booster S was applied had double the selenium herbage concentration, compared with the untreated area. The outcome of this trial gives us further confidence, that the Booster range of fertilisers can influence positively the selenium intakes of grazing livestock.

For more of Yara’s trial results from this season please visit Agronomy Advice.