Grassland advice blog

16th Dec 2025

Yara would like to congratulate James Henderson from the Ulster Grassland Society who won the British Grassland Society Grassland Farmer of the Year competition for 2025. Yara are proud to sponsor this competition with Nufarm and Germinal.

James buys 85–90 young heifer calves in October each year, mostly British Blue and Aberdeen Angus crosses from the dairy herd, which are grazed in two mobs based on age, using a two-day paddock system. Native breeds finish off grass during their second grazing season, whilst continental crosses are housed for a further 30-40 days and fed silage plus a barley-based home-mix. Cattle are sold around 20-24 months, at 350 kg carcase weight.

The sheep flock of 220 ewes and 60-70 home-bred ewe lambs is in transition to becoming Aberfield-Belclare crosses. Meatlinc and Primera rams are used as terminal sires. Post lambing, sheep graze three-to-four-day paddocks. Ram lambs are finished on forage rape and perennial ryegrass swards, with 200 g/d of home-mix. Ewe lambs are grazed on herbal leys and red clover aftermaths, with no concentrates. The average age at sale is 168 days, with a carcase weight 21.5 kg.

Grass is measured using a rising plate meter and AgriNet software is used. Three cuts of silage are made from a PRG sward and red clover sward each year. Reseeding is undertaken after paddocks show an overall reduction in yield from plate meter readings for annual yield. This is approximately a 10- year cycle. Old leys are sprayed with roundup in October, then 10-12 tonne/acre of farm-yard manure and seaweed (from adjacent beach) is applied. It’s ploughed before a break crop of winter barley is sown, after which a herbal ley or red clover is established.

8th Dec 2025 

Writing about February and March fertiliser applications in December might seem premature but this first and second nitrogen (N) application timings are critical to maximise grass supply in the spring. A good deal of the time, the fertiliser is just not on the farm in time. The time it takes to get fertiliser delivered isn’t constant each year, some years the supply chain can’t cope resulting in longer delivery times.

Those farmers who apply N at the appropriate time in spring, are more likely to grow more grass in March and April. We recommend applying 50 – 75 kg N/ha of YaraVera Amidas (20 – 30 kg N/ha) for these early N applications. They should only be applied when you can travel with a tractor, and without any major rainfall event forecast in the next 48 hours and soil temperatures are above 5.5 degrees and rising.

The benefit of spreading this low rate of N early is a large increase in growth rates in March and early April. A grass yield response of 13 – 16 kg grass dry matter per kg N applied is typical at this rate applied in February. Many farms this year lost out on grass growth of between 500 – 1,000 kg of grass dry matter in this period because of delayed or missed applications.

On moderate to intensively stocked farms, it’s a false economy not having the fertiliser you should be applying up until the end of March on your farm by January.

If you haven’t done so already, sit down and complete a nutrient management plan and a liming plan for the year ahead. I mentioned this a few weeks ago, but it can’t be stressed enough. If new soil test results have been received, then use them and don’t leave them in a drawer or your inbox! It mightn’t be long before slurry is spread, so knowing where to spread it and how much, is the starting point to using this resource wisely. Completing a plan, allows you to buy the fertiliser you need rather than the fertiliser you always buy. For those in NVZ’s take note of when manures and fertiliser can be spread, where you can’t spread them and assess the risk of run-off before spreading.

Soil fertility is key in growing forage, and the worry is when the milk to feed price ratio is high, farmers might place less emphasis on growing sufficient high-quality forage. No na-tional data exists, but industry figures indicate that milk from forage is on a decreasing trajectory year on year. We seem to be feeding cows more like sows than cows. We have the climate to grow grass and clover to convert into milk by optimising grazed and conserved herbage in the diet of dairy cows. It’s not a straightforward sum of feeding more concentrate to produce more milk, this oversimplifies the reality and doesn’t take account of more subtle extra costs associated with pushing for more milk by feeding more concentrate and less forage.

There has been a great deal of interest over the last three years on the results of this foliar nitrogen (N) trial on grass, with this year’s yields back over 2 tonnes of dry matter on 2024, which is hardly any surprise.

The trial is modelled on a 4-cut silage system, with the first cut taking place in early May, with subsequent cuts taken every 5 weeks approximately. The total season N rate per ha for the 5 treatments is as follows: treatment 1 – 0 kg, treatment 2 – 340 kg (100% soil applied), treatment 3 – 203 kg (86% soil applied, 14% as a slow-release foliar N product), treatment 4 - 203 kg (100% soil applied), treatment 5 - 203 kg (28% soil applied, 72% as a foliar urea product + humic acid). The foliar N was applied 10 – 12 days after the previous cut to ensure there was enough leaf surface to intercept the foliar products.

2025 results - The total dry matter (DM) yield per ha was 2,358 kg, 9,978 kg, 7,415 kg, 7,231 kg and 7,182 kg of dry matter per ha for treatment 1, 2, 3, 4 and 5 respectively. The N response was 22.4 kg, 24.9 kg, 24.0 kg and 23.8 kg of dry matter per kg of applied N for treatment 2, 3, 4 and 5 respectively. In conclusion, although yields were different each year, we see the same trends each year between treatments. Foliar N was no more efficient than the same rate of N applied as a soil applied conventional solid fertiliser.

We don’t always look at soil testing as precision farming, because it has been common practice on farms for more than 50 years. In definition it is, and it’s likely that soil testing after this many years still contributes more benefits to farming than many of the new technologies that we clearly identify as precision farming tools.  

That said, soil testing alone does not deliver the benefits, it’s only when the results of soil testing are used to inform nutrient and soil management decisions that the benefits are seen. The results primarily allow you 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. 

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 nutrient management on your farm. 

Remember, leys require a continuous and balanced nutrient supply from the soil to achieve their production potential. If a farmer is regularly soil testing, then the £1 ha/year cost is money well spent. 

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

It’s important to know this autumn that if you are farming in a NVZ area in England or farming in Wales, you can still spread manufactured nitrogen fertiliser from the 15th of September to the 31st of October on grassland. This could be particularly important as livestock farms recover from the drought and see an opportunity to maximise grass growth in September and October for late silage cuts and extending the grazing season to stave off housing livestock a while longer.

If you’re in a NVZ in England or Scotland or in Wales the closed period begins on tillage land on the 1st of September, and the 15th of September on grassland. But there is an exception for grassland in England and Wales, which allows for the spreading of manufactured nitrogen (N) fertiliser between the 15th of September and the 31st of October. The rules state that you can spread a total of 80 kg N/ha during this period, and you can only apply a maximum of 40 kg N/ha at any one time. Remember you can’t exceed your annual N-max limit on grassland.

For those establishing Italian ryegrass or Westerwolds after maize for some late grazing then it’s worthwhile spreading 90 kg/ha of YaraBela Extran to aid fast establishment and crop growth. If you’re growing these primarily for winter cover and early grazing/silage in the spring, then only apply nitrogen if the crop is visibly hungry for nitrogen.

27 Aug 2025

Molybdenum (Mo) is an essential micronutrient particularly for clovers as it plays a key role in N-fixation. Mo is an important micronutrient for nitrogen (N) metabolism in plants. It helps create proteins in plant leaf cells and is required for N fixation in legumes. Mo availability from the soil declines when the pH is below 6. Therefore, adding lime can increase the availability of Mo to plants. It’s important to be aware that high levels of herbage Mo can cause a Mo-copper imbalance in grazing animals.

Clover and other legumes have a high requirement for Mo during establishment and nodulation because it aids nitrogen transformations in the plant affecting both N fixation and assimilation. Often the only sign of Mo deficiency is poor clover growth. The clover may appear N deficient being stunted with pale green or yellow leaves because N fixation has been affected. Routine clover foliage sampling (leaves only) in spring can check that the clover nutrition is adequate.

It is likely that there are parts of the UK where clover performance is being impacted by Mo deficiency. Where white clover is not performing up to expectations, then it might be worthwhile taking a clover foliage sample. In New Zealand, if white clover foliar Mo is <0.1 mg/kg and N is <4.5% then there is a high probability clover will respond to Mo application. Where clover is found to be Mo deficient, we recommend a foliar application of YaraVita Croplift Pro at 5 kg/ha.

If grass growth rates are running ahead of demand, then now is the time to focus on building grass covers on the grazing platform to increase the number of days at grass and animal performance. Teagasc estimate that on dairy farms, every extra day a cow spends out grazing is worth over €2/cow/day.

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.

Nitrogen should be spread in August and September to provide grass for later in the Autumn. Our CAN based fertiliser YaraBela Nutri Booster with sulphur at 120 kg/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.

I asked a Gloucestershire farmer this week if he had much grass, he laughed and said its only the celts that have grass! It seems rainfall is becoming less predictable and the likely hood of longer spells of depressed grass growth is now an annual occurrence. Two Co Cork dairy farmers both said they were going to cut cow numbers in 2026, because over the last couple of years they’re having to buy forage every year where before they were self-sufficient.

It’s important that farmers plan for these extremes of weather, during the season. This means farms need to keep higher stocks of preserved forage, but they also need to look at their stocking rate. Purchasing forage or feeding extra cake to plug a forage deficit, doesn’t make economic sense if it’s happening most years. Keeping less stock will likely improve livestock performance because you’re feeding that stock better.

If it’s not until the end of August that swards green up with some leaf cover, then it might be worthwhile taking a different approach to nitrogen fertilisation. When swards green up, hit them with YaraVita Safe-N at 23 L/ha. This foliar nitrogen combined with already high soil nitrogen levels will work particularly well if used from the end of August into early September on silage swards where the cutting date needs to be flexible. Using foliar nitrogen this way for late silage cuts, helps minimise any problems with high grass nitrate levels at harvest.

Dry conditions prevail over large parts of the country and many livestock farmers are in desperate need of rain to relieve grass shortages. The recovery time of swards following rain will depend on the severity of drought - the longer the drought, the longer the recovery.

Farmers will be looking to fertilise swards to maximise growth when the rain arrives, to feed grazing livestock and build silage reserves which are worryingly low on many farms. Don’t be tempted to spread fertiliser before forecasted rain. Heavy rain combined with dry and hard field surfaces is ideal for fertiliser run-off. Best to leave applications until after the initial rain.

If nitrogen (N) fertiliser has been applied over the last couple of weeks when grass growth has been well below average, then a portion of this N will still be present for the grass to utilise when a decent amount of rain arrives. How much, depends on when it was applied and the level of grass growth in the meantime. Rapid mineralisation of organic matter by soil microbes will also add to the plant available N pool following a rewetting of the soil.

When the rain arrives, reduce the target N rate for fertilising silage crops where a very light crop of grass has been harvested, by 30% to take account of N carryover from the previous fertilisation. If silage crops were fertilised within the last three weeks, then there is no requirement to reapply N. Typical fertiliser application rates of 230 – 320 kg/ha of YaraMila Sulphur Cut will be required for silage swards once soil moisture levels rise.

In early July it’s worthwhile checking what nutrients have been applied to grazing paddocks to-date, particularly how much P & K. Although silage fields have the larger P & K removal rates, slipping soil fertility on grazed swards is very common and will reduce nitrogen response from all sources of nitrogen – soil, fertiliser and manures.

The P & K maintenance rates (based on the target soil index of 2 for P and 2 for K) for grazing is 20 kg/ha for phosphate and 20 kg/ha for potash. These rates will need to be higher on intensively stocked grazing platforms as offtakes are greater – 1,000 L of milk removes 2.3 kg of P.

Potash fertility is declining on grassland farms in general, and grazed paddocks are no exception. Even though 90% of potash consumed by livestock is excreted, the 10% (1,000 L of milk removes 1.4 kg of K) utilised by livestock does add up over the course of the season. Potash is also leached from soils, albeit in small amounts.

A common practice with rotational grazing is taking out a paddock for silage to manage grass supply on the grazing platform. Where this happens, the P & K offtakes in this silage need to be added to the annual P & K maintenance rates. Each 800 kg bale (25% DM) of silage will remove 1.5 kg/P and 6.6 kg/K. YaraMila ExtraGrass and YaraMila SulphurCut are ideal products to balance P & K offtakes and maintain soil fertility on grazing paddocks.

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 Tankmix 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. 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.

With most 1st cut silage crops harvested at this stage, the focus should turn to fertilising the 2nd cut if you haven’t already done so. The dry and warm weather is hitting grass growth and particularly 2nd cut regrowth. At the time of writing this, there was no sign of impending rain in the forecast, and farmers will be asking themselves should they apply now or wait until some rain is forecasted.

My advice is to split the application and use a nitrate-based fertiliser. Apply half the fertiliser nitrogen now and then wait to apply the remainder just before rain is forecasted. Potential nitrogen losses from spreading a nitrate-based fertiliser are very low in these conditions, but nitrogen losses from urea could easily reach 30% or greater. You might say, why not wait to apply the full application rate before rain is forecasted, but sometimes we receive sudden showers of rain during these dry periods which hasn’t been forecasted.

With 39% of grassland soil samples analysed in the UK falling below the optimum, potash application rates on many farms are resulting in loss of yield on silage fields. With a tonne of grass silage dry matter removing 30 kg of K2O, a 1st cut silage crop could easily be removing 150 kg of K2O per ha. A 2nd cut could be removing 100 – 120 kg K2O per ha. Maintaining and building soil P & K fertility is a worthwhile investment. For this 2nd cut, should you be using a NPKS fertiliser such as YaraMila Sulphur Cut instead of straight N?

With 1^st cut silage making in full swing, our attention should turn to fertilising 2^nd cuts. We thread a fine line with N applications, too much produces grass with lower sugar and higher ammonia and butyric acid levels, which can make silage less palatable. Too little N compromises yield, and protein levels can be lower.

For swards with good yield potential, we advise 330 – 370 kg/ha of YaraBela AXAN for 2^nd cuts. In multi-cut systems, this rate may need to be adjusted where the cutting interval is less than 6 weeks. Calculate the rate by multiplying the rate of N uptake (assume 2.5 kg/ha per day) by the number of days between 1^st cut harvest date and the expected 2^nd cut harvest date.

Each kg of N applied should return 20-25 kg of grass dry matter (DM). If N is costing £1.00 per kg then each kg of DM is costing 5 pence to grow. In comparison, cake at £320 tonne costs 37 pence per kg DM.

Using the Fertiliser Manual (RB 209) the available N per cubic metre of 6% DM cattle slurry applied during the summer months is 0.65 kg by splash plate and 0.8 kg if band spread. If slurry doesn’t meet the P & K requirements of the crop use YaraMila SulphurCut or YaraMila NK Sulphur.

Don’t apply N without applying sulphur, even on 2^nd cuts. It’s an easy win, from both an economic and environmental perspective. Lastly, apply slurry within a few days of taking your 1^st cut and follow on with fertiliser a week later to avoid any unnecessary 2^nd cut yield loss.

Spring reseeding can give more reliable results to Autumn reseeding and allows farmers to grow increased yields of higher quality grass.

Step 1: Identify poorly performing paddocks. Step 2: assess their content of desirable grasses. If this is less than 60% consider re-seeding. Annual meadow grass and other weed grasses produce lower yields, poorer feed quality and do not respond well to applied nutrients. Yield will be reduced by 1 % for every 1 % in weed ground cover.

Before you start, be sure to complete Step 3: take a soil test and act on the results. On mineral soils the optimum pH for grass is 6.3. Failing to correct pH will severely impact the success of your reseed. Choose only varieties from the Recommended Grass and Clover Lists (RGCL) and pick those that suit your particular farm.

Step 4: Provide new swards with the correct nutrients at sowing. Failure to do so will hinder the success of the ley. Where clover isn’t included, and the soil P & K index is 2, then use 330 kg/ha YaraMila ACTYVA S (16-15-15 + 6.5% SO3) at establishment. New leys have a greater requirement for phosphate to help with root development. Good seed soil contact is essential, so roll after drilling.

Weeks 4-6 apply herbicide to prevent weeds competing for nutrients and space. Combine this with a light grazing when grass height is at 8 – 10 cm to promote new shoots, and the long-term productivity of your new sward.

For more information visit www.yara.co.uk/crop-nutrition/agronomy-advice/reseeding-advice/

For April we shouldn’t overlook the opportunity of fortifying grass for grazing and silage with selenium (Se).

Data from Yara analytical services shows that more than 90% of grass and grass silage samples tested are deficient in selenium. Increasing the Se levels in grass can significantly reduce health problems and improve reproductive performance in livestock. Using a fortified fertiliser ensures that grass or silage has Se levels which meet the animal’s requirements of 0.2-0.3 mg/kg DM.

For grazing, YaraMila Stock Booster S (25-5-5 + 5 % SO3 + Se) is a perfect choice to drive grass growth in April, by providing the N, P, K and S that grass needs as growing conditions improve. The selenium in this product will boost the selenium concentration in grass for grazing livestock which is particularly important for lactating ewes and cows. Livestock utilise the Se in grass and silage more efficiently than the Se found in boluses, licks and TMR mineral mixes.

As spring calving dairy and suckler cows reach peak milk in April and May, which coincides with the start of breeding, it’s crucial that Se intakes are adequate for lactating cows at grass to ensure good reproductive performance. By using YaraMila Nutri Booster (25% N + 5% SO3) or YaraMila Stock Booster S, you are effectively increasing the selenium levels in every bite of grass for your grazing livestock.

For more information on selenium in grass search “Yara selenium”

With 1st cut fertiliser applications beginning, it’s important to remember that 1st cut silage is the most economical cut to grow and usually supports the highest livestock performance of any silage cut. Because 1st cuts have the highest yield, they in turn have the lowest cost of production per tonne of dry matter ensiled. This is why it pays to ensure these crops receive the nutrients they require to reach their yield potential. 

We recommend productive grass only swards receive a total of 120 kg/ha of nitrogen and lowering the application rate for older less productive swards. Where cattle slurry was or will be applied, take account of the available nitrogen in the slurry. This can be determined from a recent slurry analysis using the total nitrogen content of the slurry and use RB209 to then look up what the percentage availability of the total nitrogen in the slurry. Alternatively use the book values in RB209. 

Where there is good P & K soil fertility, apply 40 kg and 80 kg of phosphate and potash respectively per ha. In the absence of a slurry analysis use these RB209 standard values of 1.2 kg and 2.5 kg of phosphate and potash respectively per cubic metre for cattle slurry. All 1st cut silage crops should routinely receive 35 – 40 kg/ha of sulphur. 10 m3 of slurry will contribute 3 kg of available sulphur. Finally, choose a quality uniform compound fertiliser such as YaraMila Sulphur Cut or YaraMila 52 S to supply the nutrients your 1st cut needs this spring. 

Phosphate (P) is a key nutrient for grass. Its role in energy supply, root growth and tillering make its availability crucial for grass growth in the spring. The plants requirement for P is small in volume when compared to nitrogen BUT its availability is essential. For grazing, P applications from the end of March and into April and May is a key period, due to soils being cold and wet, but also an increasing grass P demand, as grass growth rates increase in April and peak in May.

Typically, the phosphate in fertiliser is 100% water soluble; this however creates its own problems. As soon as you apply water soluble phosphorus to a soil, this soluble phosphorus becomes slowly fixed by iron and aluminium. The phosphate contained in YaraMila EXTRAGRASS (27-5-5+6% SO₃) and YaraMila 52 S (20.6-8.2-11.6+6.5% SO₃) is a mix of water-soluble phosphate and Di-Calcium Phosphate (DCP). This DCP is not fixed by the soil but becomes available as it is triggered by weak acids from grass root exudates. This ideal combination of two phosphate fractions rather than one results in superior availability of P for grass.

The maintenance requirement for phosphate (P₂O₅) on grazed swards is 20 kg/ha, however if your grazing platform is growing 15 t of dry matter with 80% utilisation, then your maintenance will be closer to 30 kg/ha. It’s important to choose a quality uniform compound to maximise P & K landing sites.

It’s the time of year again where early nitrogen applications are up for debate. We would recommend applying 50 – 75 kg N/ha of YaraVera Amidas (20 – 30 kg N/ha) for these early N applications. They should only be applied when you can travel with a tractor, and without any major rainfall event forecast in the next 48 hours and soil temperatures are above 5.5 degrees and rising.

The benefit of spreading this low rate of N early is a large increase in growth rates in March and early April. A grass yield response of 13 to 16 kg grass dry matter per kg N applied is typical at this rate applied in February. Many farms this year lost out on an estimated 500 – 700 kg of grass dry matter growth over the course of the year due to missing fertiliser N applications up to mid-March. Delaying this early application reduces overall grass grown.

Heavy rainfall rather than low soil temperatures has been the main cause for missed or late early N applications, but there have been missed opportunities in many cases where early N could have been spread.

The environmental risk associated with slurry spreading in early spring is greater than the application of 50 – 75 kg/ha of YaraVera Amidas when applied in the correct conditions. Have the fertiliser product you need in the yard and ready to spread. Instead of waiting to spread the whole grazing block, apply it first on areas that are likely to respond best, such as those drier, warmer and recently reseeded paddocks.