Fertiliser use this spring – what to consider

High fertiliser prices will be a real challenge for farmers, and many face a dilemma of how much and what to buy. Where there’s scope to reduce grass or silage demand, then there is some wriggle room but if demand is going to remain the same then the opportunity to reduce fertiliser volumes from previous years is limited. Farmers may be faced with prioritising nitrogen (N) this year and skipping or reducing phosphorus (P) and potassium (K) applications in a bid to offset higher fertiliser costs.

Much of the commentary on reducing the impact of higher fertiliser prices has focused on slurry N utilisation, and there is scope on some farms to shift more applications into spring, however, a large proportion of farmers won’t have access to low emission spreading equipment (LESS). This cohort of farmers will have very little opportunity to lower their fertiliser N use from previous years without lowering grass production.

The most consistent and, usually, the best response to N from a bag or from slurry is during April and May. A reduction in N rates for grazing needs to be evaluated as it means the area normally closed-up for silage is less, or alternatively, the total N rate for 1st cut silage is reduced from previous seasons. When we lower our N rate (slurry + bag) on 1st cut silage, we will reduce the cost on a per acre basis but not per tonne. We end up with less silage in the pit with no real savings.

Spring N for grazing

One of the most important factors affecting spring grass growth on farms is the timing and quantity of the first spring N fertiliser application. This early spring grass is extremely valuable as a means of increasing the proportion of grazed grass in the diet. The on farm response to early N can be variable (5 – 18 kg/DM per kg N, source: Teagasc), and coupled with higher N prices, getting timings right is more crucial than ever to make sure we justify the cost.

There’s always an element of debate around the right approach to spring N management. As a rule of thumb, the timing of the first N application should coincide with soil temperatures reaching 5 - 6oC. Looking at the Grasscheck GB website could be helpful, as participating farmers have weather stations recording soil temperature and soil moisture levels. If soil moisture is less than 10, this would indicate that soil is saturated on that particular farm. Fertiliser or slurry should not be applied when soil is saturated. A favourable weather forecast and good field conditions are also necessary when deciding when to spread.

For this first N application, we recommend using YaraBela Nutri Booster at a rate of 25 – 30 kg/ha N. The second application should aim to deliver 45 - 50 kg/ha N and be applied by the end of March on intensively stocked farms or mid-April on farms with a later turn-out date later and/or on heavier soils to take advantage of improving growing conditions. These rates are appropriate for newer swards with high perennial ryegrass content. On less intensively stocked farms or on swards that will be less responsive to N, then the above rates should be scaled back by 25%

What about P & K?

Farmers may be considering a P & K ‘holiday’ this year in an effort to offset higher fertiliser prices. This needs to be considered carefully, particularly on farms that are highly stocked. The trouble is, while the cost-saving is known, the potential penalty in lost yield is uncertain so it’s a question of risk. This is in the short term, because longer-term, any negative balance of phosphorous and potassium where these are not applied this year, will have to be made up. You don’t get something for nothing.

We have not seen the same price rises for fertiliser P & K as N, and currently, NPK’s could be considered better value for money in comparison to straight N products. On dairy farms, it may be counterproductive not to maintain current soil fertility levels this year, at the expense of growing less grass. Also, there is no certainty that the cost of fertiliser P & K will return to early 2021 price levels.

For beef and sheep farmers, it may be a case that N is prioritised, at the expense of P & K. This is not a situation that we want to see, but it may well be the reality on many farms. If only a percentage of the normal P & K rates can be spread, then late spring is the most opportune time to apply these on grassland approaching peak growth rates. Slurry should be prioritised for silage fields and the remaining if any for grazing fields/paddocks with low soil P & K fertility.

The great unknown is the weather and it ultimately has the greatest impact on fertiliser performance, so fingers crossed for an early spring where livestock can be turned out early and can stay out.

The yield impact of lower nitrogen rates

Most farms will apply through experience, roughly the same amount of N fertiliser each year to grow what forage is required on the farm. Some years you grow more grass for the same amount of N because the weather is favourable and other years you grow less. For any farmer contemplating reducing N fertiliser applications on grass, it would be worthwhile to calculate what any decrease in N rates will have on grass growth.

From Yara’s own trial work in both the UK and Ireland and other sources we can estimate that on a typical 1st cut with good yield potential and soil fertility, harvested between the 1st and 20th of May, we can expect to grow 25 kg of dry matter (DM) per kg of applied N. Late May – early June harvested 1st cuts will grow closer to 30 kg of DM per kg N.

For grazing on intensively stocked farms, N responses can be very variable in early spring, with 10 kg of DM per kg of applied N for that late-February to March period considered good. The response increases (20 – 30 kg of DM per kg N) very quickly in April with improving weather and soil conditions, rising to 30 – 40 kg DM per kg N in May.

Example: A farmer who plans to mow his/her 1st cut on the 10th of May is going to reduce the N rate from 120 kg/ha to 100 kg/ha because of the high fertiliser price. The yield loss is likely to be 500 kg/ha of DM (25 kg of DM x 25 kg N). The question is, can the farmer replace this 500 kg of DM for less than the saving on the fertiliser?

The highest and most reliable DM response year-on-year to applied N is in this April/May period, and any reduction in N rates particularly on 1st cut silage crops should be carefully considered. Because, a large portion of the cash costs associated with producing grass silage is charged on an area basis, so a reduction in yield pushes up the cost on a per tonne basis and any savings on fertiliser can be quickly eroded.

Tips for using manures more effectively

Following the recent dramatic increase in the cost of fertiliser, brought on by record-high gas prices. What can be done to lower the fertiliser requirements on farms without risking output? The distribution of manures around the farm, how and when they are spread will be key.

Before February comes around, have up-to-date soil test results to hand and use them to put a nutrient plan in place for your farm. You’ll have a fair idea how much manure you have, so it’s a matter of allocating this manure to make the best use of the nutrients in them.

If there was ever a good time to test slurry, then it would be this spring. The nutrient content of the slurry is variable and book values are averages, so therefore on a good many farms, the fertiliser replacement value of slurry is being underestimated.

Can more slurry be applied in the spring? Spreading slurry (by trailing shoe) in the spring compared to the summer increases the nitrogen availability from 30% to 40%, this would increase the available nitrogen by 0.26 kg per cubic metre or 2.5 units per 1,000 gallons. Where possible, spread slurry using low-emission equipment.

Finally, use the right fertiliser. Using a sulphur-containing product can boost yields by more than 10%, compared to straight nitrogen. On a typical 1st cut, that’s over 500 kg/ha of extra dry matter.

These marginal gains will not fully offset the increase in fertiliser prices, but they can help

 

Yara’s ‘Value of Grass’ calculator

Because most livestock farmers are growing grass to feed to livestock, it can be difficult to put a value on grass for the purpose of evaluating the economics of nitrogen applications on grassland. In an effort to help farmers understand what value to attach to grass forage, and the effect that fertiliser costs have on it, we have put together a calculator on our website to help demonstrate how valuable grass is, if we compare replacing its feed value with purchased concentrates.

The calculator is simple to use, and gives the user the opportunity to test different scenarios. The variables that can be changed include the price of fertiliser, barley and rapeseed meal, and grass yields and quality (% DM, ME MJ/kg, % CP).

We hope this calculator makes it easier to evaluate the cost of fertiliser and it’s contribution to growing grass on your farm.

Check out the value of grass calculator

Soil health is vital: Test it, review it and take action

At some stage, over the next couple of months, you should 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 2021. An NMP is really about prioritising how we 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 1 – 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, grass requires a continuous and balanced nutrient supply from the soil to achieve its production potential. If a farm is regularly soil testing, say every three years, then the £1 ha/year cost is money well spent.

Grassland agronomy advice

The latest grassland fertiliser and nutrition advice from the Yara agronomists.

What will be the cost of next year's first cut silage?

With nitrogen (N) prices where they are, what are the likely cash costs associated with producing a first cut next May? Might it be worthwhile to produce less silage in the spring, and buy more feed instead?

In reality, the cash cost will vary between farms, but with good levels of management, I calculate a cash cost of £390 per ha (or £71 per tonne dry matter (DM). This assumes a yield of 5.5 tonnes/ha DM, where the total N rate was 120 kg/ha (80 kg/ha coming from fertiliser and 40 kg/ha from slurry). N fertiliser is costed at £1.42/kg, and this accounts for 29 % of the total cash cost to produce this hypothetical first cut.

Because the lion’s share of the cost (i.e. machinery operations) are charged on a per ha basis rather than on yield, achieving good yields by optimising crop nutrition through efficient utilisation of manures and topping up with purchased N, is still the most cost-efficient option. Lower N rates will lower yields and protein %, therefore pushing up the cost of each tonne grown.

The replacement value of good quality silage with a mix of soya and barley at £368 and £170 per tonne respectively, would be £186 per tonne DM. So it costs £71 tonne to produce on-farm, but £186 to replace it. Increased fertiliser prices will push up the cost of homegrown feed next year but if the alternative is to replace forage with bought feed, then the latter option will cost more.

N or NPK: to spread or not to spread?

Spreading nitrogen (N) from mid-September onwards needs careful consideration. The growth response will have to justify the cost, and excess N not utilised by the plant is at risk of leaching. If you’re farming in an NVZ in England or Wales and within your N-max, you’re allowed up to 80 kg/ha N on grassland between the 15th September and the 31st October, with a maximum of 40 kg/ha N being allowed in any one application. Whereas in Scotland no nitrogen fertiliser may be applied from 15th September.

It's worth checking how much P & K has been applied to date, and if there’s any shortfall then apply a suitable compound NPK fertiliser like YaraMila 52 S or YaraMila NK SULPHUR to replenish this year’s P & K offtakes instead of N only. Under applying P or K this year only depletes soil fertility for next year and there is a clear relationship between good soil fertility and high grass dry matter production. So as tempting as it may seem to go with nitrogen only in this last application, we shouldn’t risk lowering soil fertility for next year.

Grass demand should dictate the N rate, but don’t forget to also consider soil conditions and the weather forecast. Take a paddock by paddock approach to spreading N rather than blanket spreading the entire grassland area. Depending on your demand for grass, apply 25 – 30 kg/ha N and earlier the better. Higher rates of N, or N applied in October, won’t be justified in most years.

Grow grass to extend your autumn grazing

From mid-September, daily grass growth will fall rapidly. After this point grass can quickly run out and either livestock performance declines or they will require housing to maintain performance. If we start to manage grass now, we can grow more grass over the coming weeks. This then allows us to build up a bank of grass for extending the grazing period and, if correctly managed, allows for an earlier turnout of livestock in the spring.

Grass DM yield response to Autumn applied fertiliser N

Grass grown now will remain leafy, albeit not as good as that grown earlier in the year. It will not require the same level of purchased feed to maintain a certain level of milk yield, or daily live weight gain, compared to feeding poorer quality forage indoors or set stocked grazing where there is poorer quality grass with lots of dead material at the base.

If we optimise grass growth over the coming weeks by applying YaraBela Nutri Booster and operating a rotational grazing system (even if it’s temporary fencing), we can save money and shorten the indoor period. This means that livestock will need to graze an area and then be moved onto a fresh area every 1-4 days, allowing the sward to recover and start growing again. The drier or ‘earlier’ parts of the farm should be grazed from mid-September and then closed off as the regrowth on these parts can be carried over the winter months for grazing first in the spring.

Grass and forage agronomy and fertiliser advice
Grass and forage agronomy and fertiliser advice

Looking for even more information ...

If you would like more information and would like to speak to one of our area managers or agronomists please find all their contact details here.

Contact your local Yara area manager or agronomist

 

Where can I buy Yara fertiliser ...

If you would like to find your nearest Yara supplier or merchant simply use this searchable map with all their contact details here.

Where can I buy Yara fertilisers >

How can I increase my soil carbon levels?

Measuring carbon levels in the soil is becoming increasingly important with the development of financial incentives for carbon sequestration. The thought behind it is that an increased amount of carbon sequestered in soil should help to lower the amount of carbon in the atmosphere, with the added benefit of increasing soil quality.

Increasing soil carbon means carefully managing its inputs and losses. If the amount of carbon going into the soil exceeds the amount of carbon being lost from the soil, then, generally speaking, the amount of carbon stored in the soil should increase.

However, some soils can store more carbon than others. Soils that have higher clay contents can store more carbon than soils with less clay. That’s because clay particles physically protect organic matter making it harder for soil micro-organisms to make contact and decompose it. Sandy soils contain less clay, so it is easier for microbes to get to the organic matter and break it down, hence sands turnover carbon much quicker and usually can’t achieve higher stored carbon levels.

The main carbon inputs to soil are from plant material such as roots, residues, root exudates and animal manure. Plants capture carbon from the atmosphere and use it to grow. Carbon makes up the majority of the mass of the plant, and when plants are returned to the soil after being excreted or incorporated, the carbon they contain is added to the soil’s carbon store.

Grass mineral analysis – a useful management tool

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 grassland to utilise silage mineral analysis to improve yields and nutrient use efficiency.

During the winter a farmer asked me to have a look at his 1st cut silage mineral analysis report received back from the Yara Analytical Services lab which highlighted a couple of potential problems. Because it was a composite sample from a number of different fields, it warranted a closer look in the spring, so three silage fields were sampled in May, 10 days before harvest.

The three fields had received the same nutrients in the spring - a combination of slurry and YaraMila EXTRAGRASS (27-5-5+6%SO3). Nitrogen, phosphorus, 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 deficient.

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 low soil pH (5.4) was the difference in the ‘deficient’ field. This makes sense, as soil pH affects nutrient availability. This again highlights the benefit of analysis and in particular the importance of acting on the results, especially correcting low soil pH.

Nitrogen – what is the rule for grazing?

As a rule of thumb we use the two units of nitrogen per day (2.5 kg N/ha/day) to guide nitrogen application rates for grass silage swards, but what about grazing? Where there is a high demand for grass on intensively stocked farms, then we should be aiming to apply 1 unit of nitrogen per day (1.25 kg N/ha/day), over the coming three months. So, if your rotation length is 21 days, then apply 21 units of nitrogen (26 kg N/ha), and aim for a total of 30-31 units of nitrogen per month (37.5 kg N/ha/month). If this seems low, remember there is nitrogen carryover from urine and dung from previous grazings.

For best results, use a nitrate-based nitrogen fertiliser, like YaraBela Nutri Booster. This CAN-based fertiliser with 5 % sulphur was specifically formulated for mid-season nitrogen applications. Nitrate based fertilisers are more reliable during the summer months. The added environmental benefit of using CAN based nitrogen products like YaraBela Nutri Booster is its very low ammonia emissions - even during the summer months.

If paddocks have a clover content of 20 – 25 %, then there is scope to stop nitrogen applications altogether from June onwards. Irish research has demonstrated that clover swards receiving 150 kg N/ha (120 units/acre) of nitrogen annually, had similar performance to perennial ryegrass swards receiving 150 kg N/ha (200 units/acre). 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 and K compound like Yara Super PK throughout the growing season are necessary for high levels of clover productivity and biological N fixation.

Listen to the latest grassland podcasts

If you are short of time why not check out our bite-size podcasts for the latest thoughts on grassland nutrition

Fertilising second cut silage

It’s fair to say, that first cut silage yields have been disappointing. It’s no wonder considering the growth we’ve had during April and early May. Some have ended up grazing fields that were intended for the first cut, so with this in mind and low silage stocks, a good second cut will be more important than ever to put tonnes in the pit for the winter ahead.

If adequately fertilised, and with favourable growing conditions these 2nd cuts crops are capable of 6 – 7 tonnes of fresh weight per acre, which isn’t far behind a good first cut. Slurry and fertiliser application rates are important considerations to make the most of second cut yield potential.

It’s best practice to apply fertiliser a week after the slurry has been applied. If no slurry is being applied, then spread the fertiliser within a couple of days of the first cut harvest or on closing up from grazing. It happens regularly that nutrients applications are delayed too long, which then results in lighter crops or crops needing a longer growing period, which in turn lowers silage quality.

New swards have excellent yield potential and respond to higher nitrogen (N) rates of up to 100 kg/ha (80 units/acre). Older swards with a high proportion of perennial ryegrass (PRG) can be fertilised to 90 kg/ha (72 units/acre) N and old meadow swards which don’t contain much PRG should receive 70 kg/ha (56 units/acre) N.

If there is no slurry applied or low volumes on account of the risk of slurry contaminating second cut grass at harvest, then make sure to use an NPKS fertiliser like YaraMila SILAGE BOOSTER.. Don’t forget sulphur on these 2nd cuts. 25 – 30 kg/ha (20 – 24 units/acre) of SO3 is enough.

Sulphur is an important nutrient, and it certainly merits using a fertiliser that contains sulphur on these second cuts. The response does vary according to soil type, regularity of manure applications and overwinter rainfall, but the majority of silage crops do respond to applications.

With over 90 % of silage samples analysed having very low selenium levels, there is also an opportunity to increase the selenium content of silage for the winter ahead by using fertiliser’s fortified with selenium like YaraMila SILAGE BOOSTER. This is most beneficial to pregnant cows and ewes.

A good second cut, requires a proactive approach to ensure these crops are optimally fertilised, so just slurry and straight N might not be the most cost-effective option in the long run, if we compare the cost of homegrown silage versus purchased feed on a dry matter basis

Finally, don’t delay applying slurry and fertiliser. The slurry should be applied immediately after the first cut is harvested and then apply the fertiliser 5 – 7 days later. If slurry isn’t being applied, then get the fertiliser out as soon as possible but it’s important to order what fertiliser is required and have it ready for spreading.

Slurry for second cut silage

If slurry is available, the amount needs to be evenly applied over the entire second cut silage area. What often happens is, too much is applied at the beginning before it’s realised there’s not enough in the tank, and then the application rates have to be reduced or even vice versa. We end up with parts of the field being undersupplied with nitrogen (N) and potassium (K).

Slurry needs to be applied as soon as the first cut has been harvested, and preferably by low emission spreading systems (LESS) like trailing shoe. On fields that are only now being closed up for silage after being grazed, then the grass needs to be well grazed down. Slurry is a great source of nutrients and reduces fertiliser costs, however, we don’t want the residues of this slurry ending up in the pit and causing issues. It really depends on how ‘watery’ or ‘thick’ the slurry is. Thick slurry would need to be applied in lower volumes for fear it mats the grass and doesn’t get washed off. Lower dry matter (DM) slurry or ‘watery’ slurry can be spread at higher rates.

The period of time between slurry application and a planned harvest will also dictate the slurry rate. If it’s less than 6 weeks then low volumes, and if it’s ‘thick’ slurry being spread by splash plate, then it might be better not to apply, and leave till later in the season.

Reach that maize yield potential with foliar nutrition

Maize has a high demand for nutrients due to its high yield potential. These high yields of 40+ tonnes/ha can only be achieved if the crop can access enough nutrients via its roots, and as the plant grows, through foliar applications.

Zinc and magnesium deficiencies are the two most widespread nutritional disorders in maize. Zinc is important for photosynthetic activity. Magnesium is essential for the early establishment of the plant. A deficiency is reflected in reduced crop yield at harvest.

Phosphorus and potash are primary nutrients, however, many soils have not got the capacity to deliver an adequate supply. Where phosphate availability is reduced because of soil pH or where its uptake is impaired due to dry soil conditions, foliar phosphate will help. It is translocated from the leaf to the roots very effectively, maintaining root development.
One or more of the above is often deficient in the growing maize plant. This nutritional shortage is particularly important as the plant reaches the 4 to 5 leaf stage as it is now that yield is being set. Maize stressed at this point can result in tall, thin plants, with poor root systems and reduced leaf area. Reduced leaf area captures less light, resulting in lower yields.
To overcome the risk of nutrient deficiency, apply foliar nutrients at the 4 to 5 leaf stage. YaraVita Maize Boost is specifically formulated for foliar applications on maize. It will deliver a high concentration of phosphate, zinc, magnesium and potash to maximise maize yield and quality this harvest.

Cold and dry spring hits grass growth

In a dry and cold spring, it’s likely that 1st cuts will be lighter, so if you’re looking to cut high-quality silage stick as close to your planned cutting date. Hopefully, we can make up this yield loss in subsequent cuts, but we won’t be able to make up for the higher costs of supplementing poorer quality silage.

On farms where 1st cuts are only being closed up, then use a nitrate-based fertiliser. If slurry hasn’t been applied then definitely go with an NPKS product like YaraMila Silage Booster to maximise silage yields. Potash (K) is a really important nutrient for silage and a low K supply can really hit silage yields. For every kg of K we apply per ha, we see a return of 20 – 30 kg of silage. If 22 – 33 m3/ha (2,000 – 3,000 gallons/acre) of cattle slurry is applied, then an N + S product like YaraBela Nutri Booster is adequate.

To calculate the N required for a 1st cut that is only being closed-up for silage, then count the days between closing-up and a planned cutting date. Subtract 5 days from this number, and then multiply by 2.5 to give the kg/ha of N required (multiply by 2 to give units/acre). The N in any cattle slurry (0.9 kg/m3 or 8 unit/1,000 gal), along with 20 % of any fertiliser N applied earlier for grazing, should be deducted from the N requirement of the silage crop to give the fertiliser N rate.

Four steps to successful reseeding

Benefit of reseeding on net rofit

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.

Step 3: Take a soil test and act on the results. Before you start, be sure to complete this step. 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 and a lower requirement for nitrogen.

My Top Tips: Weeks 4-6 (post-emergence) apply herbicide to prevent weeds competing for nutrients and space. Graze lightly with youngstock or sheep, as soon as the new plants don’t pull out of the ground, which is usually when grass height is at 6 - 7 cm or at the two-leaf stage to promote new shoots, and thus the long term productivity of your new sward.

Purchase quality compound fertiliser

At this stage, most 1st cut fertiliser applications are completed, but are you confident that your target fertiliser rate was evenly applied? Yara has demonstrated how, over 24 metres, the physical quality of a fertiliser influences the yield and quality of a grass crop.

Yara has looked at this effect by comparing YaraMila Extragrass (27-5-5+6%SO3) with a blended 27-5-5+S. The target rate for both products was 500kg/ha and the spreader settings were changed for each product on testing. The YaraMila product achieved the target rate across the whole bout width; however the application rate for the blended product varied between 400 to 648kg/ha.

We then analysed separately each of the 23 trays from the blended product, to determine the actual NPK+S content. Because the YaraMila product is a compound, we know that the product in each tray contained 27% N, 5% P2O5, 5% K2O and 6% SO3. The blended product had a variation in N across the bout width of between 91kg and 160kg, for P the variation was 10 to 19kg and for the K it was 34 – 59kg/ha. The target was 135kg, 25kg and 25kg for N, P2O5, K2O respectively.

Accounting only for unevenness of the N, in this blend, compared to the YaraMila Extragrass, there was a yield loss of nearly 400kg/ha of grass dry matter. That’s a loss of nearly 1.5 tonnes of silage, worth around £30 per ha.

Don’t take the chance, use a quality compound fertiliser.

The first cut is the cheapest

With 1st cut fertiliser applications underway, it’s important to remember that 1st cut silage is the most economical cut to grow. For all cuts the variable costs are similar. Due to the high yield of the 1st cut, it is this forage that achieves a lower cost/tonne of dry matter ensiled. The nutrition given to these crops this spring will be the main driver of how well they perform come harvest.

What nutrients are required? Slurry is available on most farms and should preferably be applied by low emission equipment. It minimises nitrogen (N) losses from ammonia volatilisation, leaving more N in the soil for the crop. 1,000 gallons/acre of cattle slurry, contributes 7 units of N if applied by splash plate (or 9.5 units if applied by trailing shoe/trailing hose). After accounting for the N in the slurry, the mineral N rate should be calculated to ensure that the crop receives a total N rate of 100 units/acre.

At least 70 units of potash should be applied for 1st cut, unless the soil index is 3 or above. A little more can be applied if the soil index is 0 or 1. If this potash rate is not supplied via slurry then apply in fertiliser. 1,000 gallons/acre of cattle slurry contains 21 units of potash. All 1st cut silage crops should routinely receive 25 – 30 units of sulphur. Where an NPKS fertiliser is required, then YaraMila Silage Booster ticks all the boxes.

The big questions in spring

How long should I leave between applications of fertiliser nitrogen (N) and slurry?, is one of the questions I am most often asked. Slurry applied on fertiliser N creates ideal conditions for denitrification, i.e., anaerobic conditions and high carbon compounds. It is recommended to leave 7 days before or after slurry spreading for application. There’s always some confusion around lime applications and urea. If lime is applied, then urea shouldn’t be spread for at least 3 months afterwards. The lime increases the soil pH which increases the rate of volatilisation of ammonia. Lime can be spread 10 days after urea applications.

I’m also asked: What are the sulphur levels in slurry and are they enough for a 1st cut silage? If 2,000 gallons/acre of cattle slurry (22 m3/ha) was applied this spring, it’s estimated to contain 6 units/acre (7 kg/ha) of crop available sulphur. This is not enough, as a decent 1st cut will remove 28 - 32 units/acre (35 – 40 kg/ha). Sulphur in autumn slurry applications may be lost via overwinter leaching. Some of the available crop sulphur (sulphate) in slurry is also lost during storage, as anaerobic storage conditions lead to the conversion of sulphate to hydrogen sulphide gas.

Phosphate is another topic. The 16 units/acre (20 kg/ha) of phosphate on my grazing area, when should I apply? My advice is to spread it over two or three applications, with two preferably in the spring and then another in early June.

Lime your grassland and reduce your greenhouse gas emissions

Research in Ireland has shown that by liming to increasing soil pH there also followed a significant reduction of N2O emissions and increased grassland productivity. Liming is well known as an agronomic measure to ameliorate acidic soils and maintain soil pH at the optimum level for high crop productivity. Liming increases the activity of soil microbes and the availability of nutrients, most notably phosphate, leading to improved plant growth. This research could be used to further support an increase in the optimum soil pH for grassland on farms with high grass yields.

The soil at the trial site was classified as acidic, with a pH of 5, but liming over 10 years resulted in soil pH ranging from 5.0 to 6.9. Increasing soil pH by liming resulted in a significant reduction of N2O emissions and increased grassland productivity compared to the un-limed plots under the same management and nitrogen fertiliser regime. The degree of reduction in N2O emissions mainly depended on the amount of lime applied across the experimental period. When soil pH was increased to 6.9, N2O emissions were reduced by 39% compared to the control soil pH of 5.0. The long-term results in terms of grass yield showed that the highest yields were achieved when liming was combined with regular phosphate application. Plots limed to pH higher than 6 had 0.5 t/ha higher dry-matter yields, while the yields in limed plots with optimal P content had 1.5 t/ha higher yields on average compared to un-limed soils with low P fertility.

Spring N for grazing - what’s your plan?

One of the most important factors affecting spring grass growth on farms is the timing and quantity of the first spring nitrogen (N) fertiliser application. Early spring grass for grazing is extremely valuable. Therefore however modest any increase in grass growth might be, it can be a big help to balance the overall feed requirement of livestock. Grass requires more N to grow, so sulphur (and potentially phosphate and potash) are also required.  

There’s always an element of debate around the right approach to spring N management. As a rule of thumb, the timing of the first N application should coincide with soil temperatures reaching 5 - 6oC. If you’re using a soil thermometer for the first time, my advice is it make sure you insert it 10 cm’s into the ground. You can also check the Grasscheck GB website for soil temperatures. Of course, a favourable weather forecast and good field conditions are also necessary when deciding when to spread.

For your first N application, we recommend using a product with sulphur such as YaraBela Nutri Booster at a rate of 20 - 23 units N/acre. The second application should aim to deliver 40 - 45 units and be timed to take advantage of improving growing conditions in early April. These rates are appropriate for newer swards with high perennial ryegrass content. On less intensively stocked farms or on swards that will be less responsive to N, then the above rates should be scaled back by 25%.

Soil health is vital: Test it, review it and take action

At some stage, over the next couple of months, you should 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 2021. An NMP is really about prioritising how we 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 1 – 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, grass requires a continuous and balanced nutrient supply from the soil to achieve its production potential. If a farm is regularly soil testing, say every three years, then the £1 ha/year cost is money well spent.

3-cut vs 4-cut Silage System: Does it make a difference?

The quality of grass silage fed to dairy cows is an important factor in cow performance and margin-over-feed cost. Silage digestibility (D-value) declines by an average of 3.3% for each week delay in harvest. Hence the move by dairy farmers to cut earlier and more frequently. A recent Northern Irish study examined cow performance and the whole system impact of offering silages produced within either a 3 or 4-cut system.

Total silage dry matter (DM) yields for the 3 and 4-cut system were 13.4 t DM/ha and 12.3 t DM/ha respectively. The average DM of the 3-cut system was 31.9% and 34.4% for the 4-cut system. The average metabolizable energy (MJ/kg DM) was 10.7 and 11.3, and average protein (% DM) was 14.3 and 16.4 for the 3 and 4-cut system respectively.

Cows on the 4-cut system had higher silage intakes (+9.5%), produced more milk (+6.4%) with higher milk protein (+2.1%) but slightly lower fat content (-2.4%). Silage production costs were calculated as £114 and £135 t/DM for the 3 and 4-cut system respectively. This includes a land charge, reseeding cost and a contractor for harvesting.

Total feed costs were 23 pence/cow/day higher with the 4-cut system, but the value of milk produced was 71 pence/cow/day higher. The margin-over-feed cost was 48 pence/cow/day higher for the 4-cut system. For a 100 cow herd over a 180 day winter period, the 4-cut system resulted in a £8,640 increase in margin-over-feed costs.

Multi-cut silage systems may not suit every farm, but bring the potential to lower feed costs, improve milk output and make dairy farms more self-reliant.

Green Ammonia – What is it and Why?

Yara announced its plan to produce Green Ammonia earlier in the year but what does this actually mean?

In order to produce ammonium nitrate (AN) fertilisers, ammonia is mixed with nitric acid to produce a liquid ammonium nitrate solution, this then goes on to produce the prills or granules that you’d recognise as fertiliser. The ammonia that is used for this process is produced with hydrogen gas from fossil fuels, mainly natural gas (methane), and therefore is classed as ‘brown’ ammonia due to its use of natural resources.

Green Ammonia is produced in a different way. H2O undergoes electrolysis, which is powered by renewable energy sources such as wind and solar power, in order to get the required hydrogen gas. Nitrogen is obtained from the atmosphere (which is 78% nitrogen gas) and two undergo the Haber-Bosch process. The end result is Green Ammonia, made from renewable sources. Unlike in the traditional ‘brown’ ammonia method, there is zero CO2 ‘waste’, therefore there is only a very low carbon footprint associated with Green Ammonia.

This is increasingly important as consumers want to know the carbon footprint of their purchases and it is thought that all food items will show a carbon footprint value in the near future. Every process needs to be sustainable and have as little impact on climate change as possible. With ammonia being the second-most-widely produced commodity chemical globally, (annual production volume of over 180 million tonnes) this new method would make a massive impact worldwide.

Grass YEN 2020 results review

Grass YEN, the industry-science platform had its end of year meeting earlier in October. Yara was once again co-sponsor of the event, and I would like to take this opportunity to thank the five farmers that we sponsored for their time and energy in participating in this year’s competition.

There were 23 silage crops entered in this year’s competition. The yield gap between 1st cuts and 2nd cuts was narrower as you would expect with the drought affecting 1st cut yields. Average 1st cut dry matter (DM) yields were 5,385 kg/ha, ranging from 3,502 – 9,014 kg/ha. Average 2nd cut DM yields were 4,602 kg/ha, and ranged from 3,218 – 8,754 kg/ha. DM yields for 3rd cuts averaged 3,028 kg/ha.

Nutrient offtakes is always an interesting aspect of Grass YEN, where grass samples from each grass crop are analysed for their mineral content and from this offtakes are calculated. The average offtakes for each tonne of DM yield across all crops was 21kg of N, 7kg of P2O5, 31kg of K2O and 5kg of SO3. With the highest yielding cuts taking off over 300kg N/ha, >400kg/ha K2O, >50kg/ha SO3.

Looking at the tissue concentrations of the crops sampled, 74% of the crops were considered sulphur deficient. If we want to improve nutrient use efficiency on farms, the use and rate of sulphur applications on silage crops needs careful consideration and could be an easy win to reduce nutrient loses, increase yields and improve silage quality.

In the battle to reduce our carbon footprint, could green ammonia be the hero?

Ammonia is a gas that is widely used to make nitrogen fertilisers. Green ammonia production is where the process of making ammonia is 100% renewable and carbon-free. One way of making green ammonia is by using hydrogen from water electrolysis and nitrogen separated from the air. These are then fed into the Haber process (also known as Haber-Bosch), all powered by sustainable electricity. In the Haber process, hydrogen and nitrogen are reacted together at high temperatures and pressures to produce ammonia (NH3).

Reducing the amount of carbon dioxide produced during the ammonia manufacturing process is critical to achieving net-zero targets by 2050. The best way to reduce carbon emissions when making ammonia is to use low-carbon hydrogen. Green hydrogen is produced using water electrolysis to generate hydrogen and oxygen, and the availability of sufficient green energy limits the production capacity of green hydrogen.

A consequence of decarbonised ammonia production is you can’t produce urea. Because urea is made by combining ammonia and the carbon dioxide (CO2) released in the earlier process where hydrogen is split from the carbon source (usually natural gas) to provide the hydrogen in ammonia (NH3) production. So it’s unlikely urea can be part of a decarbonised food chain.

It’s Yara’s goal to decarbonise fertiliser production, but it will require significant ongoing investment in R & D and production capacity. It’s interesting to note that when Yara first began producing nitrogen fertiliser in Norway, back in 1905, the process was carbon-free! The energy source back then was hydro-electricity.

Nitrogen: to spread or not to spread?

Spreading nitrogen (N) from mid-September onwards needs careful consideration. The growth response will have to justify the cost, and excess or unused soil nitrate should be minimised as we approach winter as it constitutes a risk to water quality. If you’re farming in an NVZ, then you’re allowed up to 80 kg/ha of mineral nitrogen on grassland between the 15th September and the 31st October, with a maximum of 40 kg/ha of N being allowed in any one application.

Preferably N applications should take place at a time when grass growth is sufficient to utilise it. Teagasc research on autumn applied N has shown that 30 kg/ha of N applied on the 1st of August, 1st September and 1st of October gave a grass dry matter (DM) response of 27 kg, 19 kg and 10 kg respectively, for each kg of N applied. If we assume that this grass DM contains 3% N, then our apparent N recovery rate was 80% for August, dropping to 30% for October.

It is important that any N applications take into account the requirement for grass, but don’t forget to also consider your soil and weather. I advise taking a paddock by paddock approach to spreading N rather than blanket spreading the entire grassland area. Depending on your demand for grass, apply from 20 – 25 kg N/ha, and preferably by mid-September. Higher rates of N, or N applied in October, won’t be justified in most years.

Fertiliser advice for short term leys and hybrid brassicas

Adequate fertiliser is essential to obtain the maximum yields that short term leys and hybrid brassicas are capable of producing. In general these crops are being sown after a cereal crop, and therefore soil nitrogen supply (SNS) is likely to be low.

For temporary leys following cereals, we recommend 312 kg/ha of YaraMila Actyva S (16-15-15 + 6.5% SO3) to deliver the necessary NPKS for establishment. This true uniform compound fertiliser ensures a maximum number of phosphate landing sites. The seedlings’ access to phosphate is particularly important for root development and tillering.

Remember that there’s 7.5 kg/ha of nitrogen in every 1 cm of grass growth. We would expect Italian ryegrass or Westerwolds to grow to a minimum height of 10 cm by the end of October, therefore requiring 75 kg of N. If we apply 50 kg of N from the bag, there will be enough soil residual N to provide the remaining.

Hybrid brassicas, such as Redstart and Interval, may still be drilled into late August. They have similar nutrient requirements to those of forage rape and stubble turnips. We recommend 400 kg/ha of YaraMila Silage Booster (20-4.5-14.5 + 7.5% SO3 + Se) to deliver the necessary NPKS to grow these crops on fields with an SNS of 0 or 1 and a P & K index of 2.

It is vital to get these crops off to a good start, so placing the fertiliser in the seedbed will help to establish strong healthy plants.

Grow grass to extend your autumn grazing

From mid-September daily grass growth will fall rapidly. After this point grass can quickly run out and either livestock performance declines or they will require housing to maintain performance. If we start to manage grass now, we can grow more grass over the coming weeks. This then allows us to build up a bank of grass for extending the grazing period and, if correctly managed, allows for earlier turnout of livestock in the spring.

Grass grown now will remain leafy, albeit not as good as leafy grass grown earlier in the year. It will not require the same level of purchased feed to maintain a certain level of milk yield, or daily liveweight gain, compared to feeding poorer quality forage indoors or set stocked grazing where there is poorer quality grass with lots of dead material at the base.

Grass yield response to autumn applied nitrogen

If we optimise grass growth over the coming weeks by applying nitrogen and sulphur now and operating a rotational grazing system (even if it’s temporary fencing) then we can save money and shorten the indoor period. This means that livestock will need to graze an area and then be moved onto a fresh area every 1-4 days, allowing the sward to recover and start growing again. The drier or ‘earlier’ parts of the farm should be grazed from mid-September and then closed off as the regrowth on these parts can be carried over the winter months for grazing first in the spring.

Soil fertility in grass based systems - what can we learn from Ireland

Adopting Controlled Traffic Farming (CTF) could help reduce soil compaction risk and boost yields by up to 10.5%, while also reducing nitrous oxide emissions.

In Yara’s recent grassland webinar, we were joined by Mark Plunkett, a specialist in soil and plant nutrition with Teagasc in Ireland. Mark reviewed current soil fertility trends on Irish farms. He then went on to explain why Teagasc have focused considerable effort to demonstrate why it’s worth improving soil pH, phosphate (P) and potash (K) levels to keep farms competitive.

On Irish dairy farms the trend over the last 10 years has been positive for soil fertility. This information is collated annually from Irish soil test result records. Soil pH has improved on these farms, and currently 59% of soil samples have a pH of 6.2 or above, up from 25%, 10 years ago. The optimum soil pH for grassland in Ireland is 6.2 – 6.5. Half of soil samples currently tested are at the optimum or higher for P, and 59% were at the optimum or higher for K. Crucially, the number of soil samples at the optimum or higher for pH, P and K has doubled in the last 10 years. It now stands at 21%.

Did you know up to 15% of nitrogen can be wasted if soil P is below par? As Mark discussed, using research and on-farm data demonstrates the importance of optimising soil fertility, to grow more grass cheaply and sustainably. Mark signed off with some very simple advice: soil sample regularly and follow a fertiliser plan.

Controlled traffic farming

Adopting Controlled Traffic Farming (CTF) could help reduce soil compaction risk and boost yields by up to 10.5%, while also reducing nitrous oxide emissions.

Limiting compaction at silage-making

Grassland farmers could benefit from adopting an ‘arable mindset’ and controlling the movements of machinery across fields as a means of limiting compaction and maximising grass yields.
This is according to Dr Paul Hargreaves, grassland researcher for SRUC, who has just completed a three-year study looking at CTF on silage ground. His results show grassland farmers could expect a yield increase of 8.5-10.5% by following a CTF system, while nitrogen use efficiency will also be improved.

Rather than driving anywhere on a field, CTF means machines follow set wheel marks that run parallel to the line of trajection and then around the headland. “It’s about trying to control the movements of machinery around a field to limit the area they cover and running all machinery along similar wheelings. It’s trying to think of grass as an arable crop,” says Dr Hargreaves. SRUC trial work found that about 83% of a field cut three times using a forage harvester, with slurry applied, will be covered in wheelings on a traditional system. These wheelings will suffer from soil compaction and therefore reduced yields. On a CTF system, the area covered in wheelings will reduce to about 19%.

SRUC trial results

The three-year trial at SRUC looked at long-term performance of a perennial ryegrass and red clover ley, which was established at the start of the trial. They looked at different nitrogen application rates and compared CTF and non-CTF. In the non-CTF strips, machinery was driven wherever they wanted. On the CTF strips, the fertiliser and slurry spreaders, mower, tedder, rake and forager, all followed a nine-metre working width.

Dr Hargreaves was keen to see the damage caused to the wheelings on the CTF system over the three years. Although there was an increase in soil bulk density and reduced porosity, he says there was ‘limited damage’ and no issues with water run-off from these areas.
“So far, we’ve seen a reduction in yield on those wheelings and the red clover has disappeared entirely, but the perennial ryegrass is still there,” he says.

He believes this is not a huge issue on a three-year red clover ley as the issue could be addressed as part of reseeding. If a farm was doing CTF on a five to six-year perennial ryegrass and red clover ley, some kind of mitigation work would be needed on these wheelings, such as sward lifting. Wheelings would then need to be shifted across in the next season so improvement work was not compromised.

Overall, Dr Hargreaves says focusing traffic in set areas helps minimise overall field damage.

“You are reducing the structural damage to soils so you are potentially maintaining drainage and the quality of the soil. And you know where the damage is on the field so you can deal with it specifically,” he says.

Why is compaction a problem?

  • Limiting soil compaction should form part of an holistic approach to soil management which should also look at pH and maintaining key nutrients such as potash and phosphate. There are some key reasons why compaction should be avoided:
    Prevents water infiltration – resulting in wet soils which take longer to drain.
  • Reduces soil pore spaces – so earth worms can’t do their job. Oxygen needs to get into the soils and carbon dioxide needs to escape. This is compromised if soils are compacted.
  • Reduces nitrogen utilisation – anaerobic soils will reduce the mineralisation of key nutrients such as nitrogen.
  • Increases nitrous oxide production (a greenhouse gas) – this gas is a product of denitrification, a biological process by which some nitrate in the soil is reduced to nitrous oxide. The rate of denitrification is increased in compacted soils, because of the lack of air as they’re denser and wetter for longer.
  • Reduces nutrient availability – such as phosphate.

Operating Controlled Traffic Farming

To operate CTF, Dr Hargreaves suggests thinking about the following:

What is the smallest working width of all your machinery?

If your smallest working width is nine metres, all equipment needs to work within this. This includes the slurry spreader, tedder and mower, etc. This means machinery will have to work along three-metre-wide tyre tracks in the field.

Split up fields

Divide the width of each field by the working width of your machinery. If a field is 135 metres wide and your smallest working width is nine, split it into 15 lines. If you end up travelling more on certain areas of the field, make a note of it and target soil improvement work in this area.

Use technology

Dr Hargreaves believes GPS and auto-steering technology is essential to do CTF properly. However, as a minimum he thinks GPS is essential. This will increase accuracy.
“Newer tractors being sold and equipment used by contractors often have GPS. This technology is becoming increasingly common place so it could be a case of just using the technology you’ve already got,” he says.

Use marker posts

If technology is not an option, consider using sight posts or positions in the field so machinery is driven in a particular route. All individual tractor drivers will need to pay care and attention.

Pay attention during carting

The distance between the forage harvester and silage trailers will increase with CTF – potentially to
six metres. This means the team will have to work steadily. Also, consider using high-sided trailers and not filling trailers all the way to the top.

Keep the pedal to the metal

With 1st cuts at below average, particularly those cut in the latter half of May, and very slow 2nd cut regrowth, we may be feeling slightly nervy when looking at our silage pits. Grass growth rates are well back on last year, so we’ll need some good growth in the months ahead to build up silage stocks. The rain has helped lower soil moisture deficits, but they’re still restricting grass growth.

On intensive grazing farms where growth rates have responded to rain, maintaining a 21 day rotation and keeping residuals of 4 cm is crucial. If paddocks have gone stemmy, pre-mow to get them back on track, alternatively target these for silage. Heavy covers of > 3,000 kg should be cut as surplus bales, and maintain grass growth by keeping N + S applications up-to-date. Slurry should be applied where silage/surplus bales are taken off. Remember to keep ammonia emissions as low as possible by using low emission spreading equipment such as trailing shoe. If slurry is not available, then apply a NPKS quality compound fertiliser such as YaraMila Silage Booster to replace P and high K off-take from taking surplus bales.

For N applications on a 21 day grazing rotation, 1 – 1.2 units N/acre/day is sufficient. Between the release of mineralised N from soil organic matter following the rain, together with residual N from fertiliser applications that hadn’t been used by the grass due to the drought, means there’s quite a large pool of nitrate available in the soil to meet the demands of increased growth rates. So, no benefit in over-applying N.

With 1st cuts below par and 2nd cuts delayed, it might be prudent to look for alternative ways to put tonnes of silage in the pit. Buying standing crops of spring barley for whole crop for instance or direct drilling Westerwolds into stubble for a late silage cut can make up some lost tonnes. Alternatively, drill a forage brassica crop into stubble for grazing in Autumn/Winter.

Reach that maize yield potential with foliar nutrition

Maize has a high demand for nutrients due to its high yield potential. These high yields of 40+ tonnes/ha can only be achieved if the crop can access enough nutrients via its roots, and as the plant grows, through foliar applications.

Zinc and magnesium deficiencies are the two most widespread nutritional disorders in maize. Zinc is important for photosynthetic activity. Magnesium is essential for the early establishment of the plant. A deficiency is reflected in reduced crop yield at harvest.

Phosphorus and potash are primary nutrients, however many soils have not got the capacity to deliver an adequate supply. Where phosphate availability is reduced because of soil pH or where its uptake is impaired due to dry soil conditions, foliar phosphate will help. It is translocated from the leaf to the roots very effectively, maintaining root development.

One or more of the above is often deficient in the growing maize plant. This nutritional shortage is particularly important as the plant reaches the 4 to 5 leaf stage as it is now that yield is being set. Maize stressed at this point can result in tall, thin plants, with poor root systems and reduced leaf area. Reduced leaf area captures less light, resulting in lower yields.

To overcome the risk of nutrient deficiency apply foliar nutrients at the 4 to 5 leaf stage. YaraVita MAIZE BOOST is specifically formulated for foliar applications on maize. It will deliver a high concentration of phosphate, zinc, magnesium and potash to maximise maize yield and quality this harvest.

Four steps to successful reseeding

Benefit of reseeding on net rofit

Step 1 : Identify poorly performing paddocks.

Step 2 : assess the 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.

Step 3: Take a soil test and act on the results. Before you start, be sure to complete this step. 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, and a lower requirement for nitrogen.

My Top Tips: Weeks 4-6 (post-emergence) apply herbicide to prevent weeds competing for nutrients and space. Graze lightly with youngstock or sheep, as soon as the new plants don’t pull out of the ground, which is usually when grass height is at 6 - 7 cm or at the two leaf stage to promote new shoots, and thus the long term productivity of your new sward.

Purchase quality compound fertiliser - it pays every time

At this stage, most 1st cut fertiliser applications are completed, but are you confident that your target fertiliser rate was evenly applied? Yara has demonstrated how, over 24 metres, the physical quality of a fertiliser influences the yield and quality of a grass crop.

Yara has looked at this effect by comparing YaraMila Extra Grass (27-5-5+S) with a blended 27-5-5+S. The target rate for both products was 500kg/ha and the spreader settings were changed for each product on testing. The YaraMila product achieved the target rate across the whole bout width; however the application rate for the blended product varied between 400 to 648kg/ha.

We then analysed separately each of the 23 trays from the blended product, to determine the actual NPK+S content. Because the YaraMila product is a compound, we know that the product in each tray contained 27% N, 5% P and 5% K. The blended product had a variation in N across the bout width of between 91kg and 160kg, for P the variation was 10 to 19kg and for the K it was 34 – 59kg/ha. The target was 135kg, 25kg and 25kg for N, P and K respectively. Accounting only for unevenness of the N, in this blend, compared to the YaraMila Extra Grass, there was a yield loss of nearly 400kg/ha of grass dry matter as a result of the poor spreading pattern of the N. This equates to 1.5 tonnes/ha of silage which, based on barley and rapeseed meal, would have a replacement value of £54.

Don’t take the chance, use a quality compound fertiliser

Quality grass silage starts with good crop nutrition

To understand the difference that making good quality grass silage can have on a dairy farm, we can compare the cost of achieving similar levels of milk output by balancing a diet using either a good or poorer quality silage.

My following calculations are based on a 120 cow herd producing 9,000 litre/cow, housed all year round with the forage component split 25% maize and 75% grass silage. A 30 litre cow requires 10.85kg of concentrate to achieve production using poorer silage, where as a cow fed the better silage requires 7.54kg daily. This additional feed saving would translate into £32,000 with a potential additional increase in £13,000 of improved milk yield if cows were fed the better grass silage.

The feed efficiency translated from 0.35kg/litre to 0.24kg/litre between both forages, with a purchased feed cost saving of 3.19ppl using better forage. If we incorporated the forage cost, there would be a 2.43ppl difference between the diets. This difference is less than the purchased feed cost because we are gaining more milk from forage and so must feed more forage per cow.

The first step to making quality silage is providing the right crop nutrition. If slurry has been applied, the nutrients should be accounted for in this and the balance should be supplied using a quality NPKS compound like YaraMila Silage Booster or if N+S only is required then use a product like YaraBela Nutri Booster.

Soil phosphorus levels impact greenhouse gas emissions

The role of soil fertility in mitigating Greenhouse Gas emissions has up to now been based on improving nutrient use efficiency. For example, soils at the correct soil pH can utilise soil phosphorus more efficiently. Microbial breakdown (mineralisation) of organic matter into plant-available nutrients is at its highest when soils are at their optimum pH. However, new research seems to show that soil phosphorus levels have a direct effect on soil nitrous oxide (N2O) gas emissions on permanent grassland. N2O is a very potent Greenhouse gas, and hence the importance of this research.

It is thought that certain soil microbial populations that are more dominant in low soil phosphorus situations produce more N2O. With increasing soil phosphorus levels these microbes become less dominant resulting in lower N2O emissions. These low nutrient soils are more fungi dominated, and these fungi lack a particular enzyme which predisposes them to produce more N2O. It is very welcome that this research adds another positive dimension to the existing body of knowledge that supports the key role that soil fertility plays in the future sustainability of grass-based production systems.

With the continuing poor soil conditions, very little fertiliser has been applied. So, for those with no fertiliser in the yard, order your fertiliser now. Don’t wait until field conditions are improved to order. Those that wait, may be faced with delayed deliveries if lots of farmers order at the one time.

Nutrient watch – advice for spring fertiliser and slurry applications

Daily grass growth rates are still low, so not much nitrogen (N) is required at this stage. Only apply if soil temperatures are at 5OC and above. If soil conditions are too wet or frozen, then delay application until they improve. Early fertiliser applications are appropriate on drier soils with productive PRG swards which respond to early N applications and allow early grazing. Depending on livestock demand, apply up to 30 kg/ha (24 units/acre) of N with sulphur as a 1st application for grazing.

There is scope to apply slurry rather than fertiliser N on paddocks with the lowest grass covers. Avoid slurry on heavier covers until after 1st grazing. Remember that ammonia (N) losses from slurry double for every 5OC rise in air temperature. This is why spring applications are encouraged, to reduce ammonia emissions and increase N use efficiency.

Prioritise slurry for paddocks with a potassium index of 0 or 1 (especially ones that had bales removed last year) and silage fields. Reduce the fertiliser N application rates on paddocks that have received slurry. Allow for 6 units/N per 1,000 gallons with splash plate and 9 units/N with trailing shoe. Don’t apply slurry and N fertiliser at the same time, it’s best to leave at least a week between them.

Target paddocks with a phosphorus (P) index of 0 or 1, with a YaraMila compound, such as Stock Booster S (25-5-5+5%S+Se). These colder and wetter spring conditions reduce P availability and can lower grass growth.

Nutrient watch – spring grassland

The monthly rainfall data from the Met Office from September to January confirms what we already know: its’ been a very wet autumn and winter. The rainfall for England is 35% above average for the period. However, soil temperatures are running slightly above average which is a help. But what’s the upshot of all this rain? Nitrogen and sulphur are the obvious nutrients that will be affected, but soil phosphorus availability should be considered also.

For a grass sward, 70 - 80% of all root mass down to a depth of 23cm is in the top 7.5cm. Below 23cm root mass drops considerably. In reasonable winters you’d expect that some nitrate and sulphate would remain in this surface root zone, but with over a third more rain having fallen during autumn and winter it’s reasonable to expect that very little nitrate and sulphate remains. This observation in the case of sulphur is supported by data on soil samples received in Yara’s laboratory in Pocklington during December and January.

In saturated fields, phosphorus availability will be reduced. These conditions increase the solubility of soil iron and aluminium which in turn affect the availability of soil phosphorus. It’ll be important to get some NPKS fertiliser like YaraMila Stock Booster S (25-5-5+5%S+Se) onto grass fields as soon as conditions allow, to kick-start and maintain grass growth this spring. Remember that with the prevailing soil conditions nitrogen on its own won’t be enough. In drier years a 23% growth response is usual with early sulphur and phosphorus, so be sure to use a compound NPKS fertiliser to get your grass off to the best possible start.

Phosphate applications in spring

Phosphate (P) is a key nutrient for grass. Its role in energy supply, root growth and tillering makes its availability crucial for grass growth in the spring. Although the plant’s requirement for P is small compared to that of nitrogen, its availability is essential.
On grazing farms, a portion of your total annual P requirement should be applied in early spring and have the lion’s share of it applied by the end of April. A fresh P application boosts availability, first in early spring when its natural availability is reduced in wet cold soils, and then in April and May when there is a very high demand for P from peak grass growth.

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, it becomes slowly fixed by iron and aluminium. The phosphate contained in YaraMila Stock Booster (25-5-5+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 when triggered by the 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.

Improving nitrogen use efficiency on livestock farms

Agricultural nitrogen (N) management remains a key environmental challenge and has implications for water quality, greenhouse gas and ammonia gas emissions. More efficient use of N, has a significant effect on a farmer’s bottom line. Where N is not being recovered by the grass or by the cows and turned into saleable products (milk and meat) this is a financial loss to the farming system. Increasing N efficiency by improving utilisation of N by grass will result in lower losses of N to the air and water. If a farmer can get more production (grass, milk or meat) for the same quantity of N input, or get similar production using less N input, it will lead to higher levels of nutrient efficiency. It could also potentially offset the need for expensive additional feeds or to help increase the total milk or live weight gain from each hectare.

N fertiliser planning should not just consider the seasonal grass feed demands of the herd, but also the potential of the different soils/fields and swards to utilise applied N inputs over the season for grass production. Improvements in nitrogen use efficiency (NUE) and pasture productivity can be achieved by putting together a nutrient management plan for the year, utilizing manure N sources efficiently, including low emission slurry spreading application methods, using the right N fertiliser type at the right rate and the right time, improving grazing management, reseeding poorly performing swards and optimising soil fertility, especially soil pH