'Test the nutrient status of your soils over the next few weeks and prepare to make up any shortfall in recommended levels through spring application of N, P, K and S,' is the advice which CF Fertilisers UK Ltd is currently giving arable farmers following exceptionally wet weather across many parts of the UK.
"Record breaking rainfall in December brought the UK average for 2015 to 1270mm, making it the second wettest year on record since 1910, beaten only in 2000 when 1337mm fell," Allison Grundy, an agronomist for the UK's leading fertiliser manufacturer states. "Statistics from the Met Office revealed a marked contrast in rainfall across the UK, with December the wettest on record in Scotland (333.1 mm) and Wales (321 mm), while regions such as North West England also set new highs. December was also notable for its record breaking average temperature and almost complete lack of frost in most areas, which has impacted on the canopy size of crops going into the spring.
"The sheer weight of water that has landed on soils is likely to have had a serious effect on their structure and nutrient status. Some areas received as much as 30cm in a single day, equivalent to 333kg of water falling on every square metre, which will have caused compaction, affected nutrient flows and in extreme cases even removed topsoil from fields. With crop returns under pressure and farmers looking to maximise the productivity of their land, a key factor this spring will be to ensure that sufficient nutrients are available to crops throughout their growing period.
"The main objective for growers now should be to accurately assess the situation on their own farms so that they are able to take action in good time and avoid jeopardising their crops' yield and quality potential. They should examine their soils over the next few weeks, commission nutrient tests, be ready to adapt or change their fertiliser plans and, if necessary, make up for nutrients which have been lost by applying more than in a normal season.
"Leaching will have moved Nitrogen and Sulphur further down the soil profile, critically out of the rooting zone, and any surface run off from fields is likely to have moved Phosphorus (P) out of the system along with other essential nutrients such as Potassium (K) and nutrients such as Magnesium (Mg). These will need to be replaced, so it is advisable to carry out both a standard soil test and an N-Min® analysis to determine how much N is present, and how much needs to be applied to optimise yield and quality.
"Calculating the optimum level of Nitrogen to apply is complex and depends on numerous factors, including winter rainfall, soil type, organic matter, soil temperature and previous cropping. The current crop, yield and quality expectations, the amount of Nitrogen taken up during the spring, together with many other factors also play a role in calculating the Nitrogen requirement.
"CF Fertilisers N-Min® is a unique, patented soil Nitrogen analysis service which takes the guesswork out of Nitrogen application. It measures not only the amount that is present in the soil but also the amount that will become available to the crop between spring and harvest, known as Additional Available Nitrogen (AAN). This enables us to advise the optimum level to apply and when to apply it. The best time to take N-Min soil samples is in the spring before the first fertiliser application and at least six weeks after the last manure has been applied.
"Traditionally, Phosphate, Potassium and Sulphur were applied in the autumn, but putting them on in the spring has significant advantages in terms of simplicity, flexibility and timely applications, resulting in financial savings and increases yields, so growers should not worry that they have missed the opportunity.
"Providing that sufficient fertility exists, encouraging and maintaining root development to support early crop growth, spring NPKS application using Heartland Sulphur (24-8-8 (8SO3) for example, at the time the crop requires these nutrients, will encourage rapid uptake and maximise the response. Doing so has been proven to increase the average cereal yield by 0.3t/ha*, worth £33/ha with grain at £110/t.
"Spring application is also much more convenient and results in overall operational cost savings. Taking into account the total field operation costs coupled with the yield gain, the overall financial benefit of using Heartland Sulphur over straights amounts to £14,620* across a wheat area of 400ha, equivalent to £36.55/ha. Farmers who want a highly flexible approach to Sulphur application, where P & K soil indices are healthy could opt for SingleTop® granular compound (27N 12SO3) every time N is required to boost Sulphur reserves."
Managing Crops In 2016
Tom Land, Regional Fertiliser Manager for Agrii adds: "The unprecedented weather in terms of sheer water volume and higher than averagesoil temperatures has resulted in many farmers asking how they should manage their crops during 2016.
"The warm soil temperatures will have mineralised Nitrogen and Sulphur which in some cases is being expressed in terms of the LAI (Leaf Area Index) of cereal and OSR crops. My underlying concern is actually how much N will we measure in our soils, for several reasons. The first is that because of mineralisation, soil levels could measure high but then again high rainfall levels could have reduced this N supply. Second, if the measurement is low how do I manage a crop with such a high leaf area index? Thirdly, what happens if I am starving a crop with potentially eight well developed tillers?
"Part of my advice to customers is to take CF N-Min samples, when soil conditions are suitable - when it is not waterlogged to understand how much Nitrogen remains in the soil. Agrii also have a network of strategic regional weather stations which amongst other things we use to monitor soil temperatures and rainfall.
"It is also essential that we understand the rooting capabilities of this season's crops. Due to weather conditions soils will have been more anaerobic and roots will not have penetrated deep into the soil. In my opinion, crops will not have developed as extensive root systems as we might have hoped for at this stage, which means that we need to understand timing of N so as not to build too bigger canopy which cannot sustain itself when soils dry out, which they will. This means that farmers may have to adopt more of a little-and-often approach to improve Nitrogen utilisation."