Following a relatively mild winter, with cold weather only beginning to hit hard at the end of January, it’s essential to ensure that forward crops maintain a consistent source of nitrogen (N) and micronutrients. “As growth has progressed without any strong weather events, plants have continued to absorb nutrients from the soil for longer,” says Natalie Wood, Country Arable Agronomist at YARA UK. “As a result, many farmers could be underestimating soil deficiencies going into spring, with a potentially significant impact on later yields.”
For first application, slightly higher rates of 70-100kg are recommended to get the crop off to a strong start. This ensures the plant has immediate access to the right quantities of nitrogen for early growth straight into spring. For timings, it’s best to apply once the temperature reaches 5 °C and upwards which is usually around the end of February.
If possible, use an NPKS compound fertiliser for a complete nutrition profile, ensuring the crop also gets sufficient phosphate (P) and potassium (K) alongside the nitrogen and sulphur. P isn’t available in soil at lower temperatures, so applying fresh P to the plant can enable early growth, as the readily available phosphate allows the roots to take up other nutrients from the soil more effectively.
- Apply 70 – 100kg for your first N application
- Soil temperature of 5 °C and upwards should trigger first application
- P allows earlier access to soil nutrients
- Make use of soil testing and, later, tissue testing for an overview of your soil nutrition
- Weather permitting, late February is ideal for first application
For strong crop growth through the season, it’s important to create a strong momentum right from the beginning. “Naturally, each individual farm has its own requirements, but taking soil samples should be an essential part of the whole farm plan,” says Natalie Wood. “This gives a clear picture of the overall nutrient levels, indicating any areas that require particular attention.”
The first N application – ideally with PKS – should be applied as soon as needed. However, it’s important not to go too early. Unpredictable weather conditions could offset any benefits, so it’s essential to use sound judgement and forward planning.
Once the crops start to grow, it’s wise to think about micronutrient applications. After taking tissue samples, it’s best to apply before the crop starts to extend (growth stage 30 for cereals/oilseed). At this point, consider the amount of energy required as the plants enter their period of rapid growth. Micronutrients need to be supplied at this time – or just before – to ensure the crop can meet its growth potential.
For stronger yields, it’s vital to strike the right balance. Cultivating biomass is crucial in the spring, as it offers a chance to positively influence your crops right from the start. Research has shown that 50-60% of above ground biomass is converted into grain yield, and a large root mass will create resilience against pests, disease and drought. Influencing above and below ground biomass at this vegetative stage directly results in a stronger crop. However, the timeframe for this is limited.
Biomass has been determined by approximately mid-March, at which point winter crops switch from vegetative stage to reproductive growth. This vegetative state is where inputs can have the greatest impact. Waiting until that stage, leaves a much smaller window to influence biomass.
“Keep account of your crop progression” concludes Natalie, “and make your first application earlier to boost the chances of a stronger yield.”