Fertiliser Mastery: A Year-Round Guide for Farmers
Applying the right amount of fertiliser at the right time is crucial – not only to maximise crop growth and health benefits, but also to help protect the farming environment by preventing leaching and runoff into watercourses.
In this blog we explore the intricacies of seasonal fertiliser strategies to guide farmers in making knowledgeable choices all year round.
Understanding the soil’s needs
Before planning seasonal fertiliser applications, it is vital to understand the soil’s current nutrient content.
Nutrient testing methods include:
Soil testing: Regular soil tests, preferably annually at a minimum, will provide insights into any nutrient deficiencies, enabling you to target specific nutrients with the required replenishment quantities.
Natural indicators: Sometimes, plants give visual cues of specific deficiencies. Yellowing leaves might indicate nitrogen or iron deficiency, while poor crop yielding could mean a lack of potassium.
Spring is synonymous with growth. As plants begin to break their dormancy, they require an abundant supply of nutrients, specifically macronutrients including:
- Nitrogen (N) is key for leaf and stem growth, and is fundamental to protein synthesis in plants as it is a major component of amino acids.
- Phosphorus (P) helps with root development, which is crucial for young plants. Phosphorus is also essential for energy transfer and storage within a plant.
- Potassium (K) strengthens the plant and aids in water regulation and drought resistance. Potassium also regulates the opening and closing of stomata, leaf pores that affect water regulation.
Visit our Nutrinorm blog for further information on macronutrients and to learn more about their role in crop growth.
By the summer, most crops are already in their active growth phase. For growers, the focus should be on maintaining growth momentum during this period. Key areas of focus include:
- Balanced macronutrients: Continue with a balanced N-P-K fertiliser but also pay attention to secondary nutrients like calcium, magnesium, and sulphur. These play a vital role in plant functionality and can boost resistance against pests and diseases.
- Irrigation: In some circumstances, irrigation may be necessary after fertiliser application to help meet crop demands.
After drilling and initial growth, autumn is the time when most plants prepare to go dormant. During this season, the aim is to strengthen the plants and prepare the soil for the next year. Key areas of focus include:
- Limit nitrogen: Reduce the application of nitrogen-heavy fertilisers, as this can lead to unwanted late-season growth, which might be damaged by the onset of colder temperatures. Instead, focus on phosphorus and potassium application to fortify the plants.
- Manure and organic matter: Consider applying organic matter like straw or manure. These not only provide nutrients but also enhance soil structure and water retention.
While crops might be dormant with diminished activity, this does not mean neglecting the soil.
Winter provides an opportunity for farmers to address soil health issues, such as soil pH, ahead of the next growing season without affecting standing crops.
These areas can include:
- Lime applications: Adjusting soil pH is a lengthy process. It typically takes three months for the soil to adjust to lime applications, hence why it is important to consider this during the winter, so the soil pH is then ready for the coming growth season.
Read our Nutrinorm blog for further information on balancing your soil’s pH over winter.
- Cover crops: Protect the soil from erosion by considering cover crops like clover or rye. These options not only help to prevent erosion, but also enrich the soil by fixing nitrogen and adding organic matter when worked into the soil in the spring.
Cover crops are typically grown during the winter months to cover bare soil and stubble, and in some cases are eligible for Sustainable Farming Incentive (SFI) payments.
Read our guide to cover crops for winter enrichment in our recent blog.
Tips for effective fertiliser applications
- Choose your fertiliser type based on specific crop needs: Granular fertilisers can offer phased-release, to feed plants slowly in line with crop demands, while liquid fertilisers generally give an immediate nutrient boost.
Depending on the need – immediate or prolonged nourishment – choose which fertiliser type is best suited to the crop.
- Check your machinery is set up correctly: Ensure you have a clean spreader. Over time, fertiliser can leave deposits on the spreader vanes which can build-up or cause blockages leading to uneven spreading.
Also check your speed, as this affects the application rate. So when spreading, be sure to maintain a consistent speed to ensure even coverage.
- Watch for rain: Avoid spreading fertiliser in unfavourable weather conditions such as in wind, high rainfall levels and damp and humid conditions.
Light rain will ensure the nutrients are washed down to the roots, without the wastage that can be caused by heavy rainfall.
- Avoid over-fertilising: Too much of a good thing can be harmful. Over-fertilising can lead to rapid, weak growth, making plants susceptible to pests, and even burn the plants.
Use soil tests to determine the amount of fertiliser needed, and check with your agronomist if you are unsure.
How to build a year-round fertiliser plan
Creating an effective fertiliser strategy goes beyond adhering to seasonal practices. It demands a deep understanding of the soil, including its pH and nutrient levels, and understanding of the specific needs of the crops being cultivated.
Regular soil testing, recognising visual deficiency cues from plants, and adapting to changing environmental conditions are essential components of this strategy.
By maintaining a proactive and informed approach, farmers can optimise nutrient use, reduce wastage, enhance soil health, and ultimately achieve consistent and improved yields.