A guide to wholecrop nutrition
Wholecrop cereal silage is increasingly popular among farmers as a versatile, high-energy feed option for livestock.
The most recent figures show around 2000 UK dairy farmers grow fermented wholecrop, producing approximately one million tonnes freshweight of forage annually.1 Wholecrop silage offers several benefits, including flexible harvest windows, a high level of dry matter intake (DMI), and balanced nutrients when managed properly. However, achieving optimal nutritional value from wholecrop silage relies on careful nutrient management throughout the growing cycle. This blog shares a fundamental guide to wholecrop nutrition to help get more from your forage.
Choosing the right wholecrop
The first step in achieving high-quality wholecrop nutrition is selecting the right cereal crop. Kingshay trials have shown that all the following crops are capable of a high dry matter yield and contributing to forage production targets.1
Winter wheat- Winter barley
- Winter triticale
- Winter oats
- Winter rye
- Spring wheat
- Spring barley
- Spring triticale
- Spring oats
- Spring barley and peas
- Spring barley undersown with grass
Considerations such as soil type, climate, crop rotation and the nutritional needs of your livestock will influence your choice of cereal crop. For example, heavier soils may suit wheat better, while lighter soils might be more suitable for barley or oats. When considering livestock nutrition, barley, in particular, is preferred for its higher starch content, while oats can be used when fibre is a priority.
Nutrient requirements for wholecrop
Wholecrop nutrient management starts with understanding your soil’s baseline nutrient levels. Regular soil testing is essential to determine the availability of nutrients in your fields. Using these results, the key macronutrients to consider in your wholecrop nutrient management plan include:
- Nitrogen (N):
Wholecrop cereals have high nitrogen demands to support strong vegetative growth and achieve the desired protein content, which is particularly important for silage quality. Nitrogen is vital for the formation of amino acids, proteins, and chlorophyll, which drives photosynthesis and growth. However, too much nitrogen can lead to excessive growth, causing lodging (where plants fall over). It can also reduce dry matter content at harvest, negatively impacting silage quality. Carefully balanced nitrogen applications, split between early growth and later stages, can ensure healthy crops and good silage outcomes.
Read our advice on how to improve nitrogen use efficiency in your crops.
- Phosphorus (P):
Phosphorus is critical for energy transfer within the plant and supports root development, which is especially important for wholecrop cereals. It helps plants establish quickly by enhancing early root growth and seedling vigour, which sets the foundation for optimal yield.
Phosphorus also plays a role in the formation of DNA and cell membranes. Insufficient phosphorus can limit the crop’s ability to absorb other nutrients and restrict overall growth. Soil tests will indicate phosphorus levels, allowing you to tailor application rates for efficient use of this nutrient throughout the crop cycle.
- Potassium (K):
Potassium regulates water use within the plant, which is essential for maintaining turgidity (firmness) and reducing stress from drought. It also enhances the plant’s resistance to diseases and improves the quality of silage by helping the crop retain sugar content, which is important for fermentation. As wholecrop cereals rapidly deplete potassium from the soil, a sufficient supply is necessary to support strong stem structure, reduce lodging risk, and improve overall crop resilience. Without adequate potassium, crops are more vulnerable to stress and may result in lower yields and quality.
- Sulphur (S):
Sulphur is crucial for protein synthesis and the formation of amino acids, which directly influences silage quality. Deficiencies in sulphur can result in poor growth, pale leaves, and a reduction in protein content, leading to lower nutritional value in silage. Sulphur also plays a role in nitrogen utilisation, meaning that if sulphur levels are low, nitrogen uptake is less efficient, and more fertiliser may be needed. Adding sulphur to your nutrition plan, particularly in soils that are low in organic matter, can significantly improve wholecrop yield and quality.
Nutrient inputs at key growth stages
Nutrient demand for wholecrop silage varies at different stages of crop growth, so the timing and form of nutritional inputs matters. Below is a breakdown of how nutrients can be balanced across the growth stages:
- Tillering (GS 21-29):
This is when cereals form side shoots, and the crop’s nitrogen demand is high to promote early biomass accumulation. At this stage, applying 40-60% of your total nitrogen allocation, depending on yield potential and soil reserves, helps encourage strong tillering, which contributes to higher silage yields.
Stem elongation (GS 30-39):
During this phase, cereals transition from vegetative to reproductive growth, and their nutrient demands peak. The second nitrogen application (40-60% of the total) should occur now, along with any phosphorus and potassium shortfalls, as these nutrients promote root health, water efficiency, and stalk strength. Potassium is particularly important to support water management in the plant, and to prevent lodging as the plant grows taller.
- Flag leaf emergence to grain filling (GS 39-59):
The flag leaf is responsible for up to 50% of the final grain yield in cereals, so ensuring optimal nutrient levels during this stage is essential for starch accumulation. If sulphur levels are low, a small top-up may be needed at this stage to improve protein synthesis and overall grain quality.
Learn more about OCI Dynamon, our effective nitrogen-sulphur fertiliser
Further advice on wholecrop nutrition
This blog draws on advice available within AHDB’s Nutrient Management Guide (RB209). You can explore further details on wholecrop nutrition within section three of the guide (available here), including:
- Nitrogen, phosphate, potash, magnesium and sulphur recommendations for wholecrop wheat, barley, oats and rye
- How to make adjustments according to SNS (soil nitrogen supply) index
- Guidelines on application timings
References
- Lallemand Animal Nutrition (2020) The Wholecrop Guide: https://qualitysilage.com/wp-content/uploads/2020/06/Wholecrop-Guide_LAN_Folder_Nov-2019.pdf