April has come around, and with it comes one of the busiest windows in the spray calendar. Whilst you’re planning tank mixes and chasing weather windows, it’s worth making sure manganese sits at the top of your checklist. Miss the timing, and crops can quietly lose yield potential before you’ve even had a chance to notice.
Why April Is the Critical Window for Manganese
Early spring growth is demanding. Crops are building leaf area and root structure at pace, and manganese plays a central role in that process. It drives chlorophyll synthesis and enzyme activity, meaning a shortfall at this point genuinely hurts. Interveinal browning on older leaves and uneven tillering are the tell-tale signs to look out for, but by the time you spot symptoms, the damage is often already done.
This is especially true on lighter soils, high pH land, and fields with high organic matter. Cold and wet conditions compound the problem further, reducing how much manganese the plant can actually access from the soil. With approximately two-thirds of UK soils prone to deficiency, manganese remains the number one micronutrient challenge facing growers today.
The honest truth is that many growers are dealing with the same fields, the same symptoms, and the same yield drag year after year. A more proactive approach to manganese crop feeding makes a real difference.
Why Manganese Deficiency Costs You More Than You Think
Manganese is the catalyst for photosynthesis and nitrogen metabolism. Without it, the plant’s engine effectively stalls. In cereals, this shows up as interveinal chlorosis, which is yellowing between the leaf veins. In peas, it causes marsh spot. Beyond the visible symptoms, deficiency triggers a hidden loss of vigour and root development, which hampers the plant’s ability to forage for other nutrients and quietly erodes yield potential before you realise it.
Where Mn350 Fits Into Your Spray Programme
Mn350 was built to solve a genuine frustration with standard manganese products. Basic 15% manganese sulphate simply does not deliver enough manganese quickly enough to the plant, particularly when conditions are against you. Sulphate IBCs are also cumbersome, prone to settling, and tricky in a tank mix. Carbonates, whilst better known as mixers, are often too slow to meet the immediate demands of a rapidly growing crop.
Mn350 changes all of that. As a liquid manganese fertiliser, it carries a 350g/l concentration, which is more than double the 150g/l of standard treatments, allowing for lower application rates whilst delivering a far more substantial nutrient hit. The real advantage, though, lies in its dual-source formulation. By combining manganese nitrate and manganese sulphate, Mn350 uses two distinct uptake pathways. The nitrate form provides an immediate, highly mobile hit of availability. The sulphate form follows with a more sustained release, keeping the crop consistently supplied as it moves through its growth stages.
Potassium, sulphur, and nitrogen round out the nutrient package, supporting healthy cell growth during active spring development.
It comes in 5-litre cans rather than IBCs, which means easier handling, less waste, and far simpler storage. You order what you need, use what you order, and recycle the packaging without hassle. It also integrates seamlessly with fungicides and all other plant protection products, with none of the settling issues associated with IBC sulphates.
Application rates are straightforward. Use 0.5 L/ha for maintenance and proactive care, 1 L/ha for moderate deficiency, and 1.5 L/ha where deficiency is more severe. For full details on Mn350 as a manganese crop feeder, including how it compares against standard manganese sulphate, take a look at our Getting Started with Mn350 guide.
We also took a closer look at manganese deficiency, covering the science, the tell-tale signs, and the treatment, in our first spring deep-dive on Facebook and Instagram. Worth a watch if you want to go deeper on the subject.
Starting Right: Manganese at the Seed
If you used one of Fielder’s seed treatments ahead of drilling, you’ll already have given your crop a head start. Products like Fielder Manganese Trio, Manganese Duo, and our 15% Manganese ST place manganese directly onto the seed before it goes into the ground. The nutrient is immediately available to the seedling from day one, bypassing soil limitations entirely during those vulnerable early stages.
This approach means that even in cold, wet, or poorly drained soils, the plant has access to the nutrients it needs to establish well. It can also reduce the need for early foliar applications, though in high-risk fields, following up with Mn350 later in the season still makes sense as part of a complete programme.
Building a Programme That Works
The most effective manganese programmes combine both approaches. Starting with a seed treatment gets the crop off to a well-nourished establishment, whilst a liquid manganese fertiliser like Mn350 picks up the work as the season progresses and demands increase.
Knowing your soils makes the biggest difference here. Where history tells you manganese is a recurring problem, acting early and acting with confidence consistently protects yield better than waiting for symptoms to show. A crop nutritionist can help you fine-tune rates and timings, particularly on land with a history of deficiency or where multiple micronutrients are at risk.
In the high-pressure window of spring spraying, manganese isn’t a nice-to-have. It is the foundation of the season. Get in touch with the Fielder team if you’d like help putting a programme together, and we’ll talk through what makes sense for your rotation and your soils.