Sulphur Application in Winter Wheat: Essential After a Wet Winter
After this extremely wet winter, a lot of sulphur in the form of sulphate has been flushed out of the soil. As a result, the amount of readily available sulphur will be low. Winter wheat has a moderate sulphur requirement. About 20-30 kg S per hectare. Nevertheless, insufficient sulphur is expected to be available in the soil by spring 2024. A sulphur application is essential to provide winter wheat with sufficient sulphur at the right time.
Throughout the growing period, winter wheat needs sulphur. During growth, sulphur uptake of winter wheat increases:
- At first node appearance (until April): approx. 5 kg S/ha
- From stem elongation until the tip of the ear emerges (until June): approx. 17 kg S/ha
- Until full flowering (until the end of June): approx. 21 kg S/ha
The greatest uptake takes place in the period May to June. After flowering, the plant absorbs hardly any sulphur. At that time, all the sulphur present in the plant is transported from stem and leaves towards the grain. There it is stored as grain protein.
Sulphur fertilisation in winter wheat
From the soil, sulphur becomes available to the plant from mineralisation from organic matter. This is an important source that can be taken into account in fertilisation. Among other things, good mineralisation requires a sufficiently high soil temperature. This is precisely where the problem lies. Because winter wheat needs sulphur relatively early in spring, sulphur from mineralisation becomes available too late due to the soil temperature being too low.
Especially on light soils like sandy soils, but also loess soils with low organic matter content, the total amount of sulphur from mineralisation can soon be too low. Here, a sulphur injection is then needed.
For all soils, after a winter with high precipitation, sulphur may be washed out in the form of sulphate. As a result, the directly available sulphur will be (even) lower and a sulphur application may apply to more plots than you are used to.
Sulphur and baking quality
There is increasing interest in baking wheat from the Netherlands, which is a great development for Dutch wheat growers. With baking wheat, protein content and protein quality are especially important. Sulphur is important for the protein composition in the wheat grain because the so-called sulphur bridges play a role in the bread’s dough properties. Stretchability and bread volume increase with increasing sulphur content in the grain.
Sulphur requirement
The normal sulphur requirement of winter wheat is 20-25 kg/ha of sulphur (S). Then the crop absorbs 60-75 kg/ha of sulphate (SO42-). Converted into fertilisers, 50-62.5 kg/ha of sulphur trioxide (SO3-) should be given. If a fertiliser contains 24% N and 16% SO3, this means about 400 kg of fertiliser per hectare. In this case, the nitrogen requirement advised for the first application in winter wheat is therefore directly met.
Synergy between sulphur and nitrogen
The latest addition in the field of nitrogen-sulphur fertilisers is Dynamon from OCI. This fertiliser has an ideal N/S ratio of 24% N and 7% S.
Unique is the synergy between nitrogen and sulphur. If both elements are available in sufficient quantities, a plant can absorb and utilise N and S effectively and easily. More importantly, to make proteins, the plant needs both nitrogen and sulphur. If one of the elements is missing, synthesis is affected with consequences for yield and quality.
Dynamon is applicable and effective in all arable crops.
Want to know more about OCI Dynamon? Read the information at www.oci-dynamon.co.uk