Grass Boost Range
Greenfield Fertilisers recognise the vital importance that Sulphur & Sodium has on crops.
We have developed a dedicated range of fertilisers targeting this deficiency helping farmers improve the quality and yields of what they produce.
Grass Boost
A superior CAN+S alternative
High Sulphur Content helps utilise more Nitrogen, increasing proteins and grass quality
Sodium Content increases palatability of the grass, thus increasing intake
“NK” Boost
Ideal for farmers who have high “P” indices in their soils
High Sulphur Content helps utilise more Nitrogen, increasing proteins and grass quality
Silage Boost
The solution for farmers who wish to maintain all their indices at optimum levels and produce top quality forage grass
High Sulphur Content helps utilise more Nitrogen, increasing proteins and grass quality
Why do we need Sulphur?
Sulphur is an essential nutrient for all plants, and certain crops are more vulnerable to deficiency than others.
Historically, in the UK sulphur was deposited on land from the atmosphere. However, as the burning of UK coal (high S) in power stations was switched to imported coal (low S) and natural gas, aerial deposition has declined dramatically.
This continued when emissions regulations forced flue gas desulphurisation units to be fitted, and now very little sulphur lands on our fields. As a result, applications of sulphur to crops has become an essential part of Nutrient Management Planning on farms.
Sulphur in the Soil
Sulphur in the Soil
Sulphur in the soil acts in a similar way to nitrogen. It arises naturally from the breakdown of organic matter, and to some extent from soil minerals. Soils which are organic, or heavy textured are more able to supply adequate sulphur than light and inorganic soils.
The organic sulphur compounds are broken down to inorganic forms, which are then useful to the plant. The Sulphur Cycle demonstrates these processes which are driven by microbial action, so moisture, warmth and time are required.
The Role of Sulphur in the Plant
The major role of sulphur in all plants is in support of nitrogen in protein production which is hugely important for high crop yields. For breadmaking wheat, protein production and its quality are even more important for loaf volume. In brassicas, (veg, oilseed rape, kale etc) sulphur is also in glucosinolate compounds, which give them their hot taste.
Sulphur also reduces the likelihood of immature rapeseed which faces penalty pricing in the market. This explains the greater requirement and importance of sulphur applications to brassicas.
In grass, sulphur is probably more important for improving the quality of grazing and silage, in terms of protein, than the yield increase achieved.
Deficiency of Sulphur
Deficiency symptoms in cereals, grass and brassicas show up in the younger leaves first. Symptoms are a pale-yellow appearance (chlorosis) and, later on, stunting. Much later, OSR flowers will have pale yellow, or almost white, petals.
Symptoms in some crops are easily missed, or confused with nitrogen deficiency, and may not be noticed at all, especially in cereals and grass.
Because our routine soil analysis cannot be used to predict sulphur deficiency, plant tissue testing is often used. For OSR and cereals there is the Malate Sulphate test which can be done early in the crop’s life, but it may need to be repeated later at stem extension.
Application of Sulphur
The Nutrient Management Guide (RB209) provides a helpful risk table to determine the likely need for sulphur applications, based on soil type and rainfall. In short, sulphur should be applied to most winter OSR crops, milling wheats and multi cut grass silage, grown on mineral soils. For other situations, heavier and organic soils are less likely to need sulphur, and lighter soils and high rainfall areas are more likely to need it.
For nutrient purposes, the crop requirement for sulphur and the concentration of crop-available sulphur in materials, is expressed as kg SO3/ha and % SO3 respectively. Occasionally they are quoted as kg S/ha and % S, in which case conversion to SO3 is achieved by multiplying by 2.5.
The following recommendations are only a guide due to the variable nature of crop-available sulphur coming from soils for plant uptake. For more help and guidance please contact us:
Cereals: 25-50 kg SO3/ha (usually with the first N top dressing)
OSR: 50-75 kg SO3/ha (usually with the first N top dressing)
Peas and Sugar Beet: 25 kg SO3/ha in Spring
Potatoes: 25 kg SO3/ha in the seedbed
Grass for Silage: 40 kg SO3/ha prior to each cut. NB. 2nd and subsequent cuts are the most sensitive.
Grass for Grazing: 20-30 kg SO3/ha in Spring and again mid-season.
Sources of Sulphur for Application
Both fertilisers and organic materials can be used to supply sulphur to the crop.
Firstly, Organic manures:
Solid organic materials, such as farmyard manure and biosolids contain significant amounts of sulphur, but are slow release, because the organic sulphur has to be mineralised to sulphate so the plant can take it up.
This takes several months and warmth, so they need to be applied in the autumn, despite a small amount potentially being lost through leaching of the sulphate over the winter.
Liquid organic materials, such as slurries, and poultry manure supply available sulphur much more quickly. They should be applied early in the year because autumn applications are very susceptible to leaching of the sulphate over the winter.
Secondly, Fertiliser applications:
Fertilisers with the sulphur in the sulphate form are readily soluble and rapid acting. They are applied early in the growing season, often with the first N top dressing. They are typically: N-S compounds (usually containing ammonium sulphate), sulphate of potash, kieserite, and gypsum (calcium sulphate). Gypsum is slower to dissolve and takes slightly longer to act, especially if it is very coarsely ground.
Elemental sulphur fertilisers need to convert to the sulphate form to become crop-available. These need more time to be effective and must be applied well in advance, such as the previous autumn. There is an inevitable risk that a significant amount of the sulphur is mineralised to sulphate in the autumn and this may be lost by leaching, over the winter.
The Place for Sodium
Why do we need Sodium?
Sodium fertilisers will not normally give extra grass yield but they will increase the Na content of grass which will improve the palatability of herbage and may reduce the chance of grass staggers. Sodium is also associated with a greater % of live herbage, higher D values and sugar content of grass.
Research from Bangor University indicates that these effects increase milk output and % butterfat and may also have a small benefit on somatic cell count. Grass palatability and milk output increase at herbage sodium levels up to 0.5% in the dry matter.
Deficiency of Sodium
Much of the sodium consumed by cattle and sheep is used in the production of saliva which is secreted into the rumen to maintain a constant pH by neutralising acids formed by bacteria in the rumen liquor.
If the sodium content of forage is too low, the animal automatically substitutes potassium for sodium as an alternative buffer in the saliva and diverts sodium to maintain blood Na level as first priority.
The resulting increase in K:Na ratio in the rumen leads to reduced resorption of Mg through the rumen wall into the blood – hence placing the animal at risk to hypomagnesaemia.
Symptoms of sodium deficiency in cattle may include low appetite, reduced fertility and reduced milk production.