Sodium has been recommended as an integral component of all grassland (grazing and silage) fertiliser programmes.
The benefits of the nutrient in improving palatability and mineral balances are relevant at all times of the season.
According to Origin Fertilisers, the inclusion of sodium is particularly relevant during periods of hot, dry weather.
It should be included as part of a tailored nutrient management plan to alleviate heat stress on grass and livestock.
Driving this approach is the fact that grass with access to good levels of sodium can withstand extended periods without rainfall.
Use of sodium
Grass uses salts such as potassium and sodium to regulate the movement of water and sugars.
The availability and balance of these salts is particularly important in dry conditions. If the ratio of potassium to sodium is high, there is an increased risk of hypomagnesaemia (grass staggers).
However, applying sodium in grassland fertiliser helps optimise the key potassium to sodium ratio.
In turn, this reduces the risk of staggers. Peter Scott, technical director at Origin Fertilisers, says sodium is a vital nutrient to prevent crops becoming stressed.
“A greater percentage of sodium taken up by the crop will increase digestibility and improve sugar content, making grass more palatable to livestock, even as it starts to become fibrous,” he said.
“Sodium encourages a greater percentage of live herbage, which will help livestock increase dry matter intake and get more from grass.”
In addition, where grass is being supplemented with concentrated feed, sodium can
help reduce the risk of acidosis by helping to buffer the pH in the rumen.
It also reduces the risk of pica which has been highlighted as a common sign of sodium deficiency.
Application
Fertiliser applications of sodium can continue even in drought conditions. Peter Scott recommends farmers should get the advice they need when using sodium.
This will ensure that nutrient performance is maximised from the application rates that farmers are using.
“Even in soils with a moisture deficit, a heavy overnight dew can deposit up to 0.5mm moisture,” he explained.
“This has been proven to be sufficient to start dissolving fertiliser. Where grass is visibly green, and there have been signs of growth, it is also possible to apply small amounts of fertiliser and see a response.”
As a guide, sodium should be applied at 5-6kg/ha to help alleviate stress in both grass and livestock.
So could sodium become the new sulphur? 20 years ago, sulphur was deemed not to be required as a component – at all – within grassland fertiliser programmes.
Now the nutrient is widely regarded as a key contributor of growth and forage quality, particularly within silage scenarios.
