The weather might be changeable but recent warm spell has reminded farmers of last year’s heatwave, where high temperatures stunted grass growth and reduced quality, and forced some farmers to feed additional feedstocks during the summer. However, grass with access to good levels of sodium can withstand extended periods without rainfall.

Farmers looking to make their swards more resilient to dry conditions this summer should be considering applying sodium as part of a tailored nutrient management plan to alleviate heat stress on grass and livestock.

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). Applying sodium in grassland fertiliser helps optimise the key potassium to sodium ratio which 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. Sodium encourages a greater percentage of live herbage, which will help livestock increase dry matter intake and get more from grass.”

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.

Fertiliser applications can continue even in drought conditions and Mr Scott advises that it is worth getting advice from a regional Fertiliser Advisers Certification and Training Scheme (FACTS) advisor to maximise nutrient performance and make the most of what farmers are willing to apply.

Mr Scott continues: “Even in soils with a moisture deficit, a heavy overnight dew can deposit up to 0.5mm moisture, which has been proven to be sufficient to start dissolving fertiliser. Where grass is visibly green, and there has been signs of growth, it is also possible to apply small amounts of fertiliser and see a response.”

Farmers should seek advice from a regional FACTS advisor regarding application timings and rates, but as a guide, sodium should be applied at 5-6kg/ha to help alleviate stress in both grass and livestock.