Strong return on investment for grassland best practice

Tuesday 16.04.2019 , News

This was the advice at a grass management knowledge exchange day at Four Crosses, Powys, from Germinal experts where over sixty livestock farmers gathered this week to sharpen their focus on a forage-based approach.

Speaking on the benefits of reseeding, Germinal GB’s Helen Mathieu said a cost of £200/acre to complete a full grassland reseed to the highest standard should not be a deterrent given the benefits that should result from higher pasture productivity.

Reseeding can increase dry matter

“Rates of grassland reseeding remain very low at less than 5% per annum, well below that required to maintain leys in optimum condition,” she said. “When carried out correctly, reseeding will result in a significant increase in dry matter production and grass quality, boosting homegrown feed production and reducing reliance on bought-in feeds.

“Even if we assume a modest 10% increase in dry matter yield and a lift in the ME content from 10.2 to 11.0MJ/kg as a result of reseeding, that’ll equate to around an extra 5,700 MJ/acre of extra energy from grass. For a dairy farmer, that’s enough to produce over 1,000 litres of milk, worth around £300/acre – £100/acre more than the cost of reseeding in the first year, and the ley should remain productive for several years. Similar returns can be shown for beef and sheep farmers in terms of the extra liveweight gains possible from improved grassland.”

Healthy soil fertility needed

However, as independent soil and grassland specialist Chris Duller pointed out, results such as these are only possible if factors such as soil fertility are sorted in advance.

“Soil sampling to determine pH, phosphate and potassium levels, in particular, is essential ahead of reseeding, and I recommend doing so at least six months in advance in order to allow time for any issues to be addressed,” he said. “For optimum grassland performance, soil pH, for example, should be in 6.2 – 6.5, but we commonly see soil samples that show pH lower than 6.0. This is because simple management practices like liming are all too often overlooked.”

According to independent soil and grassland consultant Chris Duller, routine liming to ensure soil pH remains at the optimum level is an essential part of maintaining grassland productivity.

Mr Duller said the difference between a field at pH 6.1 and pH 5.6 would result in a dry matter yield penalty of around 1 tonne/acre, which he estimated to be worth £200/acre. Liming at a rate of 2 tonnes/acre would cost about £70/acre, resulting in a healthy return on investment within the year for an action that should have lasting benefit.

Visitors to the grass management event, which was generously hosted by Martin Evans of Carnbwll, also heard about the importance of resolving soil compaction issues and the benefits of effective grass weed control.


Table: Typical Reseeding Benefits

 Original PastureNew Ley
Grass production (kg DM/acre)3,0003,300 (+10%)
ME content (MJ/kg DM)10.211.0 (+8 MJ/kg)
Energy output (MJ/acre)30,60036,300
Energy for Maintenance (MJ/acre/year)20,40020,400
Energy remaining for Milk (MJ/acre/year)10,20015,900
Milk production @ 5.3 MJ/litre (litres/acre)1,9243,000
Milk value @ 28 p/litre (£/acre)539840
Extra milk value (£/acre/year) 301
Typical cost of reseeding (£/acre) 200
Return on investment (year one) 101

Source: Germinal GB