Less fertiliser, lower costs

A DECLINE of almost one-third in fertiliser usage over a six-year period has brought about massive savings to farmers costs, but it has not had a knock-on effect on farm output.

Analysis of the outcome by Teagasc at Johnstown Castle Research Centre has concluded that the 30% drop in the use of P and K on soils between 1996 and 2002 has shown no decline in productivity on farms due to any change in soil fertility.

But they have found that there is a deficiency in lime on two out of every three farms under grass, and two in every five tillage farms requires more lime.

Noel Culleton, Teagasc, Johnstown Castle, said that the use of phosphorous on Irish farms declined from 62,000 tonnes in 1996 to 40,000 tonnes last year and potassium sales dropped from 120,000 tonnes in 1996 to 90,000 tonnes in 2002 resulting in a massive saving in costs for farmers.

He found that the biggest casualty in terms of fertiliser sales was the silage compound 0-7-30, the use of which fell dramatically, apparently due to many farmers changing over to using slurry as the alternative on silage ground.

He said that farmers are now definitely making better use of slurry and farmyard manures with a considerable cost saving being effected.

While there is no noticeable change in soil fertility or production from the drop in the application of P and K on grassland, there has been a note of warning in relation to the K levels on silage ground.

He said “On many intensive farms that are being cut twice for silage, the soil K levels have dropped to Index 1. One of two things is happening. Slurry is not being returned to the silage g round in adequate quantities or inadequate fertiliser K is being applied.”

“Low soil K will lead to severe thinning out of the productive grasses and ultimately poorer yields, especially in dry years“.

It was found that there is some cause for concern at the depletion of lime in the soils.

Grassland analysis showed that 63% of samples tested required at least five tonnes per hectare of lime and 42% of tillage samples tested required at least the same level of lime.

There was a necessity for between five and ten tonnes/ha on 37% of grassland and on 30% of tillage area.