Cover crops are becoming more popular and funding is a key part of this increase as crops are a significant expense to farmers.

“Early sowing is important”, when it comes to cover crops and this could not happen with the delayed harvest last year.

That was a comment made by Bridget Lynch of the Agricultural Catchments Programme (ACP) at the Teagasc National Tillage Conference.

Sampling cover crops in December showed that cover crops being monitored by the Teagasc ACP last year had an average above-ground biomass of 500kg dry matter per hectare (DM/ha).

This compares to an average of nearly 1,000kg DM/ha in previous years. As the cover crop was not as big, it is unlikely to have the same impact on nitrogen uptake and soil structure or increasing soil organic matter.

Research in the ACP is being conducted in the Castledockrell catchment area. Nutrients, mainly nitrogen, phosphorus, and sediment, are being tracked from their source on farms through the landscape and finally looking at their impact on rivers.

Nitrate loss

“Cover crops are effective at reducing nitrate loss, and it’s the number one tool for arable catchments,” Lynch said.

She explained that a lysimeter study was conducted within the catchment. A lysimeter measures nitrate leaching.

It showed that, after spring barley, there was a significant increase in nitrogen uptake by a cover crop of leafy turnip and forage rape compared to natural regeneration of stubbles with volunteers and weeds. She said there was a significant reduction in nitrate leaching under the cover crop and the uptake was greater than that of natural regeneration.

Increase in cover crops

The Farming for Water EIP project helped the cover crop acreage in the catchment rise by 87% last year.

This funding will be in place for the next three years, which will hopefully help to keep the area of cover crops high and allow their impact on reducing nitrate loss to be examined.

“While we are seeing a positive effect in the drainage water and groundwater monitoring, we need to sustain the cover crop area sown over a number of years in order to deplete the pool of nitrogen in deep aquifers and see an impact at the catchment scale and our larger river networks,” Lynch added.

A survey of farmers showed that they value cover crops very highly, especially their soil structure and health benefits in addition to water quality benefits.

Discussion groups, demonstrations, and farm walks are valued by farmers when it comes to learning about cover crops.

You learn by doing with these crops and farmers like to be able to look at the crops in the fields.