The relentless rain of last autumn will have caused significant damage to Irish tillage soils. However, the time between crops provided valuable opportunities to address soil issues.
Cover crops may have a significant part to play in this repair process.
This is an issue addressed in detail courtesy of Dr. Richie Hackett’s contribution to the latest edition of the Tillage Edge podcast.
The Teagasc research officer explained that cover crops can perform many roles. These included: nutrient loss; carbon capture and improved soil health.
“A cover crop is one that is grown during a fallow period. Typically, they are grown before a spring crop where land would be left idle over the winter period.
“They can be grown before two winter crops: specifically between two winter barley crops.
“Some people include would include green manures or fodder crops as forms of cover crops,” Dr. Hackett said.
However, these options are grown with a specific purpose in mind.
“In contrast, a cover crop is sown out to catch nutrients and to physically cover the soil without having a direct and beneficial economic impact,” he added.
Tillage soils
According to Hackett, a range of plant species can be included within a cover crop. He further explained:
“Yes, it can be a single species. However, more commonly, growers will use a mix of plant types. This is particularly so if the crops are grown under the ACRES scheme.”
Cover crops can perform a number of various roles for tillage farmers.
These include: reductions in nitrate and other nutrient leaching levels from soils into water courses; improvements in soils biological characteristics and the mitigation of soil compaction-related problems.
“Microbial and earthworm activity levels within soils are also enhanced by cover crops. But growers must know what specific role they want cover crops to play before planting them out in the first place,” Dr. Hackett said.
A number of the nutrients absorbed into a cover crop will be recycled into the next crop that is grown on the land in question.
“Cover crops can accumulate considerable amounts of nitrogen. These figures can get up to 90kg/ha in some cases.
“So when this material is ploughed-in the question becomes: how much of this is made available to the next crop?
“This figure can reach up to 30%: it really depends on the type of material that is incorporated back into the soil,” he outlined.