At this year's Teagasc National Tillage Conference there were plenty of questions from the audience. Here are some of the top queries that we took from the day.

Q: Are winter crops good at reducing nitrate leaching compared to cover crops?

Richie Hackett: “Winter crops do take up nitrogen, but it’s relatively limited, 20kg to 30kg/ha. Whereas with a cover crop, it can be 30kg to 40kg/ha, but up to 80kg or 90kg/ha with very good growth. You get a lot more growth with a cover crop than a winter crop, assuming the cover crop is sown at an optimum date.”

Q: If soil tests were conducted between 60cm and 90cm, how much more carbon would there be in the soil?

Guilia Bondi: "It could be an extra 10% to 20% at a guess, but 60cm depth is now widely used to assess carbon storage at a global level."

Q: Is there a margin/ha difference between crop establishment systems (plough, min-till, no-till)?

Dermot Forristal: “In on-farm measurements, it’s fair to say that the cost savings that were there did counter the yield loss, so there was no significant difference between the margins of the different systems.”

Q: Which species of cover crops are best for sequestering carbon?

Bridget Lynch: "It goes back to the fundamentals of photosynthesis - the more leaf area you have, the more carbon you will sequester [take in from the atmosphere and store in the soil]. Higher-yielding cover crops and fast-establishing species are going to sequester more carbon.”

Richie Hackett: “The more you grow and put into the soil, the bigger the effect it will have. It also depends on the quality of what you put into the soil. Something with a high carbon-to-nitrogen ratio like straw will add more to carbon sequestration rather than something young and leafy that will break down very quickly."