Is reseeding a strategy for improving carbon storage in the soil as well as yield and livestock performance?

The benefits of reseeding old worn out pastures are well proven with a newly reseeded sward containing 90% perennial ryegrass and 10% white clover yielding 100% more than a worn out old pasture.

The dry, cold spring this year further highlighted the benefits of reseeding with fresh, well-fertilised reseeds producing good yields, and older swards receiving fewer nutrients, often yielding poorly.

A perennial ryegrass/clover mixture can be up to 80% more efficient at responding to nitrogen than a sward containing poor species of grass with a high percentage of broad-leaved weeds. This is going to be of increasing importance as more attention is focussed on nitrogen and phosphate use efficiency over the coming years.

As well as reseeding there will be more focus on soil analysis and the value of farmyard manure (FYM) and slurry so bought in fertiliser is used to match individual farm requirements. We could be moving to systems where at one end you have intensively run farms producing a lot of food as the world population continues to increase, and at the other end, lower intensity farming where the focus will be on carbon sequestration in the soil and the increase in use of herbs and legumes.

Grassland soils which cover 60% of the UK land area can accumulate significant amounts of organic carbon, contributing as a sink to atmospheric CO2. This could be one of the main areas of focus to mitigate global warming concerns.

Farmers are likely to be encouraged by government policy to gain some of the benefits of grass/clover mixes on livestock and even arable units in the future.

As well as CO2 capture, grass/clover mixes can improve soil structure and soil health by deep rooting species and varieties being developed by the plant breeders. It is likely we will need to adopt ‘new science/breeding’ to reach the goals of sustainable, profitable, high output farming.

There is much more to learn in this area of using grassland/clover leys as a tool to combat climate change. The challenge is to reliably quantify annual rates of change of soil carbon stocks across intensively managed grasslands under the interactive effects of multiple practices. More research is needed into the effect of different management including regular additions of inorganic and organic nutrient fertilisers to the soil and the occurrence of disturbance events such as soil tillage followed by reseeding.

The good news is there’s evidence to suggest soil carbon levels have increased over the last 45 years in unfertilised soils and soils receiving the highest applications of slurry and FYM. The rate of carbon accumulation is over twice as much in the highest application of FYM and slurry in the more productive swards.

The next five years will see more emphasis on the use of farm inputs, but we must not forget we need to produce larger amounts of quality food in the UK. It was only back in May this year the French threatened to cut off electricity supplies to the Channel Islands over the fishing dispute. As a country, we should not be at the mercy of other countries controlling our food supplies.

Let’s hope the policymakers can balance the need for high-quality food production, providing a high degree of UK self-sufficiency whilst taking into account the environmental impact and ability to farm sustainably.