Farmer Innovation Group as part of YEN Yield Testing project on achieving Deeper Rooting.

Encouragement of deep burrowing earthworms might enhance yields by enabling deeper rooting, and capture of more sub-soil water.

Limited rooting depth is suspected to be a major limitation to current yields as cereal and OSR roots are not able to penetrate through strong soils. The Deeper Rooting FIG tested whether reduced soil cultivation and/or the addition of farmyard manure (FYM) would increase earthworm populations and so improve the rooting depth and subsequent yield of cereal crops. Deep burrowing (anecic) earthworms can improve soil structure by creating deep vertical burrows which provide soil aeration, drainage and channels for roots to explore. However, anecic earthworms are often absent from conventionally managed agricultural land due to frequent soil disturbance and lack of leaf litter at the soil surface.

This study used tramline trials in six fields across four farms to test whether a combination of reduced cultivations or direct drilling plus the addition of cattle FYM, could boost earthworm populations and subsequently improve crop rooting and yield.

The study found significantly improved yields with FYM additions at one of the four study sites; however this may have arisen from improved nutrition. There was a trend for higher earthworm numbers and midden counts (accumulations of leaf litter above the burrow of an anecic earthworm) in treatments where FYM had been added and cultivation methods were less disruptive, although these effects varied between fields. The effect of soil cultivation treatments and manure additions upon earthworm populations are expected to be clearer in the second year of this trial when the earthworm populations have had a longer period to recover.

View full reports on the YEN website here


The study continued as an Innovative Farmers Field lab in 2020, reported here

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ADAS provides ideas, specialist knowledge and solutions to secure our food and enhance the environment. We understand food production and the challenges and opportunities faced by organisations operating in the natural environment

Innovative Farmers was established in 2012 by the Soil Association with the aim of bringing scientific rigour to on-farm trials co-designed by farmers and researchers. With a focus on sustainability and resilience, groups come together on discrete topics and on-farm trials addressing the topics that matter to them.

Soil is an essential natural resource for all farmers. Over recent years many initiatives have sought to provide information and advice on soils and Soil Health, notably AHDB Great Soils. 

Agronomics is the science of understanding the variation in the cropped environment, identifying the management practices and system designs that work. It uses a farm centric approach of shared farm data and on-farm experimentation.

Farm-centric research generally involves On-Farm Experimentation and may be better described as 'Farm Action Research', i.e. research conducted at least in part by and for beneficiaries who also farm. 

On Farm Experimentation (OFE) is increasingly being recognised as having transformative power in improving performance in agricultural systems across the world.

Earthworms are known as ecosystem engineers due to their ability to structurally, chemically and biologically transform the soil environment in which they live.

Organic materials, including livestock manures, biosolids, compost and digestate contain valuable plant nutrients which can save farmers money on their fertiliser bills, and organic matter which can help improve soil quality.