Yields increase quickly in response to annual applications of organic materials and the value of organic material goes beyond its nutrient value, according to a new report.

The latest research findings also suggest the role of organic materials in stimulating biological activity could be more critical than the amount (weight/number) of organisms in the soil.

Dr Amanda Bennett, who manages natural resources research at AHDB, said: "To reveal the non-nutrient benefits of applying organic matter, you require trials that account for the nutrient effect and part of this work set out to do just that."

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Field trials were set up to produce full nitrogen response curves in the presence of four types of organic matter applications - anaerobic digestate, compost, farmyard manure and crop residues.

Each autumn for four consecutive years, applications were applied at several rates in field experiments at Rothamstead Research.

Yields increased quickly in response to applications. At the 2.5 tonne rate, for example, it took as little as two years for yield increases to become statistically significant, compared to the control.

Analysis of data, from multiple trials, also showed benefits continued (although at a reduced level) for at least 2 years after applications ceased.

Crops responded well to applications and yielded more than expected in relation to the nitrogen applied, around 10 per cent more.

Despite considerable effort, no clear cause of the non-nutrient yield response was found. Results, however, suggest the mass or number of soil organisms may not be as critical as the activity of the organisms present and this warrants further investigation.

Market round-up

C&D Auction Marts Ltd sold 3887 prime lambs in Longtown on Thursday to a top of £118.20 per head and 284p per kg to average 197p (no change on the week).

A large entry of 6357 cast sheep saw heavy ewes average £77.07 (-£4.83), while light ewes levelled at £38.39 (-£1.28).