Field image showing treatment effect on crop

As part of the AICC Crop Nutrition Club 2022, these two on-farm winter wheat trials tested whether the N inhibitor Didin can sufficiently slow N release to allow the whole season's N fertiliser to be applied as UAN in a single split. The 'farm standard' control treatment consisted of the same N rate applied as UAN over three split timings without an inhibitor. Trials were facilitated by a local AICC advisor, with support and Agronomics yield map analysis from ADAS.

Results summary: Applying the whole season's N in one split with Didin gave a big boost to crop size and greenness in April, visible both in the field and from satellite NDVI. However, the 'farm standard' approach of three N splits caught up by July, such that treatment differences were no longer visible in the field or in satellite imagery. Averaged across the two trials, we estimate a yield penalty of 0.13 t/ha ± 0.25 t/ha (95% confidence interval) from applying N as a single split with Didin. With current high wheat prices, the cost saving from missing two fertiliser applications is not great enough to justify this yield loss.

Other trials have shown significant yield benefits from urease inhibitors applied with UAN, relative to the same N rates and timings without inhibitors; the average benefit is about 0.2 t/ha. But these two trials suggest that inhibitors may not sufficiently slow N availability and prevent N losses to allow application of the crop’s whole N requirement as a single split.

Related Organisations

Connected Content

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

Nitrogen is required annually by most crops (except pulses) to achieve yield and quality. Judging how much N to apply is a key part of nutrient management.

  Supporting farmers with robust design and analysis of on-farm experiments in tramline trials.

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.

AICC member agronomists are now the preferred source of advice on over 2.2 million hectares, which is almost half of the UK’s arable land, and the demand for it is stronger than ever

Farmers, advisors and researchers working together to understand and improve crop nutrition on-farm

A range of products are commercially available that claim to enable more efficient nutrient uptake, allowing less nutrient to be applied as fertiliser.

AICC Advisors and farmers testing appropriate nitrogen rates and strategies for reduction in light of current high prices.  Brought together by the FarmPEP FIP project

Group of companies producing fertiliser efficiency products.