AHDB Rotations Research Partnership
Cover crops and organic amendments
In total, 96 field experiments were established as part of the Grower Platform. Most of these experiments had potatoes as a test crop, but other crops included spring and winter cereals, sugar beet and root vegetable crops.
In 32 experiments, use of cover crops was shown to increase total potato yield by 3.0 t/ha (statistically significant). Similarly, in 46 comparisons, use of an organic amendment was associated with a 1.3 t/ha increase in total potato yield (not statistically significant). Limited survey data showed, in the absence of a cover crop, average surveyed potato yields were 42.3 t/ha compared with 54.8 t/ha when a cover crop was used.
When compared with cereals or other root vegetables, potatoes were more responsive to both cover crops and organic amendments. Successful integration of cover crops into potato rotations will need careful consideration of cover crop species and management.
A three-year series of large scale, fully replicated experiments at the James Hutton Institute showed the benefits of cover crops (particularly those with a large brassica component) on the yield and quality of spring barley.
The main long-term experiment at Broom’s Barn compared, in factorial combination, historical applications of FYM (once every 3 years from 1965 to 2011) and a single application of FYM in October 2016. It showed that the potato crop responded positively to both the historic and recent application. However, subsequent crops in the rotation mainly responded to the long-term applications, suggesting that the benefit from organic amendment accrues over a period, and that single one-off applications may be of limited benefit. Initial recommendations from the organic matter model (Rothamsted Research) broadly support this approach. The model suggested that on taking on a new parcel of land, a grower should apply a large OM dressing and then, on a regular basis, smaller amounts. On leaving a parcel of land (for example at end of a rental agreement), organic inputs should be halved three years before the end and there should be no applications in the final two years. Whilst further work is required to refine the recommendations, this practice should maximise the value of amendments.
Tillage and risk of compaction
A small number of tillage experiments showed that mis-matched wheelings and over inflated tractor tyres resulted in increased soil damage and, in turn, resulted in decreased crop yield. The Terranimo model (https://terranimo.uk. was adapted to allow utilisation by UK farmers. It allows growers to select soil types, tractor, harvester types, tyres and tyre pressure; and then estimate the likely effect of this loading on soil properties and compaction.
The Fourier Transform Infra-Red (FTIR) method demonstrated that it could detect changes in organic matter content resulting from the applied treatments. Also, data from long-term experiments showed there was evidence of correlation between soil FTIR spectra and grain and straw yields, which could be an area of research in the future.
Analysis of (ERT) and electromagnetic induction (EMI) scans showed that they may be used to infer information about depth of water abstraction which may aid water management.
Flatbed scanning technology was found to provide high quality data of soil structure in a cost-effective way. Using soil cores taken from the fields of collaborating Grower Platform members, the scanning and image analysis technology was able to measure changes in soil structure due to imposed treatments.
Traditional methods of quantifying roots in soil are labour intensive and expensive. The imaging method developed showed cultivar differences in root growth of parsnip and carrots in relation to bulk density and soil water content. Preliminary analysis suggested that for young seedling, soil moisture content was more important than dry bulk density in determining growth rates.
Developing management zones
Despite the relative sparsity of yield mapping and satellite data, it was found that variation in potato yields exhibit spatial coherence and thus are amenable to a zoning approach. The zoning approach needs to be refined by using other spatially resolved data (e.g. from maps of grain yield or soil properties).