Potatoes grower collaboration project (2007-2014)

The project supported direct interaction between researchers studying potato physiology and agronomy and groups of growers.  It was a route to promote the uptake of new information arising from research work and the aim was to scale-up results from small-plot research to larger scale (e.g. split-field) demonstrations of principle. It involved collaboration, between NIAB-CUF, the levy board (Potato Council which subsequently became AHDB Potatoes), growers and their agronomists and other supply-chain partners.  Recommendations arising from completed research were applied to approx 20% of the participating growers’ production and the aim was to record the changes made and the outcomes.

The details of the crops and their agronomy are provided in the individual annual reports. Reports for 2007 to 2012 (inclusive) have been collated into a single document. Reports for 2013 and 2014 are provided as separate pdfs. The 2014 report includes an economic analysis of the Standard and Modified agronomies (2007-2014 inclusive). Paired comparisons of N application rates were only included in the analysis if the ‘standard’ and ‘improved’ crops had similar plant populations (within 10 % of each other). Comparisons of seed rates were only included if the achieved standard and modified seed rates were within 10 % of those intended and the achieved and modified seed rates differed by more than 10 %.

Nitrogen rates

In total, there were 22 valid comparisons that compared standard with reduced N application rates and the average reduction in N application rate was 28 kg N/ha. On average, reducing the N application rate was associated with a small, but statistically significant, increase in the tuber population > 10 mm. Analysis showed that this increase was mainly due to an increase in the number of tubers initiated and retained on each main stem rather than an effect of the reduced N applications on plant or stem population.

Seed rates

In total there were 41 valid comparisons of standard and reduced seed rates. The most common reason for paired comparisons to be omitted from the analysis was too large a difference between achieved and intended plant populations or too small a difference between the achieved plant populations in the standard and reduced seed rate crops. For the valid comparisons, the average reduction in seed rate was from 2.34 to 1.91 t/ha. Reducing the seed rate, reduced the total tuber population from 549 000 to 493 000/ha and this effect was highly significant. However, average total tuber FW yields were almost identical when grown using the standard or reduced seed rates. Economically, crops produced using the reduced seed rates had a larger margin over seed and N costs than the standard crops, although the increase was not statistically significant.