Thermal time assessment of suitable areas for navy bean (Phaseolus vulgaris) production in the UK

Abstract

In field trials at eight sites throughout the UK the mean thermal time requirement for navy beans from sowing to harvest for a standard cultivar, Marcus, was 2069 Ontario Heat Units (OHU). Low level plastic covers increased the range of warm environments at one site and gave a mean thermal time required of 2098 OHU.Analysis of daily air temperatures from six weather stations throughout the UK over a 29 year period, showed a 14 day possible planting period on the south coast of England, but gave a high probability of crop failure in Scotland.Maps of England and Wales indicating the probability of achieving 2000 OHU were produced from 5 km grid point temperatures. Less than 2% of the land had more than a 60% chance of receiving 2000 OHU under the present climate, however this area increased to 70% with a mean temperature rise of 1.5 "C.Although 2000 OHU is often used as the thermal time requirement of navy beans, these trials showed that it may be more accurate to use the higher figure of 2087 OHU from sowing to harvest, and restrict the use of 2000 OHU to the period between emergence and harvest. When the map was redrawn using 2087 OHU and current climate, no parts of England and Wales showed a reasonable chance of growing the present cultivars of navy beans.

Understanding Climate Change and Farming: Scientific and Farmers' Constructions of ‘Global Warming’ in Relation to Agriculture

“…As an initial attempt to study some of the issues raised above, research was undertaken with 110 farmers in two areas of the United Kingdom (Hampshire and Lincolnshire), and with three agricultural research agencies. The two areas were chosen on the basis of being identified from a scientific perspective (Dodd, 1991) as having agricultural systems which would be affected by the physical processes of climate change. The research was focused on vining peas, grown wholly under contract for freezing, and on navy beans which might be produced in the United Kingdom given certain climatic criteria.…”