The Influence of a Changed Climate on Soil Workability and Available Workdays in Scotland

Abstract

This paper represents a component of a large-scale project to investigate the effect of predicted climate change on Scottish agriculture. Weather places constraints on time available for carrying out field operations during the autumn, winter and spring because of problems arising when heavy machines operate on wet soil which has low bearing strength. Particular problems also arise for land spreading of farm wastes such as slurry, where spreading in some weather and soil conditions leads to watercourse pollution. Soil moisture is strongly influenced by rainfall, and a changed climate is expected to include a major change to winter rainfall patterns. In this study, a soil water and heat simulation model was used to predict the effect of changed climate scenarios on the number of available workdays in autumn, winter and spring (1 September–30 April) with different soil types and at a number of Scottish sites. Results showed a substantial reduction in numbers of available workdays in the changed climate because of the expected increase in winter rainfall. Also, higher winter temperatures would reduce the incidences of frozen soil and snow cover, further reducing workday numbers for tillage operations, but slightly increasing the opportunities for field spreading of wastes. In September and April only and at drier sites, higher temperature and potential transpiration values in the changed climate offset the increase in rainfall to give a small increase in workday numbers.