October marks the onset of winter in the UK, with the clocks moving back by an hour and heralding later sunrises, earlier sunsets, and colder temperatures.
For some this marks a depressing demarcation to the end of summer, but this shift in day length and temperature is a vital cue for plants and animals to move into the next stage of their life cycle.
Many animals begin hibernation as the days shorten, trees and other plants shed leaves and appear to die back, where they will spend the winter drawing on the precious reserves built up over the summer. Seasonal migrants arrive and depart, next year’s cereals are in the ground, and sugar beet is harvested.
Farming has, of course, always been closely aligned to the timing of Nature and the passing of seasons. Winter wheat, for example, is drilled in the autumn and requires a prolonged period of cold in order to trigger flowering in the spring – this is due to a genetic process (identified at the John Innes Centre in Norwich, UK).
But climate change is causing disruption of the seasons – as discovered by phenology studies of these recurring biological events. Historic farm records from the late 19th Century, for example, show that the growing season in parts of England was around 244 days, yet by 2015 it had reached 280 days. This is likely to be linked to increase in UK temperatures since the 1960s of an estimated 1°C.
But as well as seasonal changes, living things respond to a day/night cycle as well. So it is also possible to tap into this internal ticking “clock” in plants and animals to help with productivity, efficiency and welfare.
The frequency of egg-laying by poultry, for example, is heavily influenced by the light regime, and similarly the performance of many crop plants in controlled environment conditions is closely regulated to prevent “bolting” and to ensure consistency of production.
A more intricate understanding of how the daily clock ticks is revealing new insights into better ways of managing agricultural systems. For a start, there are some indications that application of inputs on broadacre arable crops is more effective at particular times in the day-night cycle (we’ll be hearing more about this at REAP 2021).
Understanding the minute changes that take place within individual plants throughout the day and night can help with better understanding of when crops might be more responsive to management regimes, and to help build resilience. Breeding programmes which incorporate the genes which control the daily – or “circadian” clocks might be enable production of plants which perform better in different climates and – as have greater resilience to climate change.
The UK is hosting the global COP26 conference in Glasgow in November, where hopes for commitments to halve emissions by 2030, and to limit global warming to no more than 1.5°C. Nature is responding to the pressures it is under – in some cases it is providing opportunities for new agriculture in fresh ways and in new locations. In others it is resulting in serious irreversible challenges.