Thursday, 7 August 2014

From wet to dry

As in June, rainfall in July this year was 76% the long term average and the month was also the eighth hottest in the past century. The hot dry June and July period follows on from one of the wettest winters. What has been going on in our fields over the past year?  Thanks to soil moisture sensors installed by SoilQuest at various locations in our School Farm demo catchment, we now have a good insight into this.

As the graph below illustrates, the soil was saturated from December to March which also happened to be a period in which there was visible soil erosion in some fields and when we recorded highest sediment loads in local streams. Soil moisture near the surface has declined since then, but at greater depths has remained remarkably constant.  That is until July when, even at 60cm depth, soil moisture dropped considerably.  This is the wheat crop's grain filling period when uptake of water by the plant influences final yield.

With a continuing trend for more frequent severe winter rainfall and higher summer temperatures with lower rainfall, we have some challenges ahead, both in terms of managing water quality, and in terms of food production.  Our research at and around Loddington will play a part in understanding how to rise to those challenges, most immediately by adapting to the inevitable changes, and in the slightly longer term, by helping to mitigate further change.
Relative values for rainfall (bars) and soil moisture at 20 cm depth (green), 40cm depth (black) and 60cm depth (blue) for a wheat field in the School Farm catchment at Loddington.

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