Thomas G. Chastain

The media is reporting that 2013 was a very dry year unlike any in the recent past.  The graphic below shows the long-term annual precipitation for Corvallis since the late 1880s.  Also on the graph is the long-term average (dashed line), a 5-year running mean, and the individual orange triangle symbols show the yearly annual precipitation.  The precipitation for 2013 is indicated by the round black symbol.

The graphic shows that while 2013 was very dry, there have been other years that have also been similarly dry or drier than the present.  Examination of the trends in the 5-year running mean show that there are cyclical wet and dry periods that are evident in the precipitation record over time with the driest period in the 1930s.  The region is currently in a dry period that began in the early 2000s.

What does this mean for the region’s seed crops?  It is too early to know at this point but we do know this, seed yield is rarely affected by annual precipitation.  Seasonal precipitation such as in spring is much more important for high seed yields in crops such as grass seed crops than annual precipitation.  Even though the year might be dry overall, yields still can be good if spring rainfall is near normal.