Under calm conditions with high nighttime relative
humidity, rice should be harvested before grain moisture
drops below about 21%. Under windy conditions with little
rehydration at night, high rice value can be obtained at
average harvest moisture
as low as 15%. Rice harvest should
proceed at maximum capacity during and immediately after
periods of drying winds in order to complete harvest of all
fields that have dried below about 21% moisture. After the
windy
period ends, HRY and rice
value will drop appreciably
because of kernel rehydration.
Under weather conditions in California, rice moisture
varies diurnally corresponding to the wide range of relative
humidity
and is af
fected by weather patterns. This means that
it is possible to harvest rice at high moisture and have low
HRY. For example, basin 2 on 7 October 2003 dropped to
22% moisture, but eight days later it was again at 22%
moisture in spite of having dropped to 17% moisture in the
intervening period (fig. 2). Rice harvested on 8 October had
a 65% HRY, and eight days later it was below 50% (data not
shown). This further demonstrates that quality is related to
the history of rice moisture, not just its value at a particular
time