Maintaining soil moisture levels throughout the growing season in Fraser fir plantations
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
areas of Michigan have just gone through the first extended period of
dry and hot weather for the 2007 growing season. At our two irrigation
research sites (Montcalm and Jackson counties), no rainfall was recorded
from June 6 to June 20. During that period, tensiometer readings (soil
moisture potential) measured at 12 inches, increasing from 10 to 20
centibars in non-irrigated plots. (Around 20 centibars, growers should
be thinking about turning on their irrigation system.) We also monitored
the gravimetric soil moisture (total soil moisture content) at the
Jackson farm, and it decreased from 13 to 6 percent at 10 cm below the
surface. Note that on sandy soils, 5 percent soil moisture could result
in permanent wilting in just a few days depending on plant rooting and
condition. (view photo)
We haven’t observed any significant plant mortality; however signs of
wilting were present especially in sites transplanted this year. Keep in
mind that maintaining good soil moisture is essential for maintaining
good health and enhancing all the physiological functions of your trees.
If you have access to irrigation, we recommend putting at least 0.5 inch of water per week on transplant and younger trees, especially in sandy soil if there has been no rainfall, and none is forecasted for the week. Don’t forget to factor in the time you need to run your system through all your irrigation zones before it is too late for the areas you reach last. You should irrigate early in your first zones to be just on-time when you get to the last block.
For more information on using tensiometers to help determine soil moisture, see MSU Extension bulletin E2977 Using Tensiometers for scheduling Irrigation of Fraser fir in Christmas Tree Production. To order this publication, please visit http://www.emdc.msue.msu.edu/intro.cfm or call 517-353-6740.