Wednesday, May 2, 2012

A good flood

     Pecan trees are native to the flood plains of major rivers in central and southcentral U.S. These trees are adapted to periodic flooding, and along the Neosho River we seem to have at least one flooding event per year.
     Last Monday night, the area around Chetopa, KS received over 10 inches of rain in a three hour period, swelling creeks over their banks and rapidly filling the Neosho River.  The river spilled out onto the flood plain on Tuesday and peaked on Wednesday.  This flood looks to be a fast rising and relatively fast falling event.
    A flooding event has both positive and negative impacts on the pecan grove. Floods can kill the groundcover and promote denitrification (loss of soil nitrogen). But floods also bring a layer of nutrient-rich silt to the orchard, recharge the water supply deep into the soil profile, and wash away any old pecans left on the ground following last year's harvest.
    This week's flood is high enough to cover the entire orchard but not high enough to cause damage to machinery and buildings.  If we have to live with flooding on the Neosho, this flood was a "good" flood.