A couple of weeks ago we took soil core samples in seven fields down to four feet in different locations around Nueces County. With the help of Dr. Dan Fromme, Extension Agronomist, we were then able to determine the amount of plant available water in the profile.
Field capacity (the amount of water remaining in the soil a few days after having been wetted and after free drainage has ceased) ranged from a low of 58 to a high of 73 percent, while the total plant available water ranged from 3.46 inches to 4.41 inches.
So what does this mean? If we consider our two common crops, grain sorghum and cotton, and assume that to produce 80 pounds of cotton lint and 500 pounds of grain we need one inch of water, today we could expect the following yields; cotton 277 to 353 pounds/acre, and 1,730 to 2,205 pounds/acre grain sorghum. This assumes that we have a crop emerged and growing now, with no additional moisture. So one can see that what we now have stored in our soil profile will require that we get some timely rainfall during our growing season if we are to make a respectable crop.
