Dry soil conditions persist within water district
Dry soil conditions persist throughout the High Plains Underground Water Conservation District, according to data collected in mid-March during the district’s annual pre-plant soil moisture survey.
“The overall average moisture deficit ranged from 3 inches in the upper 3 feet of the soil profile to almost 5 inches in the upper 5 feet of the soil. This is essentially the same as last year,” said Gerald Crenwelge, field data coordinator.
Field technicians used moisture meters to collect data at 96 permanently-installed soil moisture monitoring sites from March 11-20. These sites were selected to provide an even distribution of data throughout the district’s 16-county service area. Swisher County, annexed into the district in November 2010, did not have soil moisture sites installed for use in this year’s survey.
Readings are taken at 6-inch intervals throughout the five-foot root zone soil profile by lowering a special probe into an aluminum access tube. These data were processed to calculate the current moisture level in the soil (available moisture) and how much moisture can still be added (deficit moisture) to the soil for plant growth.
The overall average soil moisture deficit reading in 2013 is 3.1 inches in the upper 3 feet and 4.88 inches in the upper 5 feet of the soil. This means that, on average, 3.1 inches of water was needed to fill the upper 3 feet of the soil profile or 4.88 inches was needed to fill the upper 5 feet at the time of the survey.
This compares to 3.19 inches in the upper 3 feet and 4.86 inches in the upper 5 feet of the soil as recorded in 2012.
The 0 to 3 foot values will be helpful to producers who irrigate and are primarily concerned with soil moisture management in the upper portion of the soil. On the other hand, the 0 to 5 foot reading gives an overall soil moisture value, and is useful in dryland farm operations.
Maps depicting available and deficit soil moisture conditions at the time of the survey were published in the April issue of The Cross Section, the district’s monthly newsletter.
“A primary purpose of this survey is to provide general soil moisture information to assist producers in evaluating the need for pre-plant irrigation. Many of the sites surveyed are in irrigated fields. Soil moisture conditions in dry land fields located near irrigated sites will likely have lower values,” Crenwelge said.
He encourages producers to check soil moisture conditions in their respective farms to obtain more site-specific information before making pre-plant irrigation decisions.
It is important to save as much of the pre-plant soil moisture in storage as possible, Crenwelge said. Tillage practices are necessary unless no-till farming is done; however, reducing the number of tillage operations that turn moist soil to the top of the ground will help reduce moisture losses.
Crop residue management is also important.
“Maintaining crop residue at or near the soil surface for as long as possible will save soil moisture and reduce soil erosion by wind and water,” Crenwelge said.
Use of furrow dikes, contour farming, and control of plow pans are always encouraged. These practices can significantly increase the moisture that soaks into the ground during a rain and reduces water runoff from the field.
Furrow dikes and contour farming allow the rain to remain in the field longer so it can soak into the soil without running off the field. Controlling plow pans allow the moisture to move through the top part of the soil faster. These practices are also important to prevent tailwater losses from fields while irrigating.
An illustrated step-by-step procedure to determine soil moisture is found in the Water District’s Water Management Note, Estimating Soil Moisture by Feel and Appearance.
Printed copies are available by contacting the High Plains Water District office at 806-762-0181 or by email at email@example.com. A PDF of the document is available for downloading from the HPWD web site at www.hpwd.com/maps-and-charts/publications.