The economy of western Kansas almost entirely relies on water being pumped from the Ogallala Aquifer to grow the grain and forage crops for ethanol plants and livestock operations in the region. Without this water source these industries will not stay in the area, and when they go other support industries will also leave resulting in a major decline of the region’s economy and population.
Since the beginning of irrigation development, decades ago, the natural recharge of the aquifer has not, by any stretch of the imagination, kept up with the amount of water being pumped out and the aquifer continues to be depleted. If this trend continues, it just a matter of time before many wells will not pump enough water for irrigation to be feasible.
Like many other industries, irrigation technology has advanced by leaps and bounds in just a few short years. Tools like soil moisture probes and plant sensors are being used to schedule proper and efficient irrigation applications. Subsurface drip and mobile drip systems significantly reduce evaporation rates and the amount of irrigation water needed to grow the crop. But one of the issues we continue to struggle with is that many of our fields are just not in condition to infiltrate water. Decades of intensive tillage have destroyed the pore spaces the soil needs to take in water.
Many of the pore spaces are formed when the soil has stable soil aggregates. Aggregates are individual soil particles of sand, silt and clay that are bound together by root exudates and organic glues. Microbes that live in the soil, like bacteria, fungi, and other microorganisms, produce the organic glues. These microbes flourish in healthy soils where fields are in a no-till system. Other pore spaces are created by earthworms and other macrofauna like centipedes, slugs, and snails. Every time we disturb the soil, we basically destroy the habitat of these soil microbes. Tillage also physically destroys the soil aggregates by breaking them down into individual soil particles.
Maintaining a living root in the soil, as much as possible throughout the year, is also essential in maintaining the needed pore spaces in the soil. Living roots produce root exudates that help bind soil particles together into larger soil aggregates. Living plants provide a carbon source, which is food for the soil microbes, through the photosynthesis process. Decaying roots provide direct channels for water to infiltrate into the soil. Growing cover crops, between cash crops, is one way of maintaining a living root in the soil.
By incorporating some of these simple soil health practices, along with the other irrigation technologies, can reduce the amount of irrigation water needed to grow crops. This will help ensure that water will be available for all water users in the region for generations to come.
For more information about this or other soil health practices you can contact me at [email protected] or any local NRCS office.
Dale Younker is the soil health specialist for the USDA National Resources Conservation Service, Jetmore.