Healthy soils conserve water

From the Fall 2017 HPWD Conservation Connect magazine

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During a recent crop residue field day in Hale County, USDA-NRCS Zone Agronomist Brandt Underwood placed two soil samples onto pieces of mesh and then submerged them in individual cylinders filled with water.

 As the Slake Test progressed, people watched as most of the conventionally tilled soil fragments quickly dissipated within a five-minute period.  The minimum tillage soil fragments, containing higher organic matter, remained in the mesh for an extended time.

 “As this demonstrates, the minimum tillage soil has greater structure (tilth) which provides greater stability. This improves soil aeration and water retention while reducing erosion and nutrient leaching,” said Underwood.

 Many High Plains agricultural producers are working to improve their soil health to increase crop yields and better utilize their groundwater resources.

 Conservation tillage and/or no-till operations are one way to accomplish this.

 “This is a way to put the soil back in balance and return it to a natural state. Most of the soil activity is currently bacterial, which burns up organic material and nutrients. Bringing the fungal level back to a natural state will be beneficial in the long run.” said Jeff Miller with ForeFront Agronomy.

 He said soil contains 45 percent minerals, 25 percent water, 25 percent air, and five percent organic matter. Of the organic matter, 80 percent is humus, 10 percent are roots, and 10 percent are organisms, such as bacteria and fungi.

 “Water must displace air to enter the soil. The higher the bulk density, the greater the soil compaction.  Soils with high compaction are likely to have poor water infiltration rates and slower root growth. No-till can increase water infiltration rates in the soil by as much as 10 percent. There is also a 10 percent increase in rooting depth,” said Miller.

 He noted that test plots with lower crop residue required an additional 1.5 to 2.5 inches of irrigation water to achieve the same crop yield as compared to plots with residue on the surface. At the end of the growing season, plots with more residue contained an additional 1.5 inches of water in the top four feet of the soil profile as compared to those plots with no residue cover.  Plots with residue on the soil surface would save three to four inches of irrigation water as compared to bare soil.

 No-till operations have been fairly common in Kansas for many years. However, Miller said the practice is in its infancy here on the Panhandle-South Plains.

 “It got a bad rap because some folks were doing it incorrectly.  You can’t have a monoculture crop, such as cotton only. There must be multiple crops grown during multiple years for it to work properly.  With that in mind, some producers are taking a second look at no-till.  They are adding cover crops to their farming operations. Some are considering nutrient recapture to increase soil organic matter and reduce compaction,” he said.

 Miller believes no-till farming can be beneficial to the region.

 “We’ve seen advances in irrigation technology that allows water to be applied more efficiently.  Now, we’re seeing new ways to improve irrigation management and scheduling. This allows producers to make better decisions, which we hope will help slow groundwater decline in our area,” he said.

 Kelly Kettner, who operates a 4,000 acre farm in Lamb and Parmer Counties, has used no-till farming practices since 2004. His main crops include cotton, corn, sorghum, wheat, and barley.

 Initially, he stopped plowing in an attempt to halt soil erosion.  “I was frustrated by having to go out and run a sand fighter.”

 However, attendance at the 2009 No Till On The Plains conference in Kansas gave Kettner an understanding that no-till farming is much more than simply choosing not to plow fields.

 “It showed me the importance of noticing your native ecosystem and trying to mimic it through farming practices using summer and winter cover crops,” he said.  It was then that he starting using a true no-till system with cover crops and strategic crop rotations.

 The Muleshoe producer has seen many benefits from converting to no-till farming.

 “My soils are definitely healthier. I have many earthworms now—and after rain events, I see mushrooms and white fungi growing on the old crop residue. Fungus is the ‘glue’ that holds organic matter in place. This allows water and nutrients to be readily available for growing crops,” Kettner said.  He added that his soil has a soft, sponge-like texture when he plants his summer cash crop following the winter killed cover crop.

 He has also observed an increase in crop water use efficiency.

 “Water use efficiency has greatly increased since adopting no-till practices. Very seldom do I irrigate cotton before bloom and I can usually delay watering corn until the v6 stage.  The only exception is if we have a dry spring and the cover crop has depleted moisture stored in the soil profile,” he said.

 Input costs, such as fuel for plowing, have also reduced.  “I’m no longer making multiple trips across the field to plow.  The cover crops provide plant competition to control weeds. Residual weed control is important because you don’t have any mechanical options other than a hoe.”

 Kettner said patience is a virtue when converting from conventional tillage to no-till. During his 13 year experience, there were many times when he was ready to just give up and go back to conventional farming methods. Yet, through it all, he has remained focused on improving the health of his soil.

 “There is no textbook about how to farm with a no-till system. Be patient and figure out how to make no-till fit your farm management style and mix of crops. It requires more management and planning than conventional farming.  The first few years of no-till can be challenging because your soils are making the transition from a bacterial dominated system to a fungal dominated system. You may not see the full benefits at first,” he said.

 The primary disadvantage to high residue no-till farming is having cool soils at planting time.  This is not an issue with corn, but it could result in a delayed cotton crop. Miller said test plot observations showed soil temperatures at planting were 8 percent cooler with no-till as compared to conventional tillage.  However, they were about the same once crop canopy closure was achieved.

 Kettner is among a group of farmers that attend the No-Till On The Plains conference in Kansas each year.  “Call us a support group, if you will, but we have developed a relationship that allows us to bounce ideas off each other and offer suggestions to one another. Although our operations are very different, we each have a common goal in mind regarding soil health and structure,” he said.

 “It takes a while to get over the idea that the cover crop is going to use some of our precious water. You have to be able to see that the cover crop is actually going to help you capture more water for your cash crop,” he said.