ENID, Okla. —
The recent increase in oil and gas exploration has resulted in the production of more water-based mud (WBM), a by-product from the drilling process.
The most common method of disposal for this material is land application to agricultural and grazing lands. As the name implies, water is the most common component of water-based mud, but water-based mud also contains dissolved solids and sodium and a small amount on non-dissolved solids. Therefore, the primary risk associated with over-application of water-based mud is the soil becoming saline or sodic.
Soil salinity can be a problem for plants. Excessive salinity (approximately 7,800 ppm for wheat) can decrease the ability of the plant to extract water from soil, even when water is plentiful. Salts also can interfere with germination. Germination reduction due to starter fertilizers with excess nitrogen or potassium, for example, is an example of how salts can inhibit germination.
The solution for excess salt is typically water in the form of rainfall, as the water will move the salts deeper into the soil and out of the rooting zone. Unfortunately, rainfall in western Oklahoma is not always plentiful enough to achieve this downward movement and salts can accumulate.
Oklahoma State University researchers Chad Penn and Jason Warren initiated a study at Lahoma in 2012 to determine how in-season application of water-based drilling mud affected soil salinity and wheat yield. They evaluated 4,000 and 6,000 pounds per acre of total dissolved solids (6,000 pounds per is the maximum allowed by Oklahoma Corporation Commission) and five different timings from Oct. 16 to March 20. A detailed description of their findings is available in Current Report CR2272 at www.wheat. okstate.edu.
Penn and Warren found the salts from the water-based mud accumulated in the top 3 inches of soil initially. Rainfall for the next 90 days was scarce (0.5 inches total) and the salt remained largely in the top 3 inches of soil. Once rainfall picked up, however, the salts started moving downward through the soil profile. As expected the 6,000 pounds per acre total dissolved solids rate resulted in greater soil salinity than the 4,000 pounds per acre rate, so the less you apply per acre, the lower the chances of increasing soil salinity to toxic levels.
In this study, water-based mud applied to wheat prior to approximately first hollow stem did not significantly affect wheat grain yield; however, water-based mud applied March 20 (approximately jointing) reduced wheat grain yield. Their recommendation resulting from this study was not to apply water-based mud after Feb. 15.
It also is important to consider the effects of wheel traffic and associated soil compaction from applications of water-based mud.
This is a summarization of OSU Current Report 2272, “Application of Water-Based Drilling Mud To Winter Wheat: Impact Of Application Timing On Yield and Soil Properties.” You can view the entire document at http://www.wheat.okstate.edu under Wheat Management then Fertility. Penn (email@example.com) and Warren (firstname.lastname@example.org) are authors of the publication.
Nelson is Oklahoma Cooperative Extension Service ag educator for Garfield County.