Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Committee Chair(s)

Raymond W. Miller


Raymond W. Miller


Reuel Lamborn


William Campbell


The concern about the environment has required that the effects of drilling fluids (muds) on surrounding areas be known. This study was initiated to investigate the effects of various muds on plant growth and on soils.

In preliminary studies in Phase I (31 individual mud components), it was concluded that the obvious dominant effects on plant growth of detrimental drilling fluid components included excess soluble salts, excess exchangeable sodium percentage, possibly a high pH in some mixtures, and undesirable physical conditions. The latter resulted from the sodium and/or starch, gums, and bentonite.

Phase II, the second year's study of the effect of drilling fluid on six soils and on the plant growth (which is this report) was designed to use seven typical drilling fluids at ratios of 1:4 (called the low rate), and 1:1 (called the high rate) by volume of liquid mud to disturbed and settled soils using green beans and sweet corn as the test plants. The seven mud mixtures were potassium chloride mud (PCM), diesel oil emulsion mud (DOEM), high pH lime mud (HPLM), lignite lignosulfonate sodium mud (LLSM), lignite lignosulfonate potassium mud (LLPM), dichromate mud (DTM), and a mud base (MB). Each mud contained bentonite and barite plus sodium or potassium hydroxide plus a few other substances.

Too much soluble salts or too high an exchangeable sodium percentage was the major cause of reduced plant growth. The dispersing problem of mud-treated soils caused by high exchangeable sodium percentages results from the high sodium hydroxide contents added to the muds.

Early attempts at leaching the soils with tap water were unsuccessful because of low permeability. Releaching all samples finally with salty water, first with 1 percent Ca(NO3)2, and later with 0.2 percent Ca(NO3)2, and finally with tap water was effective and plant growth improved in all mud mixtures.

In unleached treatments the muds PCM, DOEM, and DTM were most limiting to plants growth.

Reclamation of soils into which drilling fluids (muds) are mixed seems to require primarily (1) the removal of excess salts, and (2) a lowering of the content of exchangeable sodium with some additions of chemical amendments (calcium salts) and adequate leaching.



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