Restoring Salt-Damaged Soil

Abstract

This paper was prepared for the Second Midwest Oil and Gas Industry Symposium of the Society of Petroleum Engineers of AIME, to be held in Indianapolis, Ind., March 28–29, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Introduction Salt-affected soils occur in Illinois naturally and man-made. The basic problem is excessively high levels of sodium. Their occurrence occupies more than 380,000 acres generally in counties located in southern Illinois. Wayne County has an estimated 6,000 to 8,000 acres, mostly 2 acres or less. Technically, they are known as natric soils, but more commonly as "slick spots" or "scalds." The naturally occurring salt-affected soils have developed from an accumulation of sodium weathered from the parent soil material and concentrated by water movement peculiar to these areas. Man-made salt affected soils are usually in oil-producing country caused by saltwater overflow from brine pits, broken lines, spillage of an oil-saltwater mixture at the well or during transporting by truck. The nature of salts in soil may be considered as "active" and "reserve." Salts dissolved in the soil solution are the "active" fraction and can be measured by a soluble salt soil test. The "reserve" fraction is the exchangeable soil sodium and undissolved salt crystals. A soil test measuring exchangeable sodium is a satisfactory measure of this amount. High levels of soluble salts are deadly to plant growth. The osmotic pressure of the soil plant growth. The osmotic pressure of the soil solution exceeds the osmotic pressure of the plant cells, and the cells die from plasmolysis plant cells, and the cells die from plasmolysis because the soil takes water from the plant. At lower salt levels, soluble salts are deleterious to plant growth because salt-affected soils dry out more slowly in the spring than associated soils. Once they are dry, their moisture storage is not easily replenished, because of their very slow permeability. The high exchangeable sodium content in the soil causes the clay to be dispersed, creating an unfavorable environment for root growth. Excessively high levels of sodium make the soil totally unfavorable for plant growth and leave the soil barren. Erosion by wind or water is serious on barren. soils. OBJECTIVES OF PROGRAM To identify salt-affected soil areas, evaluate the severity of the problem, and proceed with ameliorating practices to establish proceed with ameliorating practices to establish vegetative cover and provide protection of the soil from erosion and to correct the damaged areas. (Sediment pollution of water supplies is a serious problem in salt-affected-soil areas, and this program will lessen that type of pollution; however, reclamation of salt-affected pollution; however, reclamation of salt-affected soils will contribute salts to local water drainage.)