2002-07-08_GENERAL DOCUMENTS - M2002004 (4)

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Reclamation Review, Vol. 2, pp. 39 -42 (1979) Printed in the U.S.A. All rights reserved. Copyright c 1979 Pergamon Press Ltd t Russian Thistle for Soil Mulch in Coal Mine Reclamation A. D. DAY, T. C. TUCKER, and J. L. THAMES Arizona Agricultural Experiment Station, College of Agriculture, University of Arizona, Tucson, Arizona 85721 Greenhouse experiments, in two environments, were conducted in 1978, in Tucson, Arizona to compare Russian thistle (Salsola kali L.) mulch with barley (Hordeunt rulgare L.) straw mulch, in reducing soil- moisture loss from a coal mine soil material obtained from the Black Mesa Coal Mine, near Kayenta, Arizona. Unmined soil from the same area and Red Mesa loam soil were also included in the studies. Barley straw and Russian thistle mulches significantly reduced soil - moisture loss from all soil materials studied in Environment I (27 °C and 54% relative humidity) and Environment 11 (21 °C and 75% relative humidity). Soil- moisture loss from all soil materials was lower in Environment II than it was in Environment I; however, the moisture loss pattern was similar in the two environments. Russian thistle was as effective as barley straw, as a soil mulch, in reduc- ing soil- moisture loss from three soil materials associated with coal mines in the western United States. IN THE SEMI - ARID regions of the western United States, the annual precipitation is erratic, limited, and accompanied with high potential evaporation. In the foregoing environment, it is difficult to stablize lands disturbed by mining with vegetative cover. Mining wastes are fre- quently subjected to wind and /or water erosion that transport pollutants to the atmosphere and ground -water supply. Although supplemental ir- rigation water may assure plant establishment on coal mine wastes, in semi -arid states like Arizona the irrigation water must be obtained from a di- minishing ground -water supply, that is usually expensive and controversial. If most of the rain- fall around coal mines in the Southwest could be absorbed and retained in the soil materials over a period of time, it might be sufficient for the es- tablishment of vegetation on the disturbed areas. Dr. A. D. Day is Agronomist, Department of Plant Sciences; Dr. T. C. Tucker is Soil Scientist, Depart- ment of Soils, Water, and Engineering; and Dr. J. L. Thames is Watershed Specialist, School of Renewable Natural Resources, College of Agriculture, University of Arizonia, Tucson, Arizona 85721. 39 0160- 788X/79/010039 - 04$02.00/0 LITERATURE REVIEW Previous studies have shown that soil - moisture may be effectively conserved by mulch- ing soils with plant residues (Unger, 1975). Unger (1976) found that the amount of soil- moisture storage in clay loam and fine sandy loam soils increased with an increase in the amount of soil mulch. Using sourgrass (Andropogon inter - meditts var. acidulus Stapf) mulch at ten metric tons /ha the volumetric moisture content of a soil disturbed by earth - moving operations was 4% higher than the bare control soil after a short intervening dry period (Eavis and Cumberbatch, 1977). Unger (1978) reported that the available soil- moisture at planting was 12 and 21 cm for 0 and 12 metric tons /ha of wheat (Triticum aes- tivum L.) straw mulch, respectively. A pre- season water storage efficiency of 80% from 34 cm of precipitation was obtained by applying 22 metric tons /ha of cotton (Gossypium hirsutum L.) bur mulch on a sandy clay loam soil (Koshi and Fryrear, 1971). The efficiency for the un- mulched soil was only 46 %. Mulching conserves soil- moisture by reducing the net energy available at the soil surface for