The Salt and Sodium Affected Soils of the Eastern San Joaquin Valley

Abstract

THE SALT AND SODIUM AFFECTED SOILS OF THE EASTERN SAN JOAQUIN VALLEY Chester F. Cole Fresno State College Of California's more than 10 million acres of cultivated land, over 7 million acres, or about 70 per cent, are irrigated. Contingent upon the ratio of costs of bringing uncultivated land into irrigated production to prices and demand for agricultural crops, irrigable land mav ultimately be expanded to 19 million acres, 16 million acres in any one crop season,1 Compared to drvfarmed land, irrigated crop land is by far the more productive, and the Central Valley is particularly important with a net ultimate irrigable area of about 10 million acres. The San Joaquin Valley's eight counties will account for about 6 million acres (now 3,700,000) of this total.2 This study is concerned with some 900,000 acres of salt and sodium affected soils of the eastern San Joaquin Valley between the Tehachapi Mountains and die delta of the San Joaquin River. Some 200,000 acres of these soils are under cultivation, leaving approximately 700,000 acres available for reclamation, This constitutes about 29 per cent of the presently uncultivated but potentially irrigable land of the San Joaquin Valley.3 Classification Pedologists often classify soils of die San Joaquin Valley, at least in part, on die basis of physiographic position.* Fig. 1 is a schematic approach to the classification of soils, partially by physiographic position; it presupposes the following conditions: first, a south-north drainage way of periodic inundation known as a trough or basin from the vicinity of Buena Vista Lake to the 0 Presented at the 54th Annual Meeting of the Association of American Geographers , Santa Monica, August, 1958. 1 "The California Water Plan," Bulletin No. 3, Department of Water Resources, State of California, Sacramento, May 1957. pp. 13-14. - "Water Utilization and Requirements of California," Bulletin Nn. 2, State Water Resources Board, State of California, Sacramento, June 1955, p. 163. 3 Acreage estimates made from various soil survey maps were reconciled with estimates made especially for the writer by the Agricultural Extention Service of each of the eight San Joaquin Valley counties. In a letter dated December 31, 1957, the Principal Soil Correlator, Western States, said that an accurate tabulation of different kinds of soil will be available about I960, 4 Rodney J. Arkley, SoiL· of Eastern Merced County, Department of Soils and Plant Nutrition, College of Agriculture, University of California, Berkeley, 1954, p. 9; F. F. Harradine, L, H. Smith, er al, Soil Survey of the Caalinga Area, California , United States Department of Agriculture, Washington, D. C, Series 1944, No. 1 (issued 1952), pp. 15-Zl; R. Earl Storie and Frank Harradine, "Soils of California ," Soil Science, 85:210, 1958; R. Earl Storie and Walter W. Weir, "Generalized Soil Map of California," Manual 6, College of Agriculture, University of California , Berkeley, 1951; Map, Walter W. Weir, Soils of Madera County, California, Department ot Soils and Plant Nutrition, College of Agriculture, Universily of California, Berkeley, 195T, p. 13. 27 KETTLEMAN FT BEDROCK FnNOCHC ALLUVIAL FAN ?-??????BASW RM LO OO 5000 SEA LEVEL DOMINANT SOILS OF FRESNO COUNTY WEST-EAST CROSS SECTION MERCED BASN BOLD FRESNO B&5IN RIM HAROPAN FACED Xto DELHI WIND MODIFEO ALLUVIUM PRINT" SCHL fï-70miles HESPERIA ALLUVIAL FAN BERIES SAN JOAQUN LOW TERRACE HARDMN VISTA UPLAMO OHANiTE NEUTRAL feet 3600 HOLLAND BEA LEVEL Fig.l San Joaquin delta (see Fig. 2); second, a relatively flat area a few feet higher (basin rim), parallel to and on both sides of die basin, subjsct to a high water table caused by the lateral migration of groundwater from the basin, which was a major factor in producing salt and sodium soils;'1 and third, alluvial fans, created by streams flowing from the mountains to the valley trough, sloping gently upward from the basin rim position to older alluvial deposits, terraces, and/or the foothills. The alluvial fans frequently have undulating, wind modified soil areas, Tenaces adjacent to the foothills of the Sierra Nevada often have soils widi red iron hardpan (silica-iron cemented hardpan), While historically the trough of the San Joaquin Valley was a drainage way as described, it appears in Fig. 2 as...