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<br />3027 <br /> <br />In Soil SUlVey reports, soils are placed in groups called capability classes that show in a general way <br />their suitability for farming. Groupings are based on limitations of the soils and on their response <br />to use and management. While the system used nation-wide consists of eight broad classes, soils <br />under the Fort Lyon canal fall into four classes--classes I, II, III, and IV. The acreage of class I soils <br />is negligible and is ignored in this discussion. About 92 percent of the soils are Class II, and the <br />remaining 8 percent is split about evenly between Class III and Class IV. <br /> <br />Class II soils are the deep clay loams and silty clay loams occurring on gentle slopes of 0-3 percent. <br />These soils are said to have moderate limitations for farming. Limitations are caused by the clay <br />component of the soils which places restrictions on timing of tillage practices relative to soil moisture <br />content. Tillage when soils are too wet or too dry results in formation of hard clods. However, <br />these soils are productive and are capable of producing top yields of all crops adapted to the lower <br />Arkansas Valley. <br /> <br />Class III soils are said to have severe limitations for farming. Those soils occurring on Fort Lyon <br />lands have one or more of the following characteristics: excessive slopes (3-5%), salinity due to <br />seepage, subsoil of sand or clay, high water table, and droughtiness due to coarse soil texture. Class <br />IV are, for the most part, shallow soils over a limestone substratum which results in poor soil <br />drainage, and often a perched water table. This report refers to these lands as "marginal lands". <br /> <br />Soils of the various capability classes are distributed throughout the area under the Canal and are <br />not generally grouped in anyone area, although the Limestone Division has more of the class IV <br />soils than the other divisions. Table 3.8 shows the distribution of capability classes by canal division. <br /> <br />Table 3.8 Fort Lyon System Soil Classification Estimates by Division (Acres) <br /> Irrigated Percentage Capability Class Acres of Capability Class' <br />Division Acres' Class II Class III & Class II Class III & <br /> IV IV <br />La Junta 2,140 94% 6% 2,012 128 <br />Horse Creek 9,290 92% 8% 8,547 743 <br />Las Animas 13,960 93% 7% 12,983 977 <br />Limestone 29,900 90% 10% 26,910 2,990 <br />Lamar 36,380 93% 7% 33,833 2,547 <br />TOTALS 91,670 92% 8% 84,285 7,385 <br /> <br />t From USGS Preliminary Data; differences in total irrigated acres may be due to precision of measurement methods. <br />, Estimates based on analysis of U.S. Soil Conservation Service Soil Survey Reports for Otero (1972), Bent (1971), <br />Prowers (1966) Counties. <br /> <br />3-13 <br />