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MEMO 93 <br />4.2.1.3 1950s crop types <br />Multi-spectral satellite imagery was not available for the 1950s time period and, therefore, analysis to <br />determine 1950s irrigated parcel crop types was not possible using the methods of crop type analysis for <br />the 1970s, 1980s, and 2001. Also, crop types could not be accurately interpreted from the 1950s aerial <br />photographs. Because of these limitations, and considering requirements of the SPDSS consumptive use <br />model, State personnel decided that the 1976 crop types should be copied to the 1950s parcels. For <br />1950s parcels that were not mapped in 1976, the 1950s parcels were assigned a crop type from the nearest <br />1976 irrigated parcel. The limitations of assigning 1976 crop types to 1950s parcels was recognized, but <br />considered acceptable, and the 1950s crop types are understood to be estimates. <br />200 <br />190 <br />180 <br /> <br /> ~ <br /> <br />170 :~. <br />- <br />' <br />~ 160 ~ <br /> \ <br />t~ <br />~ <br />150 <br />,< ~ <br />- <br />_ ,,° <br />~ ` <br />D <br />z 140 <br />i <br />130 ~-- <br /> 1 <br />120 _ <br />110 <br />100 <br /> <br />4/2 4/18 5/4 5/20 6/5 6/21 7/7 7/23 8/8 8/24 9/9 9/25 10/11 10/27 <br /> Date <br />Figure 8. Example of 1976 spectral signatures (solid lines) vs. 2001 average FSA spectral signatures (dashed <br />lines) for corn (yellow), sugar beets (pink), and unknown crops (black). <br />5. Results: Irrigated Lands and Crop Type Classifications <br />Results from the irrigated lands classification and crop type classification were summarized and compared <br />to agricultural statistics. Table 2 reports irrigated lands acreage totals and crop type specific <br />Page 15 of 59 ,Rereradde ~eshn~P~gy, ~os~ <br />