Since 1992, the Zhuanglang County gradually implemented the dryland farming agricultural techniques entirely. These output data comply with the request of the improved GM(1,1) model. Thus, applying Eqs. 2–9 to data of annual output of winter wheat and potato, respectively, of Zhuanglang County from 1992 to 2005, one can calculate and obtain X1 and X2. The results are shown in Table 5. According to the results of numerical modeling (Table 5), the X2 values of Annual Winter wheat output and