| This study has tested 14 soil fertility indexes of 63 soil samples in semiarid regions of the Loess Plateau,
measured its spectral reflectance in visible bands，and then made multiple factor synthesis analysis so as to explore a method to measure soil fertility by spectral characterization. The results indicate that: (1) The spectral reflectance corre-lation of many soil fertility multiple core factors are above 0.7; (2) The spectrum correlation of soil profile fertility factor is poorer than suface soil, and the differences are significant in most fertility factors. (3) The linear correlation analysis among spectral reflection R value，reflectivity reciprocal logarithm A value， reflectivity first order derivative R′ value and soil fertility factors shows that spectrum R′ value correlation is obviously better than other two kinds of Values. The spectrum correlation coefficients of organic carbon，cationic exchange capacity， total nitrogen， available nitrogen, avail-able potassium are 0. 9063, 0. 8771, 0. 9185, 0. 8604, and 0. 744 respectively. These five factors can be used as soil fertility characterization indexes in visual band spectrum. |