Correlation between Crop Information and Soil Water-Salt Information and Cokriging Estimation

摘要

During the squaring stage in summer, 2003, the sunflower (Kang Di 105) height and stem diameter, soil EC and soil water content in the corresponding location are measured. In order to reflect the growing vigor of sunflower and decrease the measuring error, the product of the height and stem diameter of sunflower is marked as integrated index (X) and chosen as the primary variable. On the condition that the correlation coefficient is less than 0.5 and the sampling number of the primary variable is the same as that of the secondary variable, the integrated index is estimated using the Cokriging (CK) expressed by cross covariance function, at the same time, the soil EC and soil water content are all chosen as the secondary variables. The soil EC and soil water content is chosen as the secondary variable respectively, we also get the two estimation sets of the integrated index. Another estimation set of the integrated index is obtained using ordinary Kriging. The four estimation sets are compared with the original set and analyzed in different aspects. In this paper, the CK method is introduced into the scope of the crop growing index, and the two estimation methods are been evaluated deeply. This study can provide the technical support for implementing the precision farming in the Hetao irrigation district.