|Title||Estimation of vegetative cover in an arid rangeland based on soil-moisture using cokriging|
|Publication Type||Journal Article|
|Year of Publication||1992|
|Authors||Nash MS, Toorman A, Wierenga PJ, Gutjahr A, Cunningham GL|
|Keywords||article, articles, cokriging, cokriging,vegetative cover, journal, journals, kriging, rangeland, soil moisture,cokriging, technique, cokriging, technique, kriging, transect, vegetative cover|
Soil moisture and vegetative cover (ephemeral, perennial forb and perennial grass) were measured at 30-m intervals along a 2730-m transect. The spatial correlation of vegetative cover and oil moisture, and their cross-correlations, were examined. A total of 610 estimates of vegetative cover were generated at 3-m intervals along the transect, using both ordinary kriging and cokriging methods. Jackknifed estimates of mean-reduced error and reduced variance were used to validate the cokriging models. The average kriging and cokriging variances and the mean sum of squares (SSQ) were sued to compare the two methods. Based on SSQ comparisons, cokriging is the best method to estimate spring ephemeral cover (for observations form all stations) and perennial spring grass cover (for observations form alternate stations). Cokriging estimations for spring perennial grass cover and for spring ephemeral cover produced 7.14 and 2.13%, respectively, improvement of kriging. Cokriging gave better estimations when the number of observations for perennial spring grass cover and fall perennial forb and perennial grass covers were decreased.