MODELING OF SOIL TOTAL NITROGEN BASED ON SOIL ORGANIC CARBON

There are many cases in which it is desirable to determine empirical relationships among some soil physical and chemical properties. For instance, soil total nitrogen (TN) are often determined using laborious and time consuming laboratory tests, but it may be more suitable and economical to develop a method which uses easily available soil properties. In this study, a linear regression model for predicting soil TN from soil organic carbon (OC) was suggested and soil TN was estimated as a function of soil OC. The soil TN predicted from the soil TN-OC model was compared to the soil TN determined by laboratory test using the paired samples t-test and the Bland-Altman approach. The soil TN predicted by the soil TN-OC model was not significantly different from the soil TN determined by laboratory test (P> 0.05). The mean difference between the soil TN-OC model and laboratory test was-0.002 % (95 % confidence interval:-0.008 and 0.004%; P = 0.510). The standard deviation of the soil TN differences was 0.011%. The statistical results of the study indicated that the soil TN-OC model provides an easy, economic and brief methodology to estimate soil TN and in order to predict soil TN based on soil OC the soil TN-OC model TN = 0.026 + 0.067 OC with R2 = 0.83 can be recommended